Search Results (3,890)

This study investigates the control of the phase-structural state in Ni–45Ti–xCu (x = 5, 7 at.%) shape memory alloys fabricated via a shortened powder metallurgy route: mechanical activation → spark plasma sintering (SPS) → heat treatment. Compact samples were produced from mechanically alloyed powders (650–750 rpm, up to 5 h) and sintered at 900 °C. The structure and microstructure were characterized using X-ray diffraction (to identify B2/B19′/Ni₄Ti₃ phases and assess ordering) and SEM–BSE/EDS (to analyze morphology, porosity, and Ni-rich precipitates). Two post-processing treatments were applied: single-stage annealing (500 °C, 2 h) and a three-stage treatment (900 °C/30 min → water quenching → 300 °C/20 min). Mechanical alloying transformed the initial elemental powder mixture (fcc-Ni, hcp-Ti, fcc-Cu) into a supersaturated fcc-(Ni,Cu,Ti) solid solution with emerging NiTi phases, with a minimum particle size achieved after ~300 min at 750 rpm. SPS compaction yielded a high-density matrix consisting predominantly of the B2 phase. Single-stage annealing preserved B19′ martensite and Ni₄Ti₃ precipitates, particularly in the 5 at.% Cu alloy. In contrast, the three-stage treatment dissolved the Ni₄Ti₃ precipitates, suppressed the formation of B19′ and R phases, and stabilized a highly ordered B2 matrix. Increasing the Cu content from 5 to 7 at.% significantly enhanced the B2 phase fraction, reduced secondary nickel-rich phases, and improved structural homogeneity, evidenced by a continuous neck network and closed porosity. The optimized condition—7 at.% Cu combined with the three-stage annealing—produced a microstructure with >95% B2 phase, <1% Ni₄Ti₃, and ~98% relative density. This forms the prerequisite microstructural state for a narrow transformation hysteresis and high functional cyclic stability. Full article

Biodegradable packaging based on starch–polycaprolactone (PCL) composites is a promising route to reduce reliance on petroleum-derived plastics. Here, wheat starches with A- and B-type crystallinity—sourced from Kazakhstani varieties—were dual-modified by electron-beam irradiation followed by acetylation and incorporated into PCL (30–50 wt%) via melt extrusion and compression molding. The resulting films were characterized for morphology, mechanical performance, water-vapor permeability (WVP), thermal behavior, antibacterial activity, and biodegradation under soil and composting conditions. Acetylated A-type starch dispersed more uniformly within the PCL matrix, yielding smoother surfaces, higher tensile strength, and moderate WVP. In contrast, B-type starch produced a more porous microstructure with increased WVP and accelerated mass loss during composting (up to ~45% within 10 days at higher starch loadings). Incorporation of starch slightly decreased thermal stability relative to neat PCL, while agar-diffusion assays against Escherichia coli and Staphylococcus aureus showed loading-dependent inhibition zones, with A-type composites generally outperforming B-type at equivalent contents. Taken together, A-type starch–PCL films are better suited for applications requiring mechanical integrity and controlled moisture transfer, whereas B-type systems favor breathable packaging and rapid compostability. These results clarify how starch crystalline type governs structure–property–degradation relationships in PCL composites and support the targeted design of sustainable packaging materials using regionally available starch resources. Full article

Cerium dioxide (CeO₂) nanoparticles with distinct morphologies, including rods, cubes, and octahedrons, were synthesized via a straightforward hydrothermal method. The microstructure and morphology of the as-prepared samples were systematically characterized. The antibacterial activity of the samples against Escherichia coli was evaluated using the plate counting method. The antibacterial experiments revealed that the antibacterial properties of the samples were arranged in the following order: rod > cube > octahedron. Data analysis indicated that the superior antibacterial performance of the CeO₂ nanorod was attributed to the higher concentration of oxygen vacancies and adsorption of reactive oxygen species (ROS) on the surface, with ROS playing a critical role in the antibacterial mechanism of CeO₂. Additionally, density functional theory (DFT) calculations were employed to simulate the oxygen vacancy environments of CeO₂ with different morphologies and provided indirect insights into ROS behavior. Combining experimental and computational results, a mechanistic framework was proposed to elucidate the dependence relationship between morphology and antibacterial activity of CeO₂. Full article

Ti–6Al–4V (TC4) dual-phase titanium alloy is widely used in aerospace components owing to its excellent strength-to-weight ratio and high-temperature stability. However, conventional machining often generates a wide heat-affected zone (HAZ) and oxide or recast layers, which deteriorate the microstructure and reduce long-term reliability. In this study, the water-jet-guided laser (WJGL) process was applied to investigate how coupled laser–water interactions influence the groove morphology, elemental distribution, and crystallographic evolution of TC4 alloy. Under optimized parameters, the WJGL process reduced the HAZ width to less than 1 $\mathsf{\mu }$m, effectively removed the resolidified layer, and suppressed surface oxidation. SEM, EDS, and EBSD analyses confirmed that the $\alpha$ + $\beta$ dual-phase structure remained stable, with no significant phase transformation or grain coarsening. Compared with conventional laser cutting, WJGL achieved smoother surfaces, improved interfacial integrity, and reduced thermal damage. These findings highlight the potential of WJGL for precision machining of high-performance titanium alloys and provide theoretical and experimental support for enhancing the microstructural control and service reliability of aerospace TC4 components. Full article

This work presents the development and characterization of alumina–carbon black (ACB) composite membranes for enhanced hydrogen separation performance. A series of membranes containing 0–3.0 wt.% carbon black was fabricated via high-temperature sintering and systematically investigated with respect to their structural, morphological, mechanical, and gas separation properties. The addition of carbon black significantly influenced membrane microstructure, promoting pore network formation, increasing specific surface area, and enhancing gas transport. Gas permeation tests using H₂ and N₂ revealed that all ACB membranes exhibited higher hydrogen permeance than the pure Al₂O₃ membrane. Notably, the ACB3.0 specimen demonstrated the highest H₂ permeance of 508 × 10⁻⁶ mol m⁻² s⁻¹ Pa⁻¹ at 303 K, which is nearly four times greater than the unmodified membrane. At an elevated temperature (773 K), H₂/N₂ selectivity improved with increasing carbon black content, with ACB3.0 achieving a maximum selectivity of 3.82, exceeding the theoretical Knudsen value, suggesting a synergistic contribution of Knudsen diffusion and surface diffusion. These results demonstrate that carbon black is a cost-effective and versatile additive for modifying ceramic membranes, offering a promising route for advancing hydrogen purification technologies in industrial applications. Full article

Different morphologies of cobalt oxide (Co₃O₄) electrodes were prepared through the electrochemical deposition technique with various electrodeposition times from 10 min to 50 min. Platinum (Pt) nanoparticles were deposited on the Co₃O₄ electrodes through sputter coating. The crystallographic, microstructural, surface functional, textural–structural, and electric properties of the Co₃O₄ electrodes were investigated. X-ray diffraction analysis identified a pure cubic Co₃O₄ crystal structure in the samples. In the electrodeposition process, the microstructure of the electrodes varied from hierarchical 3D flower-like to 2D hexagonal porous nanoplates due to an increase in oxygen vacancies. The carrier densities of all samples were between 5.77 × 10¹⁴ cm⁻³ and 8.77 × 10¹⁴ cm⁻³. The flat band potentials of all samples were between −5.91 V and −6.21 V vs. an absolute electron potential, and the potential values for electrodes became more positive as the oxygen vacancy concentration in the film structure increased. The 2D hexagonal porous nanoplate Pt/Co₃O₄ electrodes offered the highest oxygen vacancies and thus the maximum current density of 102.66 mA/cm², with an external potential set at 1.5 V vs. an Ag/AgCl reference electrode. Full article

This study investigates the performance degradation of X70 steel weld material in high-pressure natural gas pipelines in the Sichuan-Chongqing region and its impact on pipeline safety by investigating their behavior under multiphysics environments, including varying gas media (nitrogen, methane, hydrogen-blended), pressure conditions (0.1–10 MPa), and material regions (base metal vs. weld). A key novelty of this work is the introduction of a “degradation rate” metric to quantitatively assess the deterioration of weld mechanical properties. A key novelty of this work is the explicit introduction of a “degradation rate” metric to quantitatively assess the deterioration of weld mechanical properties. Slow strain rate tensile tests, combined with fracture morphology and microstructure analysis, reveal that welds exhibit inferior mechanical properties due to microstructural inhomogeneity and residual stresses, including a yield stress reduction of 15.2–18.7%. The risk of brittle fracture was highest in the hydrogen-blended environment, while nitrogen exhibited the most benign effect. Material region changes were identified as the most significant factor affecting degradation. This research provides crucial data and theoretical support for pipeline safety design and material performance optimization. Full article

The effect of pre-strain-induced microstructural evolution on the hydrogen embrittlement (HE) resistance of an equiatomic CoCrNi medium-entropy alloy was systematically investigated by mechanical property testing, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) characterization. Three pre-strain levels (0%, 30%, and 50%) were applied to produce distinct microstructures: dislocation-free and twin-free (P0), high dislocation density with few deformation twins (P30), and high densities of both dislocations and deformation twins (P50). Mechanical tests combined with hydrogen charging revealed that the P50 specimen exhibited the highest yield strength (1163.88 MPa) and the lowest HE-induced elongation loss (2.74%), indicating an improvement in HE resistance. By using SEM, detailed observations of the fracture morphology and crack propagation paths revealed that deformation twins can effectively reduce stress concentration, delay the nucleation and propagation rates of cracks, and suppress brittle intergranular fracture, thereby improving mechanical properties and resistance to hydrogen embrittlement. A detailed analysis was conducted of the HE resistance mechanism associated with the influence of deformation twins on hydrogen transport and distribution. Full article

Forging plays a crucial role in various industries, including aerospace, automotive, oil and gas, and defense. We investigated the effect of post-processing forging on microstructural and mechanical properties of 316L stainless steel forging preforms fabricated by laser powder bed fusion. The as-built samples were subjected to hot forging in order to refine the microstructure and enhance mechanical performance. Detailed characterization was performed using Electron Backscatter Diffraction, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Tensile testing, and Hardness Testing. Substantial grain refinement (up to 97%) was observed, in addition to a reduction in porosity. The forging process effectively transformed the columnar grain morphology into equiaxed grains, increased yield and ultimate tensile strengths of 560 MPa and 740 MPa, representing 27% and 32% improvements, respectively, with a corresponding decrease in elongation to 32% from 47%. The horizontally built samples achieved the highest yield strength of 605 MPa but slightly lower UTS 710 MPa, representing 32% and 5% increment and decrease in ductility to 28% from 37.5%. These trends reflect the combined effects of work hardening and grain refinement, which enhance strength at the expense of ductility. Full article

In this study, p-type NiO_x and Cu-doped NiO_x nanoparticles (NPs) were synthesized by a simple chemical precipitation method and used as hole transport layers (HTLs) for inverted perovskite solar cells (PSCs). The microstructural property, surface morphology, elemental composition, optical property, charge recombination, and surface topography of the NiO_x and Cu-NiO_x HTLs were comprehensively characterized. The results showed that the NiO_x and Cu-NiO_x NPs were uniformly coated on the substrates without pinholes or voids. Cu incorporation into NiO_x did not change its crystalline nature and considerably improved its electrical conductivity. The Cu-NiO_x HTLs exhibited superior photoluminescence quenching and the least lifetime decay, which indicated that Cu-NiO_x exhibited higher charge transport than NiO_x HTLs. The fabricated PSC performances were further analyzed using current density–voltage characteristics, external quantum efficiency, and electrochemical impedance spectroscopy. The PSCs with PEDOT:PSS, NiO_x, and 2% Cu-NiO_x HTLs exhibited power conversion efficiencies of 11.93%, 13.72%, and 15.54%, respectively. The 2% Cu-NiO_x HTL-based device showed the best performance compared with the PEDOT:PSS- and NiO_x-based devices. Academic Editors: Chunyang Zhang, Dou Zhang Full article

This study presents an experimental investigation of steels used in special knife applications, focusing on the interrelationship between chemical composition, microstructure, heat treatment, and mechanical properties. Four representative materials were analysed: VG10 (stainless steel with nickel-laminated edges and a VG10 core), RWL₃₄^TM (powder-metallurgical steel), laminated steel K110+N695 (with a nickel interlayer), and forge-welded steel K600+K720. The steels were characterised using OES, optical microscopy and SEM, supported by EDS for local chemical analysis. Microhardness testing was applied to individual structural regions to correlate carbide morphology, layer interfaces, and heat-treatment response with hardness values. The results reveal pronounced differences in structural homogeneity and defect occurrence. Powder-metallurgical RWL₃₄^TM exhibited the most uniform microstructure with finely dispersed Cr carbides, achieving high hardness and absence of structural defects. In contrast, laminated and forge-welded steels contained large primary carbides, carbide precipitation at grain boundaries, porous cavities, and insufficient cohesion in interlayers or weld zones, which may compromise toughness. VG10 and K110+N695 showed carbide coarsening caused by inadequate heat treatment, whereas K600+K720 revealed weld-related defects and heterogeneous phase structures. Overall, the study demonstrates the critical role of heat treatment and processing route in determining blade quality and performance. The findings provide guidance for optimising steel selection and processing technologies in advanced cutlery engineering. Full article

This article reports on the synthesis and physicochemical characterization of a novel complex ferrite material, LiCr₃.₄Fe₁.₆O₈, prepared via the sol-gel method. X-ray diffraction (XRD) analysis confirmed that the synthesized compound is a single-phase material with a spinel-type structure and cubic symmetry. Raman spectroscopy was employed to investigate the vibrational modes, and the observed peaks corresponding to Fe–O and Cr–O bonds further validated the spinel-like structure of the compound. The microstructure and elemental composition were examined using scanning electron microscopy (SEM). Multiple regions of the LiCr₃.₄Fe₁.₆O₈ crystals were analyzed, revealing a homogeneous phase and providing detailed insight into the morphology and chemical composition of the surface. The synthesized ferrite particles exhibited relatively large dimensions, with sizes measured at approximately 5, 30, 100, and 200 μm. The dielectric behavior was studied to assess the material’s response to an external electric field, demonstrating its capacity for electric charge polarization. Both capacitance and electrical conductivity were found to increase with rising temperature. Electrophysical measurements were conducted using the LCR-800 system over a temperature range of 293–483 K and at frequencies of 1.5 kHz and 10 kHz. An increase in frequency to 10 kHz resulted in a decrease in the dielectric constant (ε) across the entire temperature range. Full article

The paper presents designing thermomechanical processing routes for medium-carbon boron-bearing microalloyed steel and investigates their effect on microstructure–property characteristics obtained through controlled cooling directly from hot forging temperature. Direct cooling was carried out in situ within the industrial process of hot forging, replacing conventional heat treatment with slow and accelerated air cooling, realized with a fully automated fan-cooling laboratory conveyor which accommodates the desired cooling strategy. Comparative analysis of conventionally normalized and direct-cooled microstructure and mechanical properties obtained under varied thermo-mechanical conditions is presented to investigate the potential of medium-carbon microalloyed steel with boron addition for producing tailored properties comparable to those of the normalized condition. The obtained microstructure composed of grain-boundary ferrite and pearlite which resulted in tensile properties as good as Re ≈ 610 MPa, Rm ≈ 910 MPa, and elongation A5 ≥ 12%. Although the achieved microstructure–property parameters differ from those achieved through conventional normalizing (Rm ≤ 780 MPa, Re ≤ 460 MPa, and A ≥ 14%), they are considerable in terms of selected machinability aspects. The observed effect of the imposed treatment strategies on interlamellar spacing and morphology of ferrite showed possibilities regarding the control of mechanical properties and application of direct cooling as a beneficial alternative to conventional normalizing, where energy consumption is the main concern in manufacturing high-duty parts made of boron-bearing microalloyed steel 35MnTiB4. Full article

Background/Objectives: Lung cancer is characterized by a significant microstructural heterogenicity among different histological types. Artificial intelligence and digital pathology instruments can facilitate morphological analysis by introducing calculated metrics allowing for the distinguishment of different tissue patterns. Methods: We used computer vision models to calculate a number of morphometric features of tumor vascularization and proliferation. We used two frameworks to process whole-slide images: (1) LVI-PathNet framework for vascular detection, based on the SegFormer architecture; and (2) Mito-PathNet framework for mitotic figure detection, based on the RetinaNet detector and an ensemble classification model. The results were visualized in the segmented and gradient heatmaps. Results: SegFormer for vessel segmentation achieved the following quality metrics: IoU = 0.96, FBeta-score = 0.98, and AUC-ROC = 0.98. RetinaNet + CNN ensemble achieved the following quality metrics: specificity = 0.96 and sensitivity = 0.97. The analysis of the obtained parameters allowed us to identify trophic patterns of lung cancer according to the degree of aggressiveness, which can serve as potential targets for therapy, including proliferative-vascular, hypoxic, proliferative, vascular, and inactive. Conclusions: The analysis of the obtained parameters allowed us to identify distinct quantitative characteristics for each histological type of lung cancer. These patterns could potentially become markers for therapeutic choices, such as antiangiogenic and hypoxia-induced factor therapy. Full article

The quality of heavy plates produced from low-carbon steel is directly linked to the structural characteristics inherited from the initial continuously cast thick slabs. This study explores how different casting technologies affect the morphology and distribution of allotriomorphic ferrite along prior austenite grain boundaries (PAGBs) within these slabs. Using quantitative microstructural analysis based on advanced computer vision techniques (OpenCV), the research identifies significant variations in ferrite boundary thickness and volume fraction associated with different casting methods. These microstructural differences strongly correlate with variations in Charpy V-notch impact energy (KVZ20) and susceptibility to microcrack formation during subsequent rolling processes. The results obtained allow us to evaluate the influence of the cast structure on the formation of the initial structural characteristics of the material, especially on the formation of microcracks of the slab microstructure and their propagation during further processing. Full article