Effects of parameters on welding performance of the Ti/Al butt-joint in advanced plasma-MIG hybrid welding.

An advanced plasma-MIG hybrid welding was employed for the butt-joint of titanium (Ti) alloy and aluminum (Al) alloy sheets in this study. First, the weld bead appearance and geometry of 3 mm thick Ti/Al butt-joint specimens under different hybrid welding parameters were investigated. Then, the effects of hybrid welding parameters on the mechanical properties, fracture surface, and weld bead microstructure of the specimen were researched. In addition, the fracture mechanism between weld bead geometry and failure load of specimen was further discussed. This study selected the plasma arc current, MIG welding current, and the central gas flow rate of plasma arc as the hybrid welding parameters. The results demonstrate that Ti/Al butt-joints produced at a higher MIG welding current of 110 A or a higher central gas flow rate of 0.3 L/min increase both the height of reinforcement and porosity of fusion zone. When the MIG welding current is set to 100 A and the central gas flow rate is set to 0.2 L/min, increasing the plasma arc current to 60 A improves both weld bead geometry and tensile strength. [ABSTRACT FROM AUTHOR]