Lepidolite smelting slag，a voluminous solid waste generated during lithium extraction from lepidolite，is produced at an annual rate of millions of tons. These slags still retain significant amounts of valuable metals，such as lithium （Li），rubidium （Rb），and cesium （Cs），and therefore possess considerable recovery potential. However，current approaches to their resource utilization face several challenges：conventional methods for use in building materials fail to effectively recover the valuable metals contained in the slag，resulting in resource wastage；meanwhile，existing hydrometallurgical lithium recovery technologies mainly focus on extracting lithium alone，overlooking the synergistic recovery of associated metals such as Rb and Cs. Moreover，the dissolution mechanisms underlying the leaching process remain unclear，which hinders further process optimization. To address these issues，this study developed a synchronous sulfuric acid leaching process. The effects of key parameters-including liquid-to-solid ratio，sulfuric acid concentration，leaching temperature，and leaching time-on the leaching rates of Li，Rb，and Cs were systematically investigated，and the leaching kinetics and synchronous leaching mechanisms were explored in depth. The results showed that efficient and synergistic leaching of Li，Rb，and Cs could be achieved under the following optimal conditions：leaching temperature of 80 ℃，sulfuric acid concentration of 20%，liquid-to-solid ratio of 5∶1 g·ml⁻¹，and leaching time of 2 h. Under these conditions，the leaching rates of Li，Rb，and Cs reached 91.72 %，90.40 %，and 93.16 %，respectively. Through systematic product characterization and kinetic analysis，this study revealed the intrinsic mechanism of the synchronous leaching process. Sulfuric acid primarily disrupted the crystal structure of silicate minerals in the lithium slag，releasing occluded Li⁺，Rb⁺，and Cs⁺ ions into the solution. Concurrently，the calcium sulfate surface coating formed during the reaction played a critical role：it inhibited the inward diffusion of H⁺ and hindered the outward migration of dissolved metal ions such as Li⁺，Rb⁺，and Cs⁺，especially in the later stages of leaching. Kinetic studies indicated that the leaching process followed the shrinking core model，with a rate-controlling mechanism governed by a combination of chemical reaction and internal diffusion. Detailed kinetic analysis yielded apparent activation energies of 37.759，14.076，and 35.015 kJ·mol^-1 for the leaching of Li，Rb，and Cs，respectively. These kinetic parameters offered important insights into the rate-limiting steps of the process and provide a theoretical foundation for its further optimization. The synchronous sulfuric acid leaching process developed in this study offered advantages such as a short flowsheet，simple operation，and high metal recovery. It presented a practical and feasible technical route for the comprehensive resource utilization of lepidolite smelting slag. The successful development of this process not only facilitated the effective recovery of strategic metal resources and reduced solid waste accumulation but also significantly enhanced resource utilization efficiency. Furthermore，this study contributed to strengthening China's supply security for critical strategic metals and promotes the establishment of a high-value recycling system for metallurgical solid wastes，thereby providing new technical support for the sustainable development of the metallurgical industry.

W-Cu composites/joints have attracted extensive attention in application areas such as electrodes，high-voltage electrical contacts，and plasma-facing components in magnetic confinement fusion reactors，owing to their favorable combination of thermal and mechanical properties. However，joining W and Cu remains a significant challenge，mainly due to the substantial differences in their physical and chemical properties. These include large mismatches in thermal expansion coefficients and elastic modulus，as well as the lack of mutual solubility or intermetallic compound formation in the solid state. Such mismatches can lead to high residual stress concentrations at the interface，potentially resulting in delamination or joint failure during service. Among the various joining methods reported for W-Cu systems （such as diffusion bonding，plasma spraying，explosive welding，and brazing），brazing has emerged as a practical and cost-effective technique due to its relatively low processing temperature，design flexibility，and scalability. The choice of filler metals and brazing parameters play crucial role in determining the microstructure and properties of the resulting joints. Although extensive research has been conducted on the brazing of W and Cu over the past decades，the influence of the brazing atmosphere received quite limited attention. Conducting brazing under a protective gas atmosphere has significant practical value in industrial applications. On the other hand，the presence of protective gases can alter the surface condition of the base metals and potentially affect the wettability of the filler metals. This work systematically investigated the influence of filler metal composition and brazing atmosphere on the microstructure and mechanical properties of W-Cu brazed joints. Four commercially available filler metals were selected：BAg72Cu，BCu89AgP，Ag-27Cu-3Ti and BAg49ZnCuMnNi，all in mass fraction. Brazing was conducted in a muffle furnace under pure N₂ and N₂+H₂ （N₂/H₂=6∶1，volume fraction） atmospheres，and O₂ content was below 0.5×10^-6，respectively. The joining process was performed at 900 ℃ with a holding time of 10 min，followed by furnace cooling. The brazed joints were analyzed in terms of macroscopic appearance，interfacial microstructure，elemental diffusion behavior and mechanical properties (including microhardness and shear strength). The results demonstrated a clear correlation between brazing atmosphere，filler composition，and joint quality. Under a nitrogen atmosphere，BCu89AgP and BAg49ZnCuMnNi yielded visually acceptable joints with well-filled seams and no significant unbonded areas. However，Ag-27Cu-3Ti exhibited uneven filler flow and reacted with the graphite fixture，leading to excessive accumulation of filler on one side and localized graphite adhesion. BAg72Cu showed the weakest bonding behavior，with many joints experiencing delamination of W layer during demolding. In N₂+H₂ atmosphere，BCu89AgP and BAg72Cu both produced joints with good appearance，but Ag-27Cu-3Ti showed intensified reactions with the graphite mold，and BAg49ZnCuMnNi completely failed to wet W-Cu interface，resulting in unjoined specimens. Metallographic and scanning electron microscopy/energy-dispersive spectrometry （SEM/EDS） analyses revealed that all effective joints was absence of a distinct reaction layer or intermetallic phase at W-Cu interface. For BAg72Cu，the brazed seam was composed of α-Cu and Ag-Cu eutectic phases，with no evident elemental interdiffusion into W substrate. BCu89AgP joints consisted of Cu-based solid solution and a ternary eutectic structure containing Cu₃P，Ag，and Cu. These eutectic phases improved wetting and spreading behavior and were largely unaffected by the change in atmosphere，due to the self-fluxing behavior of BCu89AgP. Ag-27Cu-3Ti joints showed a Ti-rich fine-grained region near the edge of the seam，where Ti reacted with graphite and nitrogen to form brittle phases such as TiC and TiN. Elemental mapping showed Ti preferentially dissolved in Cu matrix but was absent in Ag-rich phase. BAg49ZnCuMnNi filler in N₂ atmosphere formed a dense and uniform joint，with clear diffusion of Ni，Zn，and Mn toward W substrate. Ni，in particular，was identified as a key wetting promoter due to its partial solubility in W and ability to form intermetallics such as Ni₄W and NiW. These reactions contributed to enhanced interfacial bonding and mechanical strength. However，in N₂+H₂ atmosphere，this filler failed to spread and wet W and Cu surfaces，confirming that the hydrogen component disrupted the wetting behavior，as previously observed in wetting tests. Mechanical testing showed BAg72Cu joints had the lowest shear strength （9 MPa），due to the lack of metallurgical bonding. BCu89AgP joints exhibited consistent strengths over 200 MPa in both atmospheres，with relatively low porosity and uniform microstructure. Ag-27Cu-3Ti joints reached similar strength levels but exhibited complex fracture morphologies，including stepped features associated with Ti-rich edge zones. The highest shear strength （251 MPa） was achieved by BAg49ZnCuMnNi joints brazed in nitrogen，attributed to enhanced elemental interaction at W interface. Hardness profiling near the interface showed increased hardness values on the Cu side，due to the solution strengthening of Cu substrate caused by interdiffusion between Cu and filler metal. In conclusion，the selection of filler metal and control of brazing atmosphere were both critical to achieving high-quality W-Cu joints. BCu89AgP and BAg49ZnCuMnNi were identified as the most promising filler metals. While BCu89AgP performed well under both atmospheres，BAg49ZnCuMnNi showed superior bonding and mechanical performance in nitrogen but was incompatible with H₂-containing environments. This study provided valuable insights into the microstructure-property relationships in W-Cu brazed joints and offered practical guidance for the fabrication of high-performance components in electronic，thermal，and nuclear applications.

In the context of the global energy transition，the development of advanced energy storage systems is crucial for achieving sustainable development. Among these，magnesium-air batteries have attracted considerable attention due to their significant advantages，including high theoretical energy density，low cost，and environmental friendliness. Magnesium，serving as the sole active material in this battery system，directly determines the discharge capacity and energy density. However，the practical application of magnesium-air batteries is substantially constrained by severe anodic self-corrosion and passivation caused by discharge products. In addition，researchers highlight the "negative difference effect"，wherein the corrosion rate of magnesium can paradoxically increase under higher anodic polarization，leading to unexpected material loss and reduced anodic utilization. This review systematically addressed the primary technological bottlenecks and current research progress associated with magnesium-air batteries，emphasizing strategies aimed at optimizing anode performance. The analysis specifically examined alloying methods to introduce beneficial elements that enhance the anode's microstructure，as well as thermal treatment and plastic deformation techniques to refine grain size and optimize crystallographic texture. A core finding was that refining grain structures and achieving homogeneous distribution of secondary phases significantly enhanced anodic discharge efficiency and corrosion resistance. Specifically，grain refinement increased the density of active reaction sites at grain boundaries，promoting electrochemical reaction kinetics and producing thinner，more brittle discharge products that crack and detach more readily. This process maintained active contact between the anode and electrolyte，thus improving discharge stability and capacity. The uniform distribution of secondary phases further aided in creating evenly distributed corrosion sites，minimizing localized corrosion，and stabilizing the discharge voltage. Texture optimization was recognized as another critical factor for improving electrochemical behavior. Certain crystallographic orientations，when preferentially aligned，could promote more uniform dissolution during discharge，yielding improved electrode utilization. Indeed，studies reported that fine-tuning crystallographic texture led to thinner，more uniform oxide and hydroxide layers on the anode surface，reducing the blockage that typically hinders ionic transport and electron flow. As such，texture engineering stood out as a promising approach in tandem with alloy design. Detailed discussions illustrated that alloying magnesium with elements such as Al，Zn，Li，Ca，Bi，Sr，and various rare earth elements （RE） could significantly mitigate anodic corrosion，reduce parasitic hydrogen evolution，and improve discharge properties. Rare earth elements，including Gd，Y，and Ce，had shown promise in promoting grain refinement，modifying second-phase morphologies，and stabilizing discharge processes. Thermal treatments also played a vital role. Homogenization annealing could reduce compositional segregation and the coarseness of secondary phases，thereby improved corrosion resistance and facilitating more uniform dissolution. Solid-solution treatments could reduce the volume fraction of coarse intermetallics，allowing for a more continuous and uniform passivation layer. Meanwhile，aging treatments could precipitate finely dispersed intermetallic particles，boosting mechanical strength while adjusting local galvanic interactions. Plastic deformation methods-such as extrusion，rolling，equal channel angular pressing （ECAP），friction stir processing （FSP），and multidirectional forging （MDF）-further refined grain size and redistribute second-phase particles. Extrusion dispersed detrimental phases more homogeneously throughout the matrix. Rolling processes could tune crystallographic texture，resulting in improved corrosion resistance and higher anodic utilization. ECAP and MDF subjected the alloy to severe plastic deformation，promoting ultrafine grain structures and breaking apart large，continuous second-phase particles. FSP facilitated localized modifications，enabling microstructure homogenization and elimination of casting defects. These techniques not only enhanced corrosion performance but also stabilized discharge voltages and increase current efficiencies. Notably，magnesium-air batteries exhibited distinct operational differences compared to other metal-air counterparts-such as zinc-air or aluminum-air-given magnesium's relatively low electrode potential and high chemical reactivity. The formation of a porous discharge layer，predominantly composed of Mg（OH）₂，could significantly affect anodic dissolution kinetics. Hence，controlling discharge-product morphology and shedding behavior was central to stable long-term performance. Finally，this review provided an outlook on the prospective development of magnesium anode materials. Future research should concentrate on elucidating multi-scale relationships among grain structure，second-phase distribution，crystallographic texture，and electrochemical performance. Novel alloy systems-particularly those incorporating multiple beneficial elements without exacerbating self-corrosion-were paramount. Likewise，advanced manufacturing techniques，in-situ characterization，and computational modeling would refine the understanding of corrosion and discharge processes. Together，these approaches aimed to establish a robust framework for the large-scale application of magnesium-air batteries，supporting their potential to serve as lighter，environmentally friendly，and economically viable power solutions in consumer electronics，marine systems，and grid-level energy storage.

As a rare light metal exhibiting exceptional nuclear and physicochemical properties，beryllium has found extensive utilization in nuclear energy，high-energy physics，aerospace engineering and other fields. Owing to its unique combination of attributes including low density，high specific strength，superior corrosion resistance，remarkable thermal conductivity，minimal neutron absorption cross-section，and significant neutron scattering cross-section，beryllium serves critical functions as：1） moderator and reflector components in nuclear reactors；2） beam pipe material in particle accelerators for high-energy physics experiments；3） structural elements in spacecraft and inertial guidance systems；and 4） reflector substrates in optical systems. However，prolonged exposure to γ-radiation during operational service induces crystallographic defects （e.g.，point defects and dislocations） that progressively degrade the mechanical integrity of beryllium components. It is necessary to study the effect of γ-irradiation on the mechanical properties of beryllium. Three groups of beryllium specimens were subjected to γ-irradiation at dose levels of 10，100，and 1000 kGy respectively，with an unirradiated group serving as the control. Triplicate specimens were tested in each group. The compression test，scanning electron microscopy （SEM） and X-ray diffraction analysis （XRD） were performed on the beryllium specimens before and after irradiation to investigate the effects of γ-irradiation on the compression mechanical properties，surface microstructure and crystal structure of beryllium. The true stress-strain curves，compression mechanical properties，SEM images，roughness，XRD patterns and dislocation density of beryllium specimens with varying γ-irradiation doses were analyzed. And according to the data obtained from the compression test of beryllium specimens with different γ-irradiation doses，the irradiation hardening constitutive model was established. The results showed that irradiation hardening and embrittlement affected on beryllium specimens by γ-irradiation，resulting in enhanced strength and reduced ductility. With the increase of γ-irradiation dose，the compressive elastic modulus and compressive strength showed continuous growth，while the maximum strain continued to decrease. At the maximum tested dose of 1000 kGy，both the compressive elastic modulus and compressive strength of beryllium specimens reached their peak values，the compressive elastic modulus increased by 97.6% from 56.58 to 111.78 GPa，the compressive strength increased by 55.0% from 221.00 to 342.54 MPa，while the maximum strain decreased to its lowest value，decreasing by 32.6% from 0.555% to 0.374%. The irradiation hardening and embrittlement of beryllium were attributed to the substantial irradiation defects generated by γ-irradiation. During the irradiation process，γ-rays bombard the lattice atoms，resulting in a large number of point defects within the beryllium specimens，such as vacancies and interstitial atoms. These point defects migrated and interacted to form cavities and dislocation loops and accumulated at crystal boundaries in the specimens. When beryllium specimens underwent plastic deformation under external forces，irradiation defects increased the resistance to dislocation movement，making it difficult for crystal slip to occur，leading to material hardening and enhancing the compressive strength and elastic modulus of beryllium. On the other hand，the irradiation defects weakened crystal boundaries，causing crystal boundary cracks to initiate from the microscopic crystal slip，resulting in material embrittlement and reducing the maximum strain of beryllium. In XRD patterns of beryllium specimens，the diffraction angle corresponding to the （101） diffraction peak of Be decreased with the increase of irradiation dose，which indicated that the aggregation of a large number of irradiation defects expanded the interplanar distance of beryllium crystals. This structural evolution led to irradiation expansion in beryllium specimens. Meanwhile，γ-irradiation destroyed the microstructure of beryllium，concurrently enlarging the size of internal cavities and elevating dislocation density in beryllium. Notably，the higher the γ-irradiation dose，the larger the size of internal cavities and dislocation density in beryllium，but the increase in dislocation density gradually tended to saturate. At low irradiation doses，the dislocation density increased rapidly with the increase of γ-irradiation dose. When the irradiation dose reached a certain level，the size of internal cavities grew，and the increase in dislocation density became more gradual. As the size of internal cavities expanded to a certain extent，the surface of internal cavities absorbed vacancies and interstitial atoms，promoting the recombination of irradiation defects，and the growth of dislocation density tended to saturate. The increase in the size of internal cavities and dislocation density drove the aggregation of irradiation defects，resulting in the formation of micropores and protrusions on the surface of beryllium specimens，and the surface roughness increased with the increase of irradiation dose. By analyzing the compression test results of beryllium specimens with different γ-irradiation doses，an irradiation hardening constitutive model for beryllium was established based on Johnson-Cook constitutive model. Compared to the traditional Johnson-Cook model，the modified model incorporated an irradiation dose parameter G to quantify the effects of irradiation hardening on the mechanical properties of beryllium. The irradiation hardening constitutive model could accurately describe the compressive mechanical behavior of beryllium specimens within the range of irradiation doses from 0 to 1000 kGy.

Advances in materials science and welding technology have placed increasingly stringent demands on the performance of aluminum alloy welding wires. Currently，however，high-quality aluminum alloy welding wires produced in China still exhibit notable shortcomings，including coarse grain size，inadequate surface quality，poor wire-feeding stability，and unstable arc behavior. These deficiencies are closely associated with microstructural characteristics such as texture and recrystallization. Therefore，systematic investigation into the microstructure of aluminum alloy welding wires is essential to provide a theoretical foundation for producing high-quality wires.In this work，the cast-extruded 5356 aluminum alloy wire blanks （composition in mass fraction：5.10% Mg，0.25% Si，0.40% Fe，0.10% Cu，0.10% Zn，0.10% Mn，0.15% Cr，0.08% Ti，bal. Al） was subjected to thermal compression deformation using a Gleeble thermal simulation tester. The constitutive equation and processing map were established based on the experimental data. The microstructure and surface morphology of 5356 aluminum alloy under different deformation rates were characterized by electron backscatter diffraction （EBSD） and scanning electron microscopy （SEM）. This study systematically examined the evolution of grain size，grain boundaries，dynamic recrystallization，dislocation density，Schmid factor，surface morphology，and texture during hot compression.The results indicated that high temperature and low deformation rate were beneficial for the hot deformation of 5356 aluminum alloy. At true strain of ε=0.7，the safe processing window for 5356 aluminum alloy wire blank lay within the range of temperature of T=430~480 ℃ and deformation rate of $\dot{\epsilon }$=0.01~1 s⁻¹. According to the processing map，three specimens deformed under ε=0.7，T=450 ℃，$\dot{\epsilon }$=0.01，0.1 and 1 s⁻¹ were selected for EBSD analysis.Grain size was found to significantly influence texture evolution and surface quality. The average grain size of the wire blanks increased gradually with increasing deformation rate （7.47，8.55 and 9.45 μm），hindering grain rotation and grain-boundary migration and thereby affecting texture development. Moreover，finer grains improved deformation uniformity；as grain size decreased，the strain difference between grain interiors and grain-boundary regions was reduced，leading to more homogeneous deformation and better surface quality after processing. At $\dot{\epsilon }$=0.01 s⁻¹，the wire blank exhibited the smallest grain size （7.47 μm），the most uniform grain distribution，and the fewest surface defects.Dynamic recrystallization （DRX） was influenced by the combined effects of subgrains，geometrically necessary dislocations （GNDs），and the fractions of high-angle grain boundaries （HAGBs） and low-angle grain boundaries （LAGBs）. Subgrains served as the nucleation sites for DRX. With increasing deformation rate，the variation trend of HAGBs fraction coincided with that of the recrystallized zone，while opposing the trend of LAGBs fraction. HAGBs acted as favorable nucleation sites that promoted recrystallization. At $\dot{\epsilon }$=0.1 s⁻¹，the higher deformation rate increased the activation energy for deformation，enhancing dislocation multiplication and accumulation，which resulted in a denser distribution of LAGBs compared to $\dot{\epsilon }$=0.01 s^-1 condition. A further increase in deformation rate （$\dot{\epsilon }$=1 s^-1） led to pronounced work hardening and a rise in GNDs density. LAGBs continuously absorbed dislocations and eventually transformed into HAGBs. The heat generated during deformation also promoted the growth of subgrains and recrystallized grains，leading to the formation of a characteristic "necklace" structure，typical of dynamic recrystallization. Moreover，new grains in wire blank predominantly nucleated via grain-boundary bulging，confirming that discontinuous dynamic recrystallization （DDRX） was the dominant softening mechanism.During hot deformation，the wire blank was dominated by soft-oriented grains. Schmid factor values under the three deformation rates were relatively high，mainly distributed between 0.4 and 0.5，indicating that the grain orientations were favorable for slip and that processes such as grain rotation and grain-boundary migration actively occurred.With increasing deformation rate，different fiber textures transformed mutually，following the evolutionary path：<101>→<001> and <111>→<101>. Goss and P textures were interconvertible with B texture；initially，Goss and P textures transformed into B texture，and as deformation rate increased，B texture transformed back into Goss and P textures. Additionally，an increase in the recrystallized zone promoted the transformation of C，Cube_ND，and P textures into B and Q textures.Comprehensive analysis revealed that at$\dot{\epsilon }$=0.01 s⁻¹，the alloy exhibited the highest recrystallized fraction （21.9%），the smallest grain size （7.47 μm），a uniform distribution of recrystallized，subgrain，and deformed grains，and a randomized texture. Consequently，the wire blank demonstrated optimal workability under this condition. Deformation at this rate not only ensured adequate strength of the welding wire but also improved deformation homogeneity，thereby contributing to superior surface quality and overall mechanical properties.

The addition of tungsten （W） improves the high-temperature mechanical properties of TiAl alloys by effectively suppressing atomic diffusion. However，its low diffusivity and high melting point lead to significant microstructural inhomogeneity and complications during melting and solidification. Consequently，the systematic understanding of how W influences the microstructure of TiAl alloys remains limited. To address these challenges，powder metallurgy offers a promising route for obtaining uniform and fine microstructures suitable for detailed investigation. In this work，the effect of W diffusion on microstructure evolution and micro-/nano-mechanical properties was investigated. To promote W redistribution，solid-solution treatments （ST） were performed at three different temperatures within （α+γ） phase region. After ST，all three alloys exhibited similar microstructures，consisting mainly of a pearlite-like matrix and B2 phase. Within B2 phase，γ laths （denoted γ_p） precipitated in W-deficient zones following the Kurdjumov-Sachs （K-S） orientation relationship，forming B2（γ） region. γ_p phase nucleated directly inside B2 grains，with its growth likely governed by discontinuous coarsening. The volume fraction of γ_p within the B2 phase increased with rising ST temperature. Higher temperatures enhance atomic mobility，increasing the diffusion coefficient of W and promoting γ phase precipitation in W-depleted areas. Moreover，reduced interfacial energy at elevated temperatures provides a stronger driving force for direct nucleation，explaining the observed increase in γ_p content. During ST，the α→γ phase transition expels W into adjacent regions，resulting in a supersaturated α phase and inducing lattice distortion. To relieve the distortion energy，the hexagonal structure transforms into a body-centered cubic （B2） phase，leading to the formation of a pearlite-like microstructure. Prior homogenization annealing at 1250 ℃ for 16 h effectively reduced micro-segregation，as confirmed by a residual segregation index δ close to zero. This homogenization promoted uniform W distribution，suppressed phase transformations during subsequent ST，and ultimately yielded a segregation-free lamellar structure. These observations indicate that W segregation significantly hinders the formation of equilibrium lamellar microstructures. Micro-and nano-mechanical tests revealed that microhardness first increased and then decreased with rising ST temperature. The highest hardness of HV 440.0  was achieved after ST at 1320 ℃，followed by a decline to HV 384.3 at 1340 ℃ and HV 365.8 at 1360 ℃. After prior homogenization，hardness remained stable around HV 350.5  regardless of ST temperature. Similarly，the microhardness of B2（γ） region peaked at HV 509.2 after ST at 1320 ℃，dropping to HV 427.0 and HV 430.0  at higher temperatures. In contrast，the pearlite-like matrix showed little dependence on ST temperature，averaging HV 354.0.Nanoindentation tests were conducted to clarify the mechanisms behind these trends. The nanohardness of B2 phase decreased slightly from （7.80±0.39） GPa （1320 ℃） to （7.49±0.37）  GPa （1340 ℃） and （7.62±0.15）  GPa （1360 ℃）. Conversely，γ_p phase exhibited a notable increase from （5.94±0.53）  GPa to （6.09±0.10）  GPa and further to （6.73±0.48）  GPa under the same conditions. Load-displacement curves showed that B2-phase curves nearly overlapped across temperatures，while γ_p-phase curves gradually approached those of B2 phase with increasing temperature. EDS point analysis indicated that higher ST temperatures raised W content in both B2 and γ_p phases，enhancing solid-solution strengthening and thereby increasing nanohardness. Concurrently，the volume fraction of the softer γ_p phase grew due to the elevated nucleation drive at higher temperatures. Thus，microhardness variation is governed by two competing mechanisms tied to W diffusion：solid-solution strengthening and phase-transformation-induced softening. Furthermore，the decreasing nanohardness difference between B2 and γ_p phases reflects improved micromechanical compatibility，which helps dissipate interfacial stress concentrations and promotes more uniform deformation. This work established a theoretical basis for microstructure control through W-diffusion engineering and provided a preliminary quantitative assessment of the associated strengthening effects，offering valuable guidance for the microstructural design of TiAl alloys.

Nuclear power equipment extensively employs metallic materials such as nickel-based alloys and austenitic stainless steel due to their excellent mechanical properties and corrosion resistance. These materials are widely used in pressurized water reactor nuclear power plants，where welding dissimilar metals inevitably poses technical challenges. Dissimilar metal welded joints are commonly located in critical components of nuclear power systems，and their reliability directly influences the safe and stable operation of the plant. Achieving high-quality welding between dissimilar metals in nuclear applications is a complex and technically demanding task with stringent quality requirements，which remains a key focus in nuclear power manufacturing. The primary difficulty stems from differences in the physical and chemical properties of the dissimilar metals，leading to significant chemical and metallurgical in homogeneity during welding，as well as discontinuities in mechanical properties. These discontinuities readily induce welding defects，particularly during the solidification of the molten pool where element segregation often occurs. In welds between nickel-based alloys and austenitic stainless steel，segregation of strengthening elements such as niobium and molybdenum is frequently observed. The depletion of these elements not only weakens the material but also generates internal stresses that can promote crack formation，further degrading the tensile strength，fatigue resistance，creep resistance，and toughness of the weld. Given the advantageous characteristics of ultrasound—including high frequency，cavitation effects，and efficient energy transmission through materials—the incorporation of ultrasound into welding processes has attracted considerable research interest worldwide. In this paper，the butt welding of Inconel 718 alloy and 316L stainless steel dissimilar metal plates using the ultrasonic vibration-gas tungsten arc （UV-GTA） welding process was systematically investigated. Ultrasound was applied during welding to examine its effects on macroscopic morphology，microstructure，microhardness，and tensile properties. The roles of ultrasonic mechanical vibration，acoustic streaming，and cavitation in stirring the molten pool were explored，aiming to address issues such as elemental segregation and to enhance weld quality and stability. The findings were expected to demonstrate the potential of UV-GTA for dissimilar metal welding，broaden the application of ultrasonic-assisted arc welding techniques，and provide theoretical and technical support for the safe and reliable operation of nuclear power equipment. The results indicated that conventional GTA welds exhibited poor quality，with severe undercut and edge-biting defects on the joint surface. The average hardness of the weld zone was HV 190，and the tensile strength was the lowest among all samples，measuring only 539 MPa. Fracture surface analysis revealed an uneven distribution of dimple sizes，along with significant enrichment of elements such as Nb，Cr，and Mo in second-phase particles. In contrast，UV-GTA welded joints effectively suppressed undercut defects and improved process stability. The weld appearance was smoother，more continuous，and free from spatter or crater defects. The average hardness of the weld zone increased to HV 230. Moreover，ultrasonic vibration inhibited the formation of Laves phase and reduced the segregation of elements like Cr and Nb，which otherwise adversely affected mechanical properties. The maximum tensile strength reached 690 MPa，20% higher than that of GTA welded joints. These results underscored the considerable potential of UV-GTA method for welding thin dissimilar metals.

NiTi alloys have been widely used in various fields such as healthcare，aerospace，consumer electronics，and robotics due to their excellent shape memory effect，superelasticity，corrosion resistance，biocompatibility，good electrical and thermal conductivity. Near-equiatomic NiTi alloys are those in which the atomic percent of nickel and titanium is close to 1∶1. The nickel content is typically between 50% and 51% （atom fraction），while the titanium content is between 49% and 50% （atom fraction）. This specific composition ratio is essential for the formation of a stable austenitic phase and subsequent martensitic transformation，which is the basis for the superelasticity and shape memory effects of NiTi shape memory alloys. The excellent properties of near-equiatomic NiTi alloys are mainly due to the complex internal martensitic transformation process. In order to meet the specific requirements for material properties in different application scenarios，it is crucial to have a deep understanding and precise control of the microstructure of NiTi alloys. Appropriate heat treatment processes can significantly alter the phase composition and distribution of alloys，affecting the functionality and mechanical properties of the final product. For near-equiatomic NiTi alloys，the martensitic transformation （M_s） temperature is strongly dependent on the nickel content. For every 0.1% （atom fraction） increase in nickel，M_s temperature decreases by more than 10 ℃. Although there is a lot of literature on how various heat treatment schemes can improve the overall properties of near-equiatomic NiTi alloys，there is still a lack of research on the extremely-near-equiatomic NiTi alloys such as Ni_50.1Ti_49.9 alloy. In this paper，the effects of solid solution treatment and annealing treatment on the microstructure and mechanical properties of a near-equiatomic Ni_50.1Ti_49.9 alloy in the cold-rolled state were investigated. In addition，microscopic analysis techniques （e.g. X-ray diffraction （XRD），scanning electron microscope （SEM），electron backscatter diffraction （EBSD），etc.） were used to reveal the intrinsic relationship between microstructure and macroscopic mechanical properties，providing a theoretical basis and technical support for the subsequent development of new high performance NiTi based materials. The results showed that the rolled Ni_50.1Ti_49.9 alloy was mainly composed of B19' martensite，while the content of B2 austenite and B19' martensite in annealed and solid solution alloys was about 1∶1. A large number of martensite laths and a small amount of Ti₂Ni precipitates were found in the alloys. The thermally induced martensite in the solid solution alloy was criss-crossed and uniformly distributed within the austenite grains，with no obvious grain orientation. Differential scanning calorimetry （DSC） curve analysis showed that the phase transformation points of Ni_50.1Ti_49.9 alloy was near room temperature. The presence of dislocations and twinning in the rolled state alloy hinders the thermally induced martensitic transformation and reverse transformation，and its heat absorption and release peaks were relatively flat. After a short period of annealing，the absorption and exothermic peaks of the sample became obvious，and the onset and end temperatures of martensitic transformation and reverse transformation could be clearly distinguished. The solid solution alloy exhibited a two-step transformation process during the cooling stage，i.e.，B2→R→B19'，which was attributed to the stress field around Ti₂Ni precipitated phase suppressing the usual one-step martensitic transformation. The mechanical property tests showed that the rolled Ni_50.1Ti_49.9 alloy had excellent mechanical properties along the rolling direction，with a tensile strength of 1246.7 MPa and an elongation of 17.9%. This excellent performance was due to the texture formed during the rolling process，which optimized grain orientation and promotes effective stress transfer. The tensile curve of the rolled Ni_50.1Ti_49.9 alloy could be roughly divided into two stages：the first stage was the near-linear deformation caused by the intrinsic elastic deformation of the sample and the slow continuous stress-induced martensitic transformation （SIMT）；the second stage was mainly plastic deformation，which might be accompanied by a small amount of SIMT. The annealed state sample exhibited a typical "double yielding" phenomenon during the tensile process. The tensile curve of the annealed state alloy could be roughly divided into four stages：the first stage was the elastic deformation stage；the second stage was caused by the SIMT of B2 austenite，reorientation of self-accommodating of B19' martensitic variant together with a small amount of plastic deformation；the third stage mainly included elastic deformation of martensite，SIMT of residual B2 phase，reorientation of martensite variants previously in unfavorable orientation，and plastic deformation；the fourth stage was the plastic deformation. The strength and strain of the solid solution sample decreased significantly，but exhibited a significant shape memory effect. The tensile curve of the solid solution Ni_50.1Ti_49.9 alloy could be roughly divided into three stages，similar to the deformation mechanism of the first，second，and third stages of the annealed state alloy. After unloading at 4.5% strain，the residual strain could be fully recovered under brief thermal stimulation.

The advantages of SiC fiber reinforced titanium-aluminium （SiC_f/TiAl） composites，such as low density，high strength and high stiffness at high temperatures，have made them a much-needed high-temperature resistant，lightweight and high-strength structural material for aerospace applications. However，the TiAl matrix has low ductility at room temperature and reacts with SiC fibres to form a brittle interfacial reaction layer that can easily become a source of cracks and induce brittle fracture，which severely limits the improvement of mechanical strength of SiC_f/TiAl composites. In this work，SiC_f/C/Mo/TiAl composite was prepared by introducing Mo interfacial modification layer on C-coated SiC fibres by physical vapor deposition （PVD） technique，and their interfacial reaction and TiAl matrix near the interface were modulated to achieve the purpose of strengthening and toughening. Firstly，transmission electron microscope （TEM） was used to identify the products of interfacial reaction layer in both SiC_f/C/TiAl and SiC_f/C/Mo/TiAl composites，and then their interfacial reaction mechanism was thoroughly investigated. It was found that SiC_f/C/TiAl composites formed an interfacial reaction layer of ~2 μm thickness due to the interdiffusion of C and Ti during high-temperature consolidation，and the generation sequence of the reaction products was nanocrystalline TiC mixed with C/fine-crystalline TiC layer/coarse-crystalline TiC+Ti₂AlC MAX phase. This interfacial composition could be well explained by the diffusion-solid solution reaction mechanism，where the formation of the interfacial reaction layer was caused by the mutual diffusion of Ti and C. The diffusion rate of C into TiAl matrix was much larger than that of Ti into C coating，where the diffusion of Ti into C coating led to diffuse aggregation of Ti in C tissue，and the formation of nanocrystalline TiC and C mixed zones with a thickness of only a few tens of nanometers. At the same time，C would also diffuse toward TiAl matrix，which would produce a gradient distribution of C content along the diffusion path. In the early reaction period，C content was sufficient，Ti preferentially reacted with C for a rapid nucleation，forming fine-crystalline TiC layer. After formation of a continuous layer of fine-crystalline TiC，C was going to diffuse through TiC layer by bulk diffusion and continue to react with TiAl matrix. At this time，the grain size of TiAl matrix grew rapidly，and when C entered，two reactions occurred，Ti+C=TiC and 2Ti+Al+C=Ti₂AlC，but Ti₂AlC MAX phase was more likely to be formed，resulting in RL 3 layer mainly consisting of Ti₂AlC MAX phases with Ti-C-Ti-Al stacked structure. When the grain size of the reactive layer close to the TiAl matrix size was larger，it was more difficult to form an ordered stacking of Ti-C-Ti-Al stacking structure，and it was more likely to exist as a Ti（Al）C solid solution phase；therefore，the reaction layer of coarse crystals mainly consisted of Ti₂AlC MAX phase+TiC with large size. The generation of brittle reaction layer led to the tensile properties of SiC_f/C/TiAl composites to be significantly lower than those of SiC_f/C/Mo/TiAl composites. The tensile tests and fracture observations showed that SiC_f/C/TiAl composite exhibited typical brittle fracture and low tensile strength （675 MPa） accompanied by the appearance of penetrating cracks. As for SiC_f/C/Mo/TiAl composite，Mo was introduced as a toughened modified layer between C coating and TiAl matrix. Only a few tens of nanometer thick MoC+Mo₂C reaction layer was formed in SiC_f/C/Mo/TiAl composite，which was much thinner than SiC_f/TiAl composite. The addition of Mo interface modification layer not only inhibited the formation of too thick brittle carbide reaction layer，but also induced the formation of high-toughness β-Ti layer and Al gradient variation TiAl layer in the region near Mo layer，avoiding the interfacial stress concentrations and appearance of cracks under tensile loading，thereby realizing toughening. Through the tensile test and fracture observation，it could be found that the introduction of Mo interfacially modified layer made the penetrating crack disappear in SiC_f/C/Mo/TiAl composite and promoted the fiber pullout phenomenon，and the appropriate interface debonding and fiber pullout could greatly improve the tensile strength of the composites，so that the tensile strength of SiC_f/C/Mo/TiAl composite at 800 ℃ was increased to 1040 MPa.

With the continuous development of technology，the demand for energy in human society is increasing day by day. Fossil fuels，as the main source of energy at present，bring about huge carbon dioxide emissions，which exacerbate the greenhouse effect and cause rapid global temperature rise and seriously affecting the global climate. Reducing the use of fossil fuels and developing renewable and sustainable green energy has become a consensus among all the humanity. However，green energy sources such as solar energy，wind energy，hydropower and geothermal energy suffer from temporal and spatial imbalances and instability，making it difficult to meet the sustainable and stable requirements of human society for energy. Therefore，there is an urgent need to increase research on energy storage devices with high energy density and long cycle life to help make up the shortcomings of the green energy that we are suing now. At present，lithium batteries play an important part of large-scale commercial energy storage devices for their good comprehensive performance. They marvelously meet the above requirements while adapt to the needs of the rising industries such as new energy vehicles and smartphones. However，lithium-ion batteries have high costs and the supply of raw materials is difficult to meet the rapidly increasing demand. Reliable substitutes for lithium batteries are needed. Sodium and lithium are located in the same main group in the periodic table with similar chemical properties. Besides，sodium is widely distributed on Earth，thus it is easy to obtain and cost-effective. Sodium ion batteries work in a similar way to lithium-ion batteries. The smaller Stokes radius of sodium ions in solvents helps them achieve higher ion migration rates and numbers，making sodium ion batteries a potential alternative to lithium-ion batteries. Electrolytes，as the medium for ion transport，play an important part of batteries，greatly affecting their overall performance and safety. The electrolyte systems that use organic solvents are widely studied in sodium ion batteries. However，liquid electrolytes are difficult to control the growth of dendrites，resulting in a decrease in the cycling stability and Coulombic efficiency of the battery. Besides，the dendrites piercing through the separator can cause a short circuit in the battery，and may cause serious safety accidents such as leakage of flammable organic electrolytes and explosions. Developing solid electrolytes instead of liquid electrolytes can greatly reduce safety hazards and improve battery performance. Solid electrolytes can be mainly divided into inorganic solid electrolytes，organic solid electrolytes，and composite solid electrolytes according to their composition. The organic polymer solid electrolyte can be divided into gel electrolyte and pure solid electrolyte according to its morphology. Acrylate polymer solid electrolytes have the characteristics of easy availability，wide application，mature process，and good compatibility with electrode materials，making them popular candidate materials for developing new generation secondary batteries with high energy density and safety. Based on this，according to the role of acrylate in electrolyte，this article reviewed the research progress of acrylic polymer electrolytes in sodium ion batteries by dividing them into three categories：acrylate cross-linked copolymer electrolytes，poly-acrylate gel electrolytes，and poly-acrylate composite electrolytes. Acrylate mainly acted as the crosslinking agents in cross-linked electrolytes. While in the poly-acrylate gel electrolytes，the acrylate played the leading role，determining the electrochemical performance of the electrolyte. As for the poly-acrylate composite electrolytes，the acrylate was regarded as the matrix of electrolyte and play an important part of their electrochemical performance. Then their advantages and disadvantages were discussed. The acrylate cross-linked copolymer electrolytes could achieve multiple functions according to different needs，making them adaptable to complex scenarios. However，the electrochemical performance of acrylate crosslinking agents had not been fully utilized. The research on poly-acrylate gel electrolyte mainly focused on polymethyl methacrylate. Their electrochemical performance could satisfy the basic needs of batteries，while poor mechanical performance limited its application. As for the poly-acrylate composite electrolytes，they were the most widely studied acrylate electrolytes for their good comprehensive performance. They combined the advantages of organic and inorganic components，thus possessing excellent electrochemical，mechanical，and processing properties. They could be divided into three categories：composite with other polymers，composite with active inorganic fillers，and composite with inert inorganic fillers. Compositing with other polymers mainly improved their mechanical strength and stability，while compositing with inorganic fillers mainly enhance their ion conductivity. Compositing with inorganic fillers could provide more ion transport pathways，resulting in higher ion conductivity than inert inorganic fillers. However，the proportion of acrylate in composite electrolytes was often less than half，which failed to fully utilize the excellent electrochemical performance of the acrylate matrix. Besides，the influence of acrylate content on electrochemical properties of composite electrolytes was often ignored. More inorganic fillers increased the cost of batteries. Finally，based on the properties of different categories of acrylate electrolyte，this article proposed corresponding optimization strategies and looked forward to their trends of future development.