论文部分内容阅读
研究了VC/Cr3C2添加剂对WC-12Co超细硬质合金的显微组织、硬度和抗弯强度(TRS)的影响。结果表明,含一定比例VC/Cr3C2添加剂的合金具有更均匀的微观组织和优异的力学性能。当添加剂含量(质量分数)为0.5%VC/0.2%Cr3C2时,1430℃烧结制备的WC-12Co超细硬质合金的抗弯强度达3786MPa,硬度达91.7HRA。VC添加剂对WC晶粒的连续长大和非连续长大的抑制作用比Cr3C2添加剂更有效。此外,当烧结温度较高时,VC/Cr3C2添加剂对WC晶粒长大的抑制效果更显著。VC和Cr3C2添加剂抑制WC晶粒长大的作用机理为:VC和Cr3C2添加剂降低了WC相在粘结相中的过饱和度,从而降低烧结温度下粘结相中WC相溶解-析出过程的驱动力,起到阻碍WC晶粒长大的作用。
The effects of VC / Cr3C2 additive on the microstructure, hardness and flexural strength (TRS) of WC-12Co ultrafine cemented carbide were studied. The results show that the alloy containing a certain proportion of VC / Cr3C2 additive has more uniform microstructure and excellent mechanical properties. When the additive content (mass fraction) is 0.5% VC / 0.2% Cr3C2, WC-12Co ultrafine cemented carbide prepared by sintering at 1430 ℃ has a bending strength of 3786MPa and a hardness of 91.7HRA. VC additive is more effective than Cr3C2 additive in inhibiting the continuous growth and discontinuous growth of WC grains. In addition, the effect of VC / Cr3C2 additive on WC grain growth is more pronounced when the sintering temperature is higher. The mechanism of VC and Cr3C2 additives inhibiting WC grain growth is that VC and Cr3C2 additives reduce the supersaturation of the WC phase in the binder phase and thus reduce the dissolution of the WC phase in the binder phase at the sintering temperature Force, play a role in hinder WC grain growth.