晶粒长大抑制剂对WC-9%Co超细晶硬质合金组织及性能的影响

Effects of Grain Growth Inhibitors on Microstructures and Properties of WC-9%Co Ultrafine-grained Cemented Carbide

本文采用常规粉末冶金方法,通过单独或复合添加Cr_3C_2、VC、TiC等晶粒长大抑制剂的方法,制备了WC-9%Co超细晶硬质合金,试验对比了其显微组织和力学性能。结果显示:抑制剂的加入均可显著细化合金组织,提高硬度,但合金的断裂韧性(K_(IC))有所降低,抗弯强度(TRS)与所添加的抑制剂种类有关。其中VC抑制晶粒长大的效果最显著,其次是Cr_3C_2,再次是TiC。在本实验条件下,复合添加Cr_3C_2+VC的合金硬度最高,强韧性最差;复合添加Cr_3C_2+TiC的合金具有最好的综合力学性能。

In this paper, a series of WC-9%Co ultrafine-grained cemented carbide containing different grain growth inhibitors(GGIs) were prepared via conventional powder metallurgy method. The GGIs are one or two of Cr3 C2, VC and TiC.The effects of GGIs on the microstructure and mechanical properties of the experimental cemented carbide were studied.Results show that the GGIs can significantly refine the grain size, improve the hardness, but reduce the fracture toughness(KIC) of the model alloys. The transverse rupture strength(TRS) changes with the type of GGI. It was revealed that the effect of grain growth inhibition of VC is prominent, next to Cr3 C2 and again for TiC. In this experiment, the alloy with Cr3 C2+VC has the highest hardness but worst toughness; the alloy with Cr3 C2+TiC has the best comprehensive properties.