Modeling the dissimilar material flow and mixing in friction stir welding of aluminum to magnesium alloys

Abstract To study the dissimilar materials mixing and understand the underlying mechanism, a model for friction stir welding of aluminum to magnesium alloys is developed. The mixing dissimilar materials in the stirred zone are treated by a method similar to the functionally graded material, the physical parameters are exponentially related to the real volume fraction, and the influence of volume fraction index on the material distribution is analyzed. Furthermore, a modified method that uses a variable volume fraction index with radial distance away from the pin axis is proposed and employed. Compared with the constant volume fraction index equal to 1, the modified method can better predict the material mixing and distribution in aluminum-magnesium dissimilar joints, which lays solid foundation for analyzing the formation of intermetallic compounds in dissimilar friction stir welding of aluminum to magnesium alloys.