【摘要】 采用热等静压烧结和气淬工艺制备6种不同TaC含量的WC-9Co粗晶硬质合金。利用扫描电镜,能谱仪、X射线衍射等方法研究TaC含量对WC-9Co粗晶硬质合金显微组织、Co中Ta和W含量的影响,并对合金的力学性能进行测试和比较。结果表明:当TaC添加量为0.4%时,WC晶粒生长被明显抑制,WC-9Co的硬度和强度达到最大值,分别为HV 1124和2466 MPa。当TaC添加量超过0.6%时,WC晶粒不再进一步减小,合金显微组织中出现(W,Ta)C相;而且随着TaC含量的增加,合金的强度和韧性提高,同时Co中的(Ta+W)含量下降。这表明,对于具有正常WC+γ组织的粗晶WC-TaC-9Co合金,降低Co中的(Ta+W)含量有利于提高其力学性能。更多还原

【Abstract】 Coarse grained WC-9Co cemented carbides with 0-1.0% TaC(mass fraction) were fabricated by HIP-sintering and gas quenching. The effects of TaC on the microstructures and mechanical properties were investigated using scanning electron microscopy(SEM), energy dispersive X-ray analysis(EDS), X-ray diffractometry(XRD) and mechanical properties tests. The results show that the maximum values of hardness and strength are HV 1124 and 2466 MPa respectively when 0.4% TaC is added. When the content of TaC is more than 0.6%, the grain size of WC is no longer affected by the amount of TaC, and(W,Ta)C occurs as well. Moreover, the strength and fracture toughness increase and the(Ta+W) content decreases with the increase of TaC content. The dependence of(Ta+W) content on the mechanical properties indicates that(Ta+W) content in Co should be decreased as low as possible to improve the mechanical properties of coarse grained WC-TaC-9Co cemented carbides with the microstructure of WC+γ two phase regions.更多还原