Effects of Pre‐Placed Nano‐TiC Powder on the Performance of Steel/Aluminum Laser Welded Joints

The steel/aluminum dissimilar metal welding plays a significant role in lightweighting automotive structures. However, the formation of hard and brittle intermetallic compounds (IMCs) in steel/aluminum welded joints severely compromises their mechanical performance. Nano ceramic particles such as TiC possess characteristics that inhibit the diffusion of Fe and Al, thereby exhibiting a significant advantage in suppressing IMCs formation in steel/aluminum welded joints. In this study, an optimized laser‐welding process is employed to investigate the mechanical properties of steel/aluminum dissimilar metal joints with different concentrations of TiC nanoparticles. It is aimed to determine the optimal TiC addition concentration by comparing the mechanical performance. Additionally, the inhibitory effect of TiC particles on the formation and growth of brittle Fe–Al IMCs is explored through an analysis of IMCs growth kinetics. In the research results, it is shown that the optimal TiC addition concentration is 1%. At this concentration, the tensile strength of the steel/aluminum welded joint reaches 98.29 MPa, showing a remarkable improvement of 32.65% compared to the sample without TiC addition. The addition of TiC particles suppresses the mutual diffusion between Fe and Al, reduces the generation of brittle IMCs, and enhances the mechanical performance of the steel/aluminum joint.