摘要
采用粉末冶金法制备WC-0.5Cr3C2-0.5Co和WC-8.2(W、Ta、Ti)C-1.0Co两种合金粉末,以1 480℃/90 min真空烧结工艺和1480℃/90 min/5MPa低压烧结工艺分别制备出WC-0.5Cr3C2-0.5Co和WC-8.2(W、Ta、Ti)C-1.0Co两种无粘结相硬质合金。利用X射线衍射分析技术研究合金的物相,利用扫描电镜与能谱仪对合金微观组织结构进行观察与分析。结果表明:真空烧结工艺制备的合金晶粒细小、硬度高;低压烧结工艺制备的合金致密度较高、晶粒粗大、硬度降低。此外,Ti原子的存在使WC晶界能各向异性,从而造成W原子在粘结相中的各向异性溶解-析出,导致形成少量的板条状WC晶粒。
WC-0.5Cr3C2-0.5Co and WC-8.2（W、Ta、Ti）C-1.0Co cemented carbides were prepared by vacuum sintering at 1 480℃with a 90 min retention and low-pressure sintering process at 1 480℃and retention time of 90 min under 5 MPa Ar atmospheric pressure using WC-0.5Cr3C2-0.5Co and WC-8.2（W, Ta, Ti） C-1.0Co powders prepared by traditional powder metallurgy method as raw materials. X-ray diffraction （XRD） technology was used to study phases of the cemented carbides. Scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy were used to characterize the microstructures. The results show that the mean WC grain size of cemented carbides prepared by vacuum sintering process is finer than that of prepared by low-pressure sintering process, and the hardness of cemented carbides prepared by vacuum sintering process is higher than that of prepared by low pressure sintering process. However, the density of cemented carbides prepared by low-pressure sintering process is higher than that of prepared by vacuum sintering process. Moreover, the existence of Ti atoms may lead to the anisotropic dissolution and precipitation of W atoms in the binder phase, thus results in the formation of platelet WC grains.
出处
《粉末冶金材料科学与工程》
EI
北大核心
2014年第5期695-700,共6页
Materials Science and Engineering of Powder Metallurgy
关键词
硬质合金
粘结相
烧结
性能
微观结构
cemented carbides
binder phase
sintering
properties
microstructure
