Laser Joining of Ti3Al-Based Alloy to Ni-Based Superalloy using a Titanium Interlayer

( )Joining Ti3Al-based alloy to Ni-based superalloy is of great interest for applications in the aerospace fields. Direct welding of these two materials was very difficult and the joint usually fractured during laser welding which cannot form an effective welding joint. In this work, a pure titanium interlayer with a thickness of 0.4 mm was used between the base metals. The results indicated that the addition of titanium interlayer has a great effect on the joint performance. No macrocracks were found through the whole joint. The average room-temperature tensile strength of the joint with titanium was 177 MPa which still much lower than the two base metals. The weak link of the dissimilar joint was the Ti3Al/weld interface. The presence of Ti2Ni, alpha(2)-Ti3Al and AlNi2Ti brittle intermetallic compounds in the Ti3Al/weld interface deteriorated the joint properties.