放电等离子烧结WC-6wt.%Co-VC超细晶硬质合金力学性能和微观组织研究

Mechanical properties and microstructure of spark plasma sintered WC-6 wt.%Co-VC ultrafine grained cemented carbide

碳化钨(Tungsten carbide,WC)基超细晶硬质合金由于其良好的综合力学性能而成为制备高性能金属切削刀具的理想材料。为了获得WC基超细晶硬质合金和进一步提高其力学性能,采用放电等离子烧结技术制备了不同碳化钒(VC)含量的WC-6wt.%Co超细硬质合金,系统分析了碳化钒含量和放电等离子烧结温度对WC基超细晶硬质合金性能的影响。研究结果表明:WC晶粒平均尺寸随着VC含量增加而减小,但致密度、维氏硬度和断裂韧性随着VC含量增加而降低;当VC含量为0.2wt.%时,WC-6wt.%Co硬质合金在1250℃烧结温度下具有最好的综合力学性能,其致密度、维氏硬度、WC晶粒平均尺寸和断裂韧性分别为98.4%、22.21 GPa、247 nm和10.43 MPa·m1/2。

Ultrafine WC-based cemented carbides are ideal materials for the preparation of high-performance cutting tools due to their good comprehensive mechanical properties.In order to obtain ultrafine WC-based cemented carbides and further improve their mechanical properties,ultrafine WC-6wt.%Co cemented carbides with different vanadium carbide(VC)content are prepared by spark plasma sintering technology.The effects of the VC content and sintering temperature on the properties of ultrafine WC-based cemented carbides are investigated.The results show that the average size of WC grains,relative density,hardness and fracture toughness decrease with the increase in VC content.The WC-6wt.%Co cemented carbides doped with 0.2wt.%VC sintered at 1250℃have the excellent comprehensive mechanical properties.Its relative density,hardness,fracture toughness and average grain size were 98.4%,22.21 GPa,10.43 MPa·m1/2 and 247 nm,respectively.