Fabrication of highly dissimilar TC4/steel joint with V\Cu composite transition layer by laser melting deposition

The high production flexibility of laser additive manufacturing is a significant advantage in the fabrication of functionally graded materials such as TC4 alloy and 30CrNi2MoVA steel, which have applications in the nuclear and aerospace industries. A laser melting deposition (LMD) process was employed to bond TC4 alloy with a high-strength 30CrNi2MoVA steel by the insertion of different intermediate materials, the intermediate materials consisted of either a pure-V layer or a V/Cu composite layer. The microstructure, elements distribution, phase composition, and mechanical properties of the joints were characterized. The appropriate transition interlayer composition was determined using ThermoCalc software. The experimental results indicated that using a pure V interlayer to bond TC4 with steel via LMD was extremely difficult, due to the generation of Fe-Ti intermetallic compounds. Consequently, the maximum tensile strength was only 58 +/- 14 MPa. However, the V/Cu composition transition interlayer successfully suppressed the diffusion and mixing of Ti and Fe during LMD, forming joints between TC4 alloy and 30CrNi2MoVA steel with a tensile strength of 191 +/- 20 MPa. In summary, this paper reports a new route to prepare a relatively strong TC4/30CrNi2MoVA dissimilar joint by the insertion of a V/Cu composite transition interlayer that does not require additional supplementary processes and does not limit the component geometry. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study successfully bonded TC4 alloy with 30CrNi2MoVA steel by inserting a V/Cu composite transition interlayer, achieving a tensile strength of 191 +/- 20 MPa. This new method provides a relatively strong joint without additional supplementary processes and geometry limitations.