Modeling Hardness Evolution during the Post-Welding Heat Treatment of a Friction Stir Welded 2050-T34 Alloy

A unified constitutive model of yield strength evolution during heat treatment has been revised to simulate the hardness evolution during the post-welding heat treatment of AA2050-T34 Friction Stir Welded (FSW) plates. The model considers the strengthening by dislocations, solid solution, clusters, and the T1 phase. As a result, the successful prediction of yield strength evolution during the aging of AA2050 with different initial tempers has been achieved. The kinetics of precipitation of the T1 phase during heat treatment has been characterized by electrical resistivity on the unwelded and FSW samples. The obtained results have been used to check the ability of the model to simulate the evolution of the relative volume fraction of the T1 phase and hardness during the post-welding heat treatment in the different zones of FSW samples. Despite some observed discrepancies on the top and bottom of the weld joint, the revised numerical model captures well the overall hardness profile after the post-weld heat treatment.