1. Shenyang National Laboratory for Materials Science; Institute of Metal Research; Chinese Academy of Sciences; 72 Wenhua Road Shenyang 110016 P. R. China
2. School of Materials Science and Engineering; University of Science and Technology of China; Shenyang 110016 P. R. China
3. Materials and Manufacturing Qualification Group; Corporate Technology; Siemens Ltd., China; Beijing 100102 P. R. China