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Keywords = multicomponent alloy

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21 pages, 5415 KiB  
Article
Hierarchical 3D FeCoNi Alloy/CNT @ Carbon Nanofiber Sponges as High-Performance Microwave Absorbers with Infrared Camouflage
by Yifan Fei, Junya Yao, Wei Cheng and Wenling Jiao
Materials 2025, 18(1), 113; https://doi.org/10.3390/ma18010113 - 30 Dec 2024
Viewed by 412
Abstract
Microwave absorbers with infrared camouflage are highly desirable in military fields. Self-supporting 3D architectures with tailorable shapes, composed of FeCoNi alloy/carbon nanotubes (CNTs) @ carbon nanofibers (CNFs), were fabricated in this study. On the one hand, multiple loss mechanisms were introduced into the [...] Read more.
Microwave absorbers with infrared camouflage are highly desirable in military fields. Self-supporting 3D architectures with tailorable shapes, composed of FeCoNi alloy/carbon nanotubes (CNTs) @ carbon nanofibers (CNFs), were fabricated in this study. On the one hand, multiple loss mechanisms were introduced into the high-elastic sponges. Controllable space conductive networks caused by the in situ growth of CNTs on the CNFs contributed to the effective dielectric and resistance loss. Moreover, the uniformly distributed magnetic alloy nanoparticles (NPs) with dense magnetic coupling resulted in magnetic loss. On the other hand, heterogeneous interfaces were constructed by multicomponent engineering, causing interfacial polarization and polarization loss. Furthermore, the internal structures of sponges were optimized by regulating the alloy NPs sizes and the growth state of CNTs, then tuning the impedance matching and microwave absorption. Therefore, the high-elastic sponges with ultra-low density (7.6 mg·cm−3) were found to have excellent radar and infrared-compatible stealth properties, displaying a minimum refection loss (RLmin) of −50.5 dB and a maximum effective absorption bandwidth (EABmax) of 5.36 GHz. Moreover, the radar stealth effect of the sponges was evaluated by radar cross-section (RCS) simulation, revealing that the multifunctional sponges have a promising prospect in military applications. Full article
(This article belongs to the Special Issue Advances in Electrostatic Spinning Micro and Nano Fibers)
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10 pages, 2335 KiB  
Article
Microstructure Formation and Dry Reciprocating Sliding Wear Response of High-Entropy Hypereutectic White Cast Irons
by Willian Martins Pasini, Wojciech Polkowski, Tomasz Dudziak, Carlos Alexandre dos Santos and Vinicius Karlinski de Barcellos
Metals 2025, 15(1), 4; https://doi.org/10.3390/met15010004 - 26 Dec 2024
Viewed by 365
Abstract
White cast irons (WCI) are widely used in industries requiring high wear resistance due to their microstructure consisting of hard carbides dispersed within a metallic matrix. This study focuses on developing wear-resistant multi-component hypereutectic high chromium cast irons, merging concepts of high entropy [...] Read more.
White cast irons (WCI) are widely used in industries requiring high wear resistance due to their microstructure consisting of hard carbides dispersed within a metallic matrix. This study focuses on developing wear-resistant multi-component hypereutectic high chromium cast irons, merging concepts of high entropy alloys with the conventional metallurgy of white cast irons, specifically exploring the influence of carbide-forming elements such as V, Mo, and Ni on solidification behavior, microstructure, and wear performance. The research investigates the solidification process of the alloys using Computer-Aided Cooling Curve Analysis (CA-CCA) and characterizes the microstructures through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The wear behavior of the developed alloys is evaluated through reciprocating sliding wear tests, revealing the impact of varying chemical compositions on wear resistance. The results demonstrate that high-entropy white cast iron (HEWCI), particularly those enriched with carbide-forming elements, exhibit superior abrasion resistance compared to conventional high-chromium cast irons. The alloy with 2 Mo and 4 V content showed the best performance, presenting the lowest wear rate (61.5% lower than HCCI alloy) and CoF (values ranging from 0.20 to 0.22) due to the highest concentration of V carbides. Full article
(This article belongs to the Special Issue Casting Alloy Design and Characterization—2nd Edition)
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21 pages, 10983 KiB  
Review
Machine Learning Advances in High-Entropy Alloys: A Mini-Review
by Yibo Sun and Jun Ni
Entropy 2024, 26(12), 1119; https://doi.org/10.3390/e26121119 - 20 Dec 2024
Viewed by 620
Abstract
The efficacy of machine learning has increased exponentially over the past decade. The utilization of machine learning to predict and design materials has become a pivotal tool for accelerating materials development. High-entropy alloys are particularly intriguing candidates for exemplifying the potency of machine [...] Read more.
The efficacy of machine learning has increased exponentially over the past decade. The utilization of machine learning to predict and design materials has become a pivotal tool for accelerating materials development. High-entropy alloys are particularly intriguing candidates for exemplifying the potency of machine learning due to their superior mechanical properties, vast compositional space, and intricate chemical interactions. This review examines the general process of developing machine learning models. The advances and new algorithms of machine learning in the field of high-entropy alloys are presented in each part of the process. These advances are based on both improvements in computer algorithms and physical representations that focus on the unique ordering properties of high-entropy alloys. We also show the results of generative models, data augmentation, and transfer learning in high-entropy alloys and conclude with a summary of the challenges still faced in machine learning high-entropy alloys today. Full article
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11 pages, 3867 KiB  
Article
Influence of Nb Content on Structure and Functional Properties of Novel Multicomponent Nb–Ni–Ti–Zr–Co Alloy for Hydrogen Separation Membrane Application
by Egor B. Kashkarov, Leonid A. Svyatkin, Kirill S. Gusev, Sergey S. Ognev, Maksim Koptsev, Daria V. Terenteva, Tatyana L. Murashkina and Andrey M. Lider
Hydrogen 2024, 5(4), 929-939; https://doi.org/10.3390/hydrogen5040049 - 21 Nov 2024
Viewed by 1994
Abstract
Novel multicomponent Nb–Ni–Ti–Zr–Co alloys with 20–55 at.% Nb were synthesized from metal powders by arc melting. The resulting alloys consist primarily of Nb-rich and eutectic body-centered (BCC) phases. The content of the eutectic BCC phase is highest for an equimolar composition, while the [...] Read more.
Novel multicomponent Nb–Ni–Ti–Zr–Co alloys with 20–55 at.% Nb were synthesized from metal powders by arc melting. The resulting alloys consist primarily of Nb-rich and eutectic body-centered (BCC) phases. The content of the eutectic BCC phase is highest for an equimolar composition, while the content of the Nb-rich BCC phase increases with Nb content in the alloy. The content of secondary phases is the highest for the alloy with 32 at.% Nb. According to ab initio calculations, hydrogen occupies tetrahedral interstitial sites in the Nb-rich phase and octahedral sites in the eutectic BCC phase. For different Nb concentrations, hydrogen-binding energies were calculated. An increase in the Nb-rich phase leads to softening of multicomponent alloys. The alloys with 20 and 32 at.% Nb demonstrate high hydrogen permeability (1.05 and 0.96 × 10−8 molH2m−1s−1Pa−0.5, respectively) at 400 °C, making them promising for hydrogen purification membrane application. Multicomponent alloys with a high Nb content (55 at.%) have low resistance to hydrogen embrittlement. Full article
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13 pages, 57264 KiB  
Article
Non-Equal Contributions of Different Elements and Atomic Bonds to the Strength and Deformability of a Multicomponent Metallic Glass Zr47Cu46Al7
by Donghua Xu, Olivia Gordon, Muyang Ye, Lei Chen, Tittaya Thaiyanurak and Zhengming Wang
Molecules 2024, 29(21), 5005; https://doi.org/10.3390/molecules29215005 - 22 Oct 2024
Cited by 1 | Viewed by 1581
Abstract
Multicomponent metallic glasses (MGs) are a fascinating class of advanced alloys known for their exceptional properties such as limit-approaching strength, high hardness and corrosion resistance, and near-net-shape castability. One important question regarding these materials that remains unanswered is how the different elements and [...] Read more.
Multicomponent metallic glasses (MGs) are a fascinating class of advanced alloys known for their exceptional properties such as limit-approaching strength, high hardness and corrosion resistance, and near-net-shape castability. One important question regarding these materials that remains unanswered is how the different elements and atomic bonds within them control their strength and deformability. Here, we present a detailed visual and statistical analysis of the behaviors of various elements and atomic bonds in the Zr47Cu46Al7 (at%) MG during a uniaxial tensile test (in the z-direction) simulated using molecular dynamics. Specifically, we investigate the identities of atoms undergoing significant shear strain, and the averaged bond lengths, projected z-lengths, and z-angles (angles with respect to the z-direction) of all the atomic bonds as functions of increasing strain. We show that, prior to yielding, the Zr element and the intermediate (Zr-Zr, Cu-Al) and stronger (Zr-Al, Zr-Cu) bonds dominate the elastic deformation and strength, while the Cu and Al elements and the weaker Al-Al and Cu-Cu bonds contribute more to the highly localized shear transformation. The significant reconstruction, as signified by the cessation of bond-length increment and bond-angle decrement, of the intermediate and the stronger bonds triggers yielding of the material. After yielding, all the elements and bonds participate in the plastic deformation while the stronger bonds contribute more to the residual strength and the ultimate (fracture) strain. The results provide new insights into the atomic mechanisms underlying the mechanical behavior of multicomponent MGs, and may assist in the future design of MG compositions towards better combination of strength and deformability. Full article
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25 pages, 3036 KiB  
Review
Recent Advances in High-Entropy Ceramics: Synthesis Methods, Properties, and Emerging Applications
by Piyush Chandra Verma, Sunil Kumar Tiwari, Ashish Saurabh and Abhinav Manoj
Ceramics 2024, 7(4), 1365-1389; https://doi.org/10.3390/ceramics7040089 - 30 Sep 2024
Viewed by 1882
Abstract
High-entropy ceramics (HECs) represent an emerging class of materials composed of at least five different cations or anions in near-equiatomic proportions, garnering significant attention due to their extraordinary functional and structural properties. While multi-component ceramics have played a crucial role for many years, [...] Read more.
High-entropy ceramics (HECs) represent an emerging class of materials composed of at least five different cations or anions in near-equiatomic proportions, garnering significant attention due to their extraordinary functional and structural properties. While multi-component ceramics have played a crucial role for many years, the concept of high-entropy materials was first introduced eighteen years ago with the synthesis of high-entropy alloys, and the first high-entropy nitride films were reported in 2014. These newly developed materials exhibit superior properties over traditional ceramics, such as enhanced thermal stability, hardness, and chemical resistance, making them suitable for a wide range of applications. High-entropy carbides, borides, oxides, oxi-carbides, oxi-borides, and other systems fall within the HEC category, typically occupying unique positions within phase diagrams that lead to novel properties. HECs are particularly well suited for high-temperature coatings, for tribological applications where low thermal conductivity and similar heat coefficients are critical, as well as for energy storage and dielectric uses. Computational tools like CALPHAD streamline the element selection process for designing HECs, while innovative, energy-efficient synthesis methods are being explored for producing dense specimens. This paper provides an in-depth analysis of the current state of the compositional design, the fabrication techniques, and the diverse applications of HECs, emphasizing their transformative potential in various industrial domains. Full article
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15 pages, 22057 KiB  
Article
Effect of Phase Structure on the Viscoelasticity and Mechanical Properties of Isotactic Polypropylene Multicomponents Polymerized with Non-Conjugated α,ω-Diene
by Songmei Zhao, Jin-Yong Dong, Yawei Qin, Chuanzhuang Zhao, Yuan Yu and Weili Liu
Polymers 2024, 16(19), 2715; https://doi.org/10.3390/polym16192715 - 25 Sep 2024
Viewed by 746
Abstract
Increasing of rubber content in isotactic polypropylene/ethylene–propylene rubber (iPP/EPR) alloys can extend the applications of this kind of polyolefin. The EPR content and phase structure of isotactic polypropylene multicomponents have great effect on the viscoelasticity and mechanical properties. iPP/EPR in-reactor alloys with a [...] Read more.
Increasing of rubber content in isotactic polypropylene/ethylene–propylene rubber (iPP/EPR) alloys can extend the applications of this kind of polyolefin. The EPR content and phase structure of isotactic polypropylene multicomponents have great effect on the viscoelasticity and mechanical properties. iPP/EPR in-reactor alloys with a high EPR content were obtained through the in situ crosslinking of EPR chains with α,ω-diene. The morphological observation results indicate that the crosslinked iPP/EPR in-reactor alloys have a good spherical shape with clean and rough external surfaces. The high EPR content is finely dispersed in the crosslinked iPP/EPR alloys in areas ranging in size from tens of nanometers to several micrometers, which implies that a sufficient crosslinking degree of EPR chains can effectively prevent their aggregation and restrict macro-phase separation. The rheological results show a clear plateau in the terminal region, which reveals an entangled polymer chain network in the crosslinked iPP/EPR alloys. The well-dispersed EPR and the bi-continuous phase structure have a great effect on the mechanical properties of the isotactic polypropylene multicomponent which were assessed. Full article
(This article belongs to the Section Polymer Chemistry)
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11 pages, 2854 KiB  
Article
Study on the Alloying Elements Competition Mechanism of Nix1Crx2Cox3Al15Ti10 Alloys Based on High-Throughput Computation and Numerical Analysis
by Yu Liu, Lijun Wang, Wenjie He and Yunpeng Liu
Coatings 2024, 14(9), 1138; https://doi.org/10.3390/coatings14091138 - 4 Sep 2024
Viewed by 1013
Abstract
Previous studies on the physical properties of alloy materials often focus solely on analyzing the impact of individual alloying element content, overlooking the underlying mechanism behind the synergistic action of multiple alloying elements. Therefore, in this study, we propose a combination of high-throughput [...] Read more.
Previous studies on the physical properties of alloy materials often focus solely on analyzing the impact of individual alloying element content, overlooking the underlying mechanism behind the synergistic action of multiple alloying elements. Therefore, in this study, we propose a combination of high-throughput computation and numerical analysis to conduct single-element (SE) analysis and multi-element (ME) analysis on the internal relationships between alloying element content and physical properties for the multi-component Nix1Crx2Cox3Al15Ti10 alloys, aiming to elucidate the competition mechanism among the Ni, Cr, and Co elements. The analysis of SE reveals how the physical properties of alloys are affected by the content of each individual alloying element, and the ME analysis further unveils the underlying competitive relationships among multiple alloying elements. The order of competitive intensity for the formation of lattice constant is Cr > Co > Ni, whereas for the formation of elastic constants and elastic moduli it is Ni > Co > Cr. At the same time, there are contradictory conclusions, such as the SE analysis showing that the Ni content is positively correlated with elastic constant C11, while the ME analysis demonstrates that the Ni element produces a negative competitive direction. This outcome arises from the omission of considering the combined impacts of various alloying elements in SE analysis. Therefore, the ME analysis can compensate for the limitations of SE analysis, and the integration of these two analytical methods is more conducive to elucidating the competition mechanism among various alloying elements in shaping the physical properties of alloys, which provides a promising avenue for theoretical research. Full article
(This article belongs to the Special Issue Microstructure, Mechanical and Tribological Properties of Alloys)
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22 pages, 8022 KiB  
Article
Study of a New Novel HVOAF Coating Based on a New Multicomponent Al80Mg10Si5Cu5 Alloy
by Ester Villanueva, Iban Vicario, Carlos Vaquero, Joseba Albizuri, Maria Teresa Guraya, Nerea Burgos and Iñaki Hurtado
Coatings 2024, 14(9), 1135; https://doi.org/10.3390/coatings14091135 - 4 Sep 2024
Viewed by 1012
Abstract
This paper presents and demonstrates the development of a new lightweight coating for aluminum alloy from a novel multicomponent alloy based on the AlSiMgCu system. The coating was applied using a newly designed approach that combined high velocity oxy-fuel (HVOF) and plasma spraying [...] Read more.
This paper presents and demonstrates the development of a new lightweight coating for aluminum alloy from a novel multicomponent alloy based on the AlSiMgCu system. The coating was applied using a newly designed approach that combined high velocity oxy-fuel (HVOF) and plasma spraying processes. This hybrid technique enables the deposition of coatings with enhanced performance characteristics. The optical microscopy (OM) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM + EDS) revealed a strong adhesion and compaction between the multicomponent coating and the A6061 substrate. The new coating improved hardness by 50% and increased electrical conductivity by approximately 3.3 times compared to the as-cast alloy. Corrosion tests showed a lower corrosion rate, comparable to thermally treated A6061 alloy. Tribological tests indicated over 20% reduction in friction and over 50% reduction in wear rate. This suggests that multicomponent aluminum coatings could improve automotive and parts in contact with hydrogen by enhancing hydrogen fragilization resistance, corrosion resistance, electrical conductivity, and wear properties, with further optimization of thermal spraying potentially boosting performance even further. Full article
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18 pages, 6032 KiB  
Article
Evaluating a Fe-Based Metallic Glass Powder as a Novel Negative Electrode Material for Applications in Ni-MH Batteries
by Oscar Sotelo, John Henao, Carlos Poblano, Bernardo Campillo, Erick Castañeda, Néstor Flores, Arturo Molina and Horacio Martínez
Batteries 2024, 10(9), 312; https://doi.org/10.3390/batteries10090312 - 1 Sep 2024
Viewed by 1209
Abstract
Metallic glasses (MGs) are a type of multicomponent non-crystalline metallic alloys obtained by rapid cooling, which possess several physical, mechanical, and chemical advantages against their crystalline counterparts. In this work, an Fe-based MG is explored as a hydrogen storage material, especially, due to [...] Read more.
Metallic glasses (MGs) are a type of multicomponent non-crystalline metallic alloys obtained by rapid cooling, which possess several physical, mechanical, and chemical advantages against their crystalline counterparts. In this work, an Fe-based MG is explored as a hydrogen storage material, especially, due to the evidence in previous studies about the capability of some amorphous metals to store hydrogen. The evaluation of an Fe-based MG as a novel negative electrode material for nickel/metal hydride (Ni-MH) batteries was carried out through cyclic voltammetry and galvanostatic charge–discharge tests. A conventional LaNi5 electrode was also evaluated for comparative purposes. The electrochemical results obtained by cyclic voltammetry showed the formation of three peaks, which are associated with the formation of Fe oxides/oxyhydroxides and hydroxides. Cycling charge/discharge tests revealed activation of the MG electrode. The highest discharge capacity value was 173.88 mAh/g, but a decay in its capacity was observed after 25 cycles, contrary to the LaNi5, which presents an increment of the discharge capacity for all the current density values evaluated, reached its value maximum at 183 mAh/g. Characterization analyses performed by X-ray diffraction, Scanning Electron Microscopy and Raman Spectroscopy revealed the presence of corrosion products and porosity on the surface of the Fe-based MG electrodes. Overall, the Fe-based MG composition is potentially able to work as a negative electrode material, but degradation and little information about storage mechanisms means that it requires further investigation. Full article
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11 pages, 2613 KiB  
Article
Manufacturing of Ni-Co-Fe-Cr-Al-Ti High-Entropy Alloy Using Directed Energy Deposition and Evaluation of Its Microstructure, Tensile Strength, and Microhardness
by Ho-In Jeong, Jae-Hyun Kim and Choon-Man Lee
Materials 2024, 17(17), 4297; https://doi.org/10.3390/ma17174297 - 30 Aug 2024
Cited by 1 | Viewed by 924
Abstract
High-entropy alloys (HEAs) have drawn significant attention due to their unique design and superior mechanical properties. Comprising 5–35 at% of five or more elements with similar atomic radii, HEAs exhibit high configurational entropy, resulting in single-phase solid solutions rather than intermetallic compounds. Additive [...] Read more.
High-entropy alloys (HEAs) have drawn significant attention due to their unique design and superior mechanical properties. Comprising 5–35 at% of five or more elements with similar atomic radii, HEAs exhibit high configurational entropy, resulting in single-phase solid solutions rather than intermetallic compounds. Additive manufacturing (AM), particularly direct energy deposition (DED), is effective for producing HEAs due to its rapid cooling rates, which ensure uniform microstructures and minimize defects. These alloys typically form face-centered cubic (FCC) or body-centered cubic (BCC) structures, contributing to their exceptional strength, hardness, and mechanical performance across various temperatures. However, FCC-structured HEAs often have low yield strengths, posing a challenge for structural applications. In this study, a Ni-Co-Fe-Cr-Al-Ti HEA was manufactured using the DED method. This study proposes that the addition of aluminum and titanium creates a γ + γ′ phase structure within a multicomponent FCC-HEA matrix, enhancing the thermal stability and coarsening the resistance and strength. The γ′ phase with an ordered FCC structure significantly improves the mechanical properties. Analysis confirmed the presence of the γ + γ′ structure and demonstrated the alloy’s high tensile strength and microhardness. This approach underscores the potential of AM techniques in advancing HEA production for high-performance applications. Full article
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26 pages, 19322 KiB  
Article
Role of Quenching Temperature Selection in the Improvement of the Abrasive (Al2O3) Wear Resistance of Hybrid Multi-Component Cast Irons
by Yuliia Chabak, Vasily Efremenko, Ivan Petryshynets, Michail Golinskyi, Kazumichi Shimizu, Bohdan Efremenko, Vadim Kudin and Alexander Azarkhov
Materials 2024, 17(15), 3742; https://doi.org/10.3390/ma17153742 - 28 Jul 2024
Cited by 1 | Viewed by 1738
Abstract
In this paper, enhancing the tribological characteristics of novel cast metallic materials—hybrid multi-component cast irons—by applying a strengthening heat treatment is described. The experimental materials were the cast alloys of a nominal composition (5 wt.% W, 5 wt.% Mo, 5 wt.% V, 10 [...] Read more.
In this paper, enhancing the tribological characteristics of novel cast metallic materials—hybrid multi-component cast irons—by applying a strengthening heat treatment is described. The experimental materials were the cast alloys of a nominal composition (5 wt.% W, 5 wt.% Mo, 5 wt.% V, 10 wt.% Cr, 2.5 wt.% Ti, Fe is a balance) supplemented with 0.3–1.1 wt.% C and 1.5–2.5 wt.% B (total of nine alloys). The heat treatment was oil-quenching followed by 200 °C tempering. The quench temperature (QT) varied in the range of 900–1200 °C, with a step of 50 °C (with a 2-h holding at QT). The correlation of the QT with microstructure and properties was estimated using microstructure/worn surface characterization, differential scanning calorimetry, hardness measurement, and three-body-abrasive wear testing (using Al2O3 particles). The as-cast alloys had a multi-phase structure consisting of primary and/or eutectic borocarbide M2(B,C)5, carboborides M(C,B), M7(C,B)3, M3(C,B), and the matrix (ferrite, martensite, pearlite/bainite) in different combinations and volume fractions. Generally, the increase in the quenching temperature resulted in a gradual increase in hardness (maximally to 66–67 HRC) and a decrease in the wear rate in most alloys. This was due to the change in the phase-structure state of the alloys under quenching, namely, the secondary carboboride precipitation, and replacing ferrite and pearlite/bainite with martensite. The wear rate was found to be inversely proportional to bulk hardness. The maximum wear resistance was attributed to QT = 1150–1200 °C, when the wear rate of the alloys was lowered by three to six times as compared to the as-cast state. With the QT increase, the difference in the wear rate of the alloys decreased by three times. The highest abrasive resistance was attributed to the alloys with 1.1 wt.% C, which had a 2.36–3.20 times lower wear rate as compared with that of the reference alloy (13 wt.% Cr cast iron, hardness of 66 HRC). The effects of carbon and boron on hardness and wear behavior are analyzed using the regression models developed according to the factorial design procedure. The wear mechanisms are discussed based on worn surface characterization. Full article
(This article belongs to the Special Issue Achievements in Foundry Materials and Technologies)
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14 pages, 794 KiB  
Article
Removal and Recovery of Europium with a New Functionalized Mesoporous Silica-Based Adsorbent
by Charith Fonseka, Seongchul Ryu, Jaya Kandasamy, Harsha Ratnaweera and Saravanamuthu Vigneswaran
Sustainability 2024, 16(13), 5636; https://doi.org/10.3390/su16135636 - 30 Jun 2024
Viewed by 1378
Abstract
The discharge of acid mine drainage (AMD), characterized by a high concentration of rare earth elements (REEs), poses a significant threat to the health of ecosystems surrounding water sources. The global market demand for REEs has experienced a notable surge in the past [...] Read more.
The discharge of acid mine drainage (AMD), characterized by a high concentration of rare earth elements (REEs), poses a significant threat to the health of ecosystems surrounding water sources. The global market demand for REEs has experienced a notable surge in the past decade. Consequently, recovering REEs from waste streams like AMD not only benefits the environment but also offers financial advantages. Europium (Eu), the rarest among REEs, constitutes only 0.1% w/w in monazite and bastnaesite ores. Eu is extensively used in the production of phosphors, alloys, and additives, and is a critical raw material for developing smart devices, ranging from high-resolution color screens to circuitry. Traditional adsorbents typically exhibit limited selectivity towards REE recovery. Mesoporous silica materials, such as SBA15 (Santa Barbara Amorphous-15), provide excellent tunability and modification capabilities, making them an attractive and cost-effective alternative. This research focused on two key aspects: (i) evaluating the dynamic adsorption column performance of granulated SBA15–NH–PMIDA to preferentially recover Eu, and (ii) employing mathematical modeling to optimize the dynamic adsorption column’s operating conditions for real-world applications with a minimal number of experimental runs. Granulated SBA15–NH–PMIDA was chosen as the adsorbent due to its high adsorptive capacity and selectivity in capturing Eu. The study revealed that granulated SBA15–NH–PMIDA exhibited 57.47 mg/g adsorption capacity and an 81% selectivity towards Eu. Furthermore, SBA15–NH–PMIDA demonstrated preferential adsorption toward Eu in complex multi-component solutions, such as AMD. The linear driven force approximation model (LDFAM) provided an acceptable simulation (R2 > 0.91) under varying operational conditions. This validates the use of the model as a tool to effectively simulate and optimize column experiments that used granulated SBA15–NH–PMIDA to recover Eu. Full article
(This article belongs to the Section Environmental Sustainability and Applications)
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13 pages, 7294 KiB  
Article
Effect of Annealing and Double Aging on the Microstructure and Mechanical Properties of Hot-Rolled Al17Cr10Fe36Ni36Mo1 Alloy
by Yunji Qiu, Xinbo Shi, Xiaoming Liu, Zhihua Chen, Jianbin Wang, Xin Liu, Xiaoyu Bai, Feng He and Zhijun Wang
Metals 2024, 14(6), 726; https://doi.org/10.3390/met14060726 - 19 Jun 2024
Viewed by 1018
Abstract
AlCrFeNi multi-component alloys with excellent mechanical properties have been designed and extensively investigated in recent years. The massive fabrication of sheets will be an effective way for industrial application, where hot rolling is the inevitable process. After hot rolling, the mechanical properties could [...] Read more.
AlCrFeNi multi-component alloys with excellent mechanical properties have been designed and extensively investigated in recent years. The massive fabrication of sheets will be an effective way for industrial application, where hot rolling is the inevitable process. After hot rolling, the mechanical properties could be further tailored. In this study, the effects of heat treatments on a dual-phase Al17Cr10Fe36Ni36Mo1 hot-rolled plate were systematically investigated, including: (i) annealing (700 °C, 850 °C, 1000 °C and 1150 °C for 1 h, respectively), (ii) solution and single aging (1150 °C for 1 h and 700 °C for 4 h), (iii) solution and double aging (1150 °C for 1 h, 700 °C for 4 h and 650 °C for 1 h). The B2 precipitates with varied morphologies were observed in the FCC matrix of the hot-rolled alloy after a heat treatment range from 700 °C to 1000 °C for 1 h, and the BCC particles in the B2 matrix were dissolved when the heat treatment temperature was higher than 1000 °C. The hot-rolled alloy heat treated at 700 °C for 1 h had the highest yield strength, and the hot-rolled alloy treated at 1150 °C for 1 h showed the lowest yield strength. After a solution at 1150 °C for 1 h, aging at 700 °C for 4 h and 650 °C for 1 h, the L12 phase and BCC particles were precipitated in the FCC and B2 matrices, and B2 nanoprecipitates were observed around the FCC grain boundaries. The solution and double aging alloy exhibit the tensile strength of 1365.7 ± 9.5 MPa, a fracture elongation of 14.2 ± 1.5% at 20 °C, a tensile strength of 641.4 ± 6.0 MPa, and a fracture elongation of 16.9 ± 1.0% at 700 °C, showing great potential for application. Full article
(This article belongs to the Special Issue Design, Processing and Characterization of Metals and Alloys)
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14 pages, 7311 KiB  
Article
Synthesis of AgCoCuFeNi High Entropy Alloy Nanoparticles by Hydrogen Reduction-Assisted Ultrasonic Spray Pyrolysis
by Srecko Stopic, Ayadjenou Humphrey Hounsinou, Tatjana Volkov Husovic, Elif Emil-Kaya and Bernd Friedrich
ChemEngineering 2024, 8(3), 63; https://doi.org/10.3390/chemengineering8030063 - 18 Jun 2024
Viewed by 1518
Abstract
Because of their high mixing entropies, multi-component alloys can exhibit enhanced catalytic activity compared to traditional catalysts in various chemical reactions, including hydrogenation, oxidation, and reduction processes. In this work, new AgCoCuFeNi high entropy alloy nanoparticles were synthesized by the hydrogen reduction-assisted ultrasonic [...] Read more.
Because of their high mixing entropies, multi-component alloys can exhibit enhanced catalytic activity compared to traditional catalysts in various chemical reactions, including hydrogenation, oxidation, and reduction processes. In this work, new AgCoCuFeNi high entropy alloy nanoparticles were synthesized by the hydrogen reduction-assisted ultrasonic spray pyrolysis method. The aim was to investigate the effects of processing parameters (reaction temperature, precursor solution concentration, and residence time) on the microstructure, composition, and crystallinity of the high entropy alloy nanoparticles. The characterization was performed with scanning electron microscope, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The syntheses performed at 600, 700, 800, and 900 °C, resulted in smaller and smoother spherical particles with a near-equiatomic elemental composition as the temperature increased to 900 °C. With 0.25, 0.1, and 0.05 M precursor solutions, narrower size distribution and uniform AgCoCuFeNi nanoparticles were produced by reducing the solution concentration to 0.05 M. A near-equiatomic elemental composition was only obtained at 0.25 and 0.05 M. Increasing the residence time from 5.3 to 23.8 s resulted in an unclear particle microstructure. None of the five metal elements were formed in the large tubular reactor. X-ray diffraction revealed that various crystal phase structures were obtained in the synthesized AgCoCuFeNi particles. Full article
(This article belongs to the Special Issue Process Intensification for Chemical Engineering and Processing)
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