1. Department of Materials Science
and Engineering, University of California, Berkeley, California 94720, United States
2. National Center for Electron
Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. State Key Laboratory
for Mechanical
Behavior of Materials and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049,
China
4. General Motors Research and Development Center, Warren, Michigan 48090, United
States