The competition for future resources lies in the deep sea and the key to the development of deep-sea resources depends on the level of deep-sea equipment. To manufacture the equipment served in the deep sea, the key issue is to prepare the metal materials with required properties. High-entropy alloys are gaining increasing attention due to their excellent corrosion resistance in harsh environments, such as the deep sea. It is crucial to reveal the corrosion mechanisms of high-entropy alloys to develop alloys with excellent corrosion resistance and expand the applications of high-entropy alloys. In this review, the corrosion mechanisms and evaluation methods of high-entropy alloys are comprehensively reviewed based on the galvanic corrosion theory, point defect theory, and passivation theory. In addition, the strategies, including alloying and heat treatment, to improve the corrosion resistance of high-entropy alloys are summarized. The aim is to better understand the corrosion behavior of high-entropy alloys and provide theoretical guidance for developing high-entropy alloys with excellent corrosion resistance.

In recent years, implementing “carbon neutral” political measures has made developing and utilizing new energy sources a key focus in addressing current energy challenges. Aqueous zinc-ion batteries (AZIBs) have emerged as a research hotspot in energy storage devices due to their low cost, high safety, and high energy density. The high theoretical capacity, diverse valence states, and unique structural properties of vanadium-based compounds contribute to their recognition as the most promising cathode materials in AZIBs research. In this work, we delve into the energy storage mechanism of AZIBs, review the preparation strategies and electrochemical properties of the commonly studied vanadium-based materials (V₂O₅, VO₂, V₂O₃, etc.), in recent years, providing a guidance for further optimization of cathode materials for future AZIBs applications. However, vanadium-based materials still face challenges such as low capacity and poor cycling performance, which limit the widespread application of AZIBs. Further development and research on vanadium-based electrode materials are still needed.

The temperature response, mechanical properties and microstructural evolution of 1060-H24 pure aluminum sheet under different current densities and loading directions were systematically studied by using electric pulse-assisted tensile test and characterization techniques including electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM), and the athermal effect mechanism of strength−plasticity improvement was revealed. The findings demonstrate that following the application of electric pulse treatment at a current density of 5 A/mm², the yield strengths and fracture strains in the 0°, 45° and 90° directions are increased by 0.33%−3.34% and 2.62%−14.84%, respectively. Under the condition that the Joule temperature rise (≤2.4 °C) caused by this current density is negligible, pulse current changes the intensities of Copper, Brass and S textures and causes the decrease of the geometrically necessary dislocations (GNDs) density and fraction of low-angle grain boundaries, which confirms the athermal effect. The slight strength increase stems from the competition between reduced dislocation strengthening due to GNDs decrease and enhanced strength through transformation of high-energy dislocation tangles into low-energy dislocation networks that optimize the hard-oriented {111}//RD texture. The improved fracture strain is attributed to current-induced uniform dislocation distribution and dislocation disentanglement-reorganization into nets.

The flow characteristics and deformation mechanism of Al−Mg−Si alloy were studied at various temperatures (77−298 K) and strain rates (900−7000 s⁻¹) using the Hopkinson pressure bar method, electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that increasing the strain rate and decreasing the deformation temperature significantly enhanced the work hardening ability of Al−Mg−Si alloy, thereby markedly improving the plasticity. A dislocation density-based constitutive model for the Al−Mg−Si alloy was established, incorporating dislocation accumulation and dynamic recovery mechanisms, which accurately described the flow behaviors under different conditions. Microstructural observation revealed that the combination of cryogenic temperature and high strain rate significantly suppressed dislocation cross-slip, which led to the formation of numerous slip bands. As strain accumulated, these slip bands interacted and facilitated recrystallization, thereby obviously accelerating the grain refinement process.

Magnesium rare earth alloy castings with varying degrees of contraction constraints were designed by combining rods and flanges with different cross-sectional sizes, and the constrained contraction behavior of Mg−9Gd−3Y−0.5Zr alloy castings was investigated under low-pressure and gravity casting conditions. Precise dimensional measurements were performed using a 3D scanner, and the data obtained were used to analyze trends in constrained contraction coefficient (CC) values from multiple perspectives. Several evaluation factors, including the ratios of flange to rod area and casting to envelope volume, as well as the combination of geometric characteristics and casting modulus, were explored for their effectiveness in assessing the degree of constraint on the castings. The geometric characteristics and casting modulus were integrated through regression analysis to determine optimized evaluation parameters, based on which an equation for correlating free and constrained CC values was established.

To objectively verify microstructural heredity in a rare-earth magnesium alloy during heat-treatment and deformation processes under pulsed current condition, we proposed a pulsed current method during homogenization and rolling processes. We then compared the macroscopic edge cracks, microstructures, and mechanical properties of sheets which were formed using pulsed homogenization (PH)/industrial homogenization (IH) followed by hot rolling (HR)/ electroplastic rolling (ER). The results showed that the PH + ER forming method produced an alloy with the most obviously enhanced deformation ability, with the tensile strength increasing from 145 MPa (IH + HR) to 266 MPa (PH + ER). Inside the PH + ER sample, the nonthermal and thermal effects of the pulsed current promoted atomic diffusion, regulating the proportion and morphology of the secondary phase, thereby improving the forming ability of the material.

The Elinvar behavior of Ti−22Nb−6Zr shape memory alloy was studied to determine the mechanism of such behavior and find the way to control this effect. The temperature dependences of elastic properties were studied using torsional pendulum experiments. The stability of phase composition was evaluated by X-ray diffraction analysis. Compression mechanical testing and classical atomistic simulations were used to confirm the obtained results on the macroscopic and atomic levels. The heating/cooling rate of ≥9 °C/min allows realization of the two-way Elinvar behavior in the 150−550 °C range with a temperature coefficient of f_r² ~10⁻⁵ °C⁻¹; this behavior is stable, repeatable, and independent of the β-phase state, whether the alloy has a polygonized dislocation substructure or a recrystallized structure. The study concludes that the Elinvar behavior observed is an intrinsic property of ВСС β-phase.

Ti150 powders were deposited on the as-forged Ti180 alloy by selective laser melting under different laser powers. The microstructure and mechanical properties of the Ti150/Ti180 bimetallic alloys were systematically studied. The results showed that the Ti150/Ti180 bimetallic alloy samples can be categorized into three regions: the forging zone, the bonding zone, and the deposition zone. The forging zone exhibited duplex microstructure. The bonding zone had no macroscopic defects. In the lower region, the Ti180 alloy underwent rapid melting and solidification, and formed a unique microstructure after undergoing multiple thermal cycles. In the upper region, there was a continuous variation in solute element concentrations, leading to the gradual transformation of the microstructure into Widmanstätten structure. The deposition zone consisted of Widmanstätten structure that was composed of α phase and residual β phase. As the laser power increased, the density in the deposition zone initially increased and then decreased. The main defect type shifted from lack-of-fusion to pores. The tensile properties showed a trend of initial improvement followed by deterioration. When the laser power was 287 W, the deposition zone has the lowest defect content, with a relative density of 99.58%. The ultimate tensile strength and elongation of the sample at room temperature were 1151 MPa and 4.8%, and those at 450 ℃ were 969 MPa and 14.0%, respectively.

The incorporation of 2 wt.% silver (Ag) nanoparticles into TC4-ELI titanium alloy via electrostatic assembly was investigated, followed by laser powder bed fusion additive manufacturing. The objective was to enhance the alloy’s mechanical properties, corrosion resistance, and antibacterial performance to test its potential application in body implants. The results show that electrostatically assembled TC4-ELI/Ag samples achieve a relative density of 99.5%, an ultimate tensile strength of 1250.3 MPa, and an elongation of 16.13%, significantly surpassing unmodified TC4-ELI and ball-milled TC4-ELI/Ag samples. The electrochemical analysis confirms enhanced corrosion resistance, with TAM3 samples (electrostatically assembled) exhibiting superior passivation and a lower corrosion current density of 0.239 μA/cm². Antibacterial tests demonstrate the best performance for TAM3, with a marked reduction in bacterial growth attributed to the uniform dispersion and controlled release of Ag ions.

The effect of F⁻ on the passivation and repassivation of titanium in a simulated spent fuel reprocessing environment was examined using a custom-designed scratching electrode device. Electrochemical experiments and characterization of the passive film revealed that F⁻ accelerates both cathodic and anodic reactions of titanium. The critical concentration phenomenon of F⁻ on intact and scratched titanium surfaces in hot HNO₃ solutions can be attributed to competitive adsorption between F⁻ and NO₃⁻. Below the critical concentration, F⁻ primarily affects the outer layer of the passive film, while above it, F⁻ penetrates the entire passive film, significantly reducing corrosion resistance. The lower critical concentration on scratched surfaces (0.5 mmol/L) compared to intact surfaces (1 mmol/L) is due to enhanced F⁻ adsorption caused by the presence of scratches. It is indicated that regular monitoring of F⁻ concentrations and minimizing scratches on titanium surfaces to prevent corrosion failure are imperative during the spent fuel reprocessing process.

A novel solid-state joining approach was proposed, demonstrating the feasibility of effectively joining refractory metals at relatively low temperatures. Employing advanced characterization techniques, the underlying mechanisms governing the bonding of tantalum (Ta) and titanium (Ti) were systematically investigated. The results reveal that Ta−Ti metallurgical bonding occurs at a peak temperature of approximately 600 °C, representing 18.15% and 32.61% of the melting points of Ta and Ti, respectively. Ultrasonic vibrations can facilitate the phase transformation of Ti from hexagonal close-packed (HCP) α-Ti to body-centered cubic (BCC) β-Ti, effectively enhancing its plasticity and enabling mechanical interlocking with Ta. Additionally, ultrasonic vibrations can promote atomic diffusion at the Ta−Ti interface, leading to the formation of a transition layer with a thickness ranging from 0.3 to 0.8 μm at the bonding interface, which substantially improves the bonding strength of Ta−Ti joint.

The martensite transformation of Co−Cr−Mo alloys during cooling after holding at different austenitization temperatures (T_a), was investigated via high-temperature confocal laser scanning microscopy (HT-CLSM). The martensite starting temperature (M_s) increases with increasing T_a. Martensite area fraction (f_M) firstly decreases, then increases, and finally decreases with increasing T_a. Additionally, inverse martensite transformation, grain growth, and σ phase decomposition were examined during heating via differential scanning calorimetry and HT-CLSM. The effects of T_a on martensite transformation and phase composition of the alloys were analyzed. M_s and f_M were influenced by both grain size and pre-existing martensite at T_a of 900−950 °C, grain size alone at 950−1100 °C, and both grain size and elemental diffusion at 1100−1200 °C. This study will provide basic theoretical guidance for regulating the microstructure and enhancing the mechanical properties of Co−Cr−Mo alloys.

Ti was introduced into the WMoTaV refractory high-entropy alloy (RHEA) to improve its mechanical properties. WMoTaVTi_x (x=0, 0.5, 1, 1.5, and 2; x denotes the molar fraction, %) RHEAs were synthesized by high-energy ball milling and spark plasma sintering. The effect of Ti addition on the microstructure and mechanical properties of the WMoTaV RHEA was investigated. The results indicated that the addition of Ti significantly enhanced sintering densification and improved mechanical properties of the alloy, with compressive yield strength initially increasing and then decreasing as Ti addition rose. The WMoTaVTi_1.5 RHEA exhibited optimal mechanical properties, with a compressive yield strength of 1862 MPa, fracture strength of 2892 MPa, and fracture strain of 15.63%. Compared with the alloy without Ti addition, the yield strength and fracture strain of the WMoTaVTi_1.5 alloy increased by 35% and 53%, respectively. The improvement is attributed to solid solution strengthening, fine grain strengthening, and TiO_x secondary-phase-particle precipitation strengthening.

The notable stress hysteresis and strong temperature dependence limit the application of superelastic alloys. In this study, we developed a Ni−Mn−Ti−Fe−Co superelastic high-entropy alloy system with low temperature dependence by integrating high-entropy alloy principles into the Ni−Mn−Ti system through arc-melting technology. By designing a fully eutectic microstructure, the alloy demonstrated stable superelasticity with minimal hysteresis energy dissipation, maintaining a 5% strain across a broad temperature range from 113 to 433 K. Furthermore, it exhibited fully reversible superelasticity of 5% after 12010 cycles at room temperature and demonstrated significant pseudoelasticity of about 8.2% under a high stress of 1600 MPa. Its excellent elasticity, minimal hysteresis energy dissipation, and near-constant stress−temperature dependence over a wide temperature range are attributed to its unique eutectic microstructure and weak first-order phase transformation, making it a promising candidate for applications requiring reliable superelastic performance across diverse temperature environments.

The impact of interstitial carbon on recrystallization behavior was investigated in designed carbide-free FeMnCoNiC_x high-entropy alloys (HEAs) by utilizing weak carbide-forming elements. The results indicate that recrystallization and grain growth are both effectively facilitated in carbon-containing high-entropy alloys. Under identical cold rolling conditions, carbon-containing HEAs exhibit higher dislocation density and deformation stored energy, which facilitates the recrystallization behavior. Meanwhile, the activation energy for grain growth in carbon-containing alloys is lower than that in carbon-free alloys. Diffusion couple experiments reveal that the addition of carbon increases the diffusion coefficients of metallic elements, thereby reducing the activation energy for grain growth and consequently accelerating grain coarsening. This phenomenon stands in sharp contrast to the conventional understanding, in which carbon suppresses recrystallization by forming carbide secondary phases that pin grain boundaries.

The influence of oxygen partial pressure on the microstructure, element distribution, and physical properties of Ag−Sn−In−Ni−Sb alloy after oxidation was investigated by thermodynamic calculation, XRD, OM, EPMA, and AFM. The results show that the higher the oxygen partial pressure is, the more fully the alloy is oxidized, the smaller the oxide particle size is, the more uniform the microstructure is, and the better the physical properties of the oxidized samples are. The relative density of the sample oxidized at 0.9 MPa is 98.3%, the conductivity is 60.2% (IACS), and the hardness is HV 130.1. The NiSbSn intermetallic compound in Ag−Sn−In−Ni−Sb alloy is oxidized to six different oxide configurations. In addition, the relationships among oxygen partial pressure, oxide particle size and physical properties were established, and the influencing mechanism of oxygen partial pressure on microstructure was also discussed.

WC−ZrO₂ ceramic matrix composites were fabricated via spark plasma sintering (SPS), and the effects of SPS on the microstructure, properties and grain growth kinetics of the composites were investigated. The phase compositions, morphologies and particle sizes of all samples were studied using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the optimal SPS parameters were 1650 °C, 5 min and 40 MPa. WC−10 wt.%ZrO₂ possessed optimal comprehensive properties with a relative density, hardness, and fracture toughness of 99.9%, HV 2003, and 11.3 MPa·m^1/2, respectively. The values of the growth kinetics index and growth activation energy for WC−10wt.%ZrO₂ in the long-axis and short-axis directions were approximately 2.173 and 421.342 kJ/mol, and 2.326 and 457.685 kJ/mol, respectively. The growth mass transfer mechanisms of WC ceramic and WC−ZrO₂ ceramic matrix composites were controlled respectively by ion random diffusion and grain boundary diffusion.

To mitigate the issues of severe volume expansion (>259%) and electrode pulverization in Sn-based anodes (theoretical specific capacity: 993 mA·h/g) for next-generation lithium-ion batteries (LIBs), we designed a CoSn₂/Sn@C core−shell structure to accommodate the volume change and stabilize the cycling performance of LIBs. The Co₃O₄/SnO₂ nanocubes were firstly prepared from CoSn(OH)₆ precursor via a sintering and oxidation process in an air atmosphere. Subsequently, glucose was coated on Co₃O₄/SnO₂ nanocubes, and then the composites were sintered under a reduction atmosphere to form CoSn₂/Sn@C nanocubes with a core−shell structure. The CoSn₂/Sn@C nanocubes exhibited shortened ion transport paths and excellent reaction kinetics due to their well-designed structures and controlled compositions. The electrochemical test results show that an excellent specific capacity of 672.2 mA·h/g after 500 cycles at a current density of 1 A/g was maintained for CoSn₂/Sn@C electrode. The core−shell structure design of the elaborated CoSn₂/Sn@C nanocubes holds significant implications for the development of high-performance anode materials for LIBs.

O3-type NaNi_0.5Mn_0.5O₂ cathode material was modified with NH₄VO₃ solution through a one-step liquid-phase method. The effects of NH₄VO₃ solution treatment on the phase structure and electrochemical performance of NaNi_0.5Mn_0.5O₂ were investigated. X-ray diffraction reveals that the use of auxiliary solvent and secondary heat treatment induces the formation of a V₂O₃/P2/O3 multiphase structure. The electrochemical results indicate that the multi-level structure can alleviate Jahn-Teller distortion and suppress irreversible phase transitions. Besides, the in-situ reconstruction layer can hinder the formation of hydrated phases, further enhancing the environmental stability of NaNi_0.5Mn_0.5O₂. Consequently, the modified NaNi_0.5Mn_0.5O₂ cathode material achieves an excellent capacity retention of 74.9% after 1000 cycles at 5C (1C=150 mA/g), whereas the original sample only retains 42.6% of its capacity. These results indicate that NH₄VO₃ surface treatment is an effective strategy for improving the stability of NaNi_0.5Mn_0.5O₂.