Enhancing the reliability of laser welded-brazed aluminum/stainless steel joints via laser-chemical hybrid surface texturing.

• A novel strategy is proposed to improve the strength of aluminum/stainless steel weld-brazed joints. • High-quality multiscale surfaces were achieved via hybrid fabrication of laser and chemical microtexturing. • The maximum linear load of 495.9 N/mm for regulated joints was 61 % higher than untreated joints. • Strengthening mechanism was elucidated through a comprehensive analysis of reaction, wetting, and failure behaviors. Surface microtexture is a promising technique for enhancing the quality of heterogeneous joints. This study developed a novel surface texturing method to improve the reliability of laser welded-brazed aluminum/stainless steel joints. The method combined laser etching and chemical etching to create high-quality multi-scale surfaces with large grooves and small wrinkles. The designed microtexture promoted atomic transfer and induced the generation of nanoscale η-Fe 2 (Al,Si) 5 phases during the welding-brazing process. It reduced the spreading activation energy along the groove direction, which enlarged the joining area. It also optimized the strain-stress distribution to enhance the deformation tolerance of the bonding interface throughout the structural strengthening mechanism. Through the synergistic regulation, the joint achieved a maximum line load of 495.9 N/mm, which was 61 % higher than the untextured joint of 307.5 N/mm. The joint performance reached 95 % of the Al/Al lap joint (519.3 N/mm) with the same welding parameters. This study provided new insights into the high-quality joining of aluminum/steel systems or other heterogeneous materials. [ABSTRACT FROM AUTHOR]