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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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12 pages, 3959 KB  
Article
Effect of Prior Austenite Grain Size on the Hydrogen Diffusion Behavior in 30MnB5 Steel
by Hyunbin Nam, Minseok Seo and Cheolho Park
Materials 2026, 19(5), 940; https://doi.org/10.3390/ma19050940 - 28 Feb 2026
Cited by 1 | Viewed by 605
Abstract
In this study, we investigated the effect of heat treatment-induced grain size on the hydrogen embrittlement (HE) resistance of 30MnB5 steel, focusing particularly on the variation in prior austenite grain (PAG) size. As the heat treatment time increased, the PAGs coarsened, leading the [...] Read more.
In this study, we investigated the effect of heat treatment-induced grain size on the hydrogen embrittlement (HE) resistance of 30MnB5 steel, focusing particularly on the variation in prior austenite grain (PAG) size. As the heat treatment time increased, the PAGs coarsened, leading the martensite packets, blocks, and lath sizes to also coarsen. As the microstructure became more refined, the boundary density of the packet–block–lath structure increased along with a significant increase in the low-angle grain boundary (LAGB) fraction. The microstructure refinement accelerated the initial permeation rate of hydrogen, while the high density of LAGBs and trap sites effectively suppressed its long-term diffusion/localization. The slow strain rate tensile test confirmed that the tensile strength and elongation of 30MnB5 steel in a hydrogen environment were lower than those in air, indicating HE. Furthermore, the results showed that the HE sensitivity decreased in the fine microstructure condition, as evidenced by the smaller reduction in elongation compared to the coarse microstructure. The study results will enhance the understanding of hydrogen-induced degradation in hot-stamped automotive steels and offer fundamental insights for optimizing heat treatment strategies applied to 30MnB5 steel for mitigating HE. Full article
(This article belongs to the Special Issue Welding and Joining Technologies for Advanced Structural Alloys and Multifunctional Materials)
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32 pages, 2048 KB  
Review
Biocompatible Thin Films Deposited by Laser Techniques
by Andrei Teodor Matei and Anita Ioana Visan
Materials 2026, 19(5), 925; https://doi.org/10.3390/ma19050925 - 28 Feb 2026
Cited by 1 | Viewed by 793
Abstract
Biocompatible thin films are essential for advancing biomedical devices, as they enhance integration with biological tissues, improve device longevity, and reduce complications. The rapid evolution of both medical needs and materials science has led to a diverse array of deposition techniques, each offering [...] Read more.
Biocompatible thin films are essential for advancing biomedical devices, as they enhance integration with biological tissues, improve device longevity, and reduce complications. The rapid evolution of both medical needs and materials science has led to a diverse array of deposition techniques, each offering unique advantages and challenges for tailoring surface properties without compromising the bulk characteristics of implants and sensors. While laser-based methods—such as pulsed laser deposition (PLD) and Matrix-Assisted Pulsed Laser Evaporation (MAPLE)—are renowned for their precision, ability to preserve complex material stoichiometry, and suitability for low-temperature processing, the broader landscape includes several other important approaches. Physical Vapor Deposition (PVD) techniques, including magnetron sputtering and pulsed electron deposition, are widely used for their ability to create uniform, adherent coatings with controlled thickness and composition, making them suitable for both hard and soft biomedical substrates. Chemical Vapor Deposition (CVD) and its plasma-enhanced variant (PECVD) offer conformal coatings and excellent control over film chemistry, which is particularly valuable for functional polymer and ceramic films. Other methods, such as sol–gel processing, ion beam deposition, and electrophoretic deposition, provide additional flexibility in terms of coating composition, adhesion, and processing temperature, allowing for the fabrication of films with tailored mechanical, chemical, and biological properties. Despite these advances, the field faces ongoing challenges in optimizing film properties for specific clinical applications, ensuring reproducibility, and scaling up production for widespread use. The necessity of this review lies in its comprehensive comparison of laser-based techniques with alternative deposition methods, providing critical insights into their respective strengths, limitations, and suitability for different biomedical scenarios. By synthesizing recent developments and highlighting current gaps, this review aims to guide researchers and clinicians in selecting the most appropriate thin-film deposition strategies to meet the evolving demands of next-generation biomedical devices. Full article
(This article belongs to the Special Issue Laser Techniques for Surface and Interface Engineering: Protocols and Applications in Materials Science)
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23 pages, 2098 KB  
Article
Valorization of Tomato Stems into Biochar for Efficient Adsorptive Removal of Cationic and Anionic Dyes from Aqueous Solutions
by Beata Doczekalska, Krzysztof Kuśmierek and Andrzej Świątkowski
Materials 2026, 19(5), 867; https://doi.org/10.3390/ma19050867 - 26 Feb 2026
Cited by 1 | Viewed by 708
Abstract
The biochars obtained by pyrolyzing tomato stems at temperatures of 400, 500, 600, and 700 °C were characterized, and their ability to absorb anionic (Direct Orange 26, DO26) and cationic (Rhodamine B, RhB) dyes from aqueous solutions was investigated. The effects of solution [...] Read more.
The biochars obtained by pyrolyzing tomato stems at temperatures of 400, 500, 600, and 700 °C were characterized, and their ability to absorb anionic (Direct Orange 26, DO26) and cationic (Rhodamine B, RhB) dyes from aqueous solutions was investigated. The effects of solution pH and ionic strength were studied. It was found that the adsorption process of both dyes was pH-dependent, but no effect of ionic strength was observed. The kinetics of dye adsorption on biochars were well described by the pseudo-second-order model. The equilibrium adsorption data were analyzed using the Freundlich, Langmuir, and Temkin isotherms. All three equations described dye adsorption on biochars quite well, although a slightly better fit was observed for the Freundlich model. The maximum adsorption capacities of BCs ranged from 54.44 mg/g (BC400) to 108.1 mg/g (BC700) for DO26 and from 4.483 mg/g (BC700) to 8.887 mg/g (BC400) for RhB. The study reveals that biochars derived from tomato stems can be used as efficient, low-cost adsorbents for the removal of anionic and cationic dyes from water. Full article
(This article belongs to the Special Issue Adsorption Materials and Their Applications (3rd Edition))
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11 pages, 277 KB  
Article
Berezinskii–Kosterlitz–Thouless Quantum Transition in Two Dimensions
by M. Cristina Diamantini, Carlo A. Trugenberger and Valerii M. Vinokur
Materials 2026, 19(5), 868; https://doi.org/10.3390/ma19050868 - 26 Feb 2026
Viewed by 769
Abstract
The Berezinskii–Kosterlitz–Thouless (BKT) transition is the prototype of a phase transition driven by the formation and interaction of topological defects in two-dimensional (2D) systems. In typical models, these are vortices: above a transition temperature TBKT, vortices are free; below this transition [...] Read more.
The Berezinskii–Kosterlitz–Thouless (BKT) transition is the prototype of a phase transition driven by the formation and interaction of topological defects in two-dimensional (2D) systems. In typical models, these are vortices: above a transition temperature TBKT, vortices are free; below this transition temperature, they get confined. In this work, we extend the concept of BKT transition to quantum systems in two dimensions. In particular, we demonstrate that a zero-temperature quantum BKT phase transition driven by a coupling constant can occur in 2D models governed by an effective gauge field theory with a diverging dielectric constant. One particular example is that of a compact U(1) gauge theory with a diverging dielectric constant, where the quantum BKT transition is induced by non-relativistic, purely 2D magnetic monopoles, which can be viewed also as electric vortices. These quantum BKT transitions have the same diverging exponent z as the quantum Griffiths transition but are not related to disorder. Full article
(This article belongs to the Section Quantum Materials)
22 pages, 3852 KB  
Article
Reusable NiCo/Cu Catalysts for Sustainable Hydrogen Generation
by Gitana Valeckytė, Zita Sukackienė, Virginija Kepenienė, Raminta Šakickaitė, Jūratė Vaičiūnienė, Loreta Tamašauskaitė-Tamašiūnaitė, Jolanta Stupakova and Eugenijus Norkus
Materials 2026, 19(5), 852; https://doi.org/10.3390/ma19050852 - 25 Feb 2026
Cited by 1 | Viewed by 1038
Abstract
The generation of high-purity hydrogen via chemical reaction from hydrogen-rich materials is one of the ways in the alternative energy industry. In this approach, the utilization of catalytic materials that possess the capacity to initiate the decomposition of the starting material and the [...] Read more.
The generation of high-purity hydrogen via chemical reaction from hydrogen-rich materials is one of the ways in the alternative energy industry. In this approach, the utilization of catalytic materials that possess the capacity to initiate the decomposition of the starting material and the subsequent release of hydrogen is of paramount importance. In this study, nickel/cobalt-plated copper catalysts (NiCo/Cu) are presented, comprising from 4 to 90 wt.% of cobalt as catalytic materials for hydrogen generation via sodium borohydride (NaBH4) hydrolysis reaction. The NiCo/Cu catalysts were synthesized via electroless deposition from glycine-based baths, utilizing Ni2+ and Co2+ ions as metal sources and morpholine borane (MB) as the reducing compound. The catalytic performance in alkaline NaBH4 hydrolysis was found to correlate with the cobalt loading in the coating. The maximum rate of hydrogen production, which was determined to be 14.22 L min−1 gcat−1, was achieved at 343 K for a catalyst composed of 90 wt.% Co. The reaction proceeded with the activation energy of 52.5 kJ mol−1, while the catalyst exhibited high durability, preserving nearly 88% of its initial activity after five successive reaction cycles. The combination of nickel and cobalt, along with their synergistic effect and high efficiency in the borohydride hydrolysis reaction, makes them promising catalysts. Full article
(This article belongs to the Section Catalytic Materials)
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18 pages, 4197 KB  
Article
First-Principles Investigation of Ag Doping Effects on Phase Stability and Mechanical Properties in Rare-Earth Magnesium Alloy Mg24(Gd,Y)5
by Jiachun Yuan, Dengjun Wu, Jiamin Li, Juan Hou and Hao Wang
Materials 2026, 19(4), 797; https://doi.org/10.3390/ma19040797 - 18 Feb 2026
Viewed by 670
Abstract
The limited ductility of the VW63K rare-earth magnesium alloy fabricated via cold metal transfer wire arc additive manufacturing (CMT-WAAM) was targeted in this work. An integrated approach that combines first-principles calculations with experimental characterization was employed to achieve this goal. This approach was [...] Read more.
The limited ductility of the VW63K rare-earth magnesium alloy fabricated via cold metal transfer wire arc additive manufacturing (CMT-WAAM) was targeted in this work. An integrated approach that combines first-principles calculations with experimental characterization was employed to achieve this goal. This approach was used to systematically investigate how Ag doping alters the microstructure and mechanical properties of the alloy. First-principles calculations performed on the primary precipitate phase Mg24(Gd,Y)5 demonstrated that Ag atoms preferentially occupy the Mg lattice sites and form pronounced orbital hybridization with neighboring rare-earth atoms. These interactions were found to enhance critical mechanical parameters, including the Cauchy pressure, B/G ratio, and Poisson’s ratio, which are indicative of enhanced ductility and toughness of the phase. Experimental results indicate that the fracture strain of the VW63K-Ag alloy was increased from approximately 4% to above 12% following Ag doping. This resulted in a significant improvement in ductility. The ultimate tensile strength (UTS) underwent only a moderate reduction. Using a closed-loop approach integrating theoretical prediction and experimental validation, the microstructural modification and strengthening mechanisms of Ag in the VW63K alloy fabricated via CMT-WAAM were clarified. These findings offer a theoretical foundation and experimental evidence for compositional design and optimizing additive manufacturing (AM) processes for rare-earth magnesium alloys. Full article
(This article belongs to the Special Issue Design, Characterization and Optimization of Additively Manufactured High-Performance Alloys)
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13 pages, 4699 KB  
Article
Self-Powered Flexible Humidity Sensor Based on HACC/LiCl Composite Electrolyte
by Baojian Zhao, Fanfeng Yi, Shangping Gao, Hong Zhang and Caideng Yuan
Materials 2026, 19(4), 760; https://doi.org/10.3390/ma19040760 - 15 Feb 2026
Viewed by 780
Abstract
To address the challenges of traditional flexible humidity sensors, such as reliance on external power supply, complex fabrication processes, and poor adaptability to energy-limited scenarios, this study successfully developed a low-cost, easily scalable, self-powered flexible humidity sensor based on hydroxypropyl trimethyl ammonium chitosan/lithium [...] Read more.
To address the challenges of traditional flexible humidity sensors, such as reliance on external power supply, complex fabrication processes, and poor adaptability to energy-limited scenarios, this study successfully developed a low-cost, easily scalable, self-powered flexible humidity sensor based on hydroxypropyl trimethyl ammonium chitosan/lithium chloride (HACC/LiCl) composite electrolyte using a screen-printing process. The device employs A4 paper as the flexible substrate, and interdigitated manganese dioxide (MnO2) positive electrodes, zinc (Zn) negative electrodes, and HACC/LiCl composite electrolyte layers are sequentially fabricated via screen-printing, ultimately constructing a simple primary battery structure. Through a series of performance screening and optimization, 0.1 mol/L LiCl-modified HACC (HL-1) is identified as the optimal electrolyte system. The test results show that the HL-1 sensor exhibits a wide humidity detection range of 11~97% relative humidity (RH), with the output voltage displaying a good quadratic function relationship with humidity (R2 = 0.996), and a peak output voltage of up to 1.2 V. The device possesses excellent cyclic stability and long-term stability, with no significant fluctuation in output voltage under different bending deformation states. This sensor demonstrates broad application prospects in fields such as respiratory monitoring and non-contact sensing, providing a feasible technical path for the development of low-cost passive humidity monitoring equipment. Full article
(This article belongs to the Special Issue Fabrication, Characteristics and Applications of Multifunctional Polymer Nanocomposites (Second Edition))
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23 pages, 25064 KB  
Review
Welding of Advanced Aluminum–Lithium Alloys: Weldability, Processing Technologies, and Grain Structure Control
by Qi Li, Qiman Wang, Yangyang Xu, Peng Sun, Kefan Wang, Xin Tong, Guohua Wu, Liang Zhang, Yong Xu and Wenjiang Ding
Materials 2026, 19(4), 738; https://doi.org/10.3390/ma19040738 - 14 Feb 2026
Cited by 2 | Viewed by 1020
Abstract
Aluminum–lithium (Al-Li) alloys are extensively employed in aerospace and space structures because of their low density, high specific stiffness, and excellent fatigue resistance. However, welding of these alloys remains challenging, since the joints typically exhibit unique microstructural features, including equiaxed grain zones (EQZ) [...] Read more.
Aluminum–lithium (Al-Li) alloys are extensively employed in aerospace and space structures because of their low density, high specific stiffness, and excellent fatigue resistance. However, welding of these alloys remains challenging, since the joints typically exhibit unique microstructural features, including equiaxed grain zones (EQZ) along the fusion boundary and coarse columnar grains in the fusion zone, which degrade mechanical performance and increase susceptibility to cracking. This review provides an overview of the generational evolution of Al-Li alloys and their associated weldability, highlights the advantages and limitations of major welding processes, such as laser, arc, and hybrid techniques, and systematically examines the formation mechanisms of EQZ, columnar grains, and equiaxed grain bands. Various strategies for microstructural control are compared, including filler design, pulsed current, and external-field-assisted welding. Special attention is given to grain refinement achieved through heterogeneous nucleation, dendrite fragmentation, and columnar-to-equiaxed transition. Finally, prospects for advanced microstructural control strategies are discussed, with the goal of achieving high-quality welds for next-generation lightweight structural applications. Full article
(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)
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16 pages, 3880 KB  
Article
Foam Rubber-Based Three-Layer Flexible Composite for High-Efficiency Infrared Stealth and Joule Heating
by Haishuo Li, Xiaojie Chen, Yushu Wang, Yaozong Li, Junjie Jiang and Wentao Zhai
Materials 2026, 19(4), 710; https://doi.org/10.3390/ma19040710 - 12 Feb 2026
Viewed by 662
Abstract
With the rapid development of infrared detection methods and military surveillance technologies, flexible and wearable infrared stealth materials (ISM) have attracted increasing attention. Inspired by the layered structure of penguins’ fat–feather–oil, this study prepared a three-layer MXene/waterborne polyurethane (WPU)-foam rubber-phase change microcapsule (PCM)/WPU [...] Read more.
With the rapid development of infrared detection methods and military surveillance technologies, flexible and wearable infrared stealth materials (ISM) have attracted increasing attention. Inspired by the layered structure of penguins’ fat–feather–oil, this study prepared a three-layer MXene/waterborne polyurethane (WPU)-foam rubber-phase change microcapsule (PCM)/WPU composite material (M-F-P) via the solution blending and doctor-blading method. The outermost layer of the M-F-P composite is an MXene/WPU conductive film, which features a low infrared emissivity and Joule heating performance to adapt to suddenly cold environments. The porous foam rubber in the middle layer provides excellent thermal insulation performance, which effectively inhibits heat conduction and enhances infrared stealth efficiency. Meanwhile, as a four-directional elastic material, it exhibits deformation recovery capability in both the warp and weft directions as well as the 45° direction. The bottom layer of the PCM/WPU film has a phase change enthalpy of 154.3 J/g and possesses efficient thermal management capability. It achieves dynamic thermal regulation through the cycle of heat absorption at high temperatures and heat release at low temperatures. Full article
(This article belongs to the Special Issue Advanced Composite Materials: Forming, Processing, Assembly and Maintenance)
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12 pages, 480 KB  
Article
In Vitro Analysis of Heavy Metal Adsorption by Zeolite Skin Care Formulations Using a Quality by Design Approach
by Alessandro Nencioni, Michela Bulfoni and Emanuele Nencioni
Materials 2026, 19(4), 685; https://doi.org/10.3390/ma19040685 - 11 Feb 2026
Cited by 1 | Viewed by 722
Abstract
Zeolites are microporous aluminosilicate minerals widely recognized for their adsorption and ion-exchange properties. Their capacity to capture toxic heavy metals has prompted growing interest in their use as anti-pollution agents in skin care formulations. This study investigates zeolite-based creams through an in vitro [...] Read more.
Zeolites are microporous aluminosilicate minerals widely recognized for their adsorption and ion-exchange properties. Their capacity to capture toxic heavy metals has prompted growing interest in their use as anti-pollution agents in skin care formulations. This study investigates zeolite-based creams through an in vitro permeation test using Franz diffusion cells within a Quality by Design (QbD) framework. A 2 × 2 × 2 full factorial design was applied to evaluate the effects of three critical factors: membrane type (Strat-M® vs. silicone), dosage (10 vs. 20 mg), and dosage regimen. The adsorption and retention of five heavy metals, cadmium (Cd), cobalt (Co), chromium (Cr), lead (Pb), and nickel (Ni), were assessed over 12 h using an in vitro membrane model. The cream containing Zeolite demonstrated significantly higher adsorption of Cr, Co, and Cd compared to placebo and membrane controls, while Ni and Pb exhibited less consistent patterns. No sampling of the receptor compartment was performed; therefore, the analysis focused on metal residues in the donor and membrane compartments. Statistical analyses confirmed the significance of these findings, and graphical trends further supported zeolite’s selective adsorption behavior. Overall, the results provide mechanistic and statistical evidence supporting zeolite as a promising active ingredient for the development of anti-pollution skin care formulations and offer a methodological framework for assessing metal adsorption in topical products. Full article
(This article belongs to the Special Issue Research on Zeolites and Zeolite-Like Materials: Synthesis, Structure, Properties and Application (Second Edition))
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19 pages, 2977 KB  
Article
Impact of Cold Radiofrequency Air Plasma Treatment on the Bulk Properties of Polypropylene Films
by Artem Gilevich, Oleg Gendelman, Yuri Mikhlin, Shraga Shoval and Edward Bormashenko
Materials 2026, 19(4), 693; https://doi.org/10.3390/ma19040693 - 11 Feb 2026
Cited by 1 | Viewed by 649
Abstract
Extruded polypropylene (PP) films were exposed to cold air plasma treatment, which resulted in significant changes in their bulk properties. The maximal elongation, ultimate tensile strength (UTS), and toughness of the films were increased. The toughness of the films increased from [...] Read more.
Extruded polypropylene (PP) films were exposed to cold air plasma treatment, which resulted in significant changes in their bulk properties. The maximal elongation, ultimate tensile strength (UTS), and toughness of the films were increased. The toughness of the films increased from UT0=(3323±400) MPa to UT_PT=(4434±400) MPa, which is due to the growth of both the maximal elongation and the UTS of the plasma-treated samples. We relate the improvement of the mechanical properties of PP to the morphological transformations revealed in the plasma-treated PP films. Plasma treatment of PP samples was also followed by the modification of their surface properties. Plasma treatment resulted in hydrophilization of PP films followed by hydrophobic recovery. The bulk and surface properties of the plasma-treated PP films evolve with time. The following hierarchy of the temporal scales related to the studied relaxation processes is established: τHR>τε=τT=τUTS>τE, where τHR, τε, τT, τUTS and τE are the time scales of the change in the apparent contact angle (hydrophobic recovery), elongation, toughness, ultimate tensile strength, and Young modulus, respectively. The longest of the relaxation times is related to the surface processes, i.e., hydrophobic recovery. The stress–strain curves of the untreated virgin and plasma-treated PP are well described with the twin-slope linear dependencies. The post-plasma-treatment recovery of the tangent modulus is reported. Cold plasma treatment of polypropylene produces surface oxidation and functionalization, evidenced by the emergence of C–O, C=O, and COOH functionalities. Full article
(This article belongs to the Section Thin Films and Interfaces)
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18 pages, 2627 KB  
Article
Application of Machine Learning Techniques in the Prediction of Surface Geometry
by Aneta Gądek-Moszczak, Dominik Nowakowski and Norbert Radek
Materials 2026, 19(4), 661; https://doi.org/10.3390/ma19040661 - 9 Feb 2026
Cited by 1 | Viewed by 753
Abstract
The article presents an attempt by the authors to generate a digital representation of the analyzed surface layer of WC-Co-Al2O3 coating deposited by the ESD method. The WC-Co-Al2O3 surface layer is superhard and abrasion-resistant, significantly increasing the [...] Read more.
The article presents an attempt by the authors to generate a digital representation of the analyzed surface layer of WC-Co-Al2O3 coating deposited by the ESD method. The WC-Co-Al2O3 surface layer is superhard and abrasion-resistant, significantly increasing the exploitation time of working elements. The authors aim to develop a method for generating series of digital surfaces with similar geometry parameters based on data collected through profilometric analysis. Therefore, the advanced integration of machine learning (ML) techniques with classical statistical approaches for modeling and predicting stochastic processes. While traditional models such as ARMA/ARIMA and hidden Markov models (HMMs) offer mathematical rigor, they often impose assumptions of stationarity and linearity, which limits their application to complex, noisy data. This paper proposes a model for surface geometry generation based on experimental data that combines recurrent neural networks (RNNs) and Monte Carlo simulation. Additionally, the study reviews emerging methods, including generative adversarial networks (GANs) for stochastic simulation and expectation-maximization (EM) algorithms for parameter estimation. An empirical case study on WC-Co-AL2O3 surface geometries demonstrates the effectiveness of ML–stochastic hybrids in capturing both deterministic structures and random fluctuations. The findings underscore not only the benefits but also the limitations of such models, including high computational demands and interpretability challenges, while proposing future research directions toward physics-informed ML and explainable AI. Full article
(This article belongs to the Special Issue Advances in Surface Engineering: Functional Films and Coatings)
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17 pages, 4864 KB  
Article
Tribological Performance of Stellite 6/TiN Composite Coatings on Austenitic Stainless Steel
by Shuai Xu, Xiaokang Wu, Jinlong Gu, Jiaqiang Li, Xing Zhang, Gangxian Zhu, Changyong Chen and Chuanyang Wang
Materials 2026, 19(4), 658; https://doi.org/10.3390/ma19040658 - 9 Feb 2026
Cited by 1 | Viewed by 664
Abstract
To enhance the quality and longevity of valve sealing surfaces, this study fabricated the Stellite 6/TiN composite coatings on F347 austenitic stainless steel. The process involved a plasma transferred arc (PTA) of Stellite 6 coating onto the substrate followed by physical vapor deposition [...] Read more.
To enhance the quality and longevity of valve sealing surfaces, this study fabricated the Stellite 6/TiN composite coatings on F347 austenitic stainless steel. The process involved a plasma transferred arc (PTA) of Stellite 6 coating onto the substrate followed by physical vapor deposition (PVD) of a TiN coating onto the Stellite 6 layer. Mechanical testing revealed that the composite coatings achieved high hardness (~2110 HV), excellent adhesion (critical load Lc2 ~74 N), and superior wear resistance versus uncoated steel and single-layer Stellite 6. At 500 °C, the composite reduced wear volume by 97.2% compared to the uncoated substrate. Wear mechanisms for the Stellite 6 and composite coatings at high temperatures were elucidated, highlighting the role of Stellite 6/TiN composite coatings in enhancing tribological performance. Full article
(This article belongs to the Section Metals and Alloys)
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11 pages, 2952 KB  
Article
Development and Application of Carbon Deposition State Diagram for H-C-O Systems
by Zhimin Ding, Xiangyang Pan, Yan Zhang, Shuo Wang, Haiyan Zheng and Fengman Shen
Materials 2026, 19(4), 648; https://doi.org/10.3390/ma19040648 - 8 Feb 2026
Viewed by 531
Abstract
In both preparing and using hydrogen-rich reducing gas (H2RG) in direct reduction, carbon deposition occurs if operating parameters are improperly controlled, affecting the entire process. Therefore, a universally applicable method is needed to determine carbon deposition in the CH4-H [...] Read more.
In both preparing and using hydrogen-rich reducing gas (H2RG) in direct reduction, carbon deposition occurs if operating parameters are improperly controlled, affecting the entire process. Therefore, a universally applicable method is needed to determine carbon deposition in the CH4-H2-CO-H2O-CO2 system, especially the broader H-C-O system. This study establishes a novel method based on the H-C-O system’s mass balance and chemical equilibrium diagram, alongside multi-phase/multi-reaction equilibrium principles. Critical carbon deposition point coordinates (O/C, H/C) were determined under varying conditions including temperatures typically ranging from 550 °C to 900 °C, total pressures from 0.1 to 2.0 MPa, and H2/CO ratios of approximately 2.0–6.9. Connecting points under identical parameters generated critical carbon deposition curves, forming a comprehensive “carbon deposition state diagram for H-C-O system”. This diagram allows precise determination of system state and carbon deposition occurrence, providing a theoretical basis for optimizing process parameters to avoid deposition. To overcome complex diagram calculations, specialized analysis software was developed. Validation using experimental and industrial data confirmed the diagram’s rationality and practicality. The diagram offers a simple, rapid, and accurate means to predict carbon deposition under specified conditions. Crucially, it guides efforts to prevent deposition while simultaneously minimizing energy consumption and costs in natural gas-based hydrogen production processes. Consequently, the “carbon deposition state diagram for H-C-O system” effectively guides actual production towards cost reduction, lower consumption, stability, and smooth operation. Full article
(This article belongs to the Section Materials Chemistry)
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16 pages, 3760 KB  
Article
Low-Temperature Plasma Activation of Biomaterials and Its Stability over Time and Post-Sterilisation Effects
by Piotr Trębacz, Mateusz Pawlik, Aleksandra Kurkowska, Karolina Wilk, Agata Piątek and Michał Czopowicz
Materials 2026, 19(3), 643; https://doi.org/10.3390/ma19030643 - 6 Feb 2026
Cited by 2 | Viewed by 1289
Abstract
Low-temperature plasma (LTP) activation is increasingly used as a surface modification technique to enhance the wettability and biological performance of metallic implants. However, the stability of plasma-induced surface changes and their interaction with standard sterilisation procedures remain insufficiently understood. This study aimed to [...] Read more.
Low-temperature plasma (LTP) activation is increasingly used as a surface modification technique to enhance the wettability and biological performance of metallic implants. However, the stability of plasma-induced surface changes and their interaction with standard sterilisation procedures remain insufficiently understood. This study aimed to evaluate the effects of LTP activation, steam sterilisation, and their combination with the wettability of metallic implant materials, as well as the temporal stability of these effects. Samples manufactured from Ti6Al4V sheet, additively manufactured Ti6Al4V, and additively manufactured cobalt–chromium alloy were subjected to low-temperature plasma activation, steam sterilisation, or both procedures. Surface wettability was assessed by measuring the contact angle of canine blood droplets immediately after treatment and over a five-day observation period. Low-temperature plasma activation resulted in a substantial reduction in the contact angle for all tested materials, indicating a pronounced increase in surface wettability. However, this effect gradually diminished over time. Steam sterilisation alone moderately improved wettability and showed relatively stable effects. When steam sterilisation was applied after plasma activation, the plasma-induced enhancement was significantly attenuated and rapidly lost during storage. These findings demonstrate that while LTP activation effectively improves surface wettability, its benefits are highly time-dependent and strongly influenced by subsequent sterilisation. Plasma activation should therefore be performed immediately before implantation or combined with sterilisation and storage strategies that preserve surface modifications. Full article
(This article belongs to the Special Issue Smart Biomaterials in Regenerative Engineering)
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15 pages, 4969 KB  
Article
Mechanical Response and Functional Performance of Heat-Treated LPBF NiTi Shape Memory Alloys
by Jerzy Ratajski, Błażej Bałasz, Agnieszka Peła, Paweł Krupski, Kamil Bochenk, Michał Tacikowski and Łukasz Major
Materials 2026, 19(3), 627; https://doi.org/10.3390/ma19030627 - 6 Feb 2026
Cited by 1 | Viewed by 701
Abstract
This study evaluates how solution treatment and aging influence the deformation mechanisms, phase transformations and functional performance of NiTi alloys produced by laser powder bed fusion (LPBF). Tensile tests performed at room temperature (RT) and −20 °C (LT) were combined with Differential Scanning [...] Read more.
This study evaluates how solution treatment and aging influence the deformation mechanisms, phase transformations and functional performance of NiTi alloys produced by laser powder bed fusion (LPBF). Tensile tests performed at room temperature (RT) and −20 °C (LT) were combined with Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) analyses to correlate mechanical response with transformation thermodynamics and microstructural evolution. In the as-fabricated (AF) condition, deformation is governed by twinning and martensitic plasticity due to suppressed stress-induced martensite (SIM). Solution treatment (ST) restores reversible SIM at RT and preserves partial recoverability at LT as a result of microstructural homogenization and internal stress relief. Aging at 500 °C (A1h, A20h) promotes Ni4Ti3 precipitation, increasing transformation temperatures and stabilizing martensite, which leads to entirely irreversible deformation at both temperatures. These findings establish a clear functional continuum—ranging from recoverable (ST) to dissipative (AF) and fully irreversible (A20h) behavior—and provide a mechanistic framework for tailoring LPBF NiTi components for actuators, energy-storage and energy-dissipation applications. Full article
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications, Third Edition)
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18 pages, 1859 KB  
Article
Fit of Three-Unit Posterior Fixed Dental Prostheses Made from Tetragonal Zirconia Polycrystal by 3D Printing and Milling
by Jana Kostunov, Jannis Crocoll, Sebastian Hetzler, Peter Rammelsberg, Jonas Zeiß, Andreas Zenthöfer and Stefan Rues
Materials 2026, 19(3), 597; https://doi.org/10.3390/ma19030597 - 3 Feb 2026
Cited by 2 | Viewed by 710
Abstract
(1) Objective: To compare the marginal and internal fit of 3D-printed and milled three-unit fixed dental prostheses (FDPs) made from tetragonal zirconia polycrystal (3Y-TZP). (2) Methods: Three-unit FDPs were designed for a typodont maxillary model with crown preparation for the second premolar and [...] Read more.
(1) Objective: To compare the marginal and internal fit of 3D-printed and milled three-unit fixed dental prostheses (FDPs) made from tetragonal zirconia polycrystal (3Y-TZP). (2) Methods: Three-unit FDPs were designed for a typodont maxillary model with crown preparation for the second premolar and second molar. Nominal cement gap widths were set to 30 µm at the margins and 80 µm internally. A total of 40 FDPs (n = 10/group) differing in wall thickness (w = 0.6/1.0 mm) and support structures (with/without a stiffening frame) were fabricated from 3Y-TZP by 3D printing. A total of 10 milled FDPs with w = 0.6 mm served as a control group. After adhesive cementation on the respective replicated maxillary models, FDPs were sectioned and the cement gap dimension was assessed with a digital microscope. The marginal and internal fit found for the different test groups were compared using non-parametric tests. (3) Results: The best marginal fit—qualified by median/maximum marginal gap width—was given for milled FDPs (79/127 µm vertical; 85/171 µm tangential), whereas the marginal fit of 3D-printed FDPs with w = 0.6 mm and regular support structures was the worst (144/284 µm vertical; 107/198 µm tangential). Use of an additional support frame improved the marginal fit of 3D-printed FDPs, in particular FDPs with w = 0.6 mm (108/197 µm vertical; 87/161 µm tangential). (4) Conclusions: 3D-printed zirconia FDPs showed conditionally comparable marginal and internal fit as their milled counterparts, but with slightly higher scattering. When fabricating thinner 3D-printed FDPs, additional support structures are mandatory to achieve clinically well-fitting restorations. Full article
(This article belongs to the Section Biomaterials)
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34 pages, 2781 KB  
Review
A Review on Sustainable Recycling of NdFeB Waste: Methodologies, Challenges, and the Integration of Machine Learning (ML)
by Rehan Ullah, Jason Daza, Asma Wederni, Lluisa Escoda, Joan Saurina and Joan-Josep Suñol
Materials 2026, 19(3), 594; https://doi.org/10.3390/ma19030594 - 3 Feb 2026
Cited by 2 | Viewed by 1946
Abstract
The increasing demand and production of neodymium-iron-boron-based permanent magnets (NdFeB-PMs) for the electronics, energy sector, and automobile industries led to disposal consequences. The NdFeB-PMs contain a substantial amount of rare earth elements (REEs). Although China is the largest exporter of REEs to the [...] Read more.
The increasing demand and production of neodymium-iron-boron-based permanent magnets (NdFeB-PMs) for the electronics, energy sector, and automobile industries led to disposal consequences. The NdFeB-PMs contain a substantial amount of rare earth elements (REEs). Although China is the largest exporter of REEs to the world, it has applied some restrictive policies in terms of supply chain and taxes. To address such issues, this review systematically examines current recycling techniques, including short-loop, hydrometallurgy, pyrometallurgy, and hybrid processes, and the integration of Machine Learning (ML) to the leaching process, with a particular focus on their impact on industrial capability, economic viability, and environmental concerns. However, a comparative study highlights ongoing challenges to large-scale implementation, including fragmented waste sources, gaps between efficient processes and environmental sustainability, and a lack of regulatory and infrastructure support. To address these challenges, technical innovation in automated disassembly systems and selective REE recovery via ML was discussed, along with legislative initiatives such as Extended Producer Responsibility (EPR) and waste monitoring procedures. Furthermore, ecologically and economically feasible solutions were optimized through ML-based recycling procedures to increase the leaching efficiency and the recovery of the REEs. This analysis emphasizes the importance of collective technological, environmental, and policy initiatives to achieve sustainable NdFeB recycling and long-term resource availability. These findings offer important perspectives into developing effective and environmentally friendly NdFeB waste recycling solutions via the integration of ML. Full article
(This article belongs to the Special Issue Advances in Magnetic Materials and Applications)
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41 pages, 10153 KB  
Review
A Comprehensive Review on Sustainable Triboelectric Energy Harvesting Using Biowaste-Derived Materials
by Wajid Ali, Tabinda Shabir, Shahzad Iqbal, Syed Adil Sardar, Farhan Akhtar and Woo Young Kim
Materials 2026, 19(3), 592; https://doi.org/10.3390/ma19030592 - 3 Feb 2026
Cited by 4 | Viewed by 2500
Abstract
The growing demand for sustainable and distributed energy solutions has driven increasing interest in triboelectric nanogenerators (TENGs) as platforms for energy harvesting and self-powered sensing. Biowaste-based triboelectric nanogenerators (BW-TENGs) represent an attractive strategy by coupling renewable energy generation with waste valorization under the [...] Read more.
The growing demand for sustainable and distributed energy solutions has driven increasing interest in triboelectric nanogenerators (TENGs) as platforms for energy harvesting and self-powered sensing. Biowaste-based triboelectric nanogenerators (BW-TENGs) represent an attractive strategy by coupling renewable energy generation with waste valorization under the principles of the circular bioeconomy. This review provides a comprehensive overview of BW-TENGs, encompassing fundamental triboelectric mechanisms, material categories, processing and surface-engineering strategies, device architectures, and performance evaluation metrics. A broad spectrum of biowaste resources—including agricultural residues, food and marine waste, medical plastics, pharmaceutical waste, and plant biomass—is critically assessed in terms of physicochemical properties, triboelectric behavior, biodegradability, biocompatibility, and scalability. Recent advances demonstrate that BW-TENGs can achieve electrical outputs comparable to conventional synthetic polymer TENGs while offering additional advantages such as environmental sustainability, mechanical compliance, and multifunctionality. Key application areas, including environmental monitoring, smart agriculture, wearable and implantable bioelectronics, IoT networks, and waste management systems, are highlighted. The review also discusses major challenges limiting large-scale deployment, such as material heterogeneity, environmental stability, durability, and lack of standardization, and outlines emerging solutions involving material engineering, hybrid energy-harvesting architectures, artificial intelligence-assisted optimization, and life cycle assessment frameworks. Full article
(This article belongs to the Special Issue Materials, Design, and Performance of Nanogenerators)
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15 pages, 10949 KB  
Article
Thermo-History-Dependent Copper Enrichment During High-Temperature Oxidation of Recycled Steels
by Yuhe Huang, Fangbo Yang, Jun Lu, Shuize Wang and Xinping Mao
Materials 2026, 19(3), 595; https://doi.org/10.3390/ma19030595 - 3 Feb 2026
Cited by 2 | Viewed by 790
Abstract
The utilization of recycled steel is essential for achieving carbon neutrality and sustainable engineering, yet repeated recycling inevitably leads to the accumulation of residual elements that are difficult to remove during conventional refining. Among them, copper (Cu) readily enriches in scrap-based steels and [...] Read more.
The utilization of recycled steel is essential for achieving carbon neutrality and sustainable engineering, yet repeated recycling inevitably leads to the accumulation of residual elements that are difficult to remove during conventional refining. Among them, copper (Cu) readily enriches in scrap-based steels and is a primary cause of surface hot shortness during high-temperature processing due to its segregation at the oxide/steel interface. While the compositional effects of Cu have been extensively studied, the influence of thermo-history associated with different industrial processing routes remains poorly understood. In this work, Cu enrichment during high-temperature oxidation was systematically investigated under thermo-histories representative of conventional hot rolling, thin slab continuous casting and rolling (TSCR), and strip casting. Plain carbon steels containing 0.05–0.30 wt.% Cu were oxidized at 1000–1200 °C, and interfacial microstructures were characterized using SEM–EDS. The results show that Cu enrichment is highly sensitive to both temperature and thermal exposure time, with a critical temperature range of 1100–1150 °C promoting the formation of continuous Cu-rich liquid films. Prolonged thermo-history in conventional hot rolling markedly enhances Cu enrichment, TSCR partially suppresses interfacial segregation, whereas strip casting effectively inhibits Cu enrichment even at elevated Cu contents. These findings highlight thermo-history as a dominant factor controlling Cu-induced surface hot shortness and provide guidance for process optimization in recycled steels. Full article
(This article belongs to the Special Issue Advances in Microstructure and Mechanical Behavior of High-Strength Steels)
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25 pages, 4447 KB  
Article
Process–Microstructure–Property Characteristics of Aluminum Walls Fabricated by Hybrid Wire Arc Additive Manufacturing with Friction Stir Processing
by Ahmed Nabil Elalem and Xin Wu
Materials 2026, 19(3), 580; https://doi.org/10.3390/ma19030580 - 2 Feb 2026
Cited by 4 | Viewed by 2053
Abstract
Wire Arc Additive Manufacturing (WAAM) is a cost-effective method for fabricating large aluminum components; however, it tends to suffer from heat accumulation and coarse anisotropic microstructures, which can limit the part’s performance. In this study, a wall is fabricated using a hybrid unified [...] Read more.
Wire Arc Additive Manufacturing (WAAM) is a cost-effective method for fabricating large aluminum components; however, it tends to suffer from heat accumulation and coarse anisotropic microstructures, which can limit the part’s performance. In this study, a wall is fabricated using a hybrid unified additive deformation manufacturing process (UAMFSP) method, which integrates friction stir processing (FSP) into WAAM, and is compared with a Metal Inert Gas (MIG)-based WAAM wall. Infrared (IR) thermography revealed progressive heat buildup in MIG walls, with peak layer temperatures of about 870 to 1000 °C. In contrast, in the UAMFSP process, heat was redistributed through mechanical stirring, maintaining more uniform sub-solidus profiles below approximately 400 °C. Also, optical microscopy and quantitative image analysis showed that MIG walls developed coarse, dendritic grains with a mean grain area of about 314 µm2, whereas the UAMFSP produced refined, equiaxed grains with a mean grain area of about 10.9 µm2. Microhardness measurement (Vickers HV0.2, 200 gf) confirmed that the UAMFSP process can improve the hardness by 45.8% compared to the MIG process (75.8 ± 7.7 HV vs. 52.0 ± 1.3 HV; p = 0.0027). In summary, the outcomes of this study introduce the UAMFSP process as a method for addressing the thermal and microstructural limitations of WAAM. These findings provide a framework for further extending hybrid additive–deformation strategies to thicker builds, alternative alloys, and service-relevant mechanical evaluations. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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21 pages, 4116 KB  
Article
Potential of Wood Processing Residues as Eco-Friendly Adsorbents for Wastewater Treatment
by Silviya Lavrova and Nikolay Yavorov
Materials 2026, 19(3), 578; https://doi.org/10.3390/ma19030578 - 2 Feb 2026
Cited by 2 | Viewed by 1005
Abstract
In the context of global warming mitigation through energy conservation and pollution control, integrating green waste into treatment processes has become more popular. This study evaluated the potential of raw wood processing residues generated from furniture manufacturing as renewable sorbents for water treatment. [...] Read more.
In the context of global warming mitigation through energy conservation and pollution control, integrating green waste into treatment processes has become more popular. This study evaluated the potential of raw wood processing residues generated from furniture manufacturing as renewable sorbents for water treatment. Comparative studies assessed the Mn(II) removal efficiency of raw walnut (WW) and cherry (CW) wood shavings and the derived biochars (BChWW, BChCW) produced by hydropyrolysis. SEM, BET, FTIR, and TGA analyses characterized their surface and structural properties. CW demonstrated a higher adsorption capacity compared to WW. Physical activation enhanced the surface properties and Mn(II) adsorption affinity of the materials. Maximum adsorption capacities ranged from 2.1 to 2.2 mg/g for CW and WW, and 2.4 to 2.5 mg/g for BChCW and BChWW. The Freundlich model best fits to the data obtained using CW (R2 = 0.997) and BChCW (R2 = 0.984), while the RALF isotherm almost perfectly describes the mechanism of the Mn(II) adsorption onto WW (R2 = 0.999) and BChWW (R2 = 1.000). The pseudo second-order kinetic model shows strong agreement with experimental data, which suggests chemisorption on a heterogeneous surface. The results underscore the potential of wood industry byproducts as efficient and low-cost adsorbents for water treatment, supporting the circular economy and sustainable environmental management. Full article
(This article belongs to the Section Green Materials)
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15 pages, 3743 KB  
Article
Mechanical and Microstructural Characterization of Trapezoidal Corrugated-Core Al Sandwich Panels Under Quasi-Static Compression
by Alessandra Ceci, Girolamo Costanza and Maria Elisa Tata
Materials 2026, 19(3), 548; https://doi.org/10.3390/ma19030548 - 30 Jan 2026
Cited by 2 | Viewed by 732
Abstract
Sandwich panels with trapezoidal (corrugated) cores combine low weight, high specific stiffness, and energy absorption capability. This study analyzes four configurations with different core heights by means of microstructural analyses (optical microscopy, SEM/EDS, XRD) and quasi-static compression tests. The tests yield stress–strain curves [...] Read more.
Sandwich panels with trapezoidal (corrugated) cores combine low weight, high specific stiffness, and energy absorption capability. This study analyzes four configurations with different core heights by means of microstructural analyses (optical microscopy, SEM/EDS, XRD) and quasi-static compression tests. The tests yield stress–strain curves with an initial linear stage, a peak, a plateau, and a densification stage. Peak stresses range from 0.5 MPa for the thickest core (P1) to 6.2 MPa for the thinnest core (P4), while the energy absorbed density (EAD) increases with strain: at ε = 30% it varies from 0.031 to 0.670 J/cm3, and at ε = 50% the thin-core configuration reaches ≈1.113 J/cm3. The face sheets and the core are both manufactured from AA 3000 series (Al–Mn) aluminum alloy; widespread micro-porosity and Fe/Mn-rich phases are observed by SEM/EDS. XRD confirms aluminum with different peak intensities ascribable to the manufacturing texture. Increasing the core height promotes earlier local/global instabilities and reduces the peak stress; the thinnest core displays higher stiffness and peak loads. These findings support the use of trapezoidal corrugation where low weight and progressive strain are required. Full article
(This article belongs to the Special Issue Advances in Design and Characterization of Graded and Hierarchical Honeycomb Materials (2nd Edition))
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14 pages, 2209 KB  
Article
NiO/Ga2O3 Heterojunction with Tunable Oxygen Vacancies for Efficient Self-Powered Solar-Blind UV Detection
by Luyu Liu, Kangxin Shen, Huimin Su, Jintao Xu, Jiajun Lin, Yaping Li, Shuguang Zhang, Linfeng Lan and Junbiao Peng
Materials 2026, 19(3), 530; https://doi.org/10.3390/ma19030530 - 29 Jan 2026
Cited by 2 | Viewed by 1491
Abstract
Solar-blind ultraviolet (UV) photodetectors based on wide-bandgap oxide semiconductors are highly desirable for environmental monitoring, flame sensing, and secure optical communication. Among them, Ga2O3 has attracted extensive attention due to its ultra-wide bandgap and intrinsic solar-blind response; however, its high [...] Read more.
Solar-blind ultraviolet (UV) photodetectors based on wide-bandgap oxide semiconductors are highly desirable for environmental monitoring, flame sensing, and secure optical communication. Among them, Ga2O3 has attracted extensive attention due to its ultra-wide bandgap and intrinsic solar-blind response; however, its high dark current, weak built-in electric field, and defect-induced instability remain critical challenges, particularly for amorphous films prepared by scalable sputtering processes. Herein, a self-powered solar-blind UV photodetector based on a NiO/Ga2O3 heterojunction is demonstrated, in which the oxygen-vacancy concentration and band structure of sputtered Ga2O3 are systematically regulated by tailoring the Ar/O2 sputtering atmosphere. Combined X-ray photoelectron spectroscopy, UV photoelectron spectroscopy, and optical measurements reveal that the variation in oxygen-vacancy concentration simultaneously modulates the Fermi-level position, band-edge alignment, and built-in potential at the NiO/Ga2O3 interface. As a result, the optimized heterojunction device exhibits a low dark current, pronounced rectifying behavior, and efficient carrier separation under zero bias, enabling self-powered operation. The photodetector delivers a responsivity of 47 mA W−1, a detectivity of 7.52 × 1011 Jones, and a high rejection ratio exceeding 104 between 254 and 365 nm. Furthermore, stable and high-contrast UV imaging is successfully demonstrated, highlighting the practical applicability of the device. This work provides an effective methodology for modulating defects and band structure in high-performance solar-blind UV photodetectors based on sputtered wide-bandgap oxide heterojunctions. Full article
(This article belongs to the Section Thin Films and Interfaces)
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15 pages, 2626 KB  
Article
Synthesis and Study of Janus-Dione-Based Compounds for Ternary Organic Solar Cells
by Armands Ruduss, Anastasija Rizkova, Fatima Zohra Boudjenane, Elizabete Praulina, Kaspars Traskovskis and Raitis Grzibovskis
Materials 2026, 19(3), 533; https://doi.org/10.3390/ma19030533 - 29 Jan 2026
Cited by 1 | Viewed by 762
Abstract
The efficiency of organic solar cells is constantly improving thanks to more advanced materials. Electron donor polymers, such as PM6 and its derivatives, as well as non-fullerene acceptors (NFAs) Y6 and ITIC and their derivatives, have become the standard materials for organic solar [...] Read more.
The efficiency of organic solar cells is constantly improving thanks to more advanced materials. Electron donor polymers, such as PM6 and its derivatives, as well as non-fullerene acceptors (NFAs) Y6 and ITIC and their derivatives, have become the standard materials for organic solar cell studies. To broaden the absorption range of solar cells, so-called ternary organic solar cells have been developed, which add a third material to the active layer. In this work, two chromophores based on the derivatives of the Janus-dione (s-indacene-1,3,5,7(2H,6H)-tetraone) central acceptor fragment, namely TIIC-1 and TIIC-2, were synthesized. Materials were characterized using theoretical and experimental methods, including UV-Vis absorption measurements, cyclic voltammetry, photoemission yield spectroscopy, and photoconductivity. The materials were incorporated as ternary components in PM6:Y7 bulk heterojunction solar cells. The power conversion efficiency (PCE) of PM6:Y7:TIIC-1 ternary solar cells was improved compared to binary PM6:Y7 reference cells. The PCE increased from 11.9% in binary blends to 12.5% in ternary cells. This increase is attributed to the cascade-like energy level arrangement, which facilitates charge transfer in the photoactive layer. Full article
(This article belongs to the Section Energy Materials)
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25 pages, 2463 KB  
Article
Green Deep Eutectic Solvents for Functionalizing Chitosan–Dialdehyde Materials with Varied Crosslinker Content
by Magdalena Gierszewska, Ewa Olewnik-Kruszkowska, Kornelia Kadac-Czapska, Małgorzata Grembecka and Eliza Knez
Materials 2026, 19(3), 529; https://doi.org/10.3390/ma19030529 - 29 Jan 2026
Viewed by 1034
Abstract
A series of chitosan-based films was obtained by combining the covalent crosslinking of chitosan with dialdehyde starch (DAS) and plasticization using a choline chloride–malonic acid deep eutectic solvent (DES), thereby engineering their structural, mechanical, and surface properties for advanced packaging applications. DAS was [...] Read more.
A series of chitosan-based films was obtained by combining the covalent crosslinking of chitosan with dialdehyde starch (DAS) and plasticization using a choline chloride–malonic acid deep eutectic solvent (DES), thereby engineering their structural, mechanical, and surface properties for advanced packaging applications. DAS was synthesized via periodate oxidation of potato starch and characterized by FTIR and quantification of aldehyde groups through acid–base titration, enabling precise control of the –NH2 (chitosan) to –CHO (DAS) molar ratios (40:1, 20:1, 10:1) used for film formation. Chitosan films (neat, DAS-crosslinked, DES-plasticized, and DES-plasticized/DAS-crosslinked) were obtained by solution casting, with constant total chitosan and/or Ch+DES mass across formulations, and subsequently examined in terms of molecular structure, density, mechanical characteristics, micro- and nanoscale morphology, color, wettability, and surface free energy. The most significant changes relevant to potential applications were observed in mechanical properties and surface free energy. The incorporation of DAS and DES into chitosan resulted in a significant reduction in Young’s modulus from 1150 MPa to 130 MPa, accompanied by a significant increase in elongation at break—from 10% to almost 90%. Moreover, it should be noticed that the addition of DAS and DES led to a nearly twofold increase in surface free energy, from 32.5 to 59.9 mJ m−2. While previous studies have predominantly focused on single modifications of chitosan—either covalent crosslinking with dialdehyde starch (DAS) or plasticization with deep eutectic solvents (DES)—this work introduces a pioneering dual-modification strategy that simultaneously integrates both techniques, representing the first systematic investigation of their synergistic effects unattainable through individual approaches. Full article
(This article belongs to the Special Issue Sustainable Materials: Preparation, Characterization and Applications)
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19 pages, 1809 KB  
Article
Multistage Static and Dynamic Optimization Framework for Composite Laminates in Lightweight Urban Rail Vehicle Car Bodies
by Alessio Cascino, Francesco Distaso, Enrico Meli and Andrea Rindi
Materials 2026, 19(3), 531; https://doi.org/10.3390/ma19030531 - 29 Jan 2026
Cited by 5 | Viewed by 633
Abstract
This paper presents a robust multistage optimization framework for the integration of composite laminates into the car body shell of a low-floor light rail vehicle (LRV). While structural design in low-floor vehicles is typically complex, this methodology successfully balances both static and dynamic [...] Read more.
This paper presents a robust multistage optimization framework for the integration of composite laminates into the car body shell of a low-floor light rail vehicle (LRV). While structural design in low-floor vehicles is typically complex, this methodology successfully balances both static and dynamic requirements through a sequential optimization process. Developed in strict accordance with reference European standards, the methodology addresses the structural challenges inherent in low-floor architectures, where complex load paths and redistributed equipment masses require targeted reinforcement. The proposed approach sequentially addresses dynamic and static requirements through a structural optimization process. Two distinct 10-ply laminate configurations, one symmetric and one asymmetric, were investigated. The results demonstrate that the multistage optimization successfully converged to a highly mass-efficient solution, achieving a 66% reduction in laminate thickness compared to the baseline design. This significant result was accomplished while maintaining full regulatory compliance; the failure index increased by approximately 22.5% and 23.3% for the two composite laminate configurations, respectively, effectively maximizing material utilization. A key finding of this study is the preservation of structural dynamic integrity; the fundamental natural frequency was maintained at approximately 16 Hz, with a high correlation across the first ten vibration modes, confirming that the global dynamic behaviour remains unaffected. These observations provide critical insights into the synergy between hybridization and structural constraints, suggesting a systematic pathway for designers to achieve an optimal trade-off between manufacturing costs, weight reduction, and performance in advanced urban transit platforms. Full article
(This article belongs to the Special Issue Architected Lattice and Composite Materials: Multiscale Design, Manufacturing, and Applications)
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18 pages, 5837 KB  
Article
Molecular Orientation and Mechanical Properties of Biomass-Derived Aliphatic Polyamide (PA11) by High-Pressure Compression Molding
by Keisuke Ura, Shotaro Nishitsuji, Yutaka Kobayashi and Hiroshi Ito
Materials 2026, 19(3), 513; https://doi.org/10.3390/ma19030513 - 28 Jan 2026
Viewed by 649
Abstract
This study investigates the effects of high-pressure compression molding on the molecular orientation and mechanical properties of biomass-derived aliphatic polyamide (PA11). Tensile fracture strength exhibited a significant increase—up to 2.4 times that of untreated samples—under conditions of 1000 kN and 140 °C. Differential [...] Read more.
This study investigates the effects of high-pressure compression molding on the molecular orientation and mechanical properties of biomass-derived aliphatic polyamide (PA11). Tensile fracture strength exhibited a significant increase—up to 2.4 times that of untreated samples—under conditions of 1000 kN and 140 °C. Differential Scanning Calorimetry (DSC) and Wide-Angle X-ray Scattering (WAXS) analyses revealed a temperature- and pressure-dependent shift in crystalline phases, suggesting a transition from α’ to phase. The δ’ phase, formed by high-pressure compression molding, is retained even after cooling to room temperature (i.e., Brill transition was not observed). In addition, polarized optical microscopy (POM) observations further supported the presence of changes in molecular orientation. This enhancement (under conditions of 1000 kN and 140 °C) is primarily attributed to the molecular orientation. However, it is also noteworthy that the formation of the δ’ phase is accompanied by an increase in the degree of crystallinity, and that this δ’ phase is retained even after cooling to room temperature without undergoing a Brill transition. In contrast, at 180 °C, although the degree of crystallinity increased, molecular orientation decreased, resulting in reduced tensile strength. These findings indicate that the mechanical properties of PA11 are governed by a complex interplay among phase transitions, molecular orientation, and crystallization, all of which are strongly influenced by temperature and pressure conditions. These findings demonstrate that high-pressure compression molding is an effective method for enhancing the mechanical properties of PA11 through controlled phase transition and orientation Full article
(This article belongs to the Special Issue Synthesis–Processing–Structure–Property Interrelationship of Multifunctional Polymeric Materials and Natural Polymers)
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33 pages, 21812 KB  
Article
Assessment of the Mechanical Properties and Durability of Cement Mortars Modified with Polyurethane Foam Waste
by Gabriela Rutkowska, Barbara Francke, Filip Chyliński, Mariusz Żółtowski, Hanna Michalak, Agnieszka Starzyk, Michał Musiał and Oskar Sierakowski
Materials 2026, 19(3), 491; https://doi.org/10.3390/ma19030491 - 26 Jan 2026
Cited by 2 | Viewed by 1435
Abstract
In the era of growing demand for sustainable solutions in construction, increasing attention is being paid to the potential use of waste materials as components of building composites. This article presents the results of a study on the impact of ground polyurethane foam [...] Read more.
In the era of growing demand for sustainable solutions in construction, increasing attention is being paid to the potential use of waste materials as components of building composites. This article presents the results of a study on the impact of ground polyurethane foam waste on the mechanical properties and durability of cement mortars. The waste, derived from industrial production processes, was used as a partial replacement for fine aggregates in various proportions. The analysis included bulk density, compressive and flexural strengths, water absorption, and resistance to freeze–thaw cycles. The results indicate that adding waste reduces the density of the mortar, which can be advantageous in applications requiring lightweight materials. The most favourable balance of strength retention, density reduction, and frost resistance was observed with a 1% addition, as the mortar maintained good mechanical performance and freeze–thaw durability while achieving reduced weight. Higher waste content (2–3%) led to significant deterioration of the mechanical properties due to increased porosity. All samples exhibited increased strength after 25 freeze–thaw cycles, possibly due to continued hydration under moist low-temperature conditions. The analysis of the microstructure of cement coatings with the addition of polyurethane foam enabled the explanation of the causes of the observed changes in physico-mechanical properties resulting from ageing factors. This study suggests that small amounts of waste can be effectively used to produce lightweight and environmentally friendly construction materials, supporting circular economy practices. Full article
(This article belongs to the Special Issue Resource Recovery in Building Materials: Developing Eco-Friendly Driven Sustainable Binders or Aggregates from Solid Waste)
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10 pages, 2356 KB  
Article
Formation of Fluorine Vacancy (FV) Centers in Diamond
by Anand B. Puthirath, Jacob Elkins, Harikishan Kannan, Alyssa Horne, Jia-Shiang Chen, Hao Zhang, Valery N. Khabashesku, Abhijit Biswas, Xiang Zhang, A. Glen Birdwell, Tony G. Ivanov, Ulrich Kentsch, Shavkat Akhmadaliev, Robert Vajtai, Xuedan Ma, Aditya D. Mohite, Ranjit Pati and Pulickel M. Ajayan
Materials 2026, 19(3), 494; https://doi.org/10.3390/ma19030494 - 26 Jan 2026
Viewed by 1378
Abstract
Diamond has been extensively examined as an appealing material for use in quantum optics and quantum information processing owing to the existence of various classes of optically active defects, referred to as “color centers,” which can be engineered into its crystal structure. Among [...] Read more.
Diamond has been extensively examined as an appealing material for use in quantum optics and quantum information processing owing to the existence of various classes of optically active defects, referred to as “color centers,” which can be engineered into its crystal structure. Among these defects, the negatively charged nitrogen-vacancy center (NV−) stands out as the most prominent type. Despite the progress made, the number of emitters characterized by reproducible fabrication processes within the desired spectral range at room temperature, with limited or no damage to the parent diamond lattice, remains restricted. Herein, we are proposing for the first time the creation of the FV− center in diamond via low-energy implantation, which is particularly interesting as it possesses characteristic light absorption and magnetic properties similar to NV− centers. The low-energy ion-implanted FV centers in diamond show more desirable optical emission properties at room temperature (RT). Additionally, as per DFT calculations, the flat bands near the Fermi energy indicate dominant electron–electron interactions, an important prerequisite for observing emergent behavior as seen in systems such as twisted bi-layer graphene. Consequently, as-developed new luminescent defects such as Fluorine Vacancy Centers (FV) with desirable spectral and quantum emission properties would be a significant breakthrough in diamond-based quantum materials. Full article
(This article belongs to the Section Quantum Materials)
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25 pages, 7370 KB  
Article
Strength Enhancement of 3D-Printed Phosphogypsum Concrete Based on Synergistic Activation of Multi-Solid Wastes
by Junjie Li, Yangbo Li, Xianqiang Ge, Ke Li, Yahui Yang and Shuo Wang
Materials 2026, 19(3), 482; https://doi.org/10.3390/ma19030482 - 25 Jan 2026
Cited by 1 | Viewed by 716
Abstract
Phosphogypsum (PG) is the main by-product of wet-process phosphoric acid production. Its annual global production reaches about 200 million tons, yet its utilization rate remains low. Consequently, long-term stockpiling of large PG volumes poses immense pressure to the ecological environment. To mitigate negative [...] Read more.
Phosphogypsum (PG) is the main by-product of wet-process phosphoric acid production. Its annual global production reaches about 200 million tons, yet its utilization rate remains low. Consequently, long-term stockpiling of large PG volumes poses immense pressure to the ecological environment. To mitigate negative environmental impacts, the utilization of PG is imperative. Despite progress in PG utilization and 3D-printing technology, there is still a significant lack of understanding about the synergistic activation mechanisms in multi-solid-waste systems. In particular, the composition design, microstructure evolution, and structure–property relationships of 3D-printed PG-based composites are not well-studied, which limits their high-value engineering applications. Three-dimensional-printed phosphogypsum concrete (3DPPGC) is proposed here, promoting PG resource utilization by leveraging the expanding applications of 3D-printed concrete (3DPC). However, the strength of 3DPPGC needs to be enhanced to meet engineering requirements. This study designed the mix proportion of 3DPPGC and fabricated the corresponding test specimens. The optimal Cement Replacement Ratio (CRR) was determined through experimental testing, and the mechanism behind the strength enhancement of the 3DPPGC was elucidated. The results indicated that the 3DPPGC’s mechanical properties peaked at the 70% CRR. Compared with cast specimens, 3DPPGC exhibited a 1.52% increase in 28-day flexural strength in the y-direction, reaching 4.69 MPa. The early-age compressive strength, flexural strength, and later-age compressive strength of 3DPPGC were significantly enhanced when PG, blast-furnace slag (BS), fly ash (FA), and silica fume (SF) were used to partially replace cement. This study provides a theoretical and experimental basis for the large-scale, high-value application of PG in intelligent construction. Full article
(This article belongs to the Special Issue Advanced Smart Materials for 3D/4D Printing: Mechanisms, Performance and Applications)
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27 pages, 5236 KB  
Review
Aperiodicity in Low Dimensions
by Pavel V. Avramov, Hao Tian and Li Li
Materials 2026, 19(3), 446; https://doi.org/10.3390/ma19030446 - 23 Jan 2026
Cited by 1 | Viewed by 742
Abstract
This review provides a comparative analysis of the structure and physical properties of low-dimensional aperiodic crystalline solids, aiming to elucidate the origin and nature of aperiodicity in reduced-dimensional lattices. The breakdown of periodicity in low-dimensional systems arises from several mechanisms, including the suppression [...] Read more.
This review provides a comparative analysis of the structure and physical properties of low-dimensional aperiodic crystalline solids, aiming to elucidate the origin and nature of aperiodicity in reduced-dimensional lattices. The breakdown of periodicity in low-dimensional systems arises from several mechanisms, including the suppression of specific force constants, thermodynamic instabilities, and topological constraints associated with imperfect space filling. At the nanoscale, certain cubic crystalline materials can form finite, zero-dimensional multiply twinned particles (MTPs) with decahedral or icosahedral symmetry. These clusters lack translational invariance and experience intrinsic structural strain due to solid-angle mismatch at twin junctions, which limits their characteristic size and renders them finite aperiodic solids. Particular attention is devoted to the electronic and spin properties of pentagonally symmetric MTPs: icosahedral particles exhibit symmetry-protected spin degeneracy consistent with centrosymmetric lattices, whereas non-centrosymmetric decahedral particles may display spin polarization and emergent low-dimensional magnetism. Collectively, these systems illustrate the diverse physical origins, manifestations, and consequences of aperiodicity in low-dimensional crystalline matter. Full article
(This article belongs to the Special Issue Quantum Transport in Novel 2D Materials and Structures)
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20 pages, 4635 KB  
Article
rGO/PAN Composite Membranes Obtained In Situ Using Hydrothermal Reduction of GO in the Polymer Bulk
by Beata Fryczkowska, Łukasz Migdał, Janusz Fabia, Czesław Ślusarczyk and Ryszard Fryczkowski
Materials 2026, 19(2), 442; https://doi.org/10.3390/ma19020442 - 22 Jan 2026
Viewed by 599
Abstract
A new method of in situ hydrothermal reduction of graphene oxide (GO) to reduced graphene oxide (rGO) in polymer bulk was developed, which involves heating GO/polyacrylonitrile (PAN) composite membranes (0.5; 1.0; 2.0% w/w of GO/PAN) in the presence of water vapor [...] Read more.
A new method of in situ hydrothermal reduction of graphene oxide (GO) to reduced graphene oxide (rGO) in polymer bulk was developed, which involves heating GO/polyacrylonitrile (PAN) composite membranes (0.5; 1.0; 2.0% w/w of GO/PAN) in the presence of water vapor at a temperature of 120 °C and a pressure of 0.2 MPa. As a result of this process, membranes containing rGO were obtained, as confirmed by FTIR, Raman, WAXS and TGA studies. The composite membranes obtained after hydrothermal reduction of GO to rGO (B60, C60, D60) were substantially different from the initial membranes containing unreduced GO (B0, C0, D0). The hydrothermal reduction process clearly influenced the physicochemical properties (reduction of apparent density, water sorption, and increase in the contact angle) and transport properties of the B60, C60, and D60 membranes (decrease in water flux by ~104 [dm3/m2 × h] and even ~348 [dm3/m2 × h] compared to the initial membranes). Full article
(This article belongs to the Special Issue Preparation, Properties and Applications of Emerging Polymer Composite Materials)
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15 pages, 1370 KB  
Article
Synthesis and Structural Characterization of Oligo(carbonate diol)s and Oligo(urethane-carbonate diol)s via a Transesterification–Polycondensation Route
by Mariusz Ł. Mamiński, Paweł G. Parzuchowski, Dominik Wołosz and Arkadiusz Zimny
Materials 2026, 19(2), 434; https://doi.org/10.3390/ma19020434 - 22 Jan 2026
Cited by 2 | Viewed by 1428
Abstract
Oligocarbonate diols (OCD) require tedious and time-consuming synthesis procedures. The most common ones use dimethyl carbonate or alkylene carbonate as starting materials. Considering the preparation of small batches of oligomerols with an atypical structure, this methodology is not convenient. Therefore, we developed a [...] Read more.
Oligocarbonate diols (OCD) require tedious and time-consuming synthesis procedures. The most common ones use dimethyl carbonate or alkylene carbonate as starting materials. Considering the preparation of small batches of oligomerols with an atypical structure, this methodology is not convenient. Therefore, we developed a simple way to obtain OCDs and oligo(urethane-carbonate) diols (OUCDs) containing aliphatic, cycloaliphatic, aromatic or oxyethylene units based on commercially available OCDs (ETERNACOLL, UBE). The process was conducted in two stages combining transesterification/transurethanization and polycondensation reactions. It resulted in novel OCDs and OUCDs with an irregular structure. Their composition was characterized using FT-IR, NMR, and MALDI-TOF techniques. The hydroxyl values were determined by potentiometric titration. The numerical average molar masses of the oligomerols ranged from approx. 1000 to 3200 g/mol, making them attractive materials for the preparation of a variety of polyurethane products. Thanks to the presence of carbonate moieties that are resistant to hydrolytic and oxidative degradation, poly(carbonate-urethane)s could find applications as coatings, thermoplastic elastomers, and biomaterials. The influence of the structural variations of the oligomerols on the properties of polyurethanes is now under investigation. Full article
(This article belongs to the Section Green Materials)
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19 pages, 11267 KB  
Article
A Dual-Dynamic Crosslinked Polysaccharide-Based Hydrogel Loaded with Exosomes for Promoting Diabetic Wound Healing
by Ding Lin, Zhenhao Li, Jianying Hao, Xiaobo Xu, Xiuqiang Li, Yuan Feng, Xiaochen Lu, Fanglian Yao, Hong Zhang and Junjie Li
Materials 2026, 19(2), 445; https://doi.org/10.3390/ma19020445 - 22 Jan 2026
Cited by 5 | Viewed by 1243
Abstract
Diabetic wounds are often accompanied by severe inflammation, which is unfavorable for vascular growth and wound repair. Therefore, promoting the healing of diabetic wounds is of great significance. In this study, carboxymethyl chitosan (CMCS) was grafted with 4-formylphenylboronic acid (FPBA) and then crosslinked [...] Read more.
Diabetic wounds are often accompanied by severe inflammation, which is unfavorable for vascular growth and wound repair. Therefore, promoting the healing of diabetic wounds is of great significance. In this study, carboxymethyl chitosan (CMCS) was grafted with 4-formylphenylboronic acid (FPBA) and then crosslinked with oxidized sodium alginate (OAlg) to form a dual-dynamic covalent hydrogel (CPOA) based on borate ester bond and Schiff base bonds. Mesenchymal stem cells’ exosomes (Exos) were incorporated into the CPOA to construct CPOA@Exos for diabetic wound healing. Owing to the dual-dynamic covalent crosslinking network, the CPOA hydrogel showed good injectability and self-healing ability. In addition, the hydrogel displayed reactive oxygen species (ROS) responsive properties, enabling both scavenging of multiple free radicals and on-demand release of Exos in the ROS-rich wound microenvironment. A diabetic wound model was established on C57 mice, and treatment with CPOA@Exos demonstrated that it could promote the polarization of macrophages toward the M2 phenotype, enhance cellular proliferation in the wounded area, and thereby accelerate the healing of diabetic wounds. In conclusion, this study provides a new hydrogel wound dressing that can inhibit inflammation for the management of diabetic wounds. Full article
(This article belongs to the Special Issue Fabrication, Characteristics and Applications of Multifunctional Polymer Nanocomposites)
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14 pages, 1063 KB  
Article
Inverse Gas Chromatography for Characterization of Adsorption Ability of Carbon–Mineral Composites for Removal of Antibiotics from Water
by Piotr Słomkiewicz, Katarzyna Piekacz and Sabina Dołęgowska
Materials 2026, 19(2), 419; https://doi.org/10.3390/ma19020419 - 21 Jan 2026
Cited by 2 | Viewed by 772
Abstract
In this study, inverse gas chromatography (IGC) was applied to characterize the key surface physicochemical properties of carbon–mineral composites and to clarify how these properties relate to removal efficiencies of selected antibiotics, with particular emphasis on surface energetic and acid–base characteristics rather than [...] Read more.
In this study, inverse gas chromatography (IGC) was applied to characterize the key surface physicochemical properties of carbon–mineral composites and to clarify how these properties relate to removal efficiencies of selected antibiotics, with particular emphasis on surface energetic and acid–base characteristics rather than bulk structural parameters. The dispersive component of surface free energy and the acid–base characteristics (Ka/Kb ratio) were determined, alongside measurements of carbon content, while specific surface areas were compared with data reported previously. We found that there is no clear correlation between bulk structural characteristics and the removal efficiency of ciprofloxacin, doxycycline, sulfamethoxazole, and tetracycline. In contrast, the removal of all investigated antibiotics was found to be correlated with the dispersive component of surface free energy and the Ka/Kb ratio. The results suggest that surface energetic parameters and acid–base properties are more closely associated with antibiotic adsorption behavior than basic structural characteristics alone. These findings demonstrate that IGC provides valuable insight into adsorption processes and highlight the importance of surface physicochemical properties for interpreting and predicting the adsorption properties of carbon–mineral composites. Full article
(This article belongs to the Section Porous Materials)
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10 pages, 1163 KB  
Communication
Controlling Ultrafast Excitations in Germanium: The Role of Pump-Pulse Parameters and Multi-Photon Resonances
by Amir Eskandari-asl and Adolfo Avella
Materials 2026, 19(2), 408; https://doi.org/10.3390/ma19020408 - 20 Jan 2026
Viewed by 597
Abstract
We employ the Dynamical Projective Operatorial Approach (DPOA) to investigate the ultrafast optical excitations of germanium under intense, ultrashort pump pulses. The method has very low resource demand relative to many other available approaches and enables detailed calculation of the residual electron and [...] Read more.
We employ the Dynamical Projective Operatorial Approach (DPOA) to investigate the ultrafast optical excitations of germanium under intense, ultrashort pump pulses. The method has very low resource demand relative to many other available approaches and enables detailed calculation of the residual electron and hole populations induced by the pump pulse. It provides direct access to the energy distribution of excited carriers and to the total energy transferred to the system. By decomposing the response into contributions from different multi-photon resonant processes, we systematically study the dependence of excited-carrier density and absorbed energy on key pump-pulse parameters: duration, amplitude, and photon energy. Our results reveal a complex interplay between these parameters, governed by resonant Rabi-like dynamics and competition between different multi-photon absorption channels. For the studied germanium setup, we find that two-photon processes are generally dominant, while one- and three-photon channels become significant under specific conditions of pump-pulse frequency, duration, and intensity. This comprehensive analysis offers practical insights for optimizing ultrafast optical control in semiconductors by targeting specific multi-photon pathways. Full article
(This article belongs to the Section Materials Physics)
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15 pages, 4006 KB  
Article
Circular Dichroism via Extrinsic Chirality in Achiral Plasmonic Nanohole Arrays
by Francesco Floris, Margherita Angelini, Konstantins Jefimovs, Dimitrios Kazazis and Franco Marabelli
Materials 2026, 19(2), 402; https://doi.org/10.3390/ma19020402 - 19 Jan 2026
Cited by 1 | Viewed by 883
Abstract
The detection of chiral properties is crucial for pharmacology and biochemistry, yet standard circular dichroism spectroscopy suffers from low sensitivity when probing minute sample volumes. While complex asymmetric chiral nanostructures can enhance these Circular Dichroic (CD) signals, their fabrication is intricate and costly. [...] Read more.
The detection of chiral properties is crucial for pharmacology and biochemistry, yet standard circular dichroism spectroscopy suffers from low sensitivity when probing minute sample volumes. While complex asymmetric chiral nanostructures can enhance these Circular Dichroic (CD) signals, their fabrication is intricate and costly. In this work, we analyzed an alternative based on extrinsic chirality in achiral square arrays of plasmonic circular NHAs realized via Displacement Talbot Lithography (DTL), thus exploring the chiroptical response arising from symmetry breaking induced by oblique illumination. Unlike isolated nanoparticles, nanohole arrays (NHAs) support propagating Surface Plasmon Polaritons (SPPs), allowing for unique light confinement capabilities essential for high-throughput sensing. A careful characterization in terms of Stokes parameters has been performed over a selected range of different optical angles of incidence and sample orientation to disentangle extrinsic chiral contribution from spurious effects related to sample imperfections. By optimizing such extrinsic chiral contributions, enhanced chiroptical response could be engineered by significantly amplifying the interaction between light and chiral biomolecules trapped within the holes. This methodology establishes DTL-fabricated achiral NHAs as an ultrasensitive, cost-effective platform for the detection and discrimination of enantiomers in biosensing applications. Full article
(This article belongs to the Section Optical and Photonic Materials)
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16 pages, 2524 KB  
Article
Degradation of Some Polymeric Materials of Bioreactors for Growing Algae
by Ewa Borucińska-Parfieniuk, Ewa Górecka, Jakub Markiewicz, Urszula Błaszczak, Krzysztof J. Kurzydlowski and Izabela B. Zglobicka
Materials 2026, 19(2), 384; https://doi.org/10.3390/ma19020384 - 18 Jan 2026
Viewed by 972
Abstract
Transparent polymeric materials such as poly(methyl methacrylate) (PMMA), polycarbonate (PC), and polyethylene terephthalate (PET) are widely used as glass alternatives in algal bioreactors, where optical clarity and mechanical stability are crucial. However, their long-term use is limited by surface degradation processes. Photodegradation, hydrolysis, [...] Read more.
Transparent polymeric materials such as poly(methyl methacrylate) (PMMA), polycarbonate (PC), and polyethylene terephthalate (PET) are widely used as glass alternatives in algal bioreactors, where optical clarity and mechanical stability are crucial. However, their long-term use is limited by surface degradation processes. Photodegradation, hydrolysis, and biofilm accumulation can reduce light transmission in the 400–700 nm range essential for photosynthesis. This study examined the aging of PMMA, PC, and PET under bioreactor conditions. Samples were exposed for 70 days to illumination, culture medium, and aquatic environments. Changes in their optical transmittance, surface roughness, and wettability were analyzed. All polymers exhibited measurable surface degradation, characterized by an average 15% loss in transparency, significant increases in surface roughness, and reduced contact angles. PMMA demonstrated the highest optical stability, maintaining strong transmission in key blue and red spectral regions, while PET performed the worst, showing low initial clarity and the steepest decline. The most severe surface degradation occurred in areas exposed to the receding liquid interface, highlighting the need for targeted cleaning and/or a reduction in the size of the liquid–vapor transition zone. Overall, the results identify PMMA and recycled PMMA (PMMAR) as durable, cost-effective materials for transparent bioreactor walls. Full article
(This article belongs to the Section Advanced Materials Characterization)
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17 pages, 2856 KB  
Article
Valley-Dependent Topological Interface States in Biased Armchair Nanoribbons of Gapless Single-Layer Graphene for Transport Applications
by Zheng-Han Huang, Jing-Yuan Lai and Yu-Shu Wu
Materials 2026, 19(2), 380; https://doi.org/10.3390/ma19020380 - 17 Jan 2026
Viewed by 1178
Abstract
Valley-dependent topological physics offers a promising avenue for designing nanoscale devices based on gapless single-layer graphene. To demonstrate this potential, we investigate an electrical bias-controlled topological discontinuity in valley polarization within a two-segment armchair nanoribbon of gapless single-layer graphene. This discontinuity is created [...] Read more.
Valley-dependent topological physics offers a promising avenue for designing nanoscale devices based on gapless single-layer graphene. To demonstrate this potential, we investigate an electrical bias-controlled topological discontinuity in valley polarization within a two-segment armchair nanoribbon of gapless single-layer graphene. This discontinuity is created at the interface by applying opposite in-plane, transverse electrical biases to the two segments. An efficient tight-binding theoretical formulation is developed to calculate electron states in the structure. In a reference configuration, we obtain energy eigenvalues and probability distributions that feature interface-confined electron eigenstates induced by the topological discontinuity. Moreover, to elucidate the implications of interface confinement for electron transport, a modified configuration is introduced to transform the eigenstates into transport-active, quasi-localized ones. We show that such states result in Fano “anti-resonances” in transmission spectra. The resilience of these quasi-localized states and their associated Fano fingerprints is examined with respect to fluctuations. Finally, a proof-of-concept band-stop electron energy filter is presented, highlighting the potential of this confinement mechanism and, more broadly, valley-dependent topological physics in designing nanoscale devices in gapless single-layer graphene. Full article
(This article belongs to the Special Issue High-Mobility Graphene Structures: Advanced Fabrication Methods and Emerging Quantum Phenomena)
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23 pages, 7092 KB  
Review
Toward High-Performance Mg-Matrix Composites: Recent Advances in Ceramic Reinforcement Strategies and Processing Innovations
by Yuefeng Ying, Weideng Wang, Guoqiang You, Yan Yang, Bin Jiang, Lin Yue and Qilin Shao
Materials 2026, 19(2), 365; https://doi.org/10.3390/ma19020365 - 16 Jan 2026
Cited by 3 | Viewed by 1246
Abstract
Magnesium matrix composites formed by incorporating ceramic particles into a magnesium alloy matrix can effectively leverage the complementary properties of the matrix and reinforcement. This approach significantly enhances the mechanical properties of the material at both room and elevated temperatures, offering a viable [...] Read more.
Magnesium matrix composites formed by incorporating ceramic particles into a magnesium alloy matrix can effectively leverage the complementary properties of the matrix and reinforcement. This approach significantly enhances the mechanical properties of the material at both room and elevated temperatures, offering a viable solution to the inherent limitations of Mg alloys, such as insufficient absolute strength, stiffness, and poor heat resistance. This article reviews the latest research progress in the field of ceramic particle-reinforced magnesium matrix composites in recent years. First, the current research status of magnesium matrix composites reinforced with different types of ceramic particles is comprehensively summarized. Subsequently, it provides a summary and in-depth analysis of the principles, key technologies, and microstructural characteristics of both mainstream and emerging preparation processes, and discusses their advantages and disadvantages. Finally, the challenges in current research are analyzed, and future cutting-edge directions for developing high-performance ceramic particle-reinforced magnesium matrix composites are discussed. Full article
(This article belongs to the Special Issue High-Performance Lightweight Alloy Materials and Their Advanced Forming Technologies)
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14 pages, 3588 KB  
Article
Durable and Robust Janus Membranes with Asymmetric Wettability Based on Poly (Vinylidene Fluoride)/Polyvinyl Alcohol for Oil–Water Separation
by Yawen Chang, Ruihong Sun and Fujuan Liu
Materials 2026, 19(2), 363; https://doi.org/10.3390/ma19020363 - 16 Jan 2026
Cited by 2 | Viewed by 1190
Abstract
With the acceleration of industrialization, the problems of water resource pollution and shortage caused by oil spills and industrial wastewater discharge have become increasingly severe, posing a major threat to ecological sustainable development. Therefore, efficient oil–water separation technology has become a key breakthrough [...] Read more.
With the acceleration of industrialization, the problems of water resource pollution and shortage caused by oil spills and industrial wastewater discharge have become increasingly severe, posing a major threat to ecological sustainable development. Therefore, efficient oil–water separation technology has become a key breakthrough to alleviate this crisis. In this study, Janus membranes with asymmetric wettability were prepared by layer-by-layer electrospinning. The influence of the thickness ratio between the hydrophobic layer and the hydrophilic layer on the mechanical properties, separation flux, and oil–water mixture efficiency of the Janus membranes was examined, and an optimized membrane configuration was determined: the optimal thickness ratio between hydrophobic and hydrophilic layers was 4:6. Under these conditions, the fracture stress of the fiber membranes reached 99% MPa, the fracture strain was 55.63 ± 4.77%, the separation flux values were 1888.22 and 1042.66 L m−2 h−1 for the oil–water mixture and water-in-oil emulsion, respectively, with the separation efficiencies all exceeding 99%. After 50 cycles of separation for two different oil-in-water emulsions, the separation flux and separation efficiency of the optimal sample remained relatively stable, demonstrating strong practicability. In general, the Janus fiber membranes met the expected requirements, laying a good foundation for future applications in oil–water separation, floating oil collection in water, and other fields. Full article
(This article belongs to the Special Issue Advanced Polymer Composites for Sustainable Technologies: Synthesis, Characterization, and Performance)
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24 pages, 3981 KB  
Article
Predicting Low-Cycle Fatigue Life Using New Energy-Based Fatigue Damage Measures
by Stanisław Mroziński, Michał Piotrowski, Władysław Egner and Halina Egner
Materials 2026, 19(2), 352; https://doi.org/10.3390/ma19020352 - 15 Jan 2026
Cited by 1 | Viewed by 679
Abstract
This work investigates methods for predicting low-cycle fatigue life by employing new energy-based fatigue damage measures. The primary goal of this research is to evaluate whether fatigue life can be predicted based on an energy accumulation graph, proposed as a generalization of the [...] Read more.
This work investigates methods for predicting low-cycle fatigue life by employing new energy-based fatigue damage measures. The primary goal of this research is to evaluate whether fatigue life can be predicted based on an energy accumulation graph, proposed as a generalization of the isodamage lines concept. The efficiency of fatigue life predictions using this approach, derived from the empirical linear Palmgren–Miner hypothesis, is compared against the physically grounded Unified Mechanics Theory thermodynamic approach, which allows for general understanding of material degradation, in contrast to empirical approaches. The study also accounts for the influence of anisotropy resulting from the sheet rolling process on the fatigue response of S420M steel. Samples were tested in orientations both parallel to the rolling direction and perpendicular to the sheet surface. Microstructural analysis revealed a visible banded structure in the perpendicular samples, which is a consequence of anisotropy. The fatigue life of samples taken perpendicular to the sheet surface was lower than that of parallel samples. Verification of the linear Palmgren–Miner damage summation hypothesis, using both the classical fatigue chart and the cumulative energy chart, resulted in calculated fatigue life consistently higher than the experimental fatigue life in all cases. The reduction in fatigue life ranged from 40% (for total strain amplitude equal to 1.0%) to almost 290% for a strain amplitude of 0.25%. A comparative analysis of the unit loop energy shows that at all tested levels of strain amplitude, the unit loop energy of parallel samples is higher than that of samples perpendicular to the surface. Full article
(This article belongs to the Special Issue Advances in Fatigue Analysis and Numerical Simulation in Engineering Materials)
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19 pages, 3563 KB  
Article
Numerical and Experimental Study of Laser Surface Modification Using a High-Power Fiber CW Laser
by Evaggelos Kaselouris, Alexandros Gosta, Efstathios Kamposos, Dionysios Rouchotas, George Vernardos, Helen Papadaki, Alexandros Skoulakis, Yannis Orphanos, Makis Bakarezos, Ioannis Fitilis, Nektarios A. Papadogiannis, Michael Tatarakis and Vasilis Dimitriou
Materials 2026, 19(2), 343; https://doi.org/10.3390/ma19020343 - 15 Jan 2026
Viewed by 942
Abstract
This work presents a combined numerical and experimental investigation into the laser machining of aluminum alloy Al 1050 H14 using a high-power Continuous Wave (CW) fiber laser. Advanced three-dimensional, coupled thermal–structural Finite Element Method (FEM) simulations are developed to model key laser–material interaction [...] Read more.
This work presents a combined numerical and experimental investigation into the laser machining of aluminum alloy Al 1050 H14 using a high-power Continuous Wave (CW) fiber laser. Advanced three-dimensional, coupled thermal–structural Finite Element Method (FEM) simulations are developed to model key laser–material interaction processes, including laser-induced plastic deformation, laser etching, and engraving. Cases for both static single-shot and dynamic linear scanning laser beams are investigated. The developed numerical models incorporate a Gaussian heat source and the Johnson–Cook constitutive model to capture elastoplastic, damage, and thermal effects. The simulation results, which provide detailed insights into temperature gradients, displacement fields, and stress–strain evolution, are rigorously validated against experimental data. The experiments are conducted on an integrated setup comprising a 2 kW TRUMPF CW fiber laser hosted on a 3-axis CNC milling machine, with diagnostics including thermal imaging, thermocouples, white-light interferometry, and strain gauges. The strong agreement between simulations and measurements confirms the predictive capability of the developed FEM framework. Overall, this research establishes a reliable computational approach for optimizing laser parameters, such as power, dwell time, and scanning speed, to achieve precise control in metal surface treatment and modification applications. Full article
(This article belongs to the Special Issue Fabrication of Advanced Materials)
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28 pages, 1597 KB  
Article
The Influence of Material and Process Parameters on Pressure Agglomeration and Properties of Pellets Produced from Torrefied Forest Logging Residues
by Arkadiusz Gendek, Monika Aniszewska, Paweł Tylek, Grzegorz Szewczyk, Jozef Krilek, Iveta Čabalová, Jan Malaťák, Jiří Bradna and Katalin Szakálos-Mátyás
Materials 2026, 19(2), 317; https://doi.org/10.3390/ma19020317 - 13 Jan 2026
Cited by 2 | Viewed by 843
Abstract
Pellets produced from raw or torrefied shredded logging residues have been investigated in the study. The research material came from pine and spruce stands in Poland, Slovakia, Czechia and Hungary. Torrefaction temperatures (Tt) of 250, 300, and 400 °C were [...] Read more.
Pellets produced from raw or torrefied shredded logging residues have been investigated in the study. The research material came from pine and spruce stands in Poland, Slovakia, Czechia and Hungary. Torrefaction temperatures (Tt) of 250, 300, and 400 °C were applied. Before pressure agglomeration, 3% wheat flour was added to the torrefaction material as a binding agent. Pellets with a diameter of 8 mm were produced at constant humidity, compaction pressure (P) of 140 or 180 MPa and agglomeration temperature (Ta) of 100, 120 or 140 °C. The produced pellets were assessed for their physicomechanical parameters (density, radial compressive strength, compression ratio, modulus of elasticity), chemical parameters (extractive compounds, cellulose, lignin) and energy parameters (ash content, elemental composition, calorific value). The results were subjected to basic statistical analysis and multi-way ANOVA. The produced pellets varied in physical, mechanical, chemical and energy properties. A significant effect of torrefaction temperature, agglomeration temperature and compaction pressure on the results was observed. In terms of physicomechanical parameters, the best pellets were produced from the raw material, while in terms of energy parameters, those produced from the torrefied material were superior. Pellets of satisfactory quality produced from torrefied logging residues could be obtained at Tt = 250 °C, Ta = 120 °C and P = 180 MPa. Pellets with specific density of approximately 1.1 g·cm−3, radial compressive strength of 3–3.5 MPa, modulus of elasticity of 60–80 MPa and calorific value of 20.3–23.8 MJ·kg−1 were produced in the process. Full article
(This article belongs to the Special Issue Catalysis for Biomass Materials Conversion)
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15 pages, 13053 KB  
Article
Development of Ti-Nb-Mo-Zr Alloys with Low Modulus and Excellent Plasticity for Biomedical Applications
by Sen Yang, Zhiyuan Jia, Xueyan Song, Junyang He and Xiaoyong Zhang
Materials 2026, 19(2), 325; https://doi.org/10.3390/ma19020325 - 13 Jan 2026
Cited by 3 | Viewed by 1921
Abstract
Metastable β titanium alloys with low elastic modulus and excellent plasticity represent highly attractive materials for biomedical stent application. Our work shows that Zr plays a crucial role in regulating β stability to significantly reduce the modulus and enhance plasticity. A series of [...] Read more.
Metastable β titanium alloys with low elastic modulus and excellent plasticity represent highly attractive materials for biomedical stent application. Our work shows that Zr plays a crucial role in regulating β stability to significantly reduce the modulus and enhance plasticity. A series of Ti-25Nb-2Mo-xZr (x = 0, 3, 9, 12 wt%) alloys were designed based on the d-electron theory, and the influence of Zr content on the microstructure, mechanical properties, and deformation mechanism were systematically investigated. The results demonstrated that as the Zr content increases, the β phase stability was significantly enhanced. This leads to, first, the suppressed formation of the high modulus α″ phase and ω phase, which results in the decrease in apparent overall elastic modulus. Second, the dominant mode of deformation shifts from martensite dislocation slip (0Zr) to martensitic variant reorientation (3Zr), then to stress-induced martensite transform (SIMT, 9Zr), and finally to a combination of SIMT and deformation twinning (12Zr). Such shifting effectively increases the alloy’s tensile plasticity. Among the series, the Ti-25Nb-2Mo-12Zr alloy exhibited the lowest elastic modulus of 56.3 GPa, together with the highest elongation to failure of 48.2%, demonstrating that the alloy possesses considerable potential for biomedical applications. Full article
(This article belongs to the Special Issue Research on Performance Improvement of Advanced Alloys (2nd Edition))
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20 pages, 2326 KB  
Article
Stability of Composite Plates with a Dense System of Ribs in Two Directions
by Jakub Marczak, Martyna Rabenda and Bohdan Michalak
Materials 2026, 19(2), 322; https://doi.org/10.3390/ma19020322 - 13 Jan 2026
Cited by 1 | Viewed by 333
Abstract
This paper presents an easy-to-use analytical method for stability analysis of composite plates with dense bidirectional microstructure. The main characteristic feature of such a defined composite is that due to its periodic nature the obtainable governing partial differential equations are characterised by discontinuous, [...] Read more.
This paper presents an easy-to-use analytical method for stability analysis of composite plates with dense bidirectional microstructure. The main characteristic feature of such a defined composite is that due to its periodic nature the obtainable governing partial differential equations are characterised by discontinuous, strongly oscillating coefficients. Such cases bring many difficulties during derivation of their solution. In order to simplify calculations, the initial governing equations are transformed with the use of the tolerance averaging technique, so a system of partial differential equations with constant coefficients is obtained. The most important finding of the presented work is that the form of the mentioned equations is similar to the classic equations, which describe the stability issue of the thin homogeneous plate. Consequently, the analytical solution to such issues is easily obtainable. Moreover, when compared to, for example, finite element method (FEM) analysis, it requires substantially less computation resources, which can be perceived as its superior feature. Therefore, the proposed method is convenient for engineering applications. In this paper, a comparative analysis of the results obtained from the proposed analytical models with the results obtained from the FEM has been carried out. The impact of materials and dimensions of microstructure on the values of critical normal and shear forces has also been analysed. Full article
(This article belongs to the Section Mechanics of Materials)
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11 pages, 2682 KB  
Article
A Metasticker Composed of Indium-Tin-Oxide-Square-Fractal Rings for Broadband Absorption
by Min-Sik Kim, Won-Woo Choi and Yongjune Kim
Materials 2026, 19(2), 297; https://doi.org/10.3390/ma19020297 - 12 Jan 2026
Viewed by 1011
Abstract
This study proposes design and fabrication methods for an electromagnetic metasurface absorber (MA) that absorbs electromagnetic waves using a metasticker attached on a dielectric substrate blocked by a copper sheet. To guarantee a high design freedom as well as make the absorption bandwidth [...] Read more.
This study proposes design and fabrication methods for an electromagnetic metasurface absorber (MA) that absorbs electromagnetic waves using a metasticker attached on a dielectric substrate blocked by a copper sheet. To guarantee a high design freedom as well as make the absorption bandwidth (BW) as broad as possible, a square-fractal ring is chosen as the metapattern, and its design is optimized using a genetic algorithm. To fabricate the square-fractal rings in a simple manner, an indium-tin-oxide film is cut by using a laser-cutting machine. Then, the metasticker is fabricated by assembling the metapatterns on a double-sided adhesive film which could be attached on the dielectric substrate using the opposite side of the film. From measured results of the finalized MA of which damaged regions caused by the laser-cutting process are compensated in the design process, a broad −10 dB reflectance BW is confirmed from 4.39 to 7.51 GHz of which the fractional BW is 52.44% for the normal incidence. Moreover, a fractional BW of 4.35% is measured in a wide incident angle range from 0° to 60° for both the transverse electric and the transverse magnetic polarizations simultaneously. Full article
(This article belongs to the Special Issue Advances in Metamaterials: Structure, Properties and Applications—Second Edition)
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27 pages, 11480 KB  
Article
Design and Characterization of Gelatin-Based Interpenetrating Polymer Networks for Biomedical Use: Rheological, Thermal, and Physicochemical Evaluation
by Roberto Grosso, Fátima Díaz-Carrasco, Elena Vidal-Nogales, M.-Violante de-Paz, M.-Jesús Díaz-Blanco and Elena Benito
Materials 2026, 19(2), 289; https://doi.org/10.3390/ma19020289 - 10 Jan 2026
Viewed by 949
Abstract
Tissue engineering is a multidisciplinary field that aims to address tissue and organ failure by integrating scientific, engineering, and medial expertise. Gelatin is valued in this field for its biocompatibility; however, it faces thermal and mechanical weaknesses that limit its biomedical utility. This [...] Read more.
Tissue engineering is a multidisciplinary field that aims to address tissue and organ failure by integrating scientific, engineering, and medial expertise. Gelatin is valued in this field for its biocompatibility; however, it faces thermal and mechanical weaknesses that limit its biomedical utility. This work proposes a strategy for improving gelatin properties by fabricating semi-interpenetrating polymer networks via in situ Diels–Alder crosslinking within gelatin colloidal solutions. Ten systems with variable polymer concentrations (2–4%) and crosslinking degrees (2–5%) were prepared and characterized. Rheological analysis revealed that elastic modulus, zero-shear viscosity, and complex viscosity were substantially enhanced, being especially dependent on the crosslinking degree, while critical strain values mostly depended on gelatin concentration. The incorporation of a synthetic Diels–Alder-crosslinked network also improved the thermal stability of gelatin hydrogels, particularly at physiological temperatures. Additionally, these systems exhibit favorable buoyancy, swelling and biodegradation profiles. Collectively, the resultant hydrogels are cytocompatible, solid-like, and mechanically robust, allowing for further tunability of their properties for specific biomedical uses, such as injectable matrices, load-bearing scaffolds for tissue repair, and 3D bioinks. Full article
(This article belongs to the Special Issue Functional Hydrogel for Biomedical Applications: Progress, Challenges, and Opportunities)
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14 pages, 2314 KB  
Article
Influence of Mo and Ni Alloying on Recrystallization Kinetics and Phase Transformation in Quenched and Tempered Thick Steel Plates
by Xabier Azpeitia, Unai Mayo, Nerea Isasti, Eric Detemple, Hardy Mohrbacher and Pello Uranga
Materials 2026, 19(2), 290; https://doi.org/10.3390/ma19020290 - 10 Jan 2026
Viewed by 751
Abstract
The production of heavy gauge quenched and tempered steel plates requires alloying strategies that ensure adequate hardenability and microstructural uniformity under limited cooling rates. Molybdenum (Mo) and nickel (Ni) are key elements in this context, as they influence both hot-working behavior and phase [...] Read more.
The production of heavy gauge quenched and tempered steel plates requires alloying strategies that ensure adequate hardenability and microstructural uniformity under limited cooling rates. Molybdenum (Mo) and nickel (Ni) are key elements in this context, as they influence both hot-working behavior and phase transformation kinetics. This study investigates the effect of Mo (0.25–0.50 wt%) and Ni (0–1.00 wt%) additions on static recrystallization and transformation behavior using laboratory thermomechanical simulations representative of thick plate rolling conditions. Multipass and double-hit torsion tests were performed to determine the non-recrystallization temperature (Tnr) and quantify softening kinetics, while dilatometry was employed to construct Continuous Cooling Transformation (CCT) diagrams and assess hardenability. Results indicate that Mo significantly increases Tnr and delays recrystallization through a solute drag mechanism, whereas Ni exerts a minor but measurable effect, likely associated with stacking fault energy rather than classical solute drag. Both elements reduce ferrite and bainite transformation temperatures, enhancing hardenability; however, Mo alone cannot suppress ferrite formation at practical cooling rates, requiring combined Mo–Ni additions to achieve fully martensitic microstructures. These findings provide insight into alloy design for thick plate applications and highlight the limitations of existing predictive models for Ni-containing steels. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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