含(W,Ti,Ta)C的超细硬质合金的性能及组织研究

摘要

In this paper, different contents of Cr3C2 and (W,Ti,Ta)C were doped in ultra-fine cemented carbides based on WC-8%Co and (VC/Cr3C2). The effects of Cr3C2 and (W,Ti,Ta)C additions on mechanical properties and microstructure of the cemented carbide were studied by TRS test, coercive force test, SEM analysis, TEM test and other methods. The results show that with Cr3C2 and (W,Ti,Ta)C increasing, the grain size of the cemented carbide has no significant change, the transverse rupture strength is decreasing, and the hardness is increasing. The microstructure similar to twin is observed in WC-8%Co-4%(W,Ti,Ta)C-0.5%(VC/Cr3C2) cemented carbide by TEM observation. According to energy dispersive X-ray results, Cr-A and (W,Ti,Ta)C are validated. The WC-8%Co-4%(W,Ti,Ta)C cemented carbide prepared by pressure sintering at 1 390 °C can achieve 99.7% density, 93.8 HRA and 2 250 MPa TRS.%本文在WC-8％Co(文中含量均为质量分数)、复合抑制剂(VC/Cr3C2)的基础上,添加不同配比的Cr3C2及(W,Ti,Ta)C,制备超细硬质合金.采用横向断裂强度检测、洛式硬度检测、SEM分析、TEM检测等方法,研究了Cr3C2和(W,Ti,Ta)C对超细硬质合金力学性能和组织结构的影响.结果表明:随着Cr3C2、(W,Ti,Ta)C的增加,晶粒大小没有显著变化,硬质合金的横向断裂强度减低,硬度提高.通过透射电镜观察,在WC-8％Co-4％(W,Ti,Ta)C-0.5％(VC/Cr3C2)硬质合金中发现了类似于李晶的结构,并通过能谱证实了Cr3C2和(W,Ti,Ta)C的存在.WC-8 ％Co-4％(W,Ti,Ta)C硬质合金经1 390℃压力烧结后,硬度为93.8 HRA,抗弯强度为2 250 MPa,相对密度为99.7％.