1. College
of Material Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P. R. China
2. School
of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003, P. R. China
3. Department
of Applied Physics, Northwestern Polytechnical University, Xi’an 710072, P. R. China
4. Xi’an Research Institute of High Technology, Xi’an 710025, P. R. China
5. Department
of Materials Science, Fudan University, Shanghai 200433, P. R. China
6. State Key
Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, P. R. China