中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 25 No. 9 September 2015 |
（1. Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China;
2. State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China;
3. Key Laboratory for Advanced Materials Processing Technology, Ministry of Education,
Tsinghua University, Beijing 100084,China;
4. Joining and Welding Research Institute, Osaka University, Osaka, Ibaraki 567-0047, Japan;
5. China Academy of Launch Vehicle Technology, Beijing 100076, China）
Abstract:The local and global mechanical responses of gas tungsten arc welds (GTAW) of a 2219-T87 aluminum alloy were investigated with experiment and numerical simulation. Digital image correlation (DIC) was used to access the local strain fields in transversely loaded welds and to determine the local stress-strain curves of various regions in the joint. The results show that the DIC method is efficient to acquire the local stress-strain curves but the curves of harder regions are incomplete because the stress and strain ranges are limited by the weakest region. With appropriate extrapolation, the complete local stress-strain curves were acquired and proved to be effective to predict the tensile behavior of the welded joint. During the tensile process, the fracture initiates from the weld toes owing to their plastic strain concentrations and then propagates along the fusion line, finally propagates into the partially melted zone (PMZ).
Key words: aluminum alloy; tensile behavior; digital image correlation; constitutive behavior;welded joint
