Microstructure and tensile properties of Ti/Al dissimilar joint by laser welding-brazing at subatmospheric pressure

Abstract In this paper, the Ti6Al4V and 6061 Al dissimilar joints were welded by laser welding-brazing process, and the effect of subatmospheric pressure and laser offset on weld formation, porosity defect, intermetallic compounds (IMCs) distribution, and tensile properties of Ti/Al dissimilar joints was investigated in detail. At a subatmospheric pressure of 101 Pa and laser offset of 0.5 mm, a sound weld formation with full penetration was obtained. The porosity defect in the fusion zone was significantly eliminated and the thickness of IMCs layer was controlled less than 2 μm due to the enhanced melt flow and uniform temperature field at low vacuum. The tensile strength reached a maximum value of 181.1 MPa with a mixed-mode of ductile and brittle fracture.