粗细WC晶粒配比对双晶结构硬质合金力学性能与组织结构的影响

Effect of Proportion of Coarse and Fine WC Particles on Mechanical Properties and Microstructure of Bi-crystallinity Cemented Carbides

采用粗细WC颗粒不同比例搭配的方法制取WC-8%Co双晶结构硬质合金,并通过对合金金相组织的观察以及硬度(HRA)、矫顽磁力(Hc)、抗弯强度(TRS)和断裂韧性(KIC)等物理、力学性能的检测对比,研究其力学性能与组织结构。结果表明,粗细WC颗粒配比和WC晶粒大小是改善非均匀结构合金力学性能与组织结构的重要因素,通过优化配比按21%~24%添加粗颗粒WC可制备出力学性能良好的双晶结构硬质合金。随着合金中粗晶粒WC比例的增大,合金的HRA、Hc略微降低,KIC从14MPa·m^1/2提高到19.7MPa·m^1/2,TRS则呈先增后降的趋势,最大值3 498MPa。

WC-8% Co bi-crystallinity cemented carbide was prepared with different proportion of coarse and fine WC particles.The mechanical properties and microstructure were studied by observing the metallographic microstructure of the alloy and comparing the physical and mechanical properties such as hardness(HRA),coercive force(Hc),bending strength(TRS)and fracture toughness(KIC).The results show that the proportion of coarse and fine WC particles and the size of WC grains are the important factors to improve the mechanical properties and microstructure of the inhomogeneous structure alloy.Based on proportion optimization,the bi-crystallinity cemented carbide with good mechanical properties can be prepared by adding 21%~24%coarse WC particles.With the increase of the ratio of coarse WC particles in the alloy,HRA and Hcslightly decrease,KICincreases from 14MPa·m^1/2 to 19.7MPa·m^1/2,and TRS increases at first and then decreases,with a maximum value of 3498MPa.