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

• Published in: Thin-walled structures 2024-06, Vol.199, p.111780, Article 111780
• Main Authors: Li, Haoyue, Xia, Hongbo, Li, Liqun, Li, Longqiu, Su, Xuan, Peng, Jin, Ma, Yunwu, Tan, Caiwang, Song, Xiaoguo, Wu, Tao
• Format: Article
• Language: English
• Subjects: Aluminum/stainless steel; Failure behavior; Reaction behavior; Surface texturing; Wetting behavior
• ISSN: 0263-8231; 1879-3223
• DOI: 10.1016/j.tws.2024.111780

•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-Fe2(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.