Evaluation of Joint Properties and Theoretical Analysis of Dissimilar Friction Welding between Al-11%Zn-3%Mg-1.4%Cu Alloy and SUS304 Stainless Steel

In this study, the joint properties of dissimilar materials joined by friction welding between an Al-11%Zn-3%Mg-1.4%Cu alloy and SUS304 stainless steel was evaluated. Additionally, to compare the weldability, friction welding was also conducted on dissimilar materials involving the A7204 alloy, A7075 alloy, and SUS304 stainless steel. The A7204/SUS304 joints and the A7075/SUS304 joints both fractured in the aluminum alloy at tensile strengths of 316 MPa (joint efficiency of approximately 75%) and 353 MPa (joint efficiency of approximately 100%), respectively. It was found that by reducing both the friction pressure and the rotational speed, the interface could be maintained at a relatively low temperature for an extended period, thereby suppressing excessive growth of the intermetallic compound (IMC) layer while still achieving the joint. In Al-11%Zn-3%Mg-1.4%Cu alloy, the tensile strength increased to 377 MPa compared to the standard alloy, but the fracture occurred at the interface. FEM analysis revealed that the stress at the interface during tensile deformation increased more significantly at the edges than at the center, leading to stress localization. It was suggested that in such cases where localized stress occurs, interface fracture is more likely to occur.