Cr含量对WC-Co硬质合金显微组织和力学性能的影响

The influence of different content of Cr on microstructure and properties of WC-Co cemented carbide

采用低压烧结技术制备了不同Cr含量的WC-8Co硬质合金,通过XRD、SEM和力学性能测试等手段分析了Cr含量对硬质合金物相、显微结构和合金的力学性能的影响。结果表明,当Cr含量<0.9%时,合金由WC+γ-(WC)相组成,添加量增至0.9%及以上时,组织中出现缺碳相Co3W3C;随着Cr含量的增加,WC晶粒不断细化,当添加量为0.6%时,合金的综合力学性能最佳,其抗弯强度、维氏硬度及断裂韧性分别为3885MPa、1632.4HV30、9.82MPa.m1/2。

WC-8Co cemented carbide added with different content of Cr was obtained by the low pressure sintering technology. The microstructure, phase of the alloys were studied by using scanning electron microscopy （SEM） and X-ray diffraction analysis （XRD） ,and compared the mechanical properties. The experiment results show that, when the content of Cr was inferior to 0.9%, the microstructure of alloys consisted of WC and 7 solid solution. As the content of Cr reached 0. 9%, the ternary W3Co3C phase emerged; the growth of WC grains was inhibited sufficiently. The better synthetically mechanical property was obtained by addition of 0.60%. The bending strength, Vickers hardness and fracture toughness were： 3885MPa, 1632. 4HV30, 9.82MPa · m^1/2.