Relationship between intermetallic compound layer thickness with deviation and interfacial strength for dissimilar joints of aluminum alloy and stainless steel

The relationship between the intermetallic compound (IMC) layer thickness including the deviation and joint strength was evaluated for the dissimilar joints between aluminum alloys and austenitic stainless steel. To evaluate the interface with various IMC layer thicknesses, the joints by friction stir welding were solution-heat-treated and artificially aged. The transitions of joint strength and fracture position were characterized for the IMC layer thickness ranging from 0 to 2.5 µm. Further, we demonstrated that the fracture position can be determined by the percentage of the joining area via the IMC layer thickness below a threshold value, which was 0.4 µm.