Ta/Cu transition region in TC4/Inconel718 bimetallic structure fabricated by laser deposition manufacturing

The bimetallic structure formed by TC4 and Inconel718 has broad potential applications in aerospace. Based on the laser deposition manufacturing technique, a TC4/Inconel718 bimetallic structure was fabricated via the Ta/Cu transition layer. The test results indicated that a Ta/Cu transition region with a width of 475.0 μm was formed. The microstructure of the transition region changed from a reticular to a rod structure, and the corresponding phase compositions were β-Ta + Ti2Cu + TiCu and TiCu+γ-Cu + Cr2Ta. Owing to the formation of Ti–Cu and Cr–Ta phases in the transition region, the Vickers hardness reached 444.0 HV. The ultimate tensile strength was 280 MPa, and the fracture morphology presented a quasi-cleavage fracture, which occurred in the Ta/Cu transition region where Ti–Cu brittle phases exist.