This study aimed to enhance the mechanical properties of Al−Li alloys through alternating magnetic field (AMF)-assisted microstructure optimization. During heat treatment, the alloys were exposed to AMF (0.06 T) to systematically study the microstructure, precipitate evolution, and mechanical properties of the alloys. Compared to conventional treatment, at 160 °C and 24 h, AMF increased tensile strength from 517.6 to 523.3 MPa and yield strength from 452.0 to 465.6 MPa, despite a minor elongation reduction (from 7.8% to 6.1%). Microstructural analysis demonstrated that the AMF promoted a more uniform distribution and refinement of the precipitate while inhibiting precipitate coarsening, thereby improving the alloy strength. Under the conditions of 160 °C and 60 mT AMF for 24 h, the Al−Li alloy achieved optimal mechanical performance: the tensile strength reached 523.3 MPa, the yield strength was 465.6 MPa, and the elongation was 6.1%.

The impact of cyclic heat treatment and acid etching on microstructure and corrosion performance of AA7075 was investigated. The microstructure of the alloy was characterized by EPMA, SEM and TEM, and the corrosion resistance of the alloy was studied by intergranular corrosion test. The results show that driven by continuous thermal energy and content gradient generated by the cyclic heat treatment and acid etching, Mg atoms in the surface layer of AA7075 continuously cross grain boundaries. Finally, a compositional gradient layer with a thickness of 185 μm is formed. The surface layer of AA7075 after the dealloying treatment demonstrates reduced intergranular corrosion susceptibility, which is due to low anodic and discontinuously distributed grain boundary precipitates in the dealloyed surface layer.

First-principles calculations were employed to investigate the effects of microalloying element X (X = Yb, Er, Sc, Zr, Hf) interactions on the formation of L1₂ phases in aluminum conductor during aging. The evolution of L1₂-Al₃X core−shell phase was examined. The analysis of interactions among solute atoms reveals a preference for elements to bind at the second nearest neighbors (2NN) distance. Particularly, Yb and Er are found to effectively attract elements to form clusters, with Sc showing a comparatively weaker attraction. Among the tri-solute combinations, Yb−Er−Zr exhibits the strongest mutual attraction. When the solute is segregated on the surface of phase, the segregation energy of remaining solute at the Al₃X/α-Al interface increases gradually with decreasing the element diffusivity. Notably, the segregation energies at the Al₃Yb/α-Al and Al₃Er/α-Al interfaces are similar and relatively low. The values of segregation energies at the interfaces are primarily determined by the solute bonding with surrounding atoms. The interface energy of Al₃X/α-Al is negatively correlated with the element diffusivity. The core−shell interfaces, such as Al₃Er/Al₃Hf, Al₃Yb/Al₃Hf, Al₃Zr/Al₃Er, and Al₃Zr/Al₃Yb, exhibit high interface stability, which is determined by the chemical bond strength between the atoms of microalloying elements at the interface.

Multi-directional forging at 450 °C combined with rolling at 300 °C and 470 °C was applied to a 7050 aluminum alloy prior to heat treatment. The effects of rolling temperature on the microstructure of the alloy were analyzed using optical microscopy, X-ray diffraction, scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. After solution treatment, the average grain size of the alloy measured from high-angle grain boundaries was approximately 20 μm, compared to 100 μm before forging. After artificial aging, the yield strength, ultimate tensile strength and elongation after fracture of the samples rolled at 300 °C were (609.9±5.5) MPa, (662.4±1.7) MPa and (18.5±1.2)%, respectively. In the case where the alloy was rolled at 470 °C, the corresponding values were (592.7±4.2) MPa, (641.0±3.9) MPa and (18.7±0.9)%, respectively.

Aiming at developing Mg alloys with good strength and ductility, an inverse temperature field equal channel angular pressing (ITF-ECAP) technique was proposed to realize the severe plastic processing of Mg−8Bi−1Al−1Zn (BAZ811, wt.%) alloy at low temperature of ~80 °C. As a result, a microstructure consisting of ultrafine grains having an average grain size (AGS) of ~506 nm and fine grains with an AGS of ~1.36 μm was constructed in BAZ811 alloy through 4-pass ITF-ECAP processing. Additionally, a large amount of nano-sized Mg₃Bi₂ phase precipitated during ITF-ECAP processing, and the micro-scale Mg₃Bi₂ particles were greatly refined. Furthermore, the ITF-ECAPed BAZ811 alloy exhibits an ultra-high strength−ductility synergy with yield strength and elongation of (381.5±4.2) MPa and (21.4±1.6)%, respectively. High strength stems from grain boundary, precipitate, and dislocation strengthening; good ductility arises from high intergranular strain coordination and weak texture plasticization.

ZK60 Mg/5083 Al composite plates with cold sprayed Cu powder interlayers were fabricated via hot rolling. The influence of Cu powder on the interfacial microstructure, mechanical properties, and crack propagation behavior of the composite plates was investigated. Results showed that the Cu powder formed a serrated Mg/Cu/Al interface with dispersed nano-polycrystalline and amorphous phases (CuMg₂, Al₂Cu and Al₇Cu₃Mg₆), exhibiting semi-coherent boundaries that enhanced the interfacial bonding strength. Crack propagation analysis revealed that the cracks required additional energy for the penetration of the Cu powder, and cracks preferentially propagated along the Cu/Al interface rather than the Mg/Cu interface. Additionally, the Cu powder promoted dynamic recovery and recrystallization of the grains near the interface, refined the grains (Mg grain size reduced by 27%), and lowered the residual stress, thus improving the deformation compatibility of Mg/Al composite plates. The synergistic effects of dispersed phases, grain refinement, and stress reduction contributed to an 89% improvement in peel resistance.

To enhance the corrosion resistance and wear performance of critical TC4 titanium alloy components in marine equipment while expanding their application scope, Ti−Al−C composite coatings were fabricated on Ti−6Al−4V (TC4) substrates using laser technology (laser cladding and post-laser heat treatment). The microstructural evolution and compositional variations of both laser-cladded and post-laser-heat-treated coatings were investigated. The laser-cladded coating exhibits the best wear performance, with a wear rate of only 28.70% that of the TC4 substrate in artificial seawater environment. This is primarily attributed to the reinforcing effect of TiC particles and the passivating effect of the mechanically mixed products formed during the friction. The post-heat-laser-treated coatings, rich in Ti₂AlC, exhibit outstanding corrosion resistance, with a corrosion current density nearly 1/10 that of the TC4 substrate. This study demonstrates that adjusting the content of Ti₂AlC in laser-cladded coatings can meet the requirements for both corrosion resistance and wear resistance of the alloy in marine environment.

Thermal oxidation was employed as a method to enhance the wear resistance of two novel TiZrAlV alloys. The obtained oxidized coatings, primarily composed of TiO₂, ZrO₂, Al₂O₃, and Ti₂ZrO₆, showed compositional variations influenced by Ti/Zr ratio. Oxidation kinetics revealed distinct kinetic behaviors: the T30Z alloy followed a linear model, whereas the T47Z alloy exhibited parabolic model. Furthermore, the specific wear rate of the T30Z alloy initially decreased from 32.18×10⁻⁴ to 22.21×10⁻⁴ mm³/(N·m) during short durations, but increased after 24 h due to coating performance degradation. In contrast, the T47Z alloy showed a consistent improvement in wear resistance under all conditions, achieving a minimum specific wear rate of 20.87×10⁻⁴ mm³/(N·m). Regarding wear mechanisms, the T30Z alloy exhibited both abrasive and adhesive wear, except after 1 h of oxidation. In comparison, the oxidized coating on the T47Z alloy effectively suppressed adhesive wear, throughout the durations, except 36 h of oxidation.

A crystal plasticity theory was coupled with a phase-field model to investigate the regulating effect of initial lattice misfits on the kinetics evolution and creep properties of Ni-based superalloys. The quantitative characteristics of the γʹ-(Ni,Co)₃(Al,Ta) phase, including morphology, particle size, element partitioning, rafting fracture, and plastic strain evolution, were systematically elucidated in a model Ni−12.2Al−6Co−2.5Ta (at.%) superalloy at 1273 K. The results reveal that reducing the initial lattice misfit between the γ and γʹ phases promotes the partitioning of Al and Ta into the γ matrix and Ni into the γʹ phase, resulting in a higher γʹ volume fraction and slower coarsening rate in the alloys. The γʹ phase undergoes coalescence and coarsening at the primary creep stage, and dissolution and fracture at the secondary creep stage. Alloys with larger initial lattice misfit exhibit higher creep strain, faster raft degradation, and shorter creep life. These findings provide insights for designing high-performance superalloys by optimizing lattice misfits.

A thick-section GH4169 superalloy joint for safety-critical hot-section components was welded via a novel vacuum laser welding process. This process utilizes a vacuum environment to enhance laser welding penetration ability. The microstructure and mechanical properties of the deep-penetration welded GH4169 superalloy were systematically investigated. The volume fraction of brittle Laves precipitate reached an exceptionally low level due to lower heat input and faster cooling rate involved in vacuum laser beam welding. The results indicated that a more than 17.5 mm-deep defect-free laser weld with a sound weld appearance was prepared. The yield strength and ultimate tensile strength of the weld joint in the as-welded condition were 434.6 and 775.9 MPa, respectively. Post-weld heat treatment promoted the precipitation of γ″ phase, which greatly improved the strength of the joint.

The shear property and fracture behavior of ZnSnCuNiAl/Cu solder joints were experimentally investigated under varying aging conditions and strain rates. The results demonstrate that higher aging temperatures can accelerate the diffusion of Cu atoms within the solder, leading to faster growth of intermetallic compounds (IMCs). Furthermore, extended aging durations result in a larger volume of IMCs. Shear tests reveal that the shear strength of the solder joint decreases as the thickness of the IMCs increases, highlighting the detrimental effect of excessive IMC formation on joint integrity. To evaluate the strain rate sensitivity of the solder joints, shear tests were conducted at different strain rates. The results indicate that the shear strength increases with higher strain rates, rising from 21.32 MPa with lower strain rates to 25.98 MPa with higher strain rates. The strain rate sensitivity index was calculated to be 0.052, confirming a positive correlation between strain rate and shear strength. At low strain rates, the solder exhibits internal ductile fracture, suggesting sufficient time for plastic deformation prior to failure. However, as the strain rate increases, the fracture location progressively shifts toward the interface between the solder and the IMCs, resulting in a mixed fracture mode characterized by both ductile feature and brittle feature.

This investigation aimed to analyze the degradation of Eriochrome Black T (EBT) dye using a semiconductor photocatalyst synthesized through mechanical alloying. Various characterization methods, including X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS), were employed to study the properties of the photocatalysts. After 35 h of milling, a ball-milled mixed metal oxide was formed as confirmed by XRD analysis. EDX and XPS analyses revealed significant differences in adsorption features with and without light exposure. The band gap of the 35 h-ball-milled sample was determined to be 4.08 eV. To optimize the EBT degradation, artificial neural network genetic algorithms were used to determine the optimal values for ZnO−La₂O₃ dosage, lamp power, and pH, which were found to be 0.43 g/L, 52.06 W, and 3, respectively. The Z-scheme mechanism, supported by band gap, Fermi level, and work function analysis, was found to be responsible for the photocatalytic process. The photocatalyst demonstrated good reusability and high stability. Overall, the results suggest that the synthesized photocatalyst holds promising potential for the degradation of EBT dye in wastewater treatment.

To overcome the limitations of low activity of single-metal sites and suboptimal interface structures of porous carbon-derived electrocatalysts, a nitrogen-doped carbon-coated CuCo nanoparticle (Cu_xCo_y−NC) catalyst was synthesized using a straightforward grinding method followed by high-temperature pyrolysis. The introduction of CuCo bimetallic sites plays a crucial role in enhancing the intrinsic catalytic activity by diversifying the active sites and optimizing the adsorption energy of oxygen intermediates. Particularly, when the Cu/Co mass ratio is 1:1, the formation of thin-walled carbon nanotubes effectively exposes the embedded metal active sites and refines the interface structure of the porous carbon matrix. As a result, the optimized Cu_xCo_y−NC (1꞉1) catalyst demonstrates exceptional electrocatalytic performance for the oxygen reduction reaction. This enhancement enables the assembled zinc−air batteries to achieve an impressive discharge specific capacity of 812 mA·h/g at 25 mA/cm².

The differences in surface chemical composition among copper, lead, and zinc concentrates, as well as flotation residues obtained from the flotation of cyanide tailings, were investigated, using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). XPS analysis revealed that oxidation of metal and sulfur ions on mineral surfaces induced by cyanide leaching diminished adsorption sites for flotation collectors. ToF-SIMS analysis revealed the surface composition differences of flotation concentrates and residues. Cyanide adsorption onto sulfide mineral surfaces during cyanide tailings leaching was a primary factor limiting the selective adsorption of flotation reagents in the flotation process of cyanide tailings. Additionally, dissolved metal ions from sulfide minerals during cyanide leaching were non-selectively adsorbed onto all mineral surfaces, weakening the boundaries of target minerals and thereby impeding effective flotation separation of sulfide minerals.

To explore the mechanism of chalcopyrite bio-oxidation in acid mine drainage (AMD), a two-factor, three-level chalcopyrite bio-oxidation experiment was designed to assess the effects of visible light and pyrrhotite, which are common environmental factors that influence AMD. Bio-oxidation results, mineral surface morphology, mineralogical phase, elemental composition and electrochemical analyses revealed that visible light and pyrrhotite promoted chalcopyrite bio-oxidation, facilitating enhanced copper release and iron/sulphur oxidation and dissolution. The results demonstrated that visible light contributed to maintaining suitable oxidation–reduction potential and eliminating passivator S⁰. Meanwhile, pyrrhotite enhanced mineral redox activity of chalcopyrite and photoelectron transfer, thus promoting chalcopyrite leaching. In addition, a considerably enhanced interaction between Acidithiobacillus ferrooxidans and chalcopyrite facilitated ferrous iron oxidation, iron/copper release and sulphuric acid generation.

To improve the efficiency of gold extraction and address environmental pollution issues associated with conventional cyanide processes, a novel process was proposed to concentrate gold stepwise by iron matte and Bi-alloy. Firstly, theoretical analysis was conducted to confirm the feasibility of the new process. Three Bi-containing agents were selected to enhance gold capture in iron matte smelting. Subsequently, the effects of agents and Bi content on gold recovery rate in iron matte smelting were investigated. The gold content of slag decreases to 0.10 g/t, with a gold recovery rate of 99.53%. The distribution of Bi in iron matte is beneficial to the gold recovery. Furthermore, molten reverse extraction was conducted, thus resulting in a gold-enriched alloy with a gold content of 182.47 g/t. Finally, the entire process experiment was conducted to recycle iron matte and increase gold content in gold-enriched alloy. The gold content of gold-enriched alloy reached more than 400 g/t.

To reveal the microscopic mechanism of leaching agent anions during the mining process of ion-adsorption type rare earth ore (IAREO), the influence of four anions (SO₄²⁻, Cl⁻, NO₃⁻ and CH₃COO⁻) in magnesium salt leaching system on the desorption behavior of La³⁺ on the kaolinite (001) surface was systematically investigated through a combination of molecular dynamics (MD) simulations and experimental analysis. The results indicated that the anion types affect the concentration distribution, coordination number and diffusion coefficient of La³⁺ in aqueous environments, thereby weakening the binding ability of the water molecule layer surrounding La³⁺ to different degrees, following the decreasing order: SO₄²⁻ > Cl⁻ > NO₃⁻ > CH₃COO⁻. Divalent sulfate ions promote ion-exchange reactions more readily than monovalent anions. Simulation results align well with the experimental findings. The results provide a theoretical basis for selecting efficient leaching agents for IAREO.