A hard magnetic high-entropy alloy (HEA) Fe35Co20Ni5Pt15B25 was designed and prepared by a two-step process of melt-spinning and subsequent annealing in high vacuum conditions. A nanocomposite structure consisting of amorphous and fcc-(Fe, Co, Ni)Pt phases was obtained in as-quenched alloy, while a composite structure composing of nanoscaled L10-(Fe, Co, Ni)Pt and (Fe, Co, Ni)2B phases was created after an appropriate vacuum annealing. The annealed HEA exhibited hard magnetic properties. The coercivity (iHc), saturation magnetizations (Bs), remanence ratio (Mr/Ms), and the maximum energy product ((BH)max) of the annealed Fe35Co20Ni5Pt15B25 high-entropy alloy were in the ranges of 207.7-996.6 kA/m, 0.50-0.77 T, 0.64-0.70, and 18.3-21.7 kJ/m3, respectively. When the annealing temperature was increased, iHc firstly increased to a maximum value of 996.6 kA/m, and then decrease. The good hard magnetic property is due to the formation of homogeneous nanocomposite structure in the annealed HEA, leading to exchange couplings among the nano-sized hard L10-(Fe, Co, Ni)Pt and soft (Fe, Co, Ni)2B magnetic phases.

Owing to their excellent corrosion resistance and weldability, 5xxx series Al-Mg alloys are widely used in marine and offshore structures. However, research on the sensitization behavior and reversion treatment of Al-Mg alloy welded joints remains underdeveloped with regard to base materials, despite welded joints being critical zones for failure. To address this limitation, the present study systematically investigated the microstructure and corrosion behavior of the base metal (BM), heat-affected zone (HAZ), and weld zone (WZ) of 5A06 alloy tungsten inert gas (TIG) welded joints under as-welded, sensitized (isothermal treatment at 175 degrees C for 100 h), and reversion-treated (isothermal treatment at 310 degrees C for 1 and 24 h) conditions. Various microstructural characterization techniques, along with the nitric acid mass loss test (NAMLT), were employed to clarify the sensitization-induced precipitation characteristics in different regions of the welded joints, as well as the effect of reversion treatment on corrosion performance. The results indicated that the as-welded BM consists of uniform, recrystallized grains formed by annealing. Due to welding thermal cycle, the grains in the HAZ were slightly coarsened, whereas the WZ exhibited equiaxed dendritic structures with notable Mg interdendritic segregation. After sensitization, continuous beta' phase precipitates formed along the grain boundaries in the BM and HAZ, leading to severe intergranular corrosion during the NAMLT. In the WZ, additional acicular beta' phase formed within the interdendritic regions, further inducing interdendritic corrosion and resulting in higher corrosion susceptibility. Reversion treatment at 310 degrees C for 1 h successfully dissolved the grain boundary beta' phase; however, complete dissolution of the interdendritic acicular beta' phase required a longer duration. Thus, to ensure the overall intergranular corrosion resistance of the joint, the reversion treatment parameters should be established based on the complete dissolution of the interdendritic acicular beta' phase in the WZ.

The regulation of the detrimental pi-Fe phase has been the primary concern in Al-7Si-Mg cast alloys. In this work, a two-stage solution treatment is conducted for the complete dissolution of the Mg2 Si phase in the low-temperature stage and for manipulating the decomposition of the pi-Fe phase in the hightemperature stage. This approach allows for a systematic investigation into the effect of solution temperature on the decomposition behavior of the pi-Fe (Al8 Mg3 FeSi6 ) phase while avoiding incipient melting. The coarse pi-Fe particles form an interconnected and branched structure in the as-cast microstructure, wrapping the alpha-Al dendritic arms and isolating the alpha-Al grains. The pi-Fe structure underwent subtle change during the solution treatment at 540 degrees C. At the elevated solution temperature of 560 degrees C, the pi-Fe phase decomposed into a fine beta-Fe phase, accompanied by particle fragmentation and shape change into the granular form. The modification of the pi-Fe phase has achieved a simultaneous enhancement in the strength and ductility of the alloy. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

The AZ31-0.9Nd-0.3Y alloy exhibits a uniform distribution of Al-RE particles at the grain scale, with Al2RE present within grains and Al11RE3 located at grain boundaries (GBs). Using quasi‑in‑situ electron backscatter diffraction, this study investigated the underlying static recrystallization (SRX) mechanisms based on this distribution, with particular attention to the interplay between particle-stimulated nucleation (PSN) and twin‑induced SRX. The results demonstrated that grain-interior Al2RE particles acted as anchoring sites for dislocations, inducing particle deformation zones (PDZs) that activated the PSN mechanism and accelerated SRX nucleation within grains. When PDZs were adjacent to twin-induced SRX grains, the strain gradient established between them drove these grains to break through twin boundaries and survive the subsequent competitive grain coarsening. Meanwhile, the PSN triggered by Al11RE3 particles generated randomly oriented SRX grains in GB regions and simultaneously accelerated SRX there. The activation of various SRX mechanisms and their interplay facilitated the nucleation of SRX grains via both intragranular and intergranular pathways. These fresh grains grew in both outward and inward directions, displaying a characteristic “face-to-face” development that consumed the parent grains from opposing sides. The interplay between the in-situ formed hard particles and twins would offer a promising way of accelerating SRX kinetics and weakening texture.

The aerobic-anaerobic corrosion transition of low-carbon steel under deep geological disposal conditions is critical in corrosion evaluation of disposal containers. In this work, the corrosion evolution behavior of Q345R low-carbon steel in Beishan underground water under sealed conditions has been investigated by electrochemical impedance spectroscopy (EIS), and besides the redox potential (Eh) evolution of the corrosion electrolyte has been recorded. The results indicate that the distribution of relaxation time (DRT) analysis on EIS data can well identify the oxygen reduction reaction (ORR)-related time-constant evolution. Therefore, it could be proposed that DRT analysis on EIS data combined with Eh monitoring is applicable for the aerobic-anaerobic corrosion transition investigation of low-carbon steel under electrolyte corrosion conditions.

Through pin-on-disk friction and wear experiments, the tribological properties and wear mechanisms of a 20 vol.% Mg2Sn/Mg composite fabricated by powder metallurgy were systematically investigated. The experimental results show that with the quenched 45 steel as the counterface material and under a sliding speed of 0.126 m/s, both the coefficient of friction (COF) and wear rate (W-r) of the composite gradually decreased with increasing load in the range of 10 to 80 N. At a load of 80 N, the COF and W-r of the composite reached 0.25 and 6 x 10(-10) mm(3)/Nm, respectively. The excellent tribological performance is primarily attributed to the formation of a hard nanocrystalline friction-affected layer during sliding, and to the effective load support and stress dispersion capabilities provided by the high-volume fraction of Mg2Sn particles.

Fine particles with carbon coating are generally necessary to achieve acceptable electrochemical performance for LiFePO4 (LFP) due to the poor intrinsic electric and ionic conductivities. In this work, the synergy of polyethylene glycol (PEG) was investigated as both grinding aid and carbon source to modify LFP toward high performance. The yielded graphite coating has a limited thickness of 8 nm, regardless of the concentration and molecular weight of PEG, while the extra concentration results in amorphous carbon dispersed among particles. A higher PEG concentration produces finer LFP particles but less active materials, while the semi-solid PEG shows the best grinding effect toward a reversible capacity close to the theoretical value. These results could be well addressed based on polymer conformations, and this work paves a more efficient way to develop high-performance LFP.

This study investigates the impact of Zn alloying on the dispersion of the reinforcing particle in Mg2Sn/Mg composites. In the composite, Zn manifests in three distinct forms: Zn segregation layer between MgMg2Sn, the solid solution and the MgZn2 phase. First-principles calculations confirm that the formation of Zn segregation layer decreases the interfacial energy of the MgMg2Sn. Importantly, this segregation layer significantly enhances the comigration capability of Mg2Sn particles with Mg matrix during sintering flow, effectively hindering the agglomeration and coarsening of the nano-sized reinforcing phase. The dense and uniformly distributed nano-sized Mg2Sn significantly increases the activity of non-basal slip, ensuring good elongation of the composite while enhancing strength. It can be concluded that enhancing the comigration-ability of reinforcing particles with the matrix is an effective strategy for achieving controlled dispersion of high-volume reinforcing particles and an excellent combination of strength and ductility in magnesium matrix composites.

Structures and magnetic properties of nanocompsite Fe-Pt-B ternary alloys were investigated in a widely compositional range. A single amorphous phase was formed in a composition range of 0-15 at. % Pt and 20-30 at. % B, while the ranges of fcc-FePt + amorphous, fcc-FePt + Fe2B and L1(0)-FePt + Fe2B/FeB phases were formed out the range of single amorphous. With more than 5 at. % of Pt, the crystallized structure was obtained consisting of nanoscale L1(0)-FePt and Fe2B/FeB phases after annealing except for alloys with 0-10 at. % Pt and 15-25 at. % B. The annealed alloys with >= 10 at. % of Pt exhibit good hard magnetic properties. Increasing the contents of Pt and B were propitious to increase the coercivity (H-i(c)) of the alloys owing to the enlargement of volume fraction for L1(0)-FePt phase. The maximum value of H-i(c) can reach 806 kA/m for the Fe50Pt25B25 alloy after annealing at 843 K for 900 s. Higher Pt content (>20 at. %) led to a decrease of the H-i(c) for alloys with more than 30 at. % B, which is due to the weakened exchange coupling between soft and hard magnetic phases in nanocomposite magnets as the precipitation of FeB phase.

Due to the inability of Zr to refine Al-containing Mg alloys, achieving pronounced grain refinement in cast AZ31 alloy has been a significant challenge for researchers. Surprisingly, we found that the reinforcement phases demonstrated a regular distribution at the grain scale after adding 0.9 wt% Nd and 0.3 wt% Y: Al2RE inside the grains and Al11RE3 agglomerated near the grain boundaries. Additionally, the grain size of AZ31 alloy was significantly reduced from 258 mu m to 65 mu m. The mechanisms of reinforcement phase distribution and grain refinement were explored through the combination of transmission electron microscope (TEM) and thermal analysis during the solidification process. Al2RE phase precipitates prior to alpha-Mg, and exhibits a specific orientation relationship with the matrix: [0110]Mg || [011]Al2RE,(0002)Mg || (222)Al2RE. This suggests that Al2RE serves as potentially effective heterogeneous nucleation sites for alpha-Mg. Moreover, Al11RE3 phase can restrict grain growth in the later stage of solidification. The tensile results show that a regular distribution of the reinforcement phase at the grain scale can not only effectively alleviate stress concentration, but suppress the formation of coarse twins by inducing grain refinement during alloy solidification process, significantly improving the strength and ductility of the alloy.

More requirements of electromagnetic interference (EMI) shielding performance are put forward for lightweight structural materials due to the development of aerospace and 5G communications. Herein, graphene oxide (GO) decorated with SnO2 coating is introduced as reinforcement into AZ31 Mg alloy. During the smelting process, the MgO layer is in situ gernerated at interface between GO and the molten Mg alloy matrix by consuming SnO2. In the solid state, such kind of interface structure can improve the GO-Mg interface bonding intensity, also significantly generate stacking faults. The AZ31 composite reinfoced by trace modified GO (0.1 wt%) exhibits high ultimate strength and almost the same elongation with AZ31 alloy. Compared with AZ31 alloy, the yield strength and ultimate tensile strength of composite are increased by 33.5% and 23.7%, respectively. Meanwhile, the multi-level electromagnetic reflection from the multi-layer structure of GO and the interface polarization caused by the MgO mid-layer can significantly improve EMI shielding performance. The appropriate interface design strategy achieves the effect of “two birds with one stone”.

Hydrogen fuel cells, boasting their technical features of cleanliness, environmental and high efficiency, have been gaining significant attention in response to the "carbon peaking and carbon neutrality" goals. In recent years, hydrogen-powered rail vehicles have achieved fruitful results as one of the effective approaches towards the low-carbon transformation and sustainable development in the rail sector. This paper began with an introduction to the current development status of hydrogen-powered rail transit at home and abroad. Then, the core technologies involved were expounded, including the integration and control of hydrogen fuel cell systems, energy management for hybrid power, and fault diagnosis and service life prediction of fuel cells, with a focus on their technical pros and cons and scopes of application. In addition, the existing issues and challenges were analyzed and the development orientations were raised according to the practical considerations. Finally, the development trends of hydrogen-powered rail transit were prospected from different perspectives to provide a reference for further development and application.

A new sort of nanoporous palladium has been synthesised by electrochemical dealloying icosahedral Al72Pd20Mn8 quasicrystal. A nanoporous cell-like pattern is formed in the dealloyed samples, with a mean pole size of 8 nm and a cell wall thickness of similar to 5 nm. The quasicrystal grains decompose into randomly orientated FCC Pd(Al) nanocrystals in the initial stage of dealloying, which assumes a prior mechanism accounting for the final microstructure size. The nanoporous palladium exhibits evident electrocatalytic activity towards the oxidation of ethanol and methanol in alkaline environment, and demonstrates the possible application as a cathode material in Li-O-2 batteries.

为了连接W和CLF-1 RAFM钢,设计出由低活化元素组成的Fe-B-Si、Fe-B-Si-Sn、Fe-B-Si-Cr-(Sn)、Fe-B-Si-P-(Cr,Sn)、Fe-B-Si-Mn-(Ga,Sn)和Fe-B-Si-(Cr,Mn,Ga,Ta,Sn)系列Fe基非晶钎料,结合熔体快淬技术制备出非晶合金箔带,并对W/CLF-1 RAFM钢接头微结构进行了对比研究.采用X-射线衍射仪对箔带样品与焊缝进行了相鉴定;通过差热分析测量了非晶箔带的熔化温度和液相线温度;利用光学金相和电子探针分析了焊缝组织形貌和元素分布.结果表明,利用 Fe-B-Si、Fe-B-Si-Cr 和 Fe-B-Si-Mn-Sn 非晶钎料可获得结构完整的W/CLF-1钢接头;前两种钎料得到的焊缝组织基体相为α-Fe固溶体,而含Mn钎料形成的焊缝基体为马氏体组织;在高温钎焊过程中,这些Fe基非晶钎料中的高B含量促使FeWB、FeW2B2和Fe3B型金属间化合物在焊缝中形成,并有效地阻止了W元素向低活化钢基体长程扩散.所设计的低活化Fe基非晶钎料可用于W和低活化钢的连接和接头性能研究.

为了解决CFC与CuCrZr合金的冶金连接问题,以二元合金Cu62Mn38(at.％)为基础成分,采用低熔点Ga作为主要合金化元素和微合金化元素Cr和Si,设计了系列固溶体钎料合金Cu62Mn37-xGaxCr0.5Si0.5(x=0～10,at.％).利用电弧熔炼、铜模吸铸和冷轧制备了 100μm厚的钎料箔带.采用Cu62Mn31Ga6Cr0.5Si0.5钎料在不同工艺条件下(875～900℃,保温 15～25min)制备了无氧铜和 CuCrZr 合金钎焊接头.通过热分析和 X-射线衍射分析了钎料熔化行为和相组成;采用光学显微镜、扫描电镜、电子探针和力学性能拉伸机对接头的组织形貌、成分分布和力学性能进行了分析.结果表明,在 880℃/保温 25min钎焊工艺下可获得无缺陷CFC/CuCrZr接头结构,焊缝的Cu固溶体基体内有少量不连续分布的粒状纳米Cr3Si析出相;在室温抗拉试验中,此接头的抗拉强度为215MPa,断后延伸率 40％,断裂模式为韧性断裂.该钎料和焊接工艺已应用于 HL-2M 偏滤器制造中碳纤维复合材料和CuCrZr合金的连接加工.

Metal oxide anode materials based on conversion reaction usually deliver a capacity much higher than that of commercial graphite anodes in lithium-ion batteries (LIBs), and the porous forms of the materials can effectively alleviate volume change associated with (de)lithiation. In this work, tetragonal γ-Fe2O3, which is a vacancy-ordered superstructure containing large vacancy clusters, is studied as the representative of intrinsic nanoporous metal oxide anode materials of LIBs. γ-Fe2O3 exhibits a reversible capacity higher than the theoretical value in initial cycles, but a steady capacity same as that of α-Fe2O3. In lithiation, γ-Fe2O3 first transforms irreversibly to an ordered rock salt Li1-xFe1+xO2 (LiTiO2 type), and the Li1-xFe1+xO2 is converted reversibly into Li2O and Fe0 upon further lithiation: γ-Fe2O3+Li→Li1-xFe1+xO2+Li ↔ Fe0+Li2O. The alternate stacking of dense tetrahedral layers and porous octahedral layers in γ-Fe2O3 enables the simultaneous formation of Li1-xFe1+xO2 phases with different Li contents in a single particle and triggers structure twinning, accounting for fast reaction and likely high capacity in initial cycles. The structural evolution disclosed in γ-Fe2O3 not only updates the understanding of conversion reactions of vacancy-ordered metal oxides, but also offers an innovative approach for the fabrication of twinning structures in metal oxides including cathode materials.

The microstructure and mechanical properties of tungsten (W) materials have strong influences on their thermal shock performance. In this work, a W-Y2O3 (0.14 wt% Y) alloy with bimodal grain structure was fabricated by swaging plus high energy rate forging of the hydrogen sintered compact. In tensile tests, the W alloy exhibits a high yield strength (& sigma;Y = 1400 MPa) and a plastic strain & epsilon; = 5.5% at room temperature, and extensive tensile strains exceeding 20% at 100-300 degrees C. Its thermal shock performance was assessed by applying cyclic edge localized mode-like long heat pulse for 100 times at room temperature with an electron beam equipment. Within the range 0.44-1.1 GW m � 2, the specimens are free of cracking, and the surface modifications change from shear step-like bulges to recrystallization with increasing absorption power density.

In the fusion irradiation environment, dislocation loop defects occur under the plasma-facing tungsten surfaces, which affect its mechanical properties and hydrogen/helium retention. This paper presents a study that dynamic behaviors of a loop with a radius of 1 nm under the W surface are simulated by using molecular dynamics simulation at the atomic level. It finds that the dislocation loop direction, bulk temperature, depth, and helium atoms have great influence on the motion of the dislocation. This study shows that the dislocation loop ( is the Burgers vector, is the surface normal direction) tends to move towards the surface and the dislocation loop tends to stay in the material. In the course of its migration, the habit plane of dislocation loop may change and the internal stress reduces gradually. The probability of a dislocation loops escaping from the surface is over 90% when the temperature is higher than 800 K and their initial depth is less than 5 nm. The dislocation loop can escape from the surface when the temperature is 800 K and the initial depth is less than 2 nm. It is found that dislocation loops decompose into dislocations at elevated temperatures. Helium atoms impedes the migration of dislocation loop and increases its retention time. The existence of dislocation loops results in the uneven distribution of helium atoms under the W surface, and will potentially affect the surface morphology of tungsten.

TiB2/AZ80 Mg matrix composite containing particle rich zone (PRZ) and particle free zone (PFZ) was parpred by simple stiring casting and cross-rolling. The percolation structure of the PRZ endows the composite with local metamaterial properties, which introduces a new electromagnetic wave (EMW) absorption mechanism, namely plasma oscillation, for Mg matrix composite. Likewise, the multiple internal reflection and the TiB2–Mg interface polarization also contribute to the high EMW absorption capacity. As a result, the electromagnetic interference (EMI) shielding performances measured by vector network analysis shows that the X-band EMI shielding performance of the as-rolled composite is significantly improved than that of the AZ80 alloy, especially its absorption shielding efficiency ratio exceeds 70%.

Atomic-scale structure properties of the epitaxial growth of the wurtzite ZnO film prepared on an a-plane sapphire (α-Al2O3) substrate have been investigated by using aberration-corrected transmission electron microscopy. The crystallographic orientation relationship of (0001)[1¯1¯20]ZnO//(112¯0)[0001]α-Al2O3 has been determined between the ZnO film and the α-Al2O3 substrate. Two types of oxygen-terminated a-plane α-Al2O3 substrate surfaces have been characterized, which leads to the formation of different heterointerface structures and ZnO domains with opposite lattice polarity. The coalescence of opposite polarity domains results in the appearance of inversion domain boundaries (IDBs) on prismatic planes, and kinks occur on basal planes during the propagation of IDBs within the film. Additionally, the structure of stacking mismatch boundaries in the film with threefold coordinated Zn and O atoms has been resolved. We believe that these findings can be helpful to advance the understanding of the complex propagation of planar defects (e.g., IDBs and stacking faults) in wurtzite films and the interface structure and polarity of wurtzite films on the a-plane sapphire substrate.