不同TaC含量的WC-Co硬质合金微观结构及其力学性能

摘要

本文采用真空液相烧结法,对掺杂不同含量TaC的WC-Co硬质合金微观结构和力学性能进行了对比分析研究.采用分析天平、维氏显微硬度计、X射线衍射仪(XRD)、场发射扫描电镜(SEM)等,先后分析了不同含量TaC配比下试样的密度、显微硬度、成份以及微观结构变化情况.结果表明:有无TaC和添加不同含量的TaC,制备的硬质合金试样微观结构和力学性能存在很大差异.没有添加TaC时,生成相中WC晶 粒尺寸明显偏大,而添加TaC可以有效抑制WC晶粒异常长大,得到分布较为均匀且晶粒细小的WC-TaC-Co系硬质合金.进一步对比分析发现,添加0.5％TaC对WC晶粒异常长大现象的抑制作用较为明显,细化后的WC晶粒尺寸约为0.5μm,同时提高试样表面硬度,HV30=21.27 GPa,比没有抑制剂的试样增加约8.98％.%WC-Co cemented carbide doped with different content of TaC was prepared hy vacuum liquid-phase sintering technology,and its microstructure and mechanical properties were compared.The density,micro-hardness,composition and microstructure of the specimen with different content of TaC were analyzed by analytical balance,Vickers hardness tester,X-ray diffraction (XRD) and field emission scanning electron microscopy (SEM),respectively.The result shows that there are great differences in microstructure and mechanical properties of the cemented carbide with different content of TaC or without TaC.The WC grain size in the cemented carbide without TaC is obviously larger than that of doping TaC,more uniform distribution and better grain size can be obtained by doping TaC in cemented carbide.The inhibiting effect when doping 0.5％ TaC is the most obvious than the others,its grain size is about 0.5 μm and the surface hardness reaches the highest value,i.e.HV30=21.27 GPa,that is about 8.98％ higher than the other specimens.