1. National Engineering Research Center of Light Alloy Net Forming School of Materials Science and Engineering & State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China
2. Center of Hydrogen Science Shanghai Jiao Tong University Shanghai 200240 P. R. China
3. Shanghai Key Laboratory of Magnetic Resonance School of Physics and Electronic Science East China Normal University Shanghai 200241 P. R. China
4. University of Chinese Academy of Science Beijing 100049 P. R. China
5. Shanghai Synchrotron Radiation Facility Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201204 P. R. China
6. Department of Materials Science and Engineering University of Michigan Ann Arbor MI 48109‐2136 USA