Laser welding of dissimilar metals joint aided by unsteady thermal convection boundary element method analysis

Abstract

The present study has proposed the noble laser welding method of dissimilar metals joint, where the solid/liquid state diffusion process is effectively adopted to avoid unfavorable intermetallic reaction layer produced in the conventional liquid/liquid process. The suitable laser welding conditions for realizing the solid/liquid state diffusion process were predicted based on the unsteady thermal convection Boundary Element Method (BEM) analysis. Laser welding experiments were carried out by using Nd:YAG laser based on the results of BEM analysis. Dissimilar joints between steel and aluminum alloy could be successfully welded by using the solid/liquid state diffusion process. The welding conditions obtained by the experiments were in good agreement with those predicted by the BEM analysis. Thin intermetallic layer at the interface was detected. The maximum failure load of the joint was 69% of that of the base metal (A5052-O), while it would depend upon the bonded width.