Effect of Defects in Lap Joints Between AZ31B and Ti-6Al-4V Alloys Processed Using Gas Tungsten Arc Welding

Lightweight applications in aerospace and automotive fields generally dictate the joining of dissimilar materials. Such lightweight materials are also finding applications in bio-implant-related applications. This study aims to determine the best possible combination of process parameters to ensure good joints of AZ31B alloy with Ti-6Al-4V alloy sheets. The defects associated with the joints are also discussed in detail. While choosing the level of current for this dissimilar material combination, care should be exercised. A low level of current (50 A) induces problems associated with poor wettability of magnesium, whereas a high current (75 A) leads to the excessive evaporation of magnesium. Macroscopically good-quality joints are processed with a welding current of 60 A and a welding speed of 0.13 m/min. During tensile-shear testing, good quality joints could sustain the ultimate load of 2073 N, while similar joints at the same parameter with microporosities have failed at 985 N. Defect-free joints have exhibited a 110% increase in joint strength when compared with the strength of the joints having microporosities at the interface.