Effect of Microstructure on Joint Strength of Fe/Al Resistance Spot Welding for Multi-Material Components

Abstract

The effects of welding conditions such as the electrode type and welding current were investigated on the microstructure and joint strength of the resistance weld of A5052 and GA590. The reaction layer formed at the joint interface was inferred to consist of Fe-Al based intermetallic compounds (IMCs) which are FeAl, FeAl2, Fe2Al5 and FeAl3 by quantitative analysis. Although the thickness of the IMCs layer decreased from the center of the nugget towards the edge of it. When the DR type electrode was used, the cross tensile force became higher than those of the joints formed with the R type one. This is because the thickness of the reaction layer formed at the nugget end of A5052 was thin in the case of the DR type electrode. Also, it was found that cross tensile force increases when the thickness of the reaction layer is thin by multiple regression analysis.