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Search Results (1,395)

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Keywords = Al-4Fe alloy

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27 pages, 9202 KiB  
Article
Enhancement in Corrosion and Wear Resistance of FeCoNiCrAl High-Entropy Alloy Coating Through Dual Heat Treatment with 3:1 N2/H2 Atmosphere
by Miqi Wang, Buxiang Li, Chi He, Jing Sun, Liyuan Li, Aihui Liu and Fang Shi
Coatings 2025, 15(9), 986; https://doi.org/10.3390/coatings15090986 - 23 Aug 2025
Abstract
This work investigated the effect of high-nitrogen/low-hydrogen mixed atmosphere heat treatment on the electrochemical corrosion and wear resistance of plasma-sprayed FeCoNiCrAl high-entropy alloy (HEA) coatings. The HEA coatings were sequentially prepared through annealing at 400, 600, and 800 °C for 6 h. The [...] Read more.
This work investigated the effect of high-nitrogen/low-hydrogen mixed atmosphere heat treatment on the electrochemical corrosion and wear resistance of plasma-sprayed FeCoNiCrAl high-entropy alloy (HEA) coatings. The HEA coatings were sequentially prepared through annealing at 400, 600, and 800 °C for 6 h. The heat treatment method was conducted in a vacuum tube furnace under 0.1 MPa total pressure, with gas flow rates set to 300 sccm N2 and 100 sccm H2. The XRD results indicated that the as-deposited coating exhibited α-Fe (BBC) and Al0.9Ni4.22 (FCC) phases, with an Fe0.64N0.36 nitride phase generated after 800 °C annealing. The electrochemical measurements suggested that an exceptional corrosion performance with higher thicknesses of passive film and double-layer capacitance can be detected based on the point defect model (PDM) and effective capacitance model. Wear tests revealed that the friction coefficient at 800 °C decreased by 3.84% compared to that in the as-sprayed state due to the formation of a dense nitride layer. Molecular orbital theory pointed out that the formation of bonding molecular orbitals, resulting from the overlap of valence electron orbitals of different atomic species in the HEA coating system, stabilized the structure by promoting atomic interactions. The wear mechanism associated with stress redistribution and energy balance from compositional synergy is proposed in this work. Full article
(This article belongs to the Section Corrosion, Wear and Erosion)
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16 pages, 3804 KiB  
Article
Design and Optimization of Trimetallic NiCoFe Catalysts for Efficient Dry Reforming of Methane
by Ghazaleh Khoshroo, Anastasiia Efremova, Haythem S. Basheer, Imre Szenti, Masoud Shirzadi Ahou Dashti, Ákos Szamosvölgyi, András Erdőhelyi, András Sápi, Ákos Kukovecz and Zoltán Kónya
Catalysts 2025, 15(8), 797; https://doi.org/10.3390/catal15080797 - 21 Aug 2025
Viewed by 123
Abstract
Dry reforming of methane is an advantageous technique to produce syngas by using greenhouse gases like CO2 and CH4. This study investigated the stability, catalytic effectiveness, and physicochemical characteristics of mono- and trimetallic catalysts based on Ni and supported on [...] Read more.
Dry reforming of methane is an advantageous technique to produce syngas by using greenhouse gases like CO2 and CH4. This study investigated the stability, catalytic effectiveness, and physicochemical characteristics of mono- and trimetallic catalysts based on Ni and supported on γ-Al2O3. Adding Co and Fe has been found to modify the structure and surface through the characterizations, including XRD, SEM, TEM, BET, H2-TPR, and XPS methods. Compared to the monometallic Ni catalyst, the trimetallic catalysts exhibited improved alloy formation, reduced particle size, increased metal dispersion, and enhanced surface area and pore structures. The 10% Ni, 2.5% Co, and 2.5% Fe-Al2O3 catalyst exhibits higher CH4 conversion, surpassing 75%, and also CO2 conversion around 85% at 700 °C, compared to 15% Ni-Al2O3, which showed CH4 conversion of about 65% and CO2 conversion of 70%. It also showed comparatively good stability in 24 h testing performed at 700 °C. According to the findings of the research on trimetallic catalysts, their capacity to improve dry reforming of methane (DRM) performance may be attributed to increased stability, which is a crucial challenge in the production of sustainable syngas, as well as higher activity and lower deactivation. Full article
(This article belongs to the Section Catalysis for Sustainable Energy)
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19 pages, 8293 KiB  
Article
Influence of Mn in Balancing the Tensile and Electrical Conductivity Properties of Al-Mg-Si Alloy
by Jiaxing He, Jiangbo Wang, Jian Ding, Yao Wang and Wenshu Qi
Metals 2025, 15(8), 923; https://doi.org/10.3390/met15080923 - 21 Aug 2025
Viewed by 72
Abstract
This study investigated the influence of manganese (Mn) on microstructure evolution and property optimization in Al-0.6Mg-0.58Si-0.24Fe-xMn alloys under both as-cast and hot-extruded conditions. The balance mechanisms of Mn in tensile properties and electrical conductivity of Al-Mg-Si alloy were elucidated, achieving synergistic optimization of [...] Read more.
This study investigated the influence of manganese (Mn) on microstructure evolution and property optimization in Al-0.6Mg-0.58Si-0.24Fe-xMn alloys under both as-cast and hot-extruded conditions. The balance mechanisms of Mn in tensile properties and electrical conductivity of Al-Mg-Si alloy were elucidated, achieving synergistic optimization of strength-elongation-conductivity. For non-equilibrium solidified as-cast alloys, JMatPro simulations coupled with Fe-rich phase size statistics reveal an inhibitory effect of Mn on β-Al5FeSi phase formation. Matthiessen’s rule analysis quantitatively clarifies Mn-induced resistivity variations through solid solution and phase morphology modifications. In hot-extruded alloys, TEM characterization was used to analyze the structure of Al-Fe-Mn-Si quaternary compounds and clarify their combined effects with typical Mg2Si phases on dislocation and subgrain configurations. The as-cast Al-0.6Mg-0.58Si-0.24Fe-0.18Mn alloy demonstrate comprehensive properties with ultimate tensile strength, elongation and electrical conductivity. The contributions of dislocations, grain boundaries and precipitates to resistivity are relatively minor, so the main source of resistivity in hot-extruded alloys is still Mn. The hot-extruded alloy containing 0.18 wt.% Mn still has better properties, with a tensile strength of 176 MPa, elongation of 24% and conductivity of 48.07 %IACS. Full article
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16 pages, 4468 KiB  
Article
Enhancing Fatigue Lifetime of Secondary AlZn10Si8Mg Alloys Through Shot Peening: Influence of Iron Content and Surface Defects
by Denisa Straková, Zuzana Šurdová, Eva Tillová, Lenka Kuchariková, Martin Mikolajčík, Denisa Závodská and Mario Guagliano
Materials 2025, 18(16), 3901; https://doi.org/10.3390/ma18163901 - 20 Aug 2025
Viewed by 221
Abstract
The rising demand for aluminium and environmental concerns highlight the need for a circular economy using recycled alloys. This study examines the effect of shot peening on the high-cycle fatigue life of secondary AlZn10Si8Mg alloys with different iron contents: Alloy A (0.14 wt.% [...] Read more.
The rising demand for aluminium and environmental concerns highlight the need for a circular economy using recycled alloys. This study examines the effect of shot peening on the high-cycle fatigue life of secondary AlZn10Si8Mg alloys with different iron contents: Alloy A (0.14 wt.% Fe) and Alloy B (0.56 wt.% Fe). Although both alloys showed similar tensile properties, Alloy B had higher porosity and finer β-Al5FeSi intermetallics. Shot peening was applied at 100% and 1000% coverage to evaluate changes in surface roughness, porosity, residual stresses, and fatigue performance. The treatment significantly reduced surface-connected porosity via plastic deformation, enhancing fatigue life despite increased roughness. Fatigue tests showed a 21% increase in fatigue limit for Alloy A and a 6% gain for Alloy B at higher coverage. Fractographic analysis revealed that 95% of fatigue cracks initiated at surface pores. Residual stress measurements confirmed compressive stresses were limited to the near-surface layer, with minimal influence on subsurface crack propagation. Overall, shot peening proves to be an effective method for improving fatigue resistance in recycled aluminium alloys, even in alloys with elevated iron content, reinforcing their potential for structural applications under cyclic loading. Full article
(This article belongs to the Special Issue Fatigue, Damage and Fracture of Alloys)
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16 pages, 8293 KiB  
Article
Thermodynamic Modeling of Microstructural Design of Lightweight Ferritic Steels
by Tamiru Hailu Kori, Adam Skowronek, Jarosław Opara, Ana Paula Domingos Cardoso and Adam Grajcar
Metals 2025, 15(8), 912; https://doi.org/10.3390/met15080912 - 16 Aug 2025
Viewed by 250
Abstract
Ferritic lightweight steels are an emerging class of low-density steels (LDSs) with promising mechanical properties. The study aimed to develop two ferritic lightweight steels with different Mn concentrations. Al was incorporated to achieve the lightweighting effect due to its relatively low atomic mass [...] Read more.
Ferritic lightweight steels are an emerging class of low-density steels (LDSs) with promising mechanical properties. The study aimed to develop two ferritic lightweight steels with different Mn concentrations. Al was incorporated to achieve the lightweighting effect due to its relatively low atomic mass of substitutional solutions. The C concentration was kept at a minimum level to avoid the precipitation of carbides and the Mn addition was intended to increase solid solution strengthening. Thermodynamic calculations (Thermo-Calc) were employed to design the composition, analyze the phase constituents, and predict the phase transformation behavior. Microstructural investigation and hardness tests were conducted to experimentally verify the calculations. Both produced alloys exhibited a fully ferritic microstructure. Compared to industrially produced DP980 steel, a density reduction of about 7.2% and 8.3% was attained for the Fe-0.04C-5.5Al-1.6Mn-0.075Nb and Fe-0.04C-5.6Al-5.5Mn-0.08Nb steels, respectively. The steel with the higher Mn content showed increased hardness attributed to its solution strengthening effect. An increase in the hardness values was also measured with the progress in hot-rolling thickness reductions for both alloys. The alloying elements influenced the microstructural characteristics, phase transformation behavior, density, and hardness of the newly designed lightweight steels. Full article
(This article belongs to the Special Issue Thermodynamic Modeling of Phase Equilibrium in Metallic Materials)
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18 pages, 768 KiB  
Article
Uncertainty-Aware Design of High-Entropy Alloys via Ensemble Thermodynamic Modeling and Search Space Pruning
by Roman Dębski, Władysław Gąsior, Wojciech Gierlotka and Adam Dębski
Appl. Sci. 2025, 15(16), 8991; https://doi.org/10.3390/app15168991 - 14 Aug 2025
Viewed by 272
Abstract
The discovery and design of high-entropy alloys (HEAs) faces significant challenges due to the vast combinatorial design space and uncertainties in thermodynamic data. This work presents a modular, uncertainty-aware computational framework with the primary objective of accelerating the discovery of solid-solution HEA candidates. [...] Read more.
The discovery and design of high-entropy alloys (HEAs) faces significant challenges due to the vast combinatorial design space and uncertainties in thermodynamic data. This work presents a modular, uncertainty-aware computational framework with the primary objective of accelerating the discovery of solid-solution HEA candidates. The proposed pipeline integrates ensemble thermodynamic modeling, Monte Carlo-based estimation, and a structured three-phase pruning algorithm for efficient search space reduction. Key quantitative results are achieved in two main areas. First, for binary alloy thermodynamics, a Bayesian Neural Network (BNN) ensemble trained on domain-informed features predicts mixing enthalpies with high accuracy, yielding a mean absolute error (MAE) of 0.48 kJ/mol—substantially outperforming the classical Miedema model (MAE = 4.27 kJ/mol). These probabilistic predictions are propagated through Monte Carlo sampling to estimate multi-component thermodynamic descriptors, including ΔHmix and the Ω parameter, while capturing predictive uncertainty. Second, in a case study on the Al-Cu-Fe-Ni-Ti system, the framework reduces a 2.4 million (2.4 M) candidate pool to just 91 high-confidence compositions. Final selection is guided by an uncertainty-aware viability metric, P(HEA), and supported by interpretable radar plot visualizations for multi-objective assessment. The results demonstrate the framework’s ability to combine physical priors, probabilistic modeling, and design heuristics into a data-efficient and interpretable pipeline for materials discovery. This establishes a foundation for future HEA optimization, dataset refinement, and adaptive experimental design under uncertainty. Full article
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19 pages, 4847 KiB  
Article
Promoted Mechanical Properties and LBE Corrosion Resistance of FeCrAlTi-ODS Coatings Deposited by Magnetron Sputtering
by Hongtao Huang, Jinfeng Li, Bao Zhang, Jianwei Zhang, Zhigang Li and Hongtao Zhao
Coatings 2025, 15(8), 942; https://doi.org/10.3390/coatings15080942 - 12 Aug 2025
Viewed by 339
Abstract
A key issue with lead-cooled fast reactors is the corrosion vulnerability of fuel cladding and core components, which will endanger the structural materials’ integrity and the operational safety of the reactor system. The FeCrAlTi-ODS (Oxide Dispersion Strengthened) alloy coatings are prepared by the [...] Read more.
A key issue with lead-cooled fast reactors is the corrosion vulnerability of fuel cladding and core components, which will endanger the structural materials’ integrity and the operational safety of the reactor system. The FeCrAlTi-ODS (Oxide Dispersion Strengthened) alloy coatings are prepared by the Magnetron Sputtering technique under different bias voltages to shield structural elements in lead-cooled fast reactors from corrosion caused by lead-bismuth eutectic (LBE). A comprehensive study examines their mechanical attributes and resistance to LBE-induced corrosion. Compared to the bare substrate of austenitic 316L steel, the FeCrAlTi-ODS alloy coatings exhibit significantly improved binding force and hardness. The hardness (H) reaches 11.52 GPa (twice that of the bare substrate), and the elastic modulus (E) reaches 172.89 GPa. After the corrosion of bare substrate 316L steel by LBE, the oxygen element penetrated was obvious, and the Nickel element underwent selective migration. The FeCrAlTi-ODS alloy coatings show promising LBE corrosion resistance, and the FeCrAlTi-ODS alloy coating prepared under different bias can effectively protect the substrate material, which is attributed to the formation of protective FeCr2O4 film on the surface. The compact oxide film significantly prevents the further infiltration of the oxygen element and the migration of metal elements. Full article
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15 pages, 3120 KiB  
Article
Effect of Cu and Ag Content on the Electrochemical Performance of Fe40Al Intermetallic Alloy in Artificial Saliva
by Jesus Porcayo-Calderon, Roberto Ademar Rodriguez-Diaz, Jonathan de la Vega Olivas, Cinthya Dinorah Arrieta-Gonzalez, Jose Gonzalo Gonzalez-Rodriguez, Jose Guadalupe Chacón-Nava and José Luis Reyes-Barragan
Metals 2025, 15(8), 899; https://doi.org/10.3390/met15080899 - 11 Aug 2025
Viewed by 310
Abstract
This study investigates the effect of copper (Cu) and silver (Ag) additions on the electrochemical behavior of the Fe40Al intermetallic alloy in artificial saliva, aiming to evaluate its potential for biomedical applications such as dental implants. Alloys with varying concentrations of Ag (0.5, [...] Read more.
This study investigates the effect of copper (Cu) and silver (Ag) additions on the electrochemical behavior of the Fe40Al intermetallic alloy in artificial saliva, aiming to evaluate its potential for biomedical applications such as dental implants. Alloys with varying concentrations of Ag (0.5, 1.0, and 3.0 wt%) and Cu (1.0, 3.0, and 5.0 wt%) were synthesized and exposed to a biomimetic electrolyte simulating oral conditions. Electrochemical techniques, including open circuit potential (OCP), linear polarization resistance (LPR), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS), were employed to assess corrosion performance. Results show that unmodified Fe40Al exhibits good corrosion resistance, attributed to the formation of a stable passive oxide layer. The addition of Cu, particularly at 3.0 wt%, significantly improved corrosion resistance, yielding lower corrosion current densities and higher polarization resistance and charge transfer resistance values, surpassing even 316L stainless steel in some metrics. Conversely, Ag additions led to a degradation of corrosion resistance, especially at 3.0 wt%, due to microstructural changes and the formation of metallic Ag precipitates, AgSCN, and galvanic cells, which promoted localized corrosion. EIS results revealed that Cu- and Ag-modified alloys developed less homogeneous and less protective passive layers over time, as indicated by increased double-layer capacitance (Cdl) and reduced constant phase element exponent (ndl) values. Overall, the Fe40Al alloy shows intrinsic corrosion resistance in simulated physiological environments, and Cu additions can enhance this performance under controlled conditions. However, Ag additions negatively affect the protective behavior of the passive layer. These findings offer critical insight into the design of Fe-Al-based biomaterials for dental or biomedical applications where corrosion resistance and electrochemical stability are paramount. Full article
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21 pages, 13122 KiB  
Article
A Novel CuAlMnFe/CeO2 Composite Alloy: Investigating the Wear and Corrosion Features
by Fatih Doğan and Erhan Duru
Solids 2025, 6(3), 43; https://doi.org/10.3390/solids6030043 - 11 Aug 2025
Viewed by 306
Abstract
Shape memory alloys (SMAs) are known for their exceptional mechanical properties, particularly their superior wear resistance compared to conventional alloys with similar surface hardness. Rare earth oxides are often used as additives to further improve these characteristics. This study investigates the effects of [...] Read more.
Shape memory alloys (SMAs) are known for their exceptional mechanical properties, particularly their superior wear resistance compared to conventional alloys with similar surface hardness. Rare earth oxides are often used as additives to further improve these characteristics. This study investigates the effects of different CeO2 (cerium dioxide) concentrations (0.01 wt.%, 0.1 wt.%, 0.5 wt.%, and 1.0 wt.%) on the properties of CuAlMnFe alloys produced via powder metallurgy (PM). Various analyses were performed, including scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray diffraction (XRD), as well as hardness, wear, and corrosion tests. The increase in wear rate is closely related to the formation of precipitates from CeO2 addition. Improvements in wear resistance and hardness are attributed to the effects of grain refinement and solid solution strengthening due to CeO2. Specifically, the wear rate increased from 1.5 × 10−3 mm3/(Nm) to 3.4 × 10−3 mm3/(Nm) with higher CeO2 content. Additionally, the friction coefficient of the CuAlMnFe alloy was reduced with CeO2 addition, indicating enhanced frictional properties. The optimal CeO2 concentration of 0.5% was found to improve grain uniformity, resulting in better wear resistance. Incorporating CeO2 particles into CuAlMnFe alloy enhances hardness and reduces wear rate when used in appropriate amounts. Additionally, it exhibits superior corrosion resistance, as evidenced by a positive shift in corrosion potential in Tafel measurements in solutions and a decrease in corrosion current density. The C0.5 specimen showed the highest corrosion potential (Ecorr, −588 V) and the lowest corrosion current density (icorr, 6.17 μA/cm2) during electrochemical corrosion in 3.5 wt.% NaCl solution. Full article
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21 pages, 8084 KiB  
Article
Microstructural and Mechanical Characterization of Co-Free AlxTixCrFe2Ni High-Entropy Alloys
by Róbert Kočiško, Ondrej Milkovič, Patrik Petroušek, Gabriel Sučik, Dávid Csík, Karel Saksl, Ivan Petryshynets, Karol Kovaľ and Pavel Diko
Metals 2025, 15(8), 896; https://doi.org/10.3390/met15080896 - 10 Aug 2025
Viewed by 269
Abstract
This study investigates the effect of Alx and Tix content (x = 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) on the microstructural evolution and mechanical properties of Co-free high-entropy AlxTixCrFe2Ni alloys in both as-cast and [...] Read more.
This study investigates the effect of Alx and Tix content (x = 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) on the microstructural evolution and mechanical properties of Co-free high-entropy AlxTixCrFe2Ni alloys in both as-cast and homogenized conditions. The research focused on the characterization of structural features, melting behavior, and mechanical performance. Microstructural characterization was carried out using optical microscopy, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), and differential thermal analysis (DTA). Mechanical properties were evaluated through Vickers hardness testing and uniaxial compression tests. Increasing the Al and Ti content induced a transformation from a single-phase FCC structure to a dual-phase BCC structure, with the primary BCC phase strengthened by spherical precipitates rich in Al, Ti, and Ni. Homogenization annealing at 1100 °C led to an overall improvement in the mechanical properties. The Al0.3Ti0.3CrFe2Ni alloy exhibited the most balanced combination of strength and ductility after annealing, achieving a compressive yield strength of 1510 MPa, a compressive strength of 3316 MPa, and a compressive plastic strain of 45%. Full article
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20 pages, 5785 KiB  
Article
Retrofitting of a High-Performance Aerospace Component via Topology Optimization and Additive Manufacturing
by Jorge Crespo-Sánchez, Claudia Solek, Sergio Fuentes del Toro, Ana M. Camacho and Alvaro Rodríguez-Prieto
Machines 2025, 13(8), 700; https://doi.org/10.3390/machines13080700 - 8 Aug 2025
Viewed by 250
Abstract
This research presents a novel methodology for lightweighting and cost reduction of components with high structural demands by integrating advanced design and manufacturing techniques. Specifically, it combines topology optimization (TO) with additive manufacturing (AM), also known as 3D printing. Unlike conventional approaches, the [...] Read more.
This research presents a novel methodology for lightweighting and cost reduction of components with high structural demands by integrating advanced design and manufacturing techniques. Specifically, it combines topology optimization (TO) with additive manufacturing (AM), also known as 3D printing. Unlike conventional approaches, the proposed method first determines the optimal geometry using an artificially stiff material, and only then evaluates real materials for structural and manufacturing feasibility. This design-first, material-second strategy enables broader material screening and maximizes weight reduction without compromising performance. The proposed workflow is applied to the design of a turbofan air intake—an aeronautical component operating under supersonic conditions—addressing both structural integrity and manufacturing feasibility. Three materials from distinct classes are assessed: two metallic alloys (aluminum alloy 6061 and titanium alloy, Ti6Al4V) and a high-performance polymer (polyetheretherketone, PEEK). This last option is preliminarily discarded after being analyzed for this specific application. Finite element (FE) simulations are used to evaluate the mechanical behavior of the optimized geometries, including bird-strike conditions. Among the evaluated manufacturing techniques, Selective Laser Melting (SLM) is identified as the most suitable for the metallic materials selected, providing an effective balance between performance, manufacturability, and aerospace compliance. This study illustrates the potential of TO–AM synergy as a sustainable and efficient design approach for next-generation aerospace components. Simulation results demonstrate a weight reduction of up to 71% while preserving critical functional regions and maintaining structural integrity in Al 6061 and Ti6Al4V cases, under the diverse loading conditions typical of real flight scenarios, while PEEK remains an attractive option for uses where mechanical demands are less stringent. Full article
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13 pages, 5981 KiB  
Article
High-Temperature Oxidation Resistance of Fe-Free AlCoCrNiNb0.2 and AlCoCr0.5NiNb0.2 High-Entropy Alloys
by Olga Samoilova, Svetlana Pratskova, Nataliya Shaburova, Ahmad Ostovari Moghaddam and Evgeny Trofimov
Materials 2025, 18(15), 3701; https://doi.org/10.3390/ma18153701 - 6 Aug 2025
Viewed by 372
Abstract
The microstructure, phase composition, and high-temperature oxidation resistance of Fe-free AlCoCrNiNb0.2 and AlCoCr0.5NiNb0.2 high-entropy alloys (HEAs) were investigated. In the as-cast HEAs, niobium was found to mainly release as a Laves phase in the interdendritic region, and its solubility [...] Read more.
The microstructure, phase composition, and high-temperature oxidation resistance of Fe-free AlCoCrNiNb0.2 and AlCoCr0.5NiNb0.2 high-entropy alloys (HEAs) were investigated. In the as-cast HEAs, niobium was found to mainly release as a Laves phase in the interdendritic region, and its solubility in the dendrites of the BCC solid solution was about 2 at.%. Both samples exhibited parabolic behavior during 100 h oxidation at 1000 °C and 1100 °C. The AlCoCrNiNb0.2 alloy demonstrated higher resistance to high-temperature oxidation compared to AlCoCr0.5NiNb0.2. The specific weight changes after 100 h of isothermal holding at 1000 °C and 1100 °C were 0.65 mg/cm2 and 1.31 mg/cm2, respectively, which are superior compared to the Fe-containing HEAs. Cr was revealed to play an important role in the oxidation behavior of the HEAs, decreasing the parabolic oxidation rate constant and increasing the activation energy of the oxidation process in the alloys. Full article
(This article belongs to the Special Issue Advanced Science and Technology of High Entropy Materials)
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10 pages, 2101 KiB  
Article
Structural and Ferromagnetic Response of B2-Type Al45Mn41.8X13.2 (X = Fe, Co, Ni) Alloys
by Esmat Dastanpour, Haireguli Aihemaiti, Shuo Huang, Valter Ström, Lajos Károly Varga and Levente Vitos
Magnetochemistry 2025, 11(8), 67; https://doi.org/10.3390/magnetochemistry11080067 - 6 Aug 2025
Viewed by 268
Abstract
To our knowledge, no magnetic B2 phase in the Al–Mn system of near-equiatomic compositions has been reported so far. Here, we investigate the structural and magnetic characteristics of Al45Mn41.8X13.2 (X = Fe, Co or Ni) alloys. We demonstrate [...] Read more.
To our knowledge, no magnetic B2 phase in the Al–Mn system of near-equiatomic compositions has been reported so far. Here, we investigate the structural and magnetic characteristics of Al45Mn41.8X13.2 (X = Fe, Co or Ni) alloys. We demonstrate that adding 13.2 atomic percent magnetic 3d metal to AlMn stabilizes a ferromagnetic B2 structure, where Al and X occupy different sublattices. We employ density functional theory calculations and experimental characterizations to underscore the role of the late 3d metals for the phase stability of the quasi-ordered ternary systems. We show that these alloys possess large local magnetic moments primarily due to Mn atoms partitioned to the Al-free sublattice. The revealed magneto-chemical effect opens alternative routes for tailoring the magnetic properties of B2 intermetallic compounds for various magnetic applications. Full article
(This article belongs to the Special Issue Advances in Functional Materials with Tunable Magnetic Properties)
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18 pages, 6311 KiB  
Article
Unraveling the Excellent High-Temperature Oxidation Behavior of FeNiCuAl-Based Alloy
by Guangxin Wu, Gaosheng Li, Lijun Wei, Hao Chen, Yujie Wang, Yunze Qiao, Yu Hua, Chenyang Shi, Yingde Huang and Wenjie Yang
Materials 2025, 18(15), 3679; https://doi.org/10.3390/ma18153679 - 5 Aug 2025
Viewed by 292
Abstract
This study synthesized FeNiCuAlX high-entropy alloys (HEAs) (where X = Cr, Co, Mn) using arc melting and investigated their high-temperature oxidation behavior in air at 900 °C. The oxidation kinetics of all alloys followed a parabolic rate, with the oxidation rate constants (kp) [...] Read more.
This study synthesized FeNiCuAlX high-entropy alloys (HEAs) (where X = Cr, Co, Mn) using arc melting and investigated their high-temperature oxidation behavior in air at 900 °C. The oxidation kinetics of all alloys followed a parabolic rate, with the oxidation rate constants (kp) of FeNiCuAlCr, FeNiCuAlCo, and FeNiCuAlMn being approximately two to three orders of magnitude lower than that of the FeNiCu alloy. Specifically, FeNiCuAlCr exhibited the lowest kp value of 1.72 × 10−6 mg2·cm4/s, which is significantly lower than those of FeNiCuAlCo (3.29 × 10−6 mg2·cm4/s) and FeNiCuAlMn (1.71 × 10−5 mg2·cm4/s). This suggests that the addition of chromium promotes the formation of a dense Al2O3/Cr2O3 oxide layer, significantly enhancing the oxidation resistance. Furthermore, corrosion resistance was assessed through potentiodynamic polarization and electrochemical impedance spectroscopy in a 3.5% NaCl solution. FeNiCuAlCr demonstrated exceptional resistance to localized corrosion, as indicated by its low corrosion current density (45.7 μA/cm2) and high pitting potential (−0.21 V), highlighting its superior corrosion performance. Full article
(This article belongs to the Special Issue Characterization, Properties, and Applications of New Metallic Alloys)
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18 pages, 13224 KiB  
Article
The Structure and Mechanical Properties of FeAlCrNiV Eutectic Complex Concentrated Alloy
by Josef Pešička, Jozef Veselý, Robert Král, Stanislav Daniš, Peter Minárik, Eliška Jača and Jana Šmilauerová
Materials 2025, 18(15), 3675; https://doi.org/10.3390/ma18153675 - 5 Aug 2025
Viewed by 332
Abstract
In this work, the microstructure and mechanical properties of the FeAlCrNiV complex concentrated alloy (CCA) were studied in the as-cast and annealed states. The material was annealed at 800 °C for 16 days to test microstructure stability and phase evolution. It was found [...] Read more.
In this work, the microstructure and mechanical properties of the FeAlCrNiV complex concentrated alloy (CCA) were studied in the as-cast and annealed states. The material was annealed at 800 °C for 16 days to test microstructure stability and phase evolution. It was found that the microstructure does not differ in the two investigated states, and the results of differential scanning calorimetry and dilatometry showed that there is almost no difference in the thermal response between the as-cast and annealed states. Both investigated states exhibit eutectic structure with bcc solid solution and ordered phase with B2 symmetry. In a single grain, several regions with B2 laths in the bcc matrix were observed. Inside the B2 laths and in the bcc matrix, bcc spheres and B2 spheres were observed, respectively. All three features—laths, matrix and spheres—are fully crystallographically coherent. Nevertheless, in the adjacent region in the grain, the crystal structure of the matrix, laths and sphere changed to the other structure, i.e., the characteristics of the microstructure feature with B2 symmetry changed to bcc, and vice versa. Compression deformation tests were performed for various temperatures from room temperature to 800 °C. The results showed that the material exhibits exceptional yield stress values, especially at high temperatures (820 MPa/800 °C), and excellent plasticity (25%). Full article
(This article belongs to the Special Issue Mechanical Behaviour of Advanced Metal and Composite Materials)
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