Regulation mechanism of mechanical properties on laser welding-brazing joint for aluminum alloy and steel via surface texture and AlSi12 precoating

To explore the improving method of mechanical properties on laser welding-brazing joints for aluminum alloys and steel, a novel laser welding connection process is proposed to efficiently improve bonding strength via surface texture and AlSi12 precoating for 6061 aluminum alloys and DP600 dual-phase steel. The role of this method in improving joint property was evaluated by the microstructure, interface structure, and wetting morphology. The results indicated that a mechanical pin structure is formed between the two materials to ensure that the two materials lock tightly. The average joint strength is 171 MPa using the surface grooves with appropriate line spacing and the preset filling metal, which is 24.5% higher than the untreated direct welded joint. Furthermore, the morphology of the cross section of the joints exhibited better wetting and spreading performance. The analysis indicated the joint strength enhancement via the combination of metallurgical bonding and mechanical interlocking. The proposed method provides an innovative technique to facilitate the manufacturing process for joining dissimilar materials and the quality of products.