Optimization of Welding Parameters During Ti-TA2/5A06Al Dissimilar Double-Sided Cold Arc Metal Inert Gas Welding

A double-sided cold arc MIG welding process was used in Ti-TA2 /5A06Al dissimilar welding. The effects of front welding heat inputs, bevel angles, and wire offsets on the Ti/Al interfacial microstructures and on the joint tensile strength were analyzed. The optimized parameter ranges were: front welding heat input of 0.94-1.24 kJ/cm, the bevel angle of 35°-45°, and wire offset of − 1. 0 to + 1. 0 mm. Under proper parameters, a straight bonding interface was formed between the titanium and the weld; no welding defects such as crack were found near the interface. Two different Ti/Al interfaces were observed in a single sample. A double-layer structure with a Ti 3 Al layer and a TiAl 3 layer was formed at the interface in the 1/4 top part of the joint, while only a serrated TiAl 3 layer was formed in other regions. The tensile strength of the joints was tested without removing the reinforcement. The ultimate tensile strength of the joints surpassed 320 MPa, and the joints were mostly broken near the Ti/Al interface.