Dissimilar gas tungsten arc welding of TC4 titanium to 304 stainless steel using CuSi3 filler wire

Dissimilar metal welding, such as welding stainless steel to the titanium alloy, provides a new method to achieve low-cost applications and keep high mechanical properties of the Ti alloys. However, the welding strength is limited by the brittle intermetallic compounds generated in the welding process. In this paper, a melt inert-gas welding (MIG) method that assisted with a CuSi3 filler is used to realize the high-strength welding of TC4 titanium alloy and 304 ss stainless steel. The influences of heat input on the microstructure composition, reaction layer thickness, mechanical properties, fracture behavior, and microhardness distribution in the interface are systematically studied to reveal the interfacial interfusion mechanism during the welding process. In addition, it was suggested that the brittle intermetallic compounds (IMCs) such as FexTi and CuxTiy in the interface are identified under the optimal welding parameters, and the maximum tensile strength of the welded joint was beyond 266 MPa. The dissimilar metal welding of TC4 and 304 ss presented in this paper has good prospects for application aerospace, nuclear industries, and offshore foundations.