【摘要】 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。更多还原

【Abstract】 Hardness,transverse rupture strength (TRS) and microstructures of VC,Cr3C2 codoped ultrafine WC-12Co were investigated. The results show that alloys with homogeneous microstructure and excellent properties were obtained when optimal proportion of additions was added. The TRS and hardness reach 3786 MPa and 91.7 HRA for the alloy with 0.5% Cr3C2/0.2%VC and sintered at 1430 ℃. VC is more effective at controlling continuous and discontinuous grain growth than Cr3C2,and the effectiveness of additions is more significant at higher sintering temperature. The mechanism of WC grain growth inhibition is that VC and Cr3C2 reduce the supersaturation of WC in the binder phase,decrease the driving force for WC grain growth from reprecipitation process and retard WC grain growth.更多还原