In response to the actual working conditions of heating phenomenon of Ti-Al-Mo alloy during long-term service in the field of ultrasonic cutting,the microstructure evolution of Ti-Al-Mo alloy before and after aging treatment was studied using X-ray fluorescence spectrometer(XRF),scanning electron microscope(SEM),and transmission electron microscope(TEM).The results indicate that the aging treatment does not change the crystal structure of the matrix.During the aging treatment,no solute atoms are dissolved from the matrix and no precipitated phase is formed.There are many dislocations in the primaryα-Ti grains of Ti-Al-Mo alloy before aging treatment,which disappear after aging treatment.The solid solubility of Mo atoms inβ-Ti is relatively high,while the solid solubility of Al atoms inα-Ti andβ-Ti is basically the same.And the solid solubility rules of Mo and Al atoms does not change with the aging process.Therefore,although Ti-Al-Mo alloy has a heating effect during long-term service,its matrix crystal structure does not change and only the dislocation configurations are affected to some extent.It can be considered that the aging process has no significant effect on the service life of the alloy.Therefore,the Ti-Al-Mo alloy is suitable for long-term service in ultrasonic cutting scene with heating effect.

Based on the problems of unstable quality,grain coarsening and poor mechanical properties of aluminum alloy during the actual production of large-scale castings,in order to improve the applicability of aluminum alloy,the influences of rare earth La and pulsed magnetic field on as-cast microstructure and mechanical properties of ZL205A aluminum alloy were studied by means of optical microscope(OM),X-ray diffractometer(XRD),scanning electron microscope-enengy dispersive spectrometer(SEM-EDS),hardness tester and universal testing machine.The results show that after adding rare earth La to ZL205A aluminum alloy and applying a pulsed magnetic field,a new rare earth intermetallic compoundβ-LaAlCu is formed in the alloy.Moreover,the primaryα-Al dendrites and the skeletal structure of theθ(Al₂Cu)phase are refined,and their distribution becomes more uniform.As the time of applying the pulsed magnetic field increases,the grain size of the alloy becomes smaller.When 0.1%rare earth La is added and a pulsed magnetic field is applied for 90 s,the yield strength,tensile strength,elongation after breaking and hardness of ZL205A aluminum alloy are 138 MPa,214 MPa,9.5%and 74 HV,respectively.Compared with the original ZL205A aluminum alloy,they are increased by 22.1%,26.6%,6.0%and 13.8%,respectively.

Sintered Nd-Fe-B magnets with different Ga contents were prepared by a powder metallurgy process.The effects of Ga content on the magnetic properties and microstructure of the sintered Nd-Fe-B magnets were systematically studied through a magnetometer,X-ray diffractometer,scanning electron microscope,energy dispersive spectrometer,electron probe microanalyzer(EPMA),and micromagnetic simulation system.The results show that the magnet with 0.4%(mass fraction)Ga addition exhibits optimal magnetic performance:its remanence Br is 13.58 kGs,coercivity Hcj is 19.71 kOe,and maximum magnetic energy product(BH)_maxis 44.63 MGOe.Additionally,its thermal stability is improved to a certain extent.The addition of an appropriate amount of Ga enhances the wettability of the grain boundary phase of the magnets,leading to formation of a continuous and smooth non-magnetic grain boundary layer and precipitation of the Nd₆Fe₁₃Ga phase.This Nd6Fe13Ga phase reduces the Fe concentration at grain boundaries,thereby decreasing the grain boundary magnetization intensity and weakening the exchange coupling among ferromagnetic grains.Consequently,the coercivity of the magnets is significantly improved.The micromagnetic simulations of demagnetization nucleation show that the addition of an appropriate amount of Ga can inhibit the agglomeration of rare earth-rich phases,effectively reduce the stray field intensity at the triangular grain boundaries and decrease the volume fraction of the triangular grain boundary phase,thereby significantly reducing the demagnetization nucleation sites,narrowing the demagnetization nucleation regions,and further significantly enhancing the coercivity of the magnets.

In order to investigate the effect of heavy rare earth on the solidification microstructure and melt fluidity of magnesium alloy,AZ91D magnesium alloys with 0.3%,0.6%,0.9%,1.2%and 1.5%(mass fraction)Gd were prepared.The phase identification and morphology and composition analysis of the solidification microstructure of the alloys were carried out by XRD and SEM-EDS.The solidification interval and dendrite coherency temperature were determined via a dual-thermocouple technique.The melt fluidity was evaluated by a spiral sample mold,and the hardness of the alloys was measured by a Rockwell hardness tester.The results show that rare earth Gd can significantly refine both theα-Mg grains andβ-Mg₁₇Al₁₂phase.When the Gd content is 0.9%,the average grain size ofα-Mg is the smallest,which is 135.87μm.The rare earth phase Al₂Gd is mainly distributed along the grain boundary and blockily precipitated.The addition of an appropriate amount of rare earth Gd reduces the solidification interval and dendrite coherency temperature of the alloy,which greatly improves the melt fluidity.With the increase of Gd content,the hardness of the alloy increases first and then decreases,reaching a peak of 75.1 HRB at 0.9%Gd.This study can provide a theoretical basis for expanding the application of magnesium alloys and realizing the comprehensive utilization of rare earth resources.

Using Ti60 high-temperature titanium alloy as the research subject,the influence of hot-pressing temperature on the interfacial microstructure and mechanical properties of the diffusion-bonded joints was studied through optical microscope(OM),scanning electron microscope(SEM),electron backscatter diffractometer(EBSD),Image J software analysis,and tensile testing.The results show that diffusion-bonded Ti60 high-temperature titanium alloy achieves good metallurgical bonding at all tested hot-pressing temperatures,and dynamic recrystallization occurs at the interface during hot-pressing,generating fineα-phase grains.With the increase of hot-pressing temperature,the area fraction of large-sizeα-phase at the interface increases.Due to crystallographic mismatch at the diffusion-bonded interface,which impedes coordinated deformation,stress concentration occurs at the interface during room-temperature tensile deformation,leading to brittle fracture and low plasticity in the alloy.During high-temperature tensile deformation,the crystallographic mismatch at the high-temperature diffusion-bonded interface is reduced,resulting in a transition in the interfacial fracture mode from brittle fracture to ductile fracture,with the interfacial plasticity close to that of the base material.

To meet the high weld depth and high-performance welding technology requirements of Be-Al alloy,the effects of different laser powers on the microstructure,tensile properties,and fracture behavior of Be-Al alloy were investigated.The results show that when the laser power is low(800 W),the weld seam exhibits a crescent shape,with a weld depth of only 0.5 mm.As the laser power increases,the weld depth significantly increases,but a banded Al phase is formed in local areas of the weld seam.Excessive heat input leads to the widening of the banded Al phase,resulting in debonding and cracking at the Be-Al interface.When the laser power increases to 1200 W,the presence of microcracks and oxide inclusions at the Be-Al interface causes the fracture to ultimately occur in the weld seam.With a laser power of 1000 W,laser welding technology can achieve high-strength welding of Be-Al alloy with a certain depth(approximately 0.9 mm),and the tensile strength reaches above 300 MPa.

The flow stress behavior and microstructural evolution of Cu-2.8Be alloy for secondary electron emission applications were investigated through hot compression tests and electron backscatter diffraction(EBSD)analysis within the temperature range of 680~830℃and strain rate range of 0.01~10 s^-1.A hot processing map was established based on the Arrhenius constitutive equation and dynamic materials model,revealing the optimal processing window at 770~830℃with a logarithmic strain rate range from-1.0 to 0.25.The calculated thermal activation energy(Q)of the alloy is 231.17 kJ/mol.EBSD analysis shows that higher strain rates shorten recrystallized grain growth time,leading to progressive grain refinement.Meanwhile,enhanced work hardening and dislocation density promote particle-stimulated nucleation,thereby increasing dynamic recrystallization(DRX)degree.As a result,the deformed alloy microstructure exhibits an increased proportion of high-angle grain boundaries along with a reduction in average dislocation density and kernel average misorientation(KAM).

As a widely used antibacterial drug,ciprofloxacin(CIP)residues have posed serious threats to ecosystems and human health.In order to solve this problem,magnetic hydroxyapatite/silver nanoparticle composite(Fe₃O₄/HAP/Ag)was synthesized via a blending method and employed as photocatalysts for CIP degradation,leveraging the photocatalytic properties of Ag.The phase and structure of the synthetic samples were characterized by X-ray diffraction(XRD)pattern,ultraviolet-visible(UV-Vis)absorption spectra and infrared(IR)spectra.The effects of CIP concentration,catalyst(Fe₃O₄/HAP/Ag)dosage and oxidant(peroxymonosulfate,PMS)amount on CIP degradation efficiency were investigated through degradation experiments.The results show that the optimized degradation conditions for 9 mL of ciprofloxacin solution are as follows:initial CIP concentration of 10 mg/L,Fe₃O₄/HAP/Ag dosage of 50 mg,and PMS amount of 5 mg.Under these conditions with 200 W light irradiation,the degradation rate of CIP reaches 70.36%within 60 min.The light irradiation can enhance the catalytic activity of the Fe₃O₄/HAP/Ag composite nanomaterials.This study establishes a novel approach for the efficient ciprofloxacin degradation.

Vanadium electrolyte serves as the core component and energy storage medium of vanadium redox flow batteries(VRFBs).Currently,the industrialization of vanadium electrolyte production is in an exploratory transition from laboratory research and pilot-scale trials to large-scale manufacturing.Based on the physicochemical properties and preparation principles of vanadium electrolyte,three typical vanadium electrolyte preparation processes are described in detail,including chemical reduction and electrolytic reduction,extraction and electrolytic reduction,and reduction roasting and direct acid dissolution.A comparative analysis of their advantages and disadvantages is also provided.Finally,the representative large-scale vanadium electrolyte production projects in the past five years(from 2020 to 2024)are statistically analyzed,and their process technology routes were introduced.This analysis can provide a valuable reference for process selection in industrial production projects of vanadium electrolyte.

In order to reduce the formation of by-products during direct lithium compensation to regenerate the retired lithium iron phosphate(LiFePO₄)cathode material and improve the controllability and application value of the process,the regeneration effect of Li₅AlO₄(LAO)as lithium compensation reagent on the retired lithium iron phosphate cathode material was discussed.The phase structure and morphology of LAO were characterized using X-ray diffractometer(XRD)and scanning electron microscope(SEM),and its electrochemical performance was evaluated.The performance of LiFePO₄regenerated with LAO was also investigated in both half-cells and full-cells.The results indicate that LAO can effectively release lithium ions,and compensate the depleted lithium in the degraded cathode material,thereby significantly enhancing its specific capacity and cycling stability.Half-cell testing shows that for degraded LiFePO₄batteries with state of health(SOH)of 90%,80%and 70%,the first-cycle charge specific capacities after lithium compensation with LAO increase to 301.5 mA·h/g,272.4 mA·h/g and 358.7 mA·h/g,respectively,indicating a significant improvement compared to the samples without LAO.After 500 charge-discharge cycles,the capacity retention rates of the above batteries after lithium compensation with LAO are 94.0%,90.1%and 95.9%,respectively,which fully proves that the lithium compensation strategy has minimal impact on the cycling stability of the batteries.Furthermore,full-cell testing further validates the direct regeneration effect of LAO as a lithium compensation reagent for retired battery cathode materials.In particular,for the batteries with a SOH of 80%,the addition of LAO increases the first-cycle charge specific capacity by 46.1 mA·h/g,demonstrating its effectiveness in lithium compensation.These findings further confirm the potential of LAO in the regeneration of LiFePO₄batteries.The efficient lithium compensation strategy with LAO proposed in this study provides crucial theoretical support and technical reference for the regeneration and recycling of LiFePO₄batteries.