Optimization of Friction-Stir Welding of 6061-T6 Aluminum Alloy
Igor Vysotskiy, Sergey Malopheyev, S. Mironov, Rustam Kaibyshev
Abstract
In this work, two simple but effective strategies were proposed to optimize friction-stir welding of 6061-T6 aluminum alloy. The first one involved an optimization of welding variables to provide a combination of a relatively high welding temperature and the shortest possible thermal cycle during friction-stir welding. This inhibited precipitation coarsening in the heat-affected zone and resulted in considerable residual stress. Accordingly, the produced welds exhibited excellent strength characteristics under static and cyclic loading conditions. The second method was based on the application of the standard postweld T6 tempering. To avoid the abnormal grain growth, which usually occurs during solutionizing of aluminum friction-stir welds, a prestrain rolling was employed prior to the material tempering. This promoted an activation of recrystallization processes during subsequent heat treatment, thus suppressing the abnormal grain growth.