CHEN Zhen-hua1, ZHAO Xiu-yuan1, WANG Hui-ping2,ZHANG Hao3,CHEN Ding1,
(1. College of Materials Science and Engineering, Hunan Univ, Changsha, Hunan 410082, China;2. Zhuzhou Cemented Carbide Group Co, Ltd, Zhuzhou,Hunan 412000, China; 3. Dept of Electromechanical Engineering, Changsha Univ,Changsha, Hunan 410022, China)