A SiC/ZrSiO₄-SiO₂ (SZS) coating was successfully fabricated on the carbon/carbon (C/C) composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resistance. The anti-oxidation properties under different oxygen partial pressures (OPP) and thermal shock resistance of the SZS coating were investigated. The results show that the SZS coated sample under low OPP, corresponding to the ambient air, during isothermal oxidation was 0.54% in mass gain after 111 h oxidation at 1500 °C and less than 0.03% in mass loss after 50 h oxidation in high OPP, corresponding to the air flow rate of 36 L/h. Additionally, the residual compressive strengths (RCS) of the SZS coated samples after oxidation for 50 h in high OPP and 80 h in low OPP remain about 70% and 72.5% of those of original C/C samples, respectively. Moreover, the mass loss of SZS coated samples subjected to the thermal cycle from 1500 °C in high OPP to boiling water for 30 times was merely 1.61%.

Particle erosion induced by foreign object damage (FOD) is an important factor that restricts the working life of thermal barrier coatings (TBCs). A dense α-Al₂O₃ overlay was prepared by magnetron sputtering and vacuum treatment on the surface of 7YSZ TBCs sprayed by plasma spray-physical vapor deposition (PS-PVD) to improve the erosion resistance of the TBCs. The FOD behavior of the TBCs was systematically studied and the interface of α-Al₂O₃/c-ZrO₂ was investigated by first principles calculations. The experimental results show that the erosion rates of the PS-PVD, atmospheric plasma spraying (APS), and electron beam-physical vapor deposition (EB-PVD) TBCs were 324, 248, and 139 μg/g, respectively, while the erosion rate of the Al₂O₃-modified PS-PVD TBCs was reduced to 199 μg/g. In addition, the highest interface adhesive energy of 3.88 J/m² observed in the top configuration model of Al₂O₃/ZrO₂-O is much higher than that of ZrO₂/Ni (2.011 J/m²), which results in improved interface bonding performance.

The development of efficient nonprecious bifunctional electrocatalysts for water electrolysis is crucial to enhance the sluggish kinetics of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). A self-supporting, multiscale porous NiFeZn/NiZn-Ni catalyst with a triple interface heterojunction on nickel foam (NF) (NiFeZn/NiZn-Ni/NF) was in-situ fabricated using an electroplating-annealing-etching strategy. The unique multi- interface engineering and three-dimensional porous scaffold significantly modify the mass transport and electron interaction, resulting in superior bifunctional electrocatalytic performance for water splitting. The NiFeZn/NiZn-Ni/NF catalyst demonstrates low overpotentials of 187 mV for HER and 320 mV for OER at a current density of 600 mA/cm2, along with high durability over 150 h in alkaline solution. Furthermore, an electrolytic cell assembled with NiFeZn/NiZn-Ni/NF as both the cathode and anode achieves the current densities of 600 and 1000 mA/cm² at cell voltages of 1.796 and 1.901 V, respectively, maintaining the high stability at 50 mA/cm² for over 100 h. These findings highlight the potential of NiFeZn/NiZn-Ni/NF as a cost-effective and highly efficient bifunctional electrocatalyst for overall water splitting.

Ti at the oxidation states of Ti³⁺ and Ti⁴⁺, was used to enhance the performance of Na₃V₂(PO₄)₂F₂O by partially substituting vanadium. After doping Ti, the crystallographic volume is decreased due to the less radii of Ti^3+/4+, and the valence of Ti is demonstrated identical to V. During sodium insertion in Ti-doped Na₃V₂(PO₄)₂F₂O, the two discharge plateaus split into three because of the rearrangement of local redox environment. Consequently, the optimized Na₃V_0.96Ti_0.04(PO₄)₂F₂O shows a specific capacity of 123 and 63 mA·h/g at 0.1C and 20C, respectively. After 350 cycles at 0.5C, the capacity is gradually reduced corresponding to a retention of 71.05%. The significantly improved performance is attributed to the rapid electrochemical kinetics, and showcases the strategy of replacing V^3+/4+ with Ti^3+/4+ for high-performance vanadium-based oxyfluorophosphates.

(Zr₅₃Al_11.6Ni_11.7Cu_23.7)_1-x(Fe_77.1C_22.9)_x (x=0-2.2, at.%) bulk metallic glasses (BMGs) were prepared by copper mold suction casting method. Their glass forming ability and physical and chemical properties were systematically investigated. The glass forming ability is firstly improved with increasing x, and then decreased when x exceeds 0.44 at.%. Both glass transition temperature and crystallization temperature are increased, while the supercooled liquid region is narrowed, with Fe-C micro-alloying. The hardness, yielding and fracture strength, and plasticity firstly increase and then decrease when x reaches up to 1.32 at.%. The plasticity of the BMG (x=1.32 at.%) is six times that of the Fe-free and C-free BMG. In addition, by the Fe-C micro-alloying, the corrosion potential is slightly decreased, while the corrosion current density increases. The pitting corrosion becomes increasingly serious with the increase of Fe and C content.

The microstructural characteristics, mechanical properties and creep resistance of Mg-(8%-12%)Zn-(2%-6%)Al alloys were investigated to get a better overall understanding of these series alloys. The results indicate that the microstructure of the alloys ZA82, ZA102 and ZA122 with the mass ratio of Zn to Al of 4-6 is mainly composed of α-Mg matrix and two different morphologies of precipitates (block τ-Mg₃₂(Al, Zn)₄₉ and dense lamellar e-Mg₅₁Zn₂₀), the alloys ZA84, ZA104 and ZA124 with the mass ratio of 2-3 contain α-Mg matrix and only block τ phases, and the alloys ZA86, ZA106 and ZA126 with the mass ratio of 1-2 consist of α-Mg matrix, block τ precipitates, lamellar f-Al₂Mg₅Zn₂ eutectics and flocculent β-Mg₁₇Al₁₂ compounds. The alloys studied with the mass ratio of Zn to Al of 2-3 exhibit high creep resistance, and the alloy ZA124 with the continuous network of τ precipitating along grain boundaries shows the highest creep resistance.

A novel Sb₂O₃/Sb₂S₃/FeOOH photoanode was fabricated via a simple solution impregnation method along with chemical bath deposition and post-sulfidation. The X-ray diffractometry, Raman measurement, and X-ray photoelectron spectroscopy show that the Sb₂O₃/Sb₂S₃/FeOOH thin films are successfully prepared. SEM-EDS analyses reveal that the surface of Sb₂O₃/Sb₂S₃ thin films becomes rough after the immersion in the FeCl₃ solution. The optimized impregnation time is found to be 8 h. The FeOOH co-catalyst loaded Sb₂O₃/Sb₂S₃ electrode exhibits an enhanced photocurrent density of 0.45 mA/cm² at 1.23 V versus RHE under simulated 1 sun, which is approximately 1.41 times compared to the photocurrent density of the unloaded one. Through the further tests of UV-Vis spectroscopy, the electrochemical impedance spectra, and the PEC measurements, the enhancement can result from the increased light-harvesting ability, the decreased interface transmission impedance, and the remarkably enhanced carrier injection efficiency.

A new hydrometallurgical route for separation and recovery of Cu from Cu-As-bearing copper electro- refining black slime was developed. The proposed process comprised oxidation acid leaching of Cu-As-bearing slime and selective sulfide precipitation of Cu from the leachate. The effects of various process parameters on the leaching and precipitation of Cu and As were investigated. At the first stage, Cu extraction of 95.2% and As extraction of 97.6% were obtained at 80 °C after 4 h with initial H₂SO₄ concentration of 1.0 mol/L and liquid-to-solid ratio of 10 mL/g. In addition, the leaching kinetics of Cu and As was successfully reproduced by the Avrami model, and the apparent activation energies were found to be 33.6 and 35.1 kJ/mol for the Cu and As leaching reaction, respectively, suggesting a combination of chemical reaction and diffusion control. During the selective sulfide precipitation, about 99.4% Cu was recovered as CuS, while only 0.1% As was precipitated under the optimal conditions using sulfide-to-copper ratio of 2.4:1, time of 1.5 h and temperature of 25 °C.

To modify the stable thermodynamics and poor kinetics of magnesium hydride (MgH₂) for solid-state hydrogen storage, MIL-100(Fe) was in situ fabricated on the surfaces of TiO₂ nano-sheets (NS) by a self-assembly method, and the prepared TiO₂ NS@MIL-100(Fe) presents an excellent catalytic effect on MgH₂. The MgH₂+ 7wt.%TiO₂ NS@MIL-100(Fe) composite can release hydrogen at 200 °C, achieving a decrease of 150 °C compared to pure MgH₂. Besides, the activation energy of dehydrogenation is decreased to 70.62 kJ/mol and 4 wt.% H₂ can be desorbed within 20 min at a low temperature of 235 °C. Under conditions of 100 °C and 3 MPa, MgH₂+7wt.%TiO₂ NS@MIL-100(Fe) absorbs 5 wt.% of H₂ in 10 min. Surprisingly, 6.62 wt.% reversible capacity is maintained after 50 cycles. The modification mechanism is confirmed that the presence of oxygen vacancies and the synergistic effect of multivalent titanium in TiO₂ NS@MIL-100(Fe) greatly enhance the kinetic and thermodynamic properties of MgH₂.

The interaction between molten Na₂CO₃-NaCl salt and Sb and the solubility of Sb in molten salt were investigated in the temperature range of 700-1000 °C. The results show that the dissolution equilibrium of Sb in molten salt can be achieved in 3 h, and the amount of Sb dissolved in the melt decreases as the viscosity decreases. The solubility limits in an eutectic mixture were determined as 5.42%, 2.42%, 0.75% and 0.68% at 700, 800, 900 and 1000 °C, respectively. A high temperature and appropriate content of NaCl will decrease the dissolution of Sb. The insoluble Sb was collected at the bottom of molten salt. The Sb dissolved on the surface of the molten salt is easily oxidized, whereas the Sb dissolved inside the molten salt is randomly distributed in terms of the form of metal Sb.

Modern hydrometallurgy has been developing for more than 100 years and the related articles keep piling up. Based on a bibliometric analysis of the articles in Hydrometallurgy, the most authoritative journal in the field of hydrometallurgy, we try to catch the research and development trends from a global perspective. Firstly, keywords burstness shows that rare earth, recycling, lithium, ionic liquid, and thorium are the hotspots in recent years, and the economic and technological reasons behind them were discussed in depth. Secondly, the proportion of biohydrometallurgy grows fast from 5% to 13% and the related articles are almost all about bioleaching. There are some new directions such as direct preparation of materials in hydrometallurgical processes and ion-imprinted techniques. Thirdly, the advanced instrument analysis methods such as XAFS (X-ray absorption fine structure), gene sequencing, and micro-CT promote the deep understanding of hydrometallurgy mechanism. Finally, the cooperation network and contribution of the main institutes were mapped.

The microstructure and creep behavior of C/Y₂O₃ synergistically micro-alloyed high-Al and low-Al TiAl alloys prepared by induction skull melting (ISM) technology were investigated by advanced electron microscopy. Microstructure analysis shows that Y₂O₃ particles are dispersed in both alloys; element C is dissolved in low-Al alloys as solid solution, while it exists as Ti₂AlC particles within lamellae in high-Al alloys. Additionally, high-density nanotwins are generated in high-Al alloys. Creep data show that C/Y₂O₃ micro-alloying significantly enhances creep resistance of TiAl alloys. This benefits from the dispersion strengthening of Y₂O₃ particles, precipitation hardening of dynamically precipitated Ti₃AlC particles and lamellar stabilization caused by dissolved C atoms or Ti₂AlC particles. This strategy causes a more significant improvement on creep resistance of high-Al TiAl alloys, which is attributed to extra twin strengthening effect. At 775-850 °C, these alloys fracture in mixed ductile-brittle mode, but the fracture characteristics change with the increase of temperature.

The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses, including electrical conductivity, mechanical properties, local corrosion properties, and slow strain rate tensile stress corrosion tests. Microstructure characterization techniques such as metallographic microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were also employed. The results indicate that the tensile strength of the alloy produced by T6I6 aging is similar to that produced by T6I4 aging, and it even exceeds 700 MPa. Furthermore, the yield strength increases by 52.7 MPa, reaching 654.8 MPa after T6I6 aging treatment. The maximum depths of intergranular corrosion (IGC) and exfoliation corrosion (EXCO) decrease from 116.3 and 468.5 μm to 89.5 and 324.3 μm, respectively. The stress corrosion factor also decreases from 2.1% to 1.6%. These findings suggest that the alloy treated with T6I6 aging exhibits both high strength and excellent stress corrosion cracking resistance. Similarly, when the alloy is treated with T6I4, T6I6 and T6I7 aging, the sizes of grain boundary precipitates (GBPs) are found to be 5.2, 18.4, and 32.8 nm, respectively. The sizes of matrix precipitates are 4.8, 5.7 and 15.7 nm, respectively. The atomic fractions of Zn in GBPs are 9.92 at.%, 8.23 at.% and 6.87 at.%, respectively, while the atomic fractions of Mg are 12.66 at.%, 8.43 at.% and 7.00 at.%, respectively. Additionally, the atomic fractions of Cu are 1.83 at.%, 2.47 at.% and 3.41 at.%, respectively.

Stress corrosion cracking (SCC) is degradation of mechanical properties under the combined action of stress and corrosive environment of the susceptible material. Out of eight series of aluminium alloys, 2xxx, 5xxx and 7xxx aluminium alloys are susceptible to SCC. Among them, 7xxx series aluminium alloys have specific application in aerospace, military and structural industries due to superior mechanical properties. In these high strength 7xxx aluminium alloys, SCC plays a vital factor of consideration, as these failures are catastrophic during the service. The understanding of SCC behaviour possesses critical challenge for this alloy. The main aim of this review paper is to understand the effect of constituent alloying elements on the response of microstructural variation in various heat-treated conditions on SCC behavior. Further, review was made for improving the SCC resistance using thermomechanical treatments and by surface modifications of 7xxx alloys. Apart from a brief review on SCC of 7xxx alloys, this paper presents the effect of stress and pre-strain, effect of constituent alloying elements in the alloy, and the effect of environments on SCC behaviour. In addition, the SCC behaviours of weldments, 7xxx metal matrix composites and also laser surface modifications were also reviewed.

Multi-wall carbon nanotubes reinforced Mg-14Li-1Al composite (MWCNTs/Mg-14Li-1Al) was prepared by the processes of electrophoretic deposition, friction stir processing, and cold rolling. The microstructure and mechanical properties of the composite were investigated. The results show that, the microhardness of the composite is up to HV 84.4, which is 91.38% higher than that of the as-cast matrix alloy (HV 44.1). The yield strength and ultimate tensile strength of the composite are 259 and 313 MPa, which are 135.45% and 115.86% higher than those of the as-cast matrix alloy, respectively, and a high specific strength of 221.98 kN·m/kg is obtained. In the composite, the MWCNTs serve as nucleation particles during the friction stir processing and cold rolling, causing dynamic recrystallization and grain refinement. Furthermore, MWCNTs hinder the movement of dislocations and transfer the load from the matrix alloy, thus improving the strength.

Aluminum matrix composites (AMCs), reinforced with novel pre-synthesized Al/CuFe multi-layered core- shell particles, were fabricated by different consolidation techniques to investigate their effect on microstructure and mechanical properties. To synthesize multi-layered Al/CuFe core-shell particles, Cu and Fe layers were deposited on Al powder particles by galvanic replacement and electroless plating method, respectively. The core-shell powder and sintered compacts were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDX), pycnometer, microhardness and compression tests. The results revealed that a higher extent of interfacial reactions, due to the transformation of the deposited layer into intermetallic phases in spark plasma sintered composite, resulted in high relative density (99.26%), microhardness (165 HV_0.3) and strength (572 MPa). Further, the presence of un-transformed Cu in the shell structure of hot-pressed composite resulted in the highest fracture strain (20.4%). The obtained results provide stronger implications for tailoring the microstructure of AMCs through selecting appropriate sintering paths to control mechanical properties.

A dual-halide solid electrolyte, Li₃YCl₃Br₃, was synthesized using a wet-chemistry route instead of the conventional mechanical ball-milling route. Li₃YCl₃B_r3 exhibits an ion conductivity of 2.08 mS/cm and an electro- chemical stability window of 3.8 V. Additionally, an all-solid-state lithium-ion battery using Li₃YCl₃Br₃ and LiNi_0.83Co_0.11Mn_0.06O₂ (NCM811) as the cathode material achieves a capacity retention of 93% after 200 cycles at 0.3C and maintains a specific capacity of 115 mA·h/g during 2C cycling. This exceptional performance is attributed to the high oxidative stability of Li₃YCl₃Br₃ and the in-situ formation of Y₂O₃ inert protective layer on the NCM811 surface under high voltage. Consequently, the study demonstrates the feasibility of a simple, cost-effective wet-chemistry route for synthesizing multi-component halides, highlighting its potential for large-scale production of halide solid electrolytes for practical applications.

To avoid high crack sensitivity of TiB-Ti composite coating during laser cladding process, network-like structure composite coating was fabricated with laser in-situ technique on titanium alloy using 5 μm TiB₂ powder as the cladding material. The microstructure, phase structure and properties of the coatings were analyzed by SEM, XRD, EPMA, TEM, hardness tester and fretting wear meter. It was observed that the outer ring of the network-like structure was mainly TiB strengthening phase, while the inner ring was α-Ti grain, and the interface between TiB and Ti matrix was very clean and had a consistent orientation relationship. The hardness of the cladding layer with network-like structure gradually decreased from the surface toward the interface, but the average hardness was nearly two times that of the substrate. In the fretting wear test, it was found that the wear resistance of the cladding layer with network-like structure was larger than that of the substrate under low load (40 N). The results revealed that the hardness and fretting wear resistance of the titanium-based composite coating could be improved by the introduction of network-like structure.

A novel method, bath smelting process, was developed to treat molybdenite concentrate aiming at the existing problems of traditional process. To understand the dissolving behavior of MoS₂ in white matte, the binary phase diagram of Cu₂S-Mo₂S was measured by the cooling curve method. The result shows that this system is a simple binary eutectic with a eutectic temperature of (1117.0±3.0) °C and a eutectic composition of (1.70±0.20)% MoS₂ in mass fraction. When the MoS₂ addition exceeds 4.48%, MoS₂ and Cu₂S can form the ternary compound containing CuMo₂S₃ or Cu₂Mo₆S₈. In the temperature range of copper smelting, 1200-1300 °C, molybdenite can dissolve in the cuprous sulfide. At 1200 °C, the solubility of molybdenite can reach 14.8%.

A physics-based temperature-dependent yield strength model without fitting parameters was developed for single-phase FCC high-entropy alloys. The model considered the temperature dependence of lattice friction stress, solid solution strengthening, grain boundary strengthening, dislocation strengthening, and their evolution with temperature to the overall yield strength. The results show that a quantitative relationship between temperature, material parameters, and yield strength was successfully captured by the model. This model can predict the yield strength at different temperatures only by using the easily available material parameters at room temperature. The accuracy of model was well verified by 17 sets of available experimental data over a wide temperature range (4.2-1273 K). Moreover, the contribution of different strengthening mechanisms to the yield strength was quantitatively analyzed and discussed from 4.2 to 1273 K, and some suggestions for improving the temperature-dependent yield strength were put forward.

Thermodynamic simulation was conducted to design a new process of stepwise precipitating NH₄VO₃ and NaHCO₃ from regulating the CO₂ carbonation of Na₃VO₄ solution. Firstly, a new V(V) speciation model for the aqueous solution containing vanadate and carbonate is established by using the Bromley-Zemaitis activity coefficient model. Subsequently, thermodynamic equilibrium calculations are conducted to clarify the behavior of vanadium, carbon, sodium, and impurity species in atmospheric or high-pressure carbonation. To ensure the purity and recovery of vanadium products, Na₃VO₄ solution is initially carbonated to the pH of 9.3-9.4, followed by precipitating NH₄VO₃ by adding (NH₄)₂CO₃. After vanadium precipitation, the solution is deeply carbonated to the final pH of 7.3-7.5 to precipitate NaHCO₃, and the remaining solution is recycled to dissolve Na₃VO₄ crystals. Finally, verification experiments demonstrate that 99.1% of vanadium and 91.4% of sodium in the solution are recovered in the form of NH₄VO₃ and NaHCO₃, respectively.

Aqueous zinc-ion batteries (AZIBs) are promising candidates for the large-scale energy storage systems due to their high intrinsic safety, cost-effectiveness and environmental friendliness. However, issues such as dendrite growth, hydrogen evolution reaction, and interfacial passivation occurring at the anode/electrolyte interface (AEI) have hindered their practical application. Constructing a stable AEI plays a key role in regulating zinc deposition and improving the cycle life of AZIBs. The fundamentals of AEI and the challenges faced by the Zn anode due to unstable interfaces are discussed. A comprehensive summary of electrolyte regulation strategies by electrolyte engineering to achieve a stable Zn anode is provided. The effectiveness evaluation techniques for stable AEI are also analyzed, including the interfacial chemistry and surface morphology evolution of the Zn anode. Finally, suggestions and perspectives for future research are offered about enabling a durable and stable AEI via electrolyte engineering, which may pave the way for developing high-performance AZIBs.

The effects of additives (polyethylene glycol (PEG), sodium dodecyl sulfate (SDS)) and WC nano-powder on the microstructure, relative density, hardness and electrical conductivity of electroplated WC-Cu composite were investigated. The preparation mechanism was also studied. The microstructure of samples was analyzed by XRD, SEM, EDS, TEM and HRTEM. The synergistic effect of PEG and SDS made the WC-Cu composite more compact during the electroplating process. The hardness of WC-Cu composites increased with the increase in WC content, while the electrical conductivity decreased with the increase in WC content. The density of samples tended to increase initially and then decreased with increase in the additive content. When the electroplating solution contained 10 g/L WC nano- powder, 0.2 g/L PEG and 0.1 g/L SDS, the WC-Cu composite exhibited hardness of HV 221 and electric conductivity of 53.7 MS/m. Therefore, the results suggest that WC-Cu composite with excellent properties can be obtained by optimizing the content of additives and WC particles.

To better understand the role of dissolved oxygen (DO) in affecting corrosion behavior of zirconium alloys, the Zr-0.85Sn-0.16Nb-0.37Fe-0.18Cr (wt.%) alloy was corroded in super-heated steam at 500 °C and 10.3 MPa under 1×10^-6 DO and deaeration conditions. The microstructure of the alloy and oxide films was investigated by SEM, TEM, EDS and EBSD. Results show that the corrosion is aggravated under 1×10^-6 DO. Compared with the deaeration condition, the oxide film is looser, and has more micro-cracks and more uneven inner surface under DO condition. For the oxide film forming under deaeration condition, the selected area diffraction (SAED) spots of planes (002)_m, and (101)_t are strong, while those of the (001)_m and are weak. However, for the oxide film forming under DO condition, the SAED spots of planes (111)_m, (200)_m and (101)_t are strong, while those of the (100)_m and (110)_m are weak. The higher DO content in super-heated steam accelerates the growth of oxide films, thus decreasing the corrosion resistance of zirconium alloys.

In order to have a better understanding on the corrosion mechanisms of bulk two-phase Ag-25Cu (at.%) alloys with different microstructures, two bulk nanocrystalline Ag-25Cu alloys and one coarse grained counterpart were prepared by liquid phase reduction (LPR), mechanical alloying (MA) and powder metallurgy (PM) methods, respectively. Their corrosion behavior was investigated comparatively using electrochemical methods in NaCl aqueous solution. Results show that the microstructure of the coarse grained PMAg-25Cu alloy is extremely inhomogeneous. On the contrary, compared with PMAg-25Cu alloy, the microstructures of the nanocrystalline LPRAg-25Cu and MAAg-25Cu alloys are more homogeneous, especially for LPRAg-25Cu alloy. The corrosion rate of MAAg-25Cu alloy is higher than that of PMAg-25Cu alloy, but lower than that of LPRAg-25Cu alloy. Furthermore, the passive films formed by three Ag-25Cu alloys exhibit n-type semiconducting properties. The passive current density of LPRAg-25Cu alloy is lower than that of PMAg-25Cu alloy, but higher that of MAAg-25Cu alloy.

Additive manufacturing (AM) technology has emerged as a viable solution for manufacturing complex- shaped WC−Co cemented carbide products, thereby expanding their applications in industries such as resource mining, equipment manufacturing, and electronic information. This review provides a comprehensive summary of the progress of AM technology in WC−Co cemented carbides. The fundamental principles and classification of AM techniques are introduced, followed by a categorization and evaluation of the AM techniques for WC−Co cemented carbides. These techniques are classified as either direct AM technology (DAM) or indirect AM technology (IDAM), depending on their inclusion of post-processes like de-binding and sintering. Through an analysis of microstructure features, the most suitable AM route for WC−Co cemented carbide products with controllable microstructure is identified as the indirect AM technology, such as binder jet printing (BJP), which integrates AM with conventional powder metallurgy.

TA1 P-Ti/AA6061 composite plate was produced by oxidizing the surface of the titanium plate and adopting a cold roll bonding process. The results revealed that the oxide film (Ti₆O) prepared on the surface of TA1 pure titanium was easy to crack during the cold roll bonding, thereby promoting the formation of an effective mechanical interlock at the interface, which can effectively reduce the minimum reduction rate of the composite plates produced by cold rolling of titanium and aluminium plates. Moreover, the composite plate subjected to oxidation treatment exhibited high shear strength, particularly at a 43% reduction rate, achieving a commendable value of 117 MPa. Based on oxidation treatment and different reduction rates, the annealed composite plates at temperatures of 400, 450, and 500 °C displayed favorable resistance to interface delamination, highlighting their remarkable strength-plasticity compatibility as evidenced by a maximum elongation of 31.845%.

The thermodynamics in zinc hydrometallurgical process was studied using a chemical equilibrium modeling code (GEMS) to predict the zinc solubility and construct the species distribution and predominance diagrams for the Zn(II)-NH₃-H₂O and Zn(II)-NH₃-Cl^--H₂O system. The zinc solubilities in ammoniacal solutions were also measured with equilibrium experiments, which agree well with the predicted values. The distribution and predominance diagrams show that ammine and hydroxyl ammine complexes are the main aqueous Zn species,  is predominant in weak alkaline solution for both Zn(II)-NH₃-H₂O and Zn(II)-NH₃-Cl^--H₂O systems. In Zn(II)-NH₃-Cl^--H₂O system, the ternary complexes containing ammonia and chloride increase the zinc solubility in neutral solution. There are three zinc compounds, Zn(OH)₂, Zn(OH)_1.6Cl_0.4 and Zn(NH₃)₂Cl₂, on which the zinc solubility depends, according to the total ammonia, chloride and zinc concentration. These thermodynamic diagrams show the effects of ammonia, chloride and zinc concentration on the zinc solubility, which can provide thermodynamic references for the zinc hydrometallurgy.

The environmentally-friendly (1-x)Ba(Zr_0.1Ti_0.9)O₃-xBa(Mg_1/3Ta_2/3)O₃ (x=0, 0.02, 0.04, 0.06, 0.08) relaxor ferroelectric ceramics were prepared by the conventional solid-state method and sintered in air at 1400 °C for 2 h. SEM and XRD analyses were utilized to study the surface morphologies and the crystalline structures, respectively. The effects of Ba(Mg_1/3Ta_2/3)O₃ on the phase transformation, dielectric and ferroelectric properties of Ba(Zr_0.1Ti_0.9)O₃ ceramics were also investigated. It is found that the average grain size of (1-x)Ba(Zr_0.1Ti_0.9)O₃-xBa(Mg_1/3Ta_2/3)O₃ (BZT-BMT) perovskite single-phase ceramics decreases as the content of Ba(Mg_1/3Ta_2/3)O₃ (BMT) increases. The relaxor ferroelectric behavior with diffuse phase transition and well-defined frequency dispersion of dielectric maximum temperature is found for the ceramic with increasing x values. 0.98BZT-0.02BMT ceramic shows very good dielectric properties with the relative permittivity and the dielectric loss, measured at 100 kHz as 6034 and 0.01399 respectively at room temperature. Both remnant polarization and coercive field decreased with increasing BMT content, indicating a transition from the ferroelectric phase to the paraelectric phase at room temperature.

The impact of Fe content on the microstructures and mechanical properties of an ultra-high strength aluminum alloy, namely, Al-10.50Zn-2.35Mg-1.25Cu-0.12Cr-0.1Mn-0.1Zr-0.1Ti, was investigated. It is found that the increase of Fe content leads to a notable rise in the volume fraction of microscale secondary phases, including (Cu,Fe,Mn,Cr)Al₇, σ phase (composed of Al, Zn, Mg, and Cu elements), and Al₃(Zr,Ti). The formation of these secondary phases results in the depletion of certain phase-forming elements, thereby significantly reducing the quantity of strengthening phases. Fe imposes minimal impact on tensile strength, but it can significantly alter the elongation (δ). For instance, the average elongation of the alloy with 0.18 wt.% Fe (δ=4.5%) is less than half that of the alloy with Fe less than 0.1 wt.% (δ=9.9%-10.9%). The reduction in elongation is attributed to the combined effects of the formation of coarse secondary phases and the diminished quantity of strengthening phases around these coarse phases.

Laser shock peening (LSP) was used to enhance the high-temperature oxidation resistance of laser melting deposited Ti45Al8Nb alloy. The microstructure and high-temperature oxidation behavior of the as-deposited Ti45Al8Nb alloy before and after LSP were investigated by scanning electron microscopy, X-ray diffraction, and electron backscatter diffraction. The results indicated that the rate of mass gain in the as-deposited sample after LSP exhibited a decrease when exposed to an oxidation temperature of 900 °C, implying that LSP-treated samples exhibited superior oxidation resistance at high temperatures. A gradient structure with a fine-grain layer, a deformed-grain layer, and a coarse-grain layer was formed in the LSP-treated sample, which facilitated the diffusion of the Al atom during oxidation, leading to the formation of a dense Al₂O₃ layer on the surface. The mechanism of improvement in the oxidation resistance of the as-deposited Ti45Al8Nb alloy via LSP was discussed.

The 6061 aluminum matrix composites reinforced with ZnO-coated Mg₂B₂O_5w were fabricated by squeeze casting method and followed by extruded under a technical equivalent condition. The mechanical properties and microstructures of the composites were investigated. The results showed that the elastic modulus of the as-cast composites increased straightly with increasing ZnO coating content. The ultimate tensile strength and yield strength of the as-cast composites rapidly increased initially and then declined with increasing ZnO coating content. However, the elongations of all the as-cast composites had similar values. The elongations of the composites were highly enhanced and the ultimate tensile strength of the composite without ZnO coating was the largest after extrusion. A number of whiskers in the composites with ZnO coating were fractured during the extrusion process, but the whiskers’ breakage extent was limited with the increase of coating content.

The effects of Si content on the microstructure and yield strength of Al-(1.44-12.40)Si-0.7Mg (wt.%) alloy sheets under the T4 condition were systematically studied via laser scanning confocal microscopy (LSCM), DSC, TEM and tensile tests. The results show that the recrystallization grain of the alloy sheets becomes more refined with an increase in Si content. When the Si content increases from 1.44 to 12.4 wt.%, the grain size of the alloy sheets decreases from approximately 47 to 10 μm. Further, with an increase in Si content, the volume fraction of the GP zones in the matrix increases slightly. Based on the existing model, a yield strength model for alloy sheets was proposed. The predicted results are in good agreement with the actual experimental results and reveal the strengthening mechanisms of the Al-(1.44-12.40)Si-0.7Mg alloy sheets under the T4 condition and how they are influenced by the Si content.

A binary Mg-6Zn biodegradable alloy was solution treated to evaluate the effects of resulting microstructure changes on the alloy’s degradation rate and mechanisms in-vitro. The treatment was conducted at 350 °C for 6-48 h. Optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction were used to analyze the as-cast and treated samples. Immersion and electrochemical tests were performed in simulated body fluid at 37 °C to assess the samples corrosion resistance. To confirm the results of the corrosion tests, pH measurement was carried out. It is found that over 24 h solution treatment dissolves intermetallic phases in matrix and produces an almost single phase microstructure. Decreasing the intermetallic phases results in lower cathode/anode region ratios and lowers corrosion rates. The results of the electrochemical and mass loss tests reveal that extended solution treatment improves the corrosion resistance of the alloy. The results also show that solution at 350 °C for 24 h enhances the corrosion resistance of the as-cast alloy more than 60%. In addition, decreasing intermetallic phases in the microstructure accompanied a lower pH rise reduced corrosion rate. Solution treatment is suggested as a corrosion improving process for the application of Mg-Zn alloys as biodegradable implant materials.

Effect of pre-annealing treatment temperature on compactibility of gas-atomized Al-27%Si alloy powders was investigated. Microstructure and hardness of the annealed powders were characterized. Pre-annealing results in decreasing Al matrix hardness, dissolving of needle-like eutectic Si phase, precipitation and growth of supersaturated Si atoms, and spheroidisation of primary Si phase. Compactibility of the alloy powders is gradually improved with increasing the annealing temperature to 400 °C. However, it decreases when the temperature is above 400 °C owing to the existence of Si-Si phase clusters and the densely distributed Si particles. A maximum relative density of 96.1% is obtained after annealing at 400 °C for 4 h. In addition, the deviation of compactibility among the pre-annealed powders reaches a maximum at a pressure of 175 MPa. Therefore, a proper pre-annealing treatment can significantly enhance the cold compactibility of gas-atomized Al-Si alloy powders.

Assessing and accounting for material consumption and environmental impact are necessary to measure environmental externalities of the aluminum industry and to construct an ecological civilization. In this research, life cycle assessment (LCA) theory was used to assess the environmental impact of primary aluminum based on the lime soda Bayer process and different power generation modes, and the sources and distributions of the four selected impact categories were analyzed. The results show that, (1) Negative environmental impact of aluminum industry generally occurs from alumina extraction, carbon anode fabrication and electrolysis, particularly electrolysis and alumina extraction. Primary energy demand (PED), water use (WU), global warming potential (GWP) and freshwater eutrophication potential (FEP) are main environmental impact categories. (2) The environmental load with thermal power is higher than that with hydropower, e.g., for the former, the greenhouse gas emission coefficient of 21800 kg CO₂ eq/t (Al) will be generated, while for the latter, 4910 kg CO₂ eq/t (Al) will be generated. (3) Both power mode methods reflect the energy structure, whereas direct emissions reflect the technical level, indicating the potential for large energy savings and emission reductions, and some policies, related to clean power, energy efficiency and technological progress, should be made for emission reduction.

From a life cycle perspective, the material flow analysis is utilized to investigate the lithium material flows in international trade from 2000 to 2019. The results reveal that at the global level, the total volume of lithium trade grew rapidly, reaching 121116 t in 2019. Lithium trade was dominated by lithium minerals, lithium carbonate and lithium hydroxide rather than final lithium products, indicating an immaturity in global lithium industry. At the intercontinental level, Asia’s import trade and Oceania’s export trade led the world, accounting for 81.22% and 39.68%, respectively. At the national level, China, Japan and Korea became the main importers, while Chile and Australia were the main exporters. In addition, China’s trade volume far exceeded that of the United States. China’s exports were dominated by lithium-ion batteries, while the United States mainly imported lithium-ion batteries, proving that the development of China’s lithium industry was relatively faster.

The effects of 0.02 wt.% Sn addition to Al-4Cu alloy on the phase transformation mechanism from θ′ to θ phase during a long-time heat exposure at 573 K for 100 h and on high temperature strength were studied through microstructure observation and tensile test. It is found that Sn micro-alloying in Al-4Cu alloy completely changes the mechanism of θ′ → θ phase transformation during the long-time heat exposure. In the alloy without Sn addition, rod-like θ phase nucleates and grows on the surface of coarsened disc-like θ? phase. However, with Sn-micro-alloying, θ phase firstly heterogeneously nucleates on β-Sn particles, and then grows into much coarser needle-like phase. Trace addition of Sn significantly increases the yield strength of T5-samples at both room temperature and 573 K, because addition of Sn increases the number density of θ′ particles and reduces its size. But, after the long-time heat exposure, the high temperature (573 K) strength of Al-4Cu alloy is severely degraded because Sn accelerates the phase transformation from θ′ to θ phase.

In order to improve the manufacturing efficiency of high-chromium superalloys, an innovative extreme high- speed laser metal deposition (EHLMD) process was used. The growth behavior of precipitated phases, high-temperature mechanical properties, wear resistance, and corrosion resistance of EHLMD K648 superalloy were investigated and compared with conventional laser metal deposition (CLMD) using transmission electron microscope, tensile tester, wear tester and electrochemical workstation, respectively. The results reveal that the precipitated phase size in EHLMD K648 superalloy is significantly smaller than that in CLMD K648 superalloy. Moreover, EHLMD K648 superalloy demonstrates higher tensile strength at 700 °C, superior wear resistance, and excellent corrosion resistance compared to CLMD K648 superalloy. Consequently, the K648 superalloy manufactured through EHLMD technique exhibits favorable comprehensive properties.

Stereolithography (SLA) combined with a two-step post-processing method “oxidation-reduction” was developed to fabricate pure copper with high complexity. The copper slurries for SLA were prepared, and particularly the influence of volume fraction of copper on the properties of copper slurries was investigated. In the two-step post-treatment process, organics were removed by oxidation and copper powder was oxidized simultaneously, and then the oxidized copper was reduced into highly reactive copper particles, improving the sintering activity of the copper green body and enhancing the relative density of the sintered part. The results show that curing depth of the copper slurries decreased with the increase of volume fraction of copper. The viscosity of the pure copper slurry rises exponentially as the volume fraction of copper exceeded 50%. The highest volume fraction of pure copper slurry for SLA is 55%. The specimens exhibited an increase in hardness and electrical conductivity with the increase of volume fraction of copper. Specifically, the maximum values of hardness and conductivity of samples with 55 vol.% copper were HV 52.7 and 57.1%(IACS), respectively.