Mechanical properties and microstructure analysis of welding-brazing of Al/ti butt joint with Zn foil additive

TIG welding-brazing features of 5052 Al alloy and Ti6Al4V alloy in butt configuration with Zn foil additive were studied with varying welding heat input. The joint morphology, mechanical performance, microstructure and joining mechanism were investigated in terms of experiment observation and analysis. Results reveal that the TIG welding-brazing process was successfully developed to join 5052 Al alloy and Ti6Al4V alloy. With low heat input, a mass of residual Zn and a thin TiAl3 IMCs layer occurred in the fusion area and brazing area respectively. And with optimal heat input, both the homogeneous diffusion of Zn atoms and the formation of clubbed interfacial reaction layer were beneficial to enhance joint performance. The optimized Al/Ti joint with the maximum joining strength of 192MPa was obtained under the current of 90A. Fracture occurred in the weld seam zone adjacent to the interface of Al/Ti and the fracture morphology was characterized by typical dimples and tearing ridges.