Bimetallic Structure of Ti6Al4V/IN718 with CuSi Interlayer for Wire-Arc Directed Energy Deposition Process

Fabricating bimetallic structures using various additive manufacturing processes is an ingenious way to integrate different material properties in a single component. This study offers a novel method for fabricating Ti6Al4V and IN718 bimetallic structures using a wire-arc-based directed energy deposition process with a CuSi interlayer, both with and without the addition of pure copper powder at the CuSi–TI6AlV interface. The Cu–Ti and Ni–Cu interfaces of the bimetallic structure have been examined in terms of their metallurgical and mechanical characteristics. The study revealed the presence of Cu₄Ti₃, Cu₃Ti₂, Cu₄Ti, CuTi₂ and Ti₅Si₃ phases at the Cu–Ti interface, whereas CuNi and NiCr₂ phases at the Ni–Cu interface. The Cu–Ti interface with copper powder shows two distinctive layers of intermetallic phases with less intermetallic thickness compared to the interface without copper powder. The maximum bonding strength of 152.31 ± 40.74 MPa and hardness of ~ 485 HV were achieved in the interface without a copper powder sample. However, for interface with copper powder sample, the presence of Ti₅Si₃ hindered the further transformation of less stable Cu–Ti phases resulting in decreased strength.