基于TiAl-xCo-Mo-Ni复合粘结相的WC基超细晶硬质合金微观组织和力学性能研究

Microstructure and Mechanical Properties of WC-based Ultrafine Grain Cemented Carbide Prepared with TiAl-xCo-Mo-Ni Composite Bonding Phase

WC/Co类超细晶硬质合金是目前制备高性能金属切削刀具的理想材料,但Co是一种宝贵资源。为了寻找代替Co的粘结相并制备性能优良的WC基超细晶硬质合金,选用TiAl-xCo-Mo-Ni作为复合粘结相,并采用放电等离子烧结(SPS)制备了WC基超细晶硬质合金,分析了SPS温度和复合粘结相成分对其性能及微观组织的影响。研究结果表明:WC晶粒平均尺寸随放电等离子烧结温度的升高而增大,样品致密度及综合力学性能均在1 400℃时达到最优,当组分为WC-10%(TiAl-Co-Mo-Ni)时具有最高的致密度以及最佳的综合力学性能,其致密度、WC晶粒平均尺寸、维氏硬度和断裂韧性分别为98.3%、285 nm、21.04 GPa和16.95 MPa·m^(1/2)。

WC/Co ultrafine grain cemented carbide is the ideal material for preparing high-performance me-tal cutting tools, but Co is a valuable resource.In order to find the bonding phase to replace Co and prepare WC-based ultrafine grain cemented carbide with excellent performance, using TiAl-xCo-Mo-Ni as the composite bonding phase, WC-based ultrafine grain cemented carbide was prepared by spark plasma sintering(SPS).The effects of SPS temperature and composition of the composite binder phase on the performance and microstructure of the cemented carbide were systematically analyzed.The results show that the ave-rage size of WC grains increases with the increase of sintering temperature, and the density and comprehensive mechanical properties are optimized at 1 400 ℃.When the composition is WC-10%(TiAl-Co-Mo-Ni),the cemented carbide has the highest density and the best comprehensive mechanical properties, and its density, average WC grain size, Vickers hardness and fracture toughness are respectively 98.3%,285 nm, 21.04 GPa and 16.95 MPa·m^(1/2).