Fabrication and Microstructure of W/Cu Functionally Graded Material
摘要
W/Cu functionally gradient material (FGM) has excellent mech anical properties since it can effectively relax interlayer thermal st resses caused by the mismatch between their thermal expansion coeffici ents. W/Cu FGM combines the advantages of tungsten such as high meltin g point and service strength, with heat conductivity and plasticity of copper at room temperature. Thus it demonstrates satisfactory heat co rrosion and thermal shock resistance and will be a promising candidate as divertor component in thermonuclear device. Owing to the dramatic difference of melting point between tungsten and copper, conventional processes meet great difficulties in fabricating this kind of FGMs. A new approach termed graded sintering under ultra-high pressure (GSUHP) is proposed, with which a near 96% relative density of W/Cu FGM that contains a full distribution spectrum (0€?00%W) has been successfully fabricated. Suitable amount of transition metals (such as nickel, zir conium, vanadium) is employed as additives to activate tungsten's sint ering, enhance phase wettability and bonding strength between W and Cu . Densification effects of different layer of FGM were investigated. M icrostructure morphology and interface elements distribution were obse rved and analyzed. The thermal shock performance of W/Cu FGM was also preliminarily tested.