Effects of laser power on the microstructural evolution and mechanical performance in laser dissimilar welding of TC4 to SiCp/6092Al composite

In this study, an overlap configuration for Ti6Al4V alloy (TC4) and SiC particle reinforced aluminum matrix composites (AMC) was achieved by laser welding process. The influence of laser power on the microstructural evolution, intermetallic compounds formation and mechanical properties of TC4/AMC joints were investigated. The presence of reinforced phase SiC complicated the metallurgical reaction in the molten pool, resulting in the formation of intermetallic compounds, such as Al4C3, TiC, TiAl, and TiAl3. The influence of laser power was more pronounced on the penetration depth compared to its impact on the weld width. The thickness of TiAl intermetallic compounds at the TC4/AMC interface increased as the laser power was raised. Abundant dislocations existed surrounding the TiAl3 phase because of the different thermal-mechanical properties between Al matrix and TiAl3 phase. The tensile shear force of TC4/AMC joints can be considerably improved by reducing the thickness of the TiAl3 phase. The maximum tensile shear force of 1675.6 N for the TC4/AMC joint was obtained at a laser power of 1500 W when the thickness of the TiAl3 layer reached the lowest value of 7.1 μm. The research results have the potential to improve laser welding techniques for TC4/AMC hybrid structures and provide valuable guidance for the design of TC4/AMC welded joints in the future.