Under the dual pressures of energy crisis and climate change，it is crucial to develop alternative energy sources to reduce dependence on fossil fuels. Hydrogen，with its high calorific value，abundant reserves，and environmental friendliness，is regarded as an effective driving force for the decarbonization and transformation of the global energy system. Carbon neutrality demands carbon-free hydrogen production，which high lights the importance of water electrolysis. At present，green hydrogen accounts for only 4% of global industrial hydrogen consumption. It is crucial to improve the energy efficiency and reduce the cost of water electrolysis technology. Water electrolysis consists of the hydrogen evolution reaction （HER）that occurs at the cathode and the oxygen evolution reaction （OER）that occurs at the anode，but the high energy barrier and multiple electron/proton transfer lead to slow reaction kinetics. Precious metal electrocatalysts，such as Pt-based and Ru-based，are expensive and exhibit limited stability. Amorphous catalysts have demonstrated significant potential in the field of water electrolysis due to their unique short-range ordered，long-range disordered structures，along with abundant active sites and other advantages. Amorphous catalysts exhibit many significant advantages in the field of water electrolysis. The disorder of the amorphous structure leads to irregular atomic arrangement，thereby forming a large number of defects and unsaturated bonds on the surface，which become abundant active sites and greatly enhance the adsorption capacity of reactants. Whether in HER or OER，amorphous catalysts can more effectively adsorb key reactants，promote the progress of the reaction，reduce the reaction activation energy，and increase the reaction rate. Compared with traditional crystal catalysts，they can show better performance under the same conditions. It significantly reduces the voltage required for electrolyzing water and improves energy conversion efficiency. Based on this，this article mainly reviewed the research progress of amorphous catalysts in the field of water electrolysis，focusing on the modification of amorphous catalysts by component regulation and the classification of amorphous catalysts in hydrogen evolution reaction （HER）and oxygen evolution reaction （OER）. In terms of the modification of amorphous catalysts by component modulation，there were several important roles. Firstly，by introducing different elements for component regulation，the electronic structure of the amorphous catalyst could be optimized. The incorporation of metal elements with specific electronic configurations could adjust the electron cloud density distribution of the catalyst，thereby optimizing the adsorption energy of the reaction intermediates and improving the catalytic activity. At the same time，changes in the electronic structure could also affect the conductivity of the catalyst，promote the electron transfer process，and further improve the performance of water electrolysis. Secondly，component regulation could enhance the active sites of amorphous catalysts. The combination of different elements could form new chemical bonds and coordination environments，produce unique active sites，and enhance the catalytic effect on hydrogen and oxygen evolution reactions. In addition，reasonable component regulation could improve the stability of amorphous catalysts. Selecting elements with good chemical stability for doping could improve the corrosion resistance and dissolution resistance of the catalyst under harsh water electrolysis conditions. Moreover，component regulation could also optimize the structural stability of the catalyst，reduce structural changes and loss of active components during the reaction，and extend the service life of the catalyst. Next，the catalytic performance of different types of amorphous catalysts （including amorphous precious metal catalysts，amorphous transition metal catalysts，etc.）in the HER and OER in water electrolysis was briefly summarized. By analyzing the structures of different types of catalysts，their catalytic mechanisms in the electrolysis of water could be revealed，providing theoretical guidance for further design and improvement of amorphous catalysts. In general，although amorphous catalysts had unique advantages in catalytic performance，they still faced some challenges，which could be simply summarized as the problem of improving stability and the problem of precise regulation of active sites. Therefore，in response to these problems，we put forward the prospects for the future development of water electrolysis，mainly through structural engineering design，interface effect optimization，self-repair and dynamic regulation，multi-scale regulation strategies，research on the correlation between surface structure and catalytic activity，and research on synergistic effects and multifunctional sites. The aim was to provide a reference basis for further promoting the efficient application of amorphous catalysts in the field of water electrolysis and facilitating their wide application.

Gallium，a critical rare metal，has become increasingly significant due to its wide range of applications in advanced technologies，particularly in semiconductors，solar cells，and light emitting diode （LED）technologies. Its unique properties，such as low melting point，high electrical conductivity，and excellent alloying capabilities，make it indispensable for various electronic and optoelectronic devices. Despite the growing demand for gallium in emerging technologies，its natural abundance is relatively low，primarily in trace amounts within bauxite，a key material used in the aluminum industry. This presents a considerable challenge，as gallium extraction from bauxite remains complex，inefficient，and costly. This paper reviewed gallium's occurrence in bauxite and the challenges in its extraction methods，emphasizing recent advancements. Gallium was found in various forms within bauxite，including ion-exchangeable gallium，lattice-substituted gallium，and surface-adsorbed gallium，and each of these forms presented distinct challenges for extraction. For example，ion-exchangeable gallium，which was loosely bound，couldbe readily extracted through solvent extraction，while lattice-substituted gallium，which was incorporated into the crystal structure of the mineral，required high-temperature treatments or the use of specialized solvents to disrupt the mineral lattice. Surface-adsorbed gallium，which was weakly bound to the surface of bauxite particles，could be recovered through adsorption techniques. For instance，solvent extraction was effective for ion-exchangeable gallium，whereas lattice-bound gallium required high-temperature treatments or specialized solvents to disrupt the mineral structure. Understanding these forms and their interactions was crucial for enhancing extraction efficiency. The predominant method for extracting gallium from bauxite was Bayer process，which was originally developed for aluminum recovery. In this process，bauxite was treated with a sodium hydroxide solution to form a sodium aluminate solution，dissolving aluminum while leaving behind most impurities，including gallium. The challenge was selectively separating gallium from the sodium aluminate solution，due to its low concentrations （0.1%~0.3%）. In this process，bauxite was treated with sodium hydroxide，forming a sodium aluminate solution that dissolves trace amounts of gallium，which must then be selectively separated. Currently，approximately 90% of gallium production relied on this method，utilizing techniques such as precipitation，electrochemical processes，solvent extraction，and ion-exchange adsorption. Precipitation and electrochemical methods were the most established for gallium recovery. Precipitation techniques，including lime milk-electrolysis and carbonation-electrolysis，involved adding lime milk or carbon dioxide （CO₂）to precipitate gallium from solution. Electrochemical methods，which applied an electric current to enhance separation，were also widely used，both face significant challenges，such as low efficiency at the trace gallium concentrations in Bayer process liquor. Additionally，high energy consumption in electrochemical processes and CO₂ emissions from carbonation-electrolysis limited their industrial scalability. Solvent extraction，utilizing organic solvents such as carboxylic and phosphonic acids，had been developed to recover gallium from bauxite-derived liquor due to its high affinity for the metal. Synergistic reagents further enhanced selectivity and efficiency，enabling effective separation of gallium from other metal ions. However，challenges remained，including high reagent costs，environmental concerns related to solvent disposal，and difficulties in scaling for industrial applications due to complex chemistry. Ion-exchange adsorption，particularly using chelating resins，had emerged as a promising technique for gallium recovery. This method selectively adsorbed gallium ions onto a resin，which could then be eluted for recovery. Compared to other techniques，ion-exchange offered higher selectivity，sustainability，and compatibility with Bayer process，achieving high recovery rates with minimal environmental impact. Its simplicity，resin renderability，and seamless integration into Bayer cycle made it an attractive option for large-scale applications. Despite the potential advantages of existing recovery methods，significant challenges persisted，including low gallium concentrations in bauxite-derived liquor，complex interactions with other metal ions，and the high costs and environmental impacts of certain techniques. Recent advancements in materials science had introduced novel chelating resins and hybrid extraction techniques that combine multiple methods to enhance recovery efficiency. These innovations，alongside improvements in electrochemical processes and solvent extraction，were expected to address the rising demand for gallium in high-tech sectors. Future research should focus on developing advanced materials，hybrid methods，and more sustainable processes to improve gallium recovery and minimize the environmental impact of extraction activities. The continued advancement of these technologies would be critical to securing a stable supply of gallium for emerging industries and meeting global technological needs.

The white paper "China's Energy Development in the New Era" directly pointed out that energy saving，low-carbon，and a diversified new type of clean enterprise system is a major development orientation for the future，promising to achieve China's carbon neutrality goal by 2060. Within this strategic framework，clean power becomes more and more important，with hydrogen being a noteworthy efficient and clean energy carrier at home and abroad. Among clean energy technologies，the production of hydrogen from water electrolysis is attractive because it is sustainable and can be used on a massive scale. The key is electrode preparation technology，determining the high rate and low cost of the whole hydrogen production process. By researching the hydrogen adsorption free energy （ΔG_H*）of electrode materials，researchers have concluded that precious metal-based electrodes （Pt，Rh，Re，Pd and Ir）are excellent for hydrogen evolution efficiency，with Pt being the best material. However，due to limited reserves and high costs，their wide application is restricted. As a result，non-precious metal catalysts have attracted attention in recent years. Ni is also considered as a non-precious metal material，due to its better reserves，relatively low price and high performance for alkaline water hydrogen production. Currently，common methods for preparing hydrogen evolution reaction （HER）electrodes include liquid-phase synthesis，chemical vapor deposition （CVD），electrodeposition，plasma spraying，magnetron sputtering，high-energy ball milling，and powder sintering，etc. 1）Liquid-phase synthesis technology：This includes solvothermal/hydrothermal methods，redox reaction methods，sol-gel processes，hydrolysis reactions，and precipitation （including direct precipitation，co-precipitation，and homogeneity precipitation）. Disadvantages are also obvious：the operation is complicated，requires higher control of reaction conditions，and may take too long. 2）CVD：The chemical composition in CVD process is complex，often involving a combination of gas-phase and surface reactions. Volatile precursors are delivered to the reaction zone using carrier gas and/or diffusion，and precursors can react with each other or decompose in the gas phase （homogeneous reactions），or adsorb upon a substrate surface and react with reactive gases （heterogeneous reactions）. Both reactions produce solid films and gas-state by-products on the substrate. This chemical process differentiates CVD from other physical deposition processes like evaporation，sputtering，and molecular beam epitaxy，with advantages like simple equipment operation and maintenance，and control over coating density. However，it has disadvantages like high reaction temperature，complex preparation process，frequent cleaning of the deposition chamber，and potential environmental pollution from exhaust gas requiring proper disposal. 3）Electrochemical deposition：Electrodeposition is a straightforward and low-cost catalyst layer preparation method，which features strong catalytic activity，simple operation，good controllability，and fast deposition rate for obtaining non-equilibrium structures. However，it requires large electrical energy consumption，and the high internal stress in the coating layer often leads to poor performance of the finished product. 4）Plasma spraying：Depending on the environment，it includes vacuum plasma spraying （VPS），low-pressure plasma spraying （LPPS），and atmospheric plasma spray （APS）. It offers good bonding strength and high efficiency and quality，but has low powder usage efficiency and expensive equipment. Under the action of an electric field，water molecules in the solution decompose to form hydrogen ions （H⁺）and hydroxyl ions （OH⁻）through a redox reaction between the anode and cathode. Hydrogen is produced at the cathode and oxygen at the anode. Hydrogen ions receive electrons to reduce into hydrogen at the cathode，while hydroxyl ions release electrons to oxidize into oxygen and water at the anode. Electrochemical hydrogen evolution occurs in three steps：Volmer step，Heyrovsky step and Tafel step. HER kinetics includes two steps：the hydrolysis of hydroxyl ions （OH⁻）and adsorption of hydrogen atoms is called Volmer step，consisting of electron reduction on catalyst surface M for example adsorption H⁺，producing adsorbed hydrogen atoms （H^*）where basic electrolytes contain H₂O as proton source，while acidic electrolytes contain H₃O⁺. The next step is the production of H₂ by Heyrovsky manner，Tafel step，or a combination of both. The formation and conversion of adsorbed hydrogen is key to HER，involving both chemical adsorption and desorption due to hydrogen adsorption free energy. This free energy describes HER reaction rate performance，with a perfect HER catalyst having moderate hydrogen adsorption free energy to ensure efficient and smooth step processes. If the free energy is higher than zero，the reaction rate is lower，a negative value helps binding and facilitates Volmer step. Too strong negative forces inhibit further reaction （Heyrovsky or Tafel steps）. Tafel slope，associated with the rate-controlling step，relates to electrode reaction rate and overpotential. In basic HER，Volmer step is typically the slowest link，influencing the total reaction rate. Controlling reaction conditions or using appropriate catalysts to lower hydrogen adsorption free energy near 0 accelerates Volmer step，improving HER rate. While non-precious metals like cobalt and mammothine have advantages in hydrogen adsorption free energy compared to nickel，storage capacity and price restrict large-scale application. Ni-based electrodes have progressed in HER research and widely studied. Future trends include combining methods to construct heterojunction interfaces or synthesize composite catalysts. Machine learning technology applied to catalytic materials design and discovery has accelerated this field，significantly contributing to the development and optimization of non-PGM （Platinum-group metals）catalysts.

To investigate the synergistic effects of hard reinforcement phases and soft lubricating phases on the microstructure and wear performance of cold-sprayed aluminum-based composite coatings. In this paper, the cold spraying technology was used to prepare pure Al coating and Al/30%B₄C coating, as well as biphase reinforced coatings of 28% B₄C/2% MoS₂, 26% B₄C/4% MoS₂ and 24% B₄C/6% MoS₂, respectively. The microstructure of the coatings was analyzed using scanning electron microscopy （SEM），and the mechanical properties were characterized using a Vickers microhardness tester. The wear performance of the coatings was tested using a friction and wear testing machine. The study aimed to investigate the influence of different ratios of reinforcing phase powders on the phase composition，microstructure，hardness，wear performance and wear mechanisms of the coatings. In the composite coating，the original powder's phase components were retained，and no new phases were found. Due to the low content of MoS₂，the diffraction peak intensity was also low in Al/B₄C/MoS₂ composite coatings，with most strong peaks originating from the aluminum matrix. The significant plastic deformation of aluminum particles occurred during the deposition process，showing flattened deformation characteristics，and the particles were tightly bonded to each other. B₄C particles were randomly distributed at the boundaries of the matrix particles. Although the matrix material exhibited considerable deformation，B₄C particles maintained their original angular shape. MoS₂ in the coating was squeezed at the interface of Al/Al particles，and MoS₂ accumulation was observed at the interface of Al/B₄C particles. With the increase in the original powder MoS₂ content，the uniformity of MoS₂ distribution within the composite coating increased. The porosity of pure aluminum coating （Coating C1）was 1.478%. The addition of hard reinforcement particles significantly reduced the porosity，with a porosity of 0.602% for the coating with only B₄C reinforcement （Coating C2）. The porosity for composite coatings with 2%，4% and 6% added MoS₂ in the raw material was 0.626%，0.678% and 0.684%，respectively. At the interface of Al/B₄C particles，there was a large gradient in the change of Al and B elements，and the high-speed particle impact caused adiabatic heating，forming a mixed region of about 0.8 μm thickness at Al/MoS₂ interface. The introduction of hard phases and the impact of particles resulted in a higher hardness of the composite coating compared to pure aluminum coating. The hardness of the aluminum-based coating with 30% B₄C reinforcement was HV_0.2 90.12，which was 46.4% higher than that of the pure aluminum coating. The hardness improvement was mainly due to the work hardening caused by subsequent particle impacts and the ability of hard B₄C particles to hinder the deformation of Al particles，thus increasing the material's resistance to indentation. With the increase in MoS₂ content，the microhardness of the composite coating with a soft phase increased. The hardness of B₄C/MoS₂ dual-phase-enhanced coating decreases by 4.4%，8.9% and 17.5% compared to 30% single-phase B₄C-enhanced coating （Coating C2）. The average friction coefficient of the pure aluminum coating （Coating C1）was 0.65，and the wear rate was 3.22×10⁻⁶ mm³‧N⁻¹‧m⁻¹. The coating with 30% B₄C （Coating C2）had an average friction coefficient of 0.57 and a wear rate of 1.53×10⁻⁶ mm³‧N⁻¹‧m⁻¹. With the addition of MoS₂，the average friction coefficient of the composite coating decreased from 0.62 （Coating C3）to 0.39 （Coating C5），and the wear rate decreased from 2.01×10⁻⁶ mm³‧N⁻¹‧m⁻¹ （Coating C3）to 1.32×10⁻⁶ mm³‧N⁻¹‧m⁻¹ （Coating C5）. The wear mechanism of the pure aluminum coating was mainly adhesive wear and oxidative wear. When only 30% B₄C was added as a reinforcing phase，the wear mechanism of the coating was mainly abrasive wear，oxidative wear，and fatigue wear. As MoS₂ content in the coating increased，the surface stratification phenomenon intensified，promoting the release of MoS₂ solid lubricating phase towards the friction interface，aiding in the formation of a lubricating film. The formation of the friction film on the surface reduces oxidative wear in B₄C/MoS₂ dual-phase composite coating. When B₄C content was 28% and MoS₂ content was 2%，MoS₂ released to the friction interface was low，and the wear mechanism was mainly abrasive wear with higher oxidative wear. When B₄C content was 26% and MoS₂ content was 4%，MoS₂ released to the friction interface increased，promoting the formation of the surface friction film，and the wear mechanism was mainly abrasive wear，oxidative wear and delamination wear. When B₄C content was 24% and MoS₂ content was 6%，although the higher MoS₂ content in the coating reduced the hardness，the significant reduction in shear action resulted in a lower friction coefficient. The wear mechanism was mainly abrasive wear，oxidative wear and severe delamination wear. The cold spray technology had successfully fabricated B₄C/MoS₂ dual-phase enhanced aluminum-based composite coating while retaining the original powder phase composition，and the addition of B₄C particles in the coating enhanced the deformation resistance of the aluminum coating. The lubricating film formed by the release of MoS₂ in the coating reduced the shear action during the friction process，and the synergistic effect of B₄C and MoS₂ collaboratively lowered the friction coefficient and wear rate of the coating.

Diffusion bonding （DB）is a highly effective technique for joining titanium alloys with equivalent strength，which avoids the defects caused by metal melting and solidification in the traditional titanium alloy welding process. DB is a good choice for many products，such as the high-speed rail，aircraft，space vehicles and so on. Ti-6Al-4V exhibits exceptional comprehensive performance，which accounts for 50% of the total output of titanium alloy at present. However，its processing difficulties lead to high cost and high price of products. Consequently，alternative materials with reduced processing operations and superior structural performance have been developed to replace Ti-6Al-4V. Compared to Ti-6Al-4V，SP-700 titanium alloy has been formulated to possess improved hot formability and machinability. The appropriate processing parameters were investigated and the impact of equiaxed and lamellar structures on the properties of SP-700 titanium alloy sheet diffusion bonding joints was explored. Experimental DB trails were conducted on SP-700 titanium alloy under 760~940 ℃ （2 MPa，2 h），0.5~2 MPa （780 ℃，2 h），1~4 h （780 ℃，2 MPa）. Uniaxial tensile specimens and shear specimens were employed to evaluate the properties of the matrix and the joints. The microstructure and fracture mechanism of the joints were analyzed using optical microscopy （OM）and scanning electron microscopy （SEM）. The results showed that：at 760~900 ℃ （2 MPa，2 h），the yield strength of the matrix gradually decreased with the increase of temperature. At 760 ℃/2 h/2 MPa，the yield strength reached peak value of 1020.3 MPa. The tensile strength of the matrix exhibited a W-shaped trend with increasing temperature. At 860 ℃，the maximum tensile strength of 1115.3 MPa was achieved under 2 MPa and 2 h. The yield strength of the matrix decreased slightly with the increase of pressure. The yield strength of the matrix under 0.5 and 2 MPa （780 ℃，2 h）was 1014.8 and 988.6 MPa，respectively. The tensile strength showed a consistent trend，with values of 1088.1 and 1068.8 MPa，respectively. When the time changed，the yield strength and tensile strength of the matrix after 4 h were significantly higher than those of 1 and 2 h （780 ℃，2 MPa）. 4 h sample demonstrated a tensile strength and yield strength of 1105.9 MPa and 1019 MPa，which were 37.1 MPa and 30.4 MPa higher than those of 2 h sample. With the increase of temperature，pressure，and time，the occurrence of holes and bonding interface diminished，leading to an enhancement of shear strength. SP-700 titanium alloy joint formed at 760 ℃ exhibited bonding interface and large interface pores，indicating suboptimal bonding quality with a shear strength of 410 MPa. With the diffusion bonding process of 780 ℃/2 h/2 MPa，the interface achieved complete bonding，resulting in a shear strength of 490.9 MPa. Under the diffusion bonding process parameters of 860 ℃/2 h/2 MPa，the grains occurred equiaxed coarsening，and both the bonding interface and micropores vanished entirely，facilitating robust bonding between the materials. This configuration exhibited the highest interface bonding strength of 589 MPa. When the bonding pressure was 0.5 MPa，the shear strength of the joint was 443 MPa. Increasing the diffusion bonding pressure to 2 MPa elevated the shear strength by 47.9 MPa. When the time was 1 h，the shear strength was 299.8 MPa，while extending the diffusion bonding time to 4 h enhanced the shear strength by 282.3 MPa. The impact of temperature and time was more pronounced than that of pressure on the quality of diffusion bonding and shear strength. According to the fourth strength theory，the shear strength of the sample at 860 ℃ was consistent with that of the matrix. When the diffusion bonding temperature was higher than 900 ℃，the microstructure type was transformed into a lamellar structure. Although the interface was completely bonded，the mechanical properties of the joint decreased due to the weakened properties of the base metal. This phenomenon underscored the influence of temperature on the plastic deformation，diffusion coefficient，and disappearance of surface protrusion area interface voids during the initial connection stage. Higher temperatures conferred greater plastic deformation capacity to the material，and the diffusion coefficient increased accordingly. Consequently，higher bonding temperatures and pressures supplied additional energy for atomic diffusion，resulting in improved bonding quality. However，excessively high temperature would cause phase transformation of the base metal，which would significantly reduce the performance of the matrix. Therefore，the diffusion bonding temperature of SP-700 titanium alloy should be selected inα+βphase region rather thanβphase region. At low bonding rate （low temperature，short time），the shear fracture morphology presented granular fracture zone and intergranular dissociation fracture，while at high bonding rate （high temperature，long time），the shear fracture mode gradually changed from brittle fracture to brittle+ductile mixed fracture.

With the lead-free and miniaturization of solder joints in microelectronic packaging，intermetallic compounds （IMCs）usually form at the Pb-free solder joints/interconnects，which are the basic premise to realize the metal interconnection. The structures and properties of IMCs have a vital influence for the integrity and reliability of lead-free solder joints. To further analyze and understand the microscopic nature of the physical properties of IMCs，and to explore the influence of IMCs on the interconnection interface in lead-free solder joints，the research mainly focuses on the properties of Cu₆Sn₅ IMCs and the influence of the third element on the properties of Cu₆Sn₅. Cu₆Sn₅ is not only the IMC formed during the reaction between Sn-based lead-free solders and Cu substrates but also serves as the primary constituent of anode materials in lithium-ion batteries. For the study of Cu₆Sn₅，the current study mainly focuses on the growth morphology and its distribution at the interface of solder joints，as well as the study of the thickness and rate of Cu₆Sn₅ growth at the interface. As for Cu₆Sn₅ IMC itself，its mechanical properties also have a very important impact on the reliability of the electronic device interconnection structure. The transformation of the high-temperature phase hexagonal structure to the low-temperature phase monoclinic structure is also a major factor causing the fracture of the electronic interconnection structure. In recent years，it has been found that the addition of some trace elements can inhibit the transition of Cu₆Sn₅ crystal structure，thus improving the stability and reliability of the solder joint interface. The essential reason for how the doping elements inhibits the transformation of Cu₆Sn₅ crystal structure is still unclear，as is the study of the effects of the added elements on the mechanical properties and other properties of Cu₆Sn₅ IMCs. In the application and research of new Sn-based composite lead-free solder，Ni element is usually used as the third element phase added to the lead-free solder or as the main component of the substrate plating layer，Ni as one of the most common elements added to Sn-based lead-free solder，can reduce the prominence of Sn crystal，effectively inhibit the solubility of Cu to the solder internal and reduce the generation of IMCs at the interface，thus playing the role of organization and improve the wettability，solder reliability. Wettability，welding reliability of the role of the appropriate amount of Ni elements can also be at the interface with Sn，Cu reaction to form the corresponding compounds，and increase the connection strength of the welded joints. The addition of Ni elements increases the resistance of the high temperature phase η-Cu₆Sn₅ to deformation. In practical applications，especially in the field of electronic packaging，an important factor affecting its reliability is the ease with which the material can undergo fracture. Bulk modulus （B），Young's modulus （E），and hardness （H）are all important parameters that simply describe the ease with which a material will fracture. From a microelectronic soldering application point of view，the addition of Ni atoms keeps Cu₆Sn₅ in a high-temperature phase structure，which is better for the realization of interconnections and thus improves the reliability and integrity of lead-free solder joints. Cu₆Sn₅ has at least two crystal structures，denoting as the high-temperatureη-Cu₆Sn₅ phase and the low-temperatureη'-Cu₆Sn₅ phase，with an allotropic transformation occurring at 186 ℃. This phase transformation has 2.15% expansion in volume which will create significant internal stress in solder joints and promote the propagation of cracks within the Cu₆Sn₅. Ni is an important alloying element in Sn-based lead-free solders. The addition of Ni has been associated with such benefits as superior solidification micro structures and lower propensity for interfacial IMCs to crack during service. With a remarkable influence on the formation and property of Cu₆Sn₅，it can also increase Young's modulus and hardness of Cu₆Sn₅. Cu₆Sn₅-xNi alloys （x=0，3% and 6%，mass fraction）were prepared by using Ni powder as doping component using high temperature melting technique. The microstructure of the alloy was characterized using X-ray diffraction （XRD），scanning electron microscopy （SEM）and other equipment，and the hardness of the alloy was tested. The effects of different contents of Ni element addition on the properties of high-temperature phase Cu₆Sn₅ IMCs were investigated，and the mechanical properties and density of states of η-Cu₆Sn₅ and （Cu，Ni）₆Sn₅ were calculated by using the first nature principle. The results showed that Cu₆Sn₅-xNi alloys were mainly present in three different forms，all of which were large masses and no other impurities or precipitates were generated. The addition of Ni inhibited the anisotropy of bulk modulus （B），Young's modulus （E），and hardness （H）of η-Cu₆Sn₅，with a more significant decrease in the elastic anisotropy on the （001）plane and a slight increase on the （100）plane. The density of states analysis yields that the orbital hybridization of Ni elements led to an enhanced bonding effect ofη-Cu₆Sn₅，which was conducive to the formation of a stable （Cu，Ni）₆Sn₅ structure.

In this paper，TA1 pure titanium plate was taken as the research object，and the TA1 pure titanium plate was rolled at 650，750，850 and 950 ℃ deformation temperature，respectively，the deformation degree was 60%，and the same heat treatment system was used to heat treat the plate samples. Electron back scatter diffraction （EBSD）technology and tensile tester were used to represent and test the microstructure，texture and mechanical properties of annealed TA1 pure titanium plate. The factors affecting the mechanical properties of TA1 pure titanium plates were analyzed and the mechanism of the influence of the texture on the mechanical properties was revealed. With the increase of the deformation temperature of the annealed plate，the tensile strength and yield strength increased，the post fracture elongation rate decreased，and the grain size increased. At the same time，with the change of the deformation temperature，the texture strength and type of the plate changed obviously. The mechanical properties of the materials were affected by grain size and texture. The growth of grain promoted the decrease of elongation rate after fracture，mainly due to the small grain boundary content of large grain，which hindered the initiation and extension of crack in the stretching process was small，leading to the decrease of plasticity. The change of the strength of TA1 pure titanium plate with the deformation temperature was mainly affected by the change of the texture，which mainly affected the different sliding systems activated during the plastic deformation of materials，and thus affected the mechanical properties of the plate. With the increase of deformation temperature，the plate crystal turned，leading to the difference of texture，which transformed from ‖normal direction （ND）at lower temperature to ‖rolling direction （RD）at low temperature and higher temperature. In the stretching process，the pyramidal texture of ‖ND formed by the annealed plate rolled at lower temperature was easier to activate {10$\overline{1}$0}< 11$\overline{2}$0> prismatic slip system under the transverse direction （TD）loading，which was easier to occur plastic deformation，resulting in lower strength，the pyramidal texture of ‖RD formed by the annealed plate rolled at higher temperature was difficult to activate the {10$\overline{1}$0}<11$\overline{2}$0> prismatic slip system under the TD loading，which was difficult to occur plastic deformation，resulting in higher strength. Therefore，with the increase of the deformation temperature，the transverse strength of the annealed plate showed an increasing trend at room temperature. The transverse yield strength and grain size of polycrystalline metallic materials followed Hall-Petch relation，and for strength factor k value of hexagonal close packed （hcp）metals in the formula was highly dependent on the crystal orientation. Mainly due to the strong mechanical property anisotropy of hcp materials，it would hinder the deformation from one grain to another grain，so that the grain boundary enhancement effect of hcp material was more obvious than that of face-centered cubic （fcc）and body-centered cubic （bcc）materials. k value reflected the magnitude of the slip propagation from a grain to its neighbor grains hindered by the grain boundary. An easier deformation transfer implied a lower boundary hindrance action and would result in a lower value of k. Thus，the effect of texture on k could be described by the ease of deformation transmission between neighboring grains. The propagation of the slip between adjacent grains depended on the externally applied stress and the stress concentration generated by the dislocation stacking at the grain boundaries. Under the action of the same external stress，due to the different crystal orientation between the adjacent particles，the sliding system activated by the particles had different split stress of the external load，and also due to the internal stress generated by the dislocation of the adjacent particles. Therefore，the change in k value with orientation was mainly attributed to the different deformation mechanisms. The deformation mechanism with higher critical tangent stress would correspond to higher k values. With the increase of deformation temperature，k value in Hall-Petch relationship increased，that was，the difficulty of deformation transmission between grains increased，which led to the increase of strength. Under external force，the deformation between adjacent grains with the same orientation was easy to transfer，which reduced the strength of the material and increases the plasticity；random crystal orientation could activate more types of slip system and lead to multiple deformation transfer modes，thus weakening the influence of orientation on the ease of grain boundary deformation transfer. Therefore，the random crystal orientation would make the plate have higher strength and better performance consistency.

The grain structure and dendrite morphology have a significant influence on the mechanical properties of cast Ni-based superalloys. The morphology，size，and distribution of γ' precipitates are also key factors that determine the mechanical properties. The regulation and control of microstructure can be achieved by adjusting the casting process parameters，including the pouring temperature，shell temperature，and cooling rate. The viscosity of the melt decreases with increasing pouring temperature，which enhances the filling ability of the melt. Fine dendrite structures and uniformly distributed precipitates can be easily obtained when the shell temperature is low，which improves the strength，toughness，and fatigue performance of the castings. An increase in cooling rate can significantly refine the dendrites，carbides，borides，and eutectic γ-γ' phase. In addition，solute redistribution occurs during solidification due to its multi-component and non-equilibrium nature of the solidification process. Different casting processes will inevitably alter the distribution of solutes in the solid-liquid phase during the solidification process，thereby affecting the microstructure and properties of the alloy. In this study，a novel Ni-based superalloy JG4247 with high B content was investigated. The test alloy was prepared using vacuum induction melting （VIM）. Three variables including pouring temperature，shell temperature，and cooling rate，were set in the pouring test. The pouring temperature was 1430 and 1460 ℃. The shell temperature was 850，950，and 1050 ℃，and the cooling rate was 8，17，and 27 ℃·min⁻¹. Samples from different states of the casting rods were cut by wire-cutting for the observation of the grain morphologies and microstructure by optical microscope （OM）and scanning electron microscope （SEM）. The effects of casting parameters on the grain size，dendrite spacing，the morphology of γ' phase，and the size of the eutectic γ-γ' phase were investigated. The relationship between the casting parameters and the microstructure of JG4247 alloy was established. The high-temperature tensile properties and stress-rupture properties of the alloy under different casting conditions were tested at 800 ℃ and 800 ℃/580 MPa，respectively. The results indicated that the size of grains and eutectic γ-γ' phases increased with the increasing pouring temperature and shell temperature，but decreased with higher cooling rate. The volume fraction of eutectic γ-γ' phases increased with the increase of pouring temperature and cooling rate，showed a trend of increasing and then decreasing with the increase of shell temperature，had a peak value when the mold shell temperature was 950 ℃. The volume fraction of borides and dendrite γ' phases increased with the increase of pouring temperature，showed a trend of first increasing and then decreasing with the increase of shell temperature，and decreased with the increase of cooling rate. The evolution of microstructures under different casting parameters was accompanied by significant changes in mechanical properties. The high-temperature mechanical properties of JG4247 alloy at 800 ℃ increased with the increase in pouring temperature and showed a trend of first increasing and then decreasing with the increase of shell temperature. The volume fraction of eutectic γ-γ' phases and the borides were the highest at 950 ℃. JG4247 alloy had the best tensile and stress-rupture properties at 950 ℃. The effect of cooling rate on microstructure was mainly reflected in the eutectic γ-γ' phase and dendriteγ' phase. When the cooling rate was 17 ℃·min⁻¹，the grain size and the volume fraction of eutectic γ-γ' phase and dendritic γ' phase reached a reasonable level，thus JG4247 alloy had the longest stress-rupture life. By summarizing the effect of casting parameters on the microstructure and properties of the JG4247 alloy，the optimum casting parameters were determined to be：pouring temperature was 1460 ℃，shell temperature was 950 ℃，and cooling rate was 17 ℃·min⁻¹. Under these conditions，the volume fraction of eutectic γ-γ' phase and dendritic γ' phase was the highest，the dendritic γ' phase possessed irregular petal-shaped morphology，which made the alloy had the best high-temperature mechanical properties. The study provided significant data for controlling the solidified microstructure of JG4247 alloy.

Titanium matrix composites，which can effectively combine the good plasticity of titanium alloy matrix with the high strength and high modulus characteristic of reinforcement phase by introducing an appropriate amount of hard reinforcement phase into titanium or titanium alloy，possess so many advantages such as high specific strength，high specific stiffness，excellent plasticity，and good corrosion resistance，demonstrating broad application prospects in aerospace filed. Melt casting method is widely used in the preparation of titanium matrix composites，that can realize the insitu self-generation of reinforcement phase through the chemical reactions between components，and maintain a good interfacial bonding between the reinforcement phase and alloy matrix，avoiding the adverse influence of oxide pollution in interface caused by external addition on its microstructures and mechanical properties. However，the microstructures of titanium matrix composites prepared by in-situ melt casting method is coarse and the distribution of reinforcement phases is uneven. Therefore，it is necessary to optimize the microstructure and morphology by combing thermal mechanical treatment such as forging，rolling and extrusion with heat treatment to achieve favorable matching of comprehensive mechanical properties. The literature indicated that the material was in three-dimensional compressive stress state during hot rolling deformation，which could utilize the good plasticity of alloy matrix and obtain a large amount of deformation. While the reinforcement phases could achieve relatively uniform distribution following the plastic flow of alloy matrix over a large rang. Recently，the researches on titanium matrix composites in the industry were mainly focused on α and α+β titanium alloys，and its microstructures and mechanical properties were mainly controlled by a single thermal mechanical treatment. There were few reports about near β titanium matrix composites，and the influence of hot rolling coupled forging thermal mechanical treatment on reinforcement phase distribution and microstructures and properties of titanium matrix composites was still unclear. Accordingly，the effects of hot-rolling deformation on microstructures，mechanical properties and work hardening rates of insitu 2%TiB/Ti-55531 （volume fraction）composite material forging stocks were investigated，which were obtained by vacuum consumable arc melting and near-isothermal thermal plastic deformation. The results showed that TiB enhanced phases were broken and distributed directly after hot-rolling deformation in α+β phase region and the fine acicular α phases dispersed in β phase matrix re-dissolve mostly，while the spherical and rod-like α phases precipitate，which resulted in the increase of plasticity and the decrease of strength and work hardening rate. After suffering the solute and aging heat treatment，the morphologies of TiB enhanced phases in the rolled TiB/Ti-55531 composite material microstructures changed little，and the spherical and rod-like α phases grewup and connected into mesh along the crystal boundary in the local area while the fine needle-like secondary α phases were precipitated which obviously optimized the strength and plasticity of rolled composite materials. Its tensile strength，yield strength，and elongation after fracture were 1444.3 MPa，1415.8 MPa and 10.3%，respectively，which achieved favorable matching of strength and plasticity. Otherwise，the annihilation of residual dislocations in TiB/Ti-55531 composite material microstructure was promoted by solute and aging heat treatment which resulted the significant reduce of initial work hardening rate and it was slower than Ti-55531 alloy matrix undergoing the same process program gradually and approaching 0 state quickly with the development of plastic deformation. Electron back-scattered diffraction （EBSD）characterization analysis and kernel average misorientation （KAM）statistical distribution of different pre-deformations indicated that the rolled TiB/Ti-55531 titanium composite material after solute and aging heat treatment had a higher geometric dislocation density than Ti-55531 alloy matrix under low plastic deformation，while it gradually decreased with the continuous plastic deformation and lower than Ti-55531 alloy matrix which was consistent with the variation of work hardening of TiB/Ti-55531 titanium composite material with plastic deformation as mentioned above.

With the rapid development of aerospace field，traditional titanium alloys can no longer meet the requirements. Improving strength while maintaining plasticity has become an important direction in this field，and titanium matrix composites （TMCs）can achieve good strength-plasticity matching through composition modulation. The addition of reinforcing phase can be categorized into direct addition and in-situ autogenous. In-situ autogenous has better interfacial bonding，better compatibility，and more thermodynamic stability than direct addition. Compared with the continuously reinforced TMCs，the discontinuously reinforced TMCs have the advantages of low preparation cost，easy processing，better performance，and isotropy. （Ti，Zr）₅Si₃ and TiB_w whiskers are generated by the in-situ autogenous reaction between Si and TiB₂ reinforcing materials and the matrix，are thermodynamically stable. They exhibit similar density and thermal expansion coefficients to those of the matrix，making themeffective reinforcing materials for titanium alloys. TA19 titanium alloy has the advantages of high strength，good toughness，and good creep resistance at high temperature. Therefore，in this study，TiB₂+Si/TA19 composite blocks were prepared by adjusting the compositions and utilizing low-energy mechanical ball milling and spark plasma sintering （SPS）techniques. SPS process featured a fast heating rate and short holding time，which could refine the grain size and result indense and uniform sintered material. Composites were prepared by a （1+6）h two-step ball milling method. The sintering temperature was 1000 ℃，with a holding time of 10 min and a sintering pressure of 40 MPa. Cylindrical blocks with a diameter of 50 mm and a thickness of 15 mm were prepared. X-ray diffraction （XRD）and metallographic specimens were cut off from the sintered cylindrical blocks using wire cutting. The room temperature tensile properties were tested using an electronic universal testing machine （model UTM5105X）at tensile rate of 1 mm·min⁻¹，with an extensometer having a gauge length of 12.5 mm. The microstructure and fracture morphology of TiB₂+Si/TA19 composites were characterized and analyzed using optical microscope （model AxioVertA1）and scanning electron microscope （model EM30AX+）. The effects of different contents of Si and TiB₂ reinforcing phases on the microstructure and mechanical properties of TA19 titanium alloy were investigated，and the optimal ratio of Si and TiB₂ reinforcing phases was determined. The results showed that when Si was added alone，β-phase was refined，α-sheet layer spacing increased. A large amount of Si dissolved into the matrix as solid-solution strengthening during sintering，while a small amount of Si precipitated out in the form of fine，diffusely distributed silica （Ti，Zr）₅Si₃ when the temperature was lower than that of α/β-phase interface in the temperature reduction process. Strengthening mechanisms included solid solution strengthening and diffusion strengthening. Continued addition of TiB₂ introduced TiB_w whiskers，which were distributed at grain boundaries and provide nucleation sites for Si，resulting in a secondary quasi-reticulation and significant grain refinement. The main strengthening mechanisms were dislocation strengthening，fine grain strengthening，and solid solution strengthening. The addition of 0.3% Si to the composites resulted in a good match of strength and plasticity，and the tensile strength of Si/TA19 composites reached 1181.1 MPa with an elongation up to 16.4%，and the fracture of 0.3%Si/TA19 composites was characterized by a plastic fracture with a typical concave morphology. With the addition of 0.5% TiB₂ on top of 0.3% Si，the tensile strength of TiB₂+Si/TA19 composites reached 1270.1 MPa and the elongation remained at 10.2%. This was attributed to the in-situ generated TiB_w whiskers distributed along the original β grain boundaries，which could effectively enhance the hindering effect of grain boundaries on the dislocation movement. The grain refinement led to an increase in the number of grain boundaries and an enhancement of the hindering effect，and at the same time，the connectivity of the plastic region inside the mesh structure was well ensured，so the strength of the composite material was improved，and the plasticity was not reduced much. When the TiB₂ addition reached 0.7%，the strength was significantly increased to 1316.1 MPa，but the plasticity was significantly reduced to 2.5%. This was because the addition of too many whiskers greatly reduced the connectivity of the matrix，and the debonding of TiB_w with the matrix was also very unfavorable to the plasticity，so the fracture elongation was significantly reduced. With the increase of TiB₂ content on the basis of 0.3% Si，the reinforcing phases were enriched at grain boundaries and dislocation plugging occurs，which led to an increase in the number of microcracks and growth of aggregation during tensile process，resulting in a decrease in the plasticity of the material. The fracture mode of the composites gradually changed from plastic fracture to mixed fracture of plastic and brittle fracture.