Improving laser wire welding process and Al-Mg alloy wire property through micro-alloying additions of scandium and zirconium

This study enhanced Al-Mg welding wire via Sc/Zr microalloying and optimized laser welding parameters using a Taguchi design. Using conventional 5183 wire, 5052 aluminum joints have a softened heat-affected zone (HAZ) and low yield strength of 115.7 MPa. Having welded by 5183 wire with Sc/Zr microalloying, the joint showed a reduced HAZ width by 35%, increasing yield strength by 11% to 128.5 MPa with even enhanced ductility. Microstructure characterization revealed that the Sc addition refined dendritic structures, suppressed segregation, and formed thermally stable Al₃(Sc,Zr,Ti) nano-precipitates. These nano-precipitates impeded dislocation motion and resulted in grain refinement of the joints, which enhanced strength and ductility synergistically. The work demonstrates the effectiveness of Sc/Zr microalloying in stabilizing weld microstructures via nanoscale precipitate-dislocation interactions, offering a strategy to improve aluminum weld performance.