Determination of local constitutive behavior and simulation on tensile test of 2219-T87 aluminum alloy GTAW joints

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).