1. State Key Laboratory of Advanced Welding and Joining; Harbin Institute of Technology; Harbin 150001 China
2. Materials Science and Engineering; University of California at San Diego; 9500 Gilman Dr. La Jolla CA 92093 USA
3. Key Laboratory of Microsystems and Microstructures Manufacturing; Ministry of Education; Harbin Institute of Technology; Harbin 150080 China
4. Institute of Metal Research; Chinese Academy of Sciences; Shenyang 110016 China