Subregion Based Prediction of Residual States in Friction Stir Welding of Dissimilar Metals

Abstract

Mechanical property changes in friction stir welding can directly affect the rebalance of the stress field in friction stir welding. This means that it reveals a high relevance with the residual states of friction stir welding. Here, we propose a subregion model in which the mechanical property changes are considered to predict the residual states in friction stir welding of dissimilar metals. Results indicate that the accuracy of the predicted distortion can be greatly increased when the different mechanical properties are considered in friction stir welding of 2024-T3 and 6061-T6. The final mechanical property is determined by the mixture of the materials at retreating and advancing sides. The final mechanical property in the stirring zone can be increased to 171 MPa for yield strength and 194 MPa for tensile strength when the strength of the advancing side material is higher. The shrinkage of material in the stirring zone during the cooling stage is the key reason for the formation of the tensile residual stress and the V-shape distortion on the cross-section in the as-weld state.