Microstructure, bonding mechanism and corrosion property of titanium TA2/copper T2 welded joint by cold metal transfer technology

This paper described a fundamental investigation of titanium TA2-copper T2 butt joint by cold metal transfer (CMT). During the welding process, wire was deviated from the edge of Cu sheet. A satisfied Ti-Cu CMT welding-brazing butt joint was obtained. Fusion welding joint was formed at copper side, while brazing joint was formed at titanium side. Welding-brazing joint was formed between titanium TA2-copper T2. Bonding mechanism of the welded joints was examined by scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS) and tensile tests. Corrosion tests of Ti/Cu welded joint were conducted in solution of 10% HCl at room temperature. Results indicated that brazing interface consisted of various intermetallic compounds, i.e. Ti₂Cu, TiCu, and AlCu₂Ti. And the weld metal was composed of α-Cu solid solution and Ti-Cu-Al-Ni-Fe multi-phase. The tensile strength of the joint can reach to 205 MPa. There were corrosion grooves in brazing interfaces after corrosion for 7 days, and self-fracture after corrosion for 14 days.