The densification characterization, phase constitution, precipitation evolution and mechanical performance of Al−Mg−Sc−Zr alloy processed by laser powder bed fusion (LPBF) were systematically investigated. Moreover, the evolution of phase constitution and precipitation behavior after heat treatment were characterized by using X-ray diffraction (XRD) and transmission electron microscope (TEM) analysis. The ultimate tensile strength (UTS) of as-built samples ranged from 396.8 to 414.6 MPa as the scanning speed decreased from 1600 to 1000 mm/s. After post heat treatment, the yield strength (YS) increased to (513.1±1.3) MPa, while the UTS increased from (414.6±5.1) to (539.2±1.5) MPa. The significant improvement of mechanical performance was ascribed to the formation of secondary Al₃(Sc,Zr) precipitates.

The impact of Mn addition on the microstructure, mechanical properties and corrosion behavior of T6-treated Al−Si−Mg−xMn (x=0.2−1.0 wt.%) alloys in a 3.5 wt.% NaCl solution was investigated. The results showed that adding 0.2 wt.% Mn to T6-treated Al−Si−Mg alloys enhanced the corrosion resistance by promoting the formation of α-AlFeMnSi phase, characterized by smaller absolute Volta potential values compared to eutectic Si, β-AlFeSi and π-AlFeMgSi phases. However, the addition of 0.5 wt.% Mn and 1.0 wt.% Mn to the T6-treated Al−Si−Mg alloys increased the size of the α-AlFeMnSi phase. This decreased the properties of T6-treated Al−Si−Mg alloys. Therefore, the optimum Mn content was 0.2 wt.%, providing a novel approach for synergistically enhancing mechanical properties and corrosion resistance of Al−Si−Mg alloys.

The creep response, mechanical properties, and microstructure evolution of the Al−Zn−Mg−Cu alloy were investigated under different initial heat treatment conditions. The results indicate that the density of geometrically necessary dislocations (GNDs) increases during the initial creep stage (<0.5 h) and undergoes dynamic changes in the stable creep stage. During creep aging, the dislocation distribution within the grains becomes more uniform, and additional subgrains are formed. The key factors influencing creep behavior are crystal orientation and the degree of initial precipitation. Grains oriented in the <001> and <101> directions are more susceptible to deformation during the creep process. Based on a strength model, the inhibitory effects of the η' phase in T6 specimens and the GP I zone in T4 specimens on dislocation motion were evaluated. This study demonstrates that selecting an appropriate initial precipitation state is an effective strategy to enhance the creep aging response and to produce high-performance components.

Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055 (SF-7055) Al alloy were investigated. Results show that with the increase of the reduction from 20% to 80%, the grain of cryogenic rolled SF-7055 Al alloy is elongated to form a fiber texture. Numerous proliferating dislocations in the microstructure accumulate into dislocation walls and cells, and eventually form subgrains. These subgrain boundaries divide the original grain, thereby reducing the grain size. Under severe deformation conditions, they even enable the formation of nanograins. Meanwhile, the Cu-rich precipitates in the matrix are also broken and refined under the action of large rolling stress. In the process of cryogenic rolling, the tensile strength and hardness of SF-7055 Al alloy gradually increase, while the plasticity decreases. Moreover, the fracture morphology of cryogenic rolled SF-7055 Al alloy gradually transforms to the ductile and quasi-cleavage hybrid fracture characteristics with increased reduction.

The microstructural evolution and mechanical properties of a vacuum electron beam welded aerospace 5B70 aluminum alloy joint were studied. Quantitative analyses of the phase composition, microstructural evolution, grain size, grain boundary density, and texture changes were performed by X-ray diffraction, scanning electron microscopy, and electron backscatter diffraction. The fusion zone (FZ) comprises equiaxed cellular crystals, and a fine ~20 μm-thick crystal layer forms in the transition zone (TZ) between the FZ and heat affected zone (HAZ). The HAZ closely resembles the base material (BM), retaining the original rolling microstructure. Mechanical property testing shows that the fine-grained layer in the TZ exhibits the highest nanohardness, with the FZ corresponding to the lowest microhardness. The welded-joint sample has lower yield strength, ultimate tensile strength, and elongation after fracture than the BM. These reductions of mechanical properties are primarily influenced by the grain size and distribution of the precipitated phases.

The effect of low concentrated green inhibitors based on Ce-adipate and Ce-chloride on the corrosion of 7075 aluminum alloy in neutral NaCl electrolyte was studied. Corrosion studies were carried out using electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) while scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to conduct surface studies of the alloy upon immersion in the corrosion media. The electrochemical experiments reveal a better inhibitory effect of Ce-adipate than Ce-chloride owing to a higher polarization resistance value (about two times), and a lower corrosion current density. However, both inhibitors act as cathodic inhibitors, show high resistance to pitting corrosion, and enable sufficient protection during prolonged immersion (240 h) in corrosion media. The XPS analysis confirms the presence of cerium in the oxidation states of Ce(III) and Ce(IV) together with the carboxylate —COO⁻ groups and C—C and C—H bonds on the tested specimen with Ce-adipate inhibitor, which are connected to the increased anti-corrosion efficiency.

The commercial AM60 (Mg−6Al−0.3Mn) die-casting alloy was modified through Mn, Ce, and La micro-alloying, each at a content below 0.2 wt.%. SEM, TEM, and Micro-CT were employed to characterize the microstructures and properties of AM60 based alloys. AM60-0.2La alloy showed excellent mechanical properties. The ultimate tensile strength, yield strength, and elongation of (288.0±1.7) MPa, (158.0±1.0) MPa, and (22.0±3.0)% were achieved in AM60-0.2La alloy. Besides, AM60-0.2La alloy exhibited the best corrosion resistance (0.29 mm/a) and fluidity among the investigated four alloys. The excellent mechanical properties and corrosion resistance are mainly attributed to the grain refinement strengthening, low porosity, and low content of large shrinkage porosity, promising for super-sized integrated automotive components.

To investigate the aging mechanisms and elucidate the correlations between unstable microstructure and performance in biodegradable Zn alloys, the accelerated aging experiment was conducted on a high-performance wrought Zn−0.1Mg alloy by annealing at 200 °C for varying durations. The findings reveal that the tensile strength of the alloy rapidly and significantly declines with prolonged annealing time, decreasing from 383 MPa for the as-received alloy to 102 MPa for the alloy subjected to 1440 min of annealing. The primary factors contributing to this considerable reduction in strength are static recrystallization, grain coarsening, and dislocation annihilation. Initially, the ductility of the alloy shows fluctuations, ultimately experiencing a marked decrease after extended annealing. This decline is linked to the grain growth and heightened texture intensity, while the unusual increase in ductility observed between 30 and 120 min of annealing is likely due to the formation of twins. In addition, due to rapid grain growth and an increase in precipitates and twins, the corrosion resistance of the alloy in Hank’s solution has worsened, with the corrosion rate rising from 0.037 to 0.069 mm/a following 300 min of annealing.

The interrupted fatigue test method was utilized to investigate the damage evolution mechanism of the notch high-cycle fatigue (NHCF) in Ti-55531 alloy with a multilevel lamellar microstructure. The results reveal that significant microvoids and microcracks predominantly initiate at α/β interfaces under various notch root radii (R). Notably, even under larger R (0.75 mm), mutual interactions of stacking faults (SFs)−deformation twins, twins−twins, and SFs−SFs are observed. Furthermore, with decreasing R (0.34 and 0.14 mm), the volume fraction of SFs escalates significantly and twins are almost absent. Moreover, activated prismatic slip system decreases with a decrease in Schmidt factor and with the further decrease in R. Finally, strain localization near α/β interfaces contributes to the initiation of fatigue microcracks.

Laser remelting (LR) was used as an auxiliary post-treatment process for the Ti6Al4V titanium alloys fabricated by laser powder bed fusion (LPBF). Optical microscope (OM), scanning electron microscope (SEM) and electron back scattering diffraction (EBSD) observations showed that the grains in melted zone (MZ) transformed into equiaxial grains with an average size of 1.31 μm, and the grains in heat affected zone (HAZ) were refined. Moreover, the texture intensity dropped significantly from 13.86 to 6.35 in MZ and 10.79 in HAZ. The temperature gradient (G) to solidification rate (R) ratio decreased when the laser scanning speed slowed down to a certain extent in the LR process, which effectively improved the highly preferred orientation and filled the hole defects in the surface of LPBF-Ti6Al4V. Furthermore, the hardness, wear resistance and corrosion resistance of the surface of the LPBF samples were improved by LR treatment.

A multistage solution treatment process was applied for nickel-based single crystal superalloys, complemented by various aging durations and cooling rates. The microstructure was characterized by scanning electron microscopy (SEM) to observe the γ' phase. Additionally, phase field simulations were conducted to model the growth of γ' precipitates during aging and analyze their morphological evolution. The experimental results demonstrated that the multistage solution treatment effectively eliminated eutectic phases and carbides. Moreover, samples aged for 10 min exhibited larger and more rectangular γ' precipitates compared with those aged for 5 min. Notably, secondary γ' precipitates were observed in samples subjected to water cooling. Two indices for quantifying rectangularization were proposed and successfully applied. Based on the simulation results, lattice mismatch induced coherency stresses and elevated stress triaxiality along the <111> direction contributed to the rectangularization of the γ' phase.

The influence of varying levels of impurity elements on the hot corrosion resistance of the DD98M alloy in Na₂SO₄+NaCl salt at 950 °C was investigated. The results indicate that the corrosion resistance of the DD98M alloy significantly decreases with an increase in impurity content, and the presence of nitrogen leads to an increase in alloy porosity. These porosities promote the rapid diffusion of molten salt and oxygen into the alloy, resulting in a bilateral diffusion of oxygen and sulfur, which leads to an accumulation of these elements at the oxide−matrix interface. This process contributes to the formation and propagation of interfacial cracks. A growth model was developed for hot corrosion products in alloys with varying impurity elements.

The use of high entropy alloy as a binder for tungsten heavy alloys offers potential advantages. The 95W-5CoCrFeMnNi alloys (95W-HEAs) were prepared via powder metallurgy at sintering temperatures of 1400−1550 °C. The microstructure analysis revealed that the tungsten phase in 95W-HEAs exhibited a nearly spherical morphology in the HEA binder matrix and the formation of a Cr−Mn oxide mixed phase was observed. The sintering temperature exerted a significant influence on the relative density, grain size, W−W contiguity, and mechanical properties of the alloys. The optimal performance was achieved when sintering at 1450 °C, yielding a relative density of 96.61%, a W−W contiguity of 0.528, an average grain size of 18.97 µm, a compressive strength of 2234.82 MPa, and a hardness of HV 400.6. The activation energy for the diffusion of tungsten in the liquid phase formed by HEA binder was calculated to be 354.514 kJ/mol, highlighting its role in controlling grain growth.

An advanced AlCrSiN/AlCrN/CrN/Cr multilayer coating was developed via hybrid multiarc ion plating and high-power impulse magnetron sputtering. The multilayer design enhanced the substrate–coating compatibility, achieving a critical load of 87.8 N. Silicon doping induced nanocrystallization and amorphization, increasing the hardness to 26 GPa. At high temperatures, a nanoscale Cr-rich (Cr,Al)₂O₃ layer was formed, effectively inhibiting oxygen diffusion. The coating underwent unique phase transformations, during which Cr₂N and amorphous Si₃N₄ were converted into dispersed SiCr₃ nanoparticles, which stabilized Cr atoms and suppressed their outward diffusion. Ab initio molecular dynamics simulations revealed that Cr atoms exhibited higher chemical activity and oxygen-capture capability than Al atoms and Si atoms served as diffusion barriers by pinning onto the oxidized surface, considerably improving the oxidation resistance of the coating.

To exploit the combined strengthening effects of nanotwins and carbon nanotubes (CNTs) in Cu matrix composites, the nanotwins with a width ranging from 3 to 30 nm were incorporated into the CNTs-reinforced Cu matrix composites using cryogenic rolling and optimizing the initial particle size of the raw Cu powders. The formation of nanotwins in the Cu matrix composite reinforced by only 0.2 wt.% CNTs is accompanied by the increased dislocation density and refined Cu grain size, resulting in much better strength−ductility synergy than the referenced composite without significant nanotwins formation. The analysis of strengthening and toughening mechanisms demonstrates that the strength increment mainly derives from grain refinement strengthening, dislocation strengthening, and nanotwin strengthening. The strength increment from the contribution of the nanotwins accounts for 19.9% of the overall strength increment for the composite. Meanwhile, the retention of good tensile ductility can be reasonably explained by the increased dislocation accommodation ability due to the formed nanotwins and the decreased induced dislocation proliferation.

The dependence of interface structure and mechanical properties on the modulation layer thickness of VN/TiN−Ni nano-multilayered films deposited on Si substrates using a reactive magnetron sputtering technique was systematically investigated. The films were characterized using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and nanoindentation. The results show that the TiN−Ni layer grows epitaxially on the VN layer, forming a coherent interface between the two sublayers. When the deposition time ratio of the two sublayers (T_TiN−Ni꞉T_VN) is 10꞉12, the films exhibit remarkable mechanical properties, with hardness, elastic modulus, and fracture toughness values of 25.9 GPa, 317 GPa, and 1.88 MPa·m^1/2, respectively. Meanwhile, fracture toughness is improved by approximately 50% compared to the VN monolithic film. This enhancement is attributed to the coherent interface between the sublayers and the phase separation in the TiN−Ni layer.

NaCu_0.2Fe_0.3Mn_0.5O₂ (NCFM) cathode material was synthesized using a simple solid-state reaction, and the effect of calcination temperature on its interlayer spacing and oxygen vacancies concentration was investigated. Through electrochemical testing and material characterizations, higher calcination temperatures increase the electrostatic repulsion between oxygen atoms in adjacent layers, resulting in an expansion of Na layer spacing. This structural change enhances the diffusion kinetics of Na⁺, thereby significantly improving the rate performance of NCFM. Furthermore, elevated calcination temperatures facilitate the reduction of oxygen vacancies, leading to improved crystallinity. This enhancement in crystallinity mitigates structural strain during phase transitions, contributing to improved cyclic stability. Consequently, the optimized NCFM shows an initial discharge specific capacity of 143.3 mA·h/g at 0.1C, with a capacity retention rate of 79.28% after 100 cycles at 1C.

The Furong pluton, located in central Hunan, China, hosts numerous tungsten veins within and around the granite, which are of great economic significance. However, its petrogenesis and related mineralization are poorly constrained. In this study, we used U−Pb dating, petrological and geochemical methods to ascertain the emplacement time, classification of granitic rock, nature of the source rocks, formation mechanism, and its geodynamic implications for the Furong pluton. It is shown that the granite is precisely determined to be formed at ~210 Ma, and belongs to the moderately-fractionated S-type granite. Combined with regional tectonic setting, it is concluded that the pluton was formed due to crust extension and thinning followed by plate collision and compression in South China. It is also revealed that tungsten mineralization and Indosinian granites exhibit a close temporal, spatial and genetic relationships, and further exploration of tungsten deposits within and around the granite in central Hunan, even in South China, is urgently needed.

The hydrogen reduction kinetics of tungsten trioxide (WO₃) was investigated via non-isothermal thermogravimetric analysis. Under the local gas–solid reduction conditions, the particle morphology of tungsten powders was found to be consistent with that of raw material WO₃. The removal of oxygen from tungsten oxide during hydrogen reduction led to the formation of porous structures between the reduced particles, which were obviously different from the polyhedral single-crystal configuration of tungsten powders obtained via chemical vapor deposition. Moreover, the two-stage hydrogen reduction mechanisms of WO₃ under the local gas–solid reduction conditions can be described using the composite autocatalytic function. The activation energies of the first and second stages of the hydrogen reduction of WO₃ were determined to be 121 and 135 kJ/mol, respectively.

The effect of temperature on molten zone length was investigated through simulation to optimize the control of molten zone length during the experimental process. The temperature gradient distribution within the molten zone during zone refining was simulated using COMSOL Multiphysics software and experimentally validated. The simulated molten zone length showed good agreement with the actual measured length. The experimental study of tellurium purification by zone refining was conducted under the following conditions: three passes of zone refining, a hydrogen flow rate of 0.5 L/min, and molten zone movement speeds of 0.5 and 1.0 mm/min. The results demonstrated that the removal efficiencies of impurities such as Ca and Cu exceeded 95%, while the removal efficiency of phosphorus (P) reached over 70%. And the purity of tellurium reached 6N.

The volatilization characteristics and kinetic mechanisms of arsenic were investigated in the temperature range of 623−773 K and pressure ranges of 10−10000 Pa. The experimental results reveal that the evaporation rate increases with increasing temperature and decreasing pressure. Surface reaction control dominates at low pressures (<100 Pa), whereas diffusion control dominates at high pressures (>5000 Pa). The evaporation behavior is successfully described by an Arrhenius-type model for temperature dependence and Logistic model for pressure dependence. Key kinetic parameters, including the critical pressure, maximum evaporation rate and evaporation coefficient, were calculated. The evaporation coefficient varies between 0.010 and 0.223, and the critical pressures vary between 281 and 478 Pa with temperature.

A CFD-based numerical model was employed to quantitatively analyze the flow characteristics of double-side-blown gas−liquid flow. Key parameters were extracted, and Spearman correlation analysis was used to quantify the relationships among bubble behavior, circulating flow, and liquid oscillations. The results show that periodic bubble behavior under steady injection drives the circulating flow of the liquid on both sides. The asynchronism of bubble behavior on both sides results in the alternation of circulating intensity, which significantly enhances gas−liquid mixing efficiency at certain liquid levels of 200 and 220 mm. Flow patterns of the double-side-blown process are classified into weak circulation, strong−weak alternating circulation, and strong circulation modes based on the influence of circulating flows on the penetration depth. The penetration depth in the strong−weak alternating circulation mode is generally greater than that in the single-side-blown process. The imbalance of circulating intensities on both sides primarily leads to the stable fluctuation in the injecting direction, which reveals the appearance of periodic oscillations in the molten bath. The effect of control parameters such as liquid level and gas flow rate on the liquid oscillations were discussed.