Dissimilar jointing of TA15 to Inconel718 by laser additive manufacturing using Nb/Cu bilayer

Abstract

High quality jointing of TA15 titanium alloy and Inconel718 (IN718) nickel based superalloy has a widespread application prospect in the aerospace industry. In the present work, we adopted a laser additive manufacturing (LAM) technique to joint dissimilar materials of TA15 and IN718, and to restrain the formation of Ti-Ni intermetallic compounds and macroscopic cracking via Nb/Cu bilayer. Research results showed that the presence of Nb/Cu bilayer was very helpful to impede the formation of brittle Ti-Ni phases and macroscopic cracking between TA15 and IN718. Microstructure results indicated that high quality metallurgical bonds were formed at the interfaces of adjacent materials. Micro-hardness results presented that the Nb/Cu bilayer was able to obtain a good plastic transition from TA15 to IN718. The tensile strength of the jointing with the Nb/Cu bilayer was 434 MPa, indicating the bonding strength exceeded that of the Nb interlayer.