Effects of heat input on microstructure and mechanical property of Al/Ti joints by rectangular spot laser welding-brazing method

A rectangular spot laser welding-brazing method was developed to join butted Ti/Al dissimilar alloys. In order to evaluate effects of heat input on mechanical property of the joints, microstructure of the joints were characterized. TiAl₃ intermetallic compounds (IMCs) were found at the joint interface in the case of low-heat input and TiAl₃, TiAl, Ti₅Si₃, and Ti₃Al IMCs were observed at high-heat input. Results of tensile test showed that the joints fracture in the fusion zone under the condition of low-heat input and in the interfacial reaction layer or the fusion zone with a mass of porosities at high-heat input. In addition, tensile strength of specimens broken at the fusion zone is higher obviously than that at the interface or the fusion zone with a mass of porosities, and tensile strength of the joints is up to 290 MPa.