Continuous drive friction welding procedures of TC4/T2 and microstructure and performance of dissimilar metal joints

The titanium alloy TC4 and pure copper T2 dissimilar metal welding was achieved by using continuous drive friction welding method. It is shown that the strong normal processing conditions, namely larger welding pressure, shorter welding time, should be adopted for continuous drive friction welding of TC4 and T2 dissimilar metals with significant thermal physical properties differences. Asymmetric flashes were formed during TC4/T2 continuous drive friction welding. With too little friction pressures, welding heat input is insufficient, and it is difficult to form regular flashes. Close TC4/T2 metallurgical bonding interfaces and a certain degree of mechanical occlusions were formed with shorter welding time of grade I. The optimum TC4/T2 continuous drive friction welding parameters are the pressures of 1.4 MPa, 1.8 MPa and 2.1 MPa are respectively emerged on the sample surfaces during grade I, grade Ⅱ and upsetting stage of continuous drive friction welding, and friction welding time of 5 s is adopted in grade I. With the optimum welding parameters, the tensile strength of the TC4/T2 continuous drive friction welding joint is 96.7% of the base metal T2.