To develop a high temperature shape memory alloy with high transformation temperature and good cold-working ability，NiTiTaHf wires with a diameter of 0.2 mm are fabricated through cold drawing and subsequent annealing.The influence of annealing temperature on microstructure，martensitic transformation and superelasitic behavior of NiTiTaHf wire are investigated. The results show that the superelasticity of NiTiTaHf wire is quite sensitive to the annealing temperature. The sample annealed at 500 ℃ displays the substantial superelasticity featuring a recoverable strain of 7.6% over a broad temperature range from 20 ℃ to 200 ℃. In contrast，the sample annealed at 700 ℃ only shows a small superelastic recoverable strain （less than 3.3%）over a narrow temperature range （140-200 ℃）.This difference in superelastic behavior is caused by the change of grain size resulting from the different annealing temperature，the grain size of the sample annealed at 500 ℃ is about 12 nm. This leads to the occurrence of strain glass state in the sample and the resultant superelasticity over a wide temperature range.

Ti6Al4V alloy is fabricated firstly by selective laser melting （SLM） and then followed by hot stamping treatment. The corrosion resistance and wear resistance of SLM Ti6Al4V alloy before and after hot stamping treatment are comparatively studied using electrochemical corrosion and friction wear tests， and the underlying mechanisms of the performance differences are elucidated. The results indicate that in simulated body fluid， the hot-stamped SLM-formed Ti6Al4V specimens exhibit reduced corrosion resistance， with an increase in corrosion current density and a decrease in passive film thickness from 3.19 nm to 1.21 nm. The primary reason is that hot stamping causes grain coarsening in the SLM-formed Ti6Al4V specimens， with grain size increasing from 1.37 μm to 1.51 μm， and the proportion of low-angle grain boundaries rising by 1.41%， thereby accelerating the corrosion rate and degrading corrosion resistance. Additionally， the volumetric wear loss of the hot-stamped specimens increases from 0.314 mm³ to 0.474 mm³， indicating a decline in wear resistance， with the wear mechanism dominated by the combined effects of abrasive wear and oxidative wear.

The control of WC grain size homogeneity in cemented carbide produced by binder jetting additive manufacturing （BJAM） is crucial for optimizing its mechanical properties；however， related studies remain limited. This research investigates the effect of vanadium carbide （VC） addition on the microstructure and mechanical properties of WC-12Co cemented carbide to prevent abnormal WC grain growth. The results demonstrate that the addition of VC significantly improves the surface roughness of WC-12Co cemented carbides. Specifically， the addition of 0.5%（mass fraction， the same below） VC and 1.0%VC reduces the surface roughness by 21.49% and 17.77%， respectively. Compared to the plain WC-12Co carbide without VC， the average WC grain size in the cemented carbides with 0.5%VC and 1.0%VC decreases from 1.83 μm to 1.57 μm and 1.61 μm， respectively. VC effectively inhibits abnormal WC grain growth and promotes a more uniform distribution of WC grain sizes. Furthermore， the addition of 0.5%VC increases the Vickers hardness by 3.3% and the bending strength by around 3%. Additionally， VC incorporation significantly reduces the friction coefficient and the wear rate of the BJAMed carbides， enhancing their wear resistance. These findings suggest that VC addition offers a promising strategy for improving the performance of cemented carbides in additive manufacturing， providing a valuable technical route for further development in this field.

The microstructural evolution and yield strength changes of medium-Mn steels with Cu， Ni， and Cu/Ni composite additions after aging at 500 ℃ are systematically compared using electron backscatter diffraction （EBSD）， transmission electron microscopy （TEM） with energy-dispersive spectroscopy （EDS）， and mechanical property tests. The precipitation strengthening mechanism is further revealed. The results show that aging at 500 ℃ increases the yield strength by approximately 125， 540 MPa， and 575 MPa for the Cu， Ni， and Cu/Ni alloyed steels， respectively， due to precipitation strengthening. The strengthening effect in the Ni and Cu/Ni alloyed steels is much greater than that in the Cu alloyed one， mainly because the number of precipitated nanoparticles in the former two steels is much greater than that in the Cu alloyed steel. Although Cu addition promotes the precipitation of NiAl phases， leading to larger size and higher number of Cu-NiAl composite precipitates in the Cu/Ni alloyed steel compared with the single NiAl precipitates in the Ni alloyed steel， the precipitation strengthening effect of the Cu-NiAl composite precipitates is not significantly higher than that of the single NiAl precipitates. This is because the latter， with its single precipitate sizes below the critical size， strengthen through the dislocation shearing mechanism， whereas the former， with its composite precipitates exceeding the critical size， strengthen via the dislocation Orowan mechanism， resulting in weakened precipitation strengthening. Consequently， the aging precipitation strengthening effect of Cu/Ni steel is not higher than that of the Ni steel.

CuNiIn coatings are prepared on the surface of TC4 titanium alloy using cold spray technology， and the effects of gas types （helium， nitrogen） and preheating temperatures （500， 700 ℃） on the microstructure， microhardness， bonding strength， and gas fretting wear performance of the coatings are investigated. The results show that under the same gas preheating temperature， the porosity of coatings sprayed with helium is lower than that of coatings sprayed with nitrogen， and microhardness， bonding strength， and wear resistance are all superior to those of coatings sprayed with nitrogen. When the gas preheating temperature increases from 500 ℃ to 700 ℃， the porosity of the coatings sprayed with both gases decreases significantly （helium： from 1.4% to 0.05%， nitrogen： from 1.7% to 0.5%）. The hardness of coatings sprayed with helium increases from 213HV to 292HV， while that of coatings sprayed with nitrogen decreases from 275HV to 237HV. The increase in gas preheating temperature has no significant effect on the bonding strength of the coatings， but the type of gas has a significant effect on the bonding strength of the coatings， the average bonding strength of sprayed coatings with helium （70 MPa） is 30 MPa higher than that of sprayed coatings with nitrogen （40 MPa）. The wear rate of coatings sprayed with helium and coatings sprayed with nitrogen decreases with the increase of gas preheating temperature （helium： from 1.8% to 1.41%， nitrogen： from 2.21% to 1.51%）. With the increase of fretting displacement amplitude， the wear form of the coatings under optimized parameters changes from adhesive wear to abrasive wear.

Diamond films prepared by conventional microwave plasma chemical vapor deposition （MPCVD） often face issues such as low growth rates，disordered grain orientations，and non-diamond phase defects，which limit further enhancement of their optical properties. This study introduces CO₂ as an auxiliary gas to deposit high-quality diamond films using the MPCVD method. Diamond film deposition is conducted by introducing different flow rates of CO₂， and the optical emission characteristics of the plasma under varying CO₂ flow rates are measured using optical emission spectroscopy （OES）. The crystallinity quality， grain orientation， surface morphology， and growth rate of the diamond films are characterized by XRD， Raman， and SEM. The results indicate that adding a certain amount of CO₂ （flow ratio of CO₂/CH₄=2/6） is conducive to obtaining diamond films with a high （110） preferred orientation （I₂₂₀/I₁₁₁=18.19）. An excessively high CO₂/CH₄ flow ratio intensifies the etching effect of oxygen-containing groups， reducing the degree of preferential grain orientation. The addition of an appropriate amount of CO₂ significantly improves the crystalline quality of the diamond， with the full width at half maximum （FWHM） of the diamond characteristic peak decreasing from 12.68 cm^-1 to 8.26 cm^-1. Furthermore， the addition of a suitable amount of CO₂ promotes diamond growth to some extent. Under the optimized flow ratio condition of CO₂/CH₄=2/6， this study successfully prepares a high （110） orientation （I₂₂₀/I₁₁₁=18.19） diamond film with a growth rate of 4 μm/h. After polishing， the self-standing diamond film achieves a transmittance of 71% at the 10.6 μm wavelength. Its transmittance in the long-wave infrared band approaches the theoretical value， meeting the requirements for applications such as long-wave infrared optical windows and extreme ultraviolet lithography machine windows.

A solvent-free epoxy modified cyanate ester resin for winding is prepared by modifying bisphenol E cyanate ester/bisphenol A cyanate ester/acetylacetone copper blend with resorcinol diglycidyl ether （RDGE）. The influence of RDGE content on the processability of the resin and the mechanical，thermomechanical，dielectric，and moisture absorption properties of cured resin is investigated. The results show that the viscosity of the resin at is 430 mPa·s @ 25 ℃，which is suitable for solvent-free winding. The processing window lasts for up to one month. RDGE has a catalytic effect on the curing reaction of cyanate esters. The curing temperature of the modified resin is 180 ℃，and the post-treatment temperature is 240 ℃. The oxazolidinone ring generated by the reaction between RDGE and cyanate ester enhances the toughness of the cured resin，while reducing BECy by an equal amount to maintain the processability of the winding process partially offsets the toughening effect. The mechanical properties of the resin cured material reach their maximum at an RDGE content of 20%，with tensile strength and modulus of 78.45 MPa and 3.50 GPa，elongation at break of 2.77%，and bending strength and modulus of 152.49 MPa and 3.48 GPa，respectively. At this point， the moisture resistance of cured resin has improved，with a water absorption rate of 1.60% after 100 h of boiling at 100 ℃.However，the glass transition temperature and dielectric properties have decreased， with a T_g of 247 ℃. The dielectric constant in the frequency range of 7-15 GHz is 3.04-3.05，and the dielectric dissipation factor is 0.013-0.014.

In order to reveal the temperature sensitivity of the impact dynamics of nitrile butadiene rubber（NBR） materials，SHPB impact test experiments under different combinations of conditions are designed by changing the loading strain rate，temperature and other parameters. The results show that： with the increase of temperature and strain rate，the specimen shows the deformation characteristics of “round cake-disc-disc crack” after impact；when the temperature is less than 70 ℃，the difference between the stress-strain curves of specimens with different strain rates is small，and the temperature sensitivity is weak，and higher than 70 ℃，the difference is larger，and the temperature sensitivity is enhanced；under the same strain rate，the yield strength is related to the temperature sensitivity of the specimen. Under the same strain rate，the yield strength is approximately linearly and negatively correlated with temperature，and under different strain rates，the larger the strain rate is，the smaller the slope of the straight line is，i.e.，the more significant the effect of temperature on the yield strength is；when the temperature is greater than 55 ℃，the dynamic modulus is negatively correlated with the temperature and shows strong temperature sensitivity，and the relationship between the two is insignificant when the temperature is less than 55 ℃. The results of the study further enrich the related research on the dynamic properties of NBR，which is of great significance for the selection of NBR materials under the complex temperature environment.

Solidification is crucial in the preparation of metal materials. The solidification process directly determines the microstructure and macroscopic properties of metal materials. When a metal is transformed from a liquid to a solid state，factors such as the formation and growth of grains，solidification rate，temperature gradient，and alloy composition lead to different microstructures，ultimately defining the final microstructure of the metal. Variations in these factors not only determine the mechanical properties of the metal but can also cause defects such as grain boundary defects， gas pores， and inclusions， etc.，thereby affecting its overall quality and service performance. Due to its high penetration and high spatiotemporal resolution，synchrotron radiation enables the real-time observation and tracking of microstructural evolution during metal solidification， leading to a deeper understanding of the underlying mechanisms. This paper reviews the latest progress of synchrotron radiation imaging technology in the study of the solidification process of metallic materials at home and abroad，with a focus on its application and research achievements in crystal nucleation and growth，the formation mechanism of solidification defects，and rapid solidification （welding and additive manufacturing）. By combining new methods such as phase field simulation and machine learning，researchers have made significant progress in grain refinement mechanisms，the formation laws of pores and hot tearing，and the control of rapid solidification modes. Finally，it is pointed out that improving the temporal and spatial resolution of synchrotron radiation，conducting multi-scale coupling characterization，integrating experiments with numerical simulations，and introducing data-driven intelligent analysis methods are important development directions for in-situ studies of the solidification process in the future. This will provide a more solid theoretical basis and technical support for the design of advanced materials and process optimization.

Synchrotron radiation technology serves as a “super microscope” for unveiling multi-scale physical metallurgy behaviors during additive manufacturing （AM）， providing groundbreaking research tools to decode the “black box” challenges inherent in AM processes. This paper review systematically summarizes recent advances in synchrotron radiation applications for AM：in imaging， ultrafast X-ray imaging with high spatiotemporal resolution enables in situ observation of melt pool dynamics， defect formation mechanisms， and solidification behavior， revealing key phenomena such as keyhole fluctuation-induced porosity and Marangoni force-driven defect suppression； in diffraction， ultrafast X-ray diffraction quantitatively resolves phase transformation kinetics and residual stress evolution during rapid solidification. Furthermore， this work explores emerging trends in integrating synchrotron technology with deep learning and multiphysics simulations， while envisioning its potential for AM process optimization， intelligent defect detection， and novel material development. It is pointed out that such technology establishes a theoretical foundation and technical pathway for transitioning AM from empirical trial-and-error to mechanism-driven methodologies.