电冶稀土WC钢结硬质合金中碳化物特征的研究

采用电渣熔铸冶金工艺，用回收的碳化钨钢结硬质合金作原料，再加入微量的稀土，制备了新型的钢结硬质合金。用透射电镜、扫描电镜、金相显微镜及X射线衍射等测试手段研究了新材料中的碳化物的特征。结果表明：在该材料的显微组织中存在原始颗粒区和扩散区。原始颗粒区组织中碳化物的特征是存在大量变化甚微的角状大尺寸原始WCp及具有明显反应层的长椭圆状WC颗粒，界面反应产物为Fe3W2C。在粗大碳化钨颗粒附近能够原位生成先共晶析出相（WC和W2C），在较远处的钢基体中分布着细网状碳化物，同时有（Cr，Fe）7C3等条状复式碳化物生成；而扩散区主要细小W2C小颗粒、WC颗粒及再结晶W-Fe-C小颗粒组成。稀土的加入可提高WC颗粒分散性。

Study of carbides characteristic in a rare-earth steel-bonded cemented carbide prepared by electroslag melting and casting

A new steel bonded cemented carbide made from raw material which is mixed by abandoned WC steel bonded cemented carbide and trace rare-earth oxide was prepared by electroslag melting and casting technique. The carbide characteristic in the new material was examined and analyzed by using TEM,SEM,XRD and optical microscope. The results show that the region of original WC particles and the region of fine carbide particles were formed in the tested maferial.The regions of original WC particles are characterized by a great deal of larger original WC particles with angularities which are slightly changed and long oval carbides with Fe_3W_3C layer. Pre-eutectic phase being WC and W_2C are in-situ separated near to coarse WCp, however, the fine net carbides and long strip carbides (Cr,Fe)_7C_3 are formed in the steel matrix far from the WCp. The region of fine carbide particles are characterized by fine grain of W_2C which was transformed from WC, a lot of fine WC crystalline and fine W-Fe-C compounds.The dispersity of WC particles is improved by the addion of rare-earth element.