Sintering characteristics and microstructure of WC-Co-VC/Cr_3C_2 ultrafine cemented carbides

作     者：LEI Yiwen WU Enxi LEI Yiwena and WU Enxib a School of Mechanical and Electronic Engineering, Tianjin Polytechnic University, Tianjin 300160, China b State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China

作者机构：School of Mechanical and Electronic Engineering Tianjin Polytechnic University Tianjin 300160 China State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2009年第28卷第5期

页      面：482-486页

核心收录：

学科分类：080503[工学-材料加工工程] 0806[工学-冶金工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0702[理学-物理学] 

基　　金：supported by the Foundation of Scientific and Technologic Development for Universityin Tianjin (No. 20060912) 

主　　题：cemented carbides sintering characteristic grain growth microstructure mechanical properties 

摘      要：The sintering characteristics, microstructure, and mechanical properties of ultrafine WC-12%Co-0.2%VC/0.5%Cr3C2 cemented carbides were investigated. Dilatometric and differential thermal analyses （DTA） indicate that the compacts start to shrink at 600°C, the shrinkage rate peak is at 1190°C, and the liquid formation temperature is lower than the W-C-Co eutectic temperature （1330°C）. Microstructure analysis results show that the cemented carbides with fine and homogeneous microstructure were obtained when sintered at 1430°C. Continuous and discontinuous grain growth was suppressed due to the synergistic action of VC/Cr3C2. The transverse rupture strength （TRS） of the samples reaches 4286 MPa, with the hardness HRA 92.1. The fine and homogeneous microstructure, alloy strengthening, and different phase constitutions of binder in the cemented carbides result in high hardness and TRS. Continuous and discontinuous grain growth was observed in the cemented carbide sintered at 1450°C, which results in significant decreases of hardness and TRS. It indicates that VC/Cr3C2 additions in the cemented carbides can only suppress the grain growth at a certain temperature.