Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 19 No. 6 December 2009|
ultrafine WC-10Co cemented carbides
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Hunan Import and Export Company of Chinese Automobile Industry, Changsha 410001, China）
Abstract:The nanocomposite WC-Co powders were prepared through planetary ball milling method. Effects of grain growth inhibitor addition and the vacuum sintering parameters on the microstructure and properties of ultrafine WC-10Co cemented carbides were investigated using X-ray diffractometer, scanning electron microscope and mechanical property tester. The results show that VC and NbC additions can refine the WC grains, decrease the volume fraction of Co3W3C phase in ultrafine WC-10Co cemented carbides, and increase the hardness and fracture toughness of the base alloys. After sintering for 60 min at 1 400 ℃, the average grain size and hardness of ultrafine-grained WC-10Co-1VC cemented carbide are 470 nm and HRA 91.5, respectively. The fracture toughness of cemented carbide WC-10Co-1NbC alloy is over 7 MN·m−3/2.
Key words: ultrafine WC-10Co cemented carbide; VC; NbC; microstructure; mechanical properties