1. Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023, P. R. China
2. Shenyang National Laboratory for Materials Science, International Centre for Materials Physics, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, P. R. China
3. Shenyang University of Technology, No.111, Shenliao West Road, Economic & Technological Development Zone, Shenyang 110870, P. R. China