Micro-zone performance of laser-MIG hybrid welded A7N01P-T4 Al alloy joints

Laser-MIG hybrid welded joint of 14mm A7N01P-T4 Al alloy for high speed train was investigated, the properties of WM (weldmetal), HAZ (heat affect zone) of joints and BM (base metal) were tested respectively, such as micro-zone tensile property, fracture toughness and so on, and the differences of micro-zone properties were analyzed by OM and SEM. BM has the best micro-zone tensile strength, while that of WM is the lowest. HAZ has the highest fracture toughness Jm(14), which can reach up to 119.580 kJ/mm² and indicatesan outstanding ability to resist crack growth in hybrid welded joints. Shapiro-Wilk normality test showed that fracture toughness of laser-MIG hybrid welded A7N01P-T4 Al alloy joints is extremely reliable.