1. Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
2. Beijing Technology Research Branch of Tian Di Science & Technology Co., Ltd., Chinese Institute of Coal Science, Beijing 100013, China
3. Welding Institute, Central Iron and Steel Research Institute, Beijing 100081, China
4. Department of Industrial and Materials Science, Chalmers University of Technology, SE-41296 Gothenburg, Sweden