<b>Microstructure and Properties of Ti-6Al-4V/Ni-Ti Heterogeneous Structure Materials with Cu-Ni Interlayer via Multi-Wire Arc Additive Manufacturing</b>

This study employs Multi-Wire Arc Additive Manufacturing (M-WAAM) to fabricate Ti-6Al-4V/Ni-Ti heterogeneous structure materials. The results show that the incorporation of the Cu-Ni interlayer effectively suppresses the formation of brittle Ti-Ni intermetallic compounds, thereby enhancing the interfacial bonding strength. This improvement is attributed to the formation of stable Ti-Cu and Ti-Ni-Cu phases at the interface. Furthermore, the microhardness within the interlayer region exhibits a substantial increase, reaching ~ 570 HV_0.2, which indicates enhanced material strength at the interface. The average ultimate tensile strength of the material is measured at 279.9 ± 15 MPa, with a strain of 5.6 % ± 2 %. The introduction of the Cu-Ni interlayer thus provides an effective approach for the design and fabrication of heterogeneous structure materials. This approach not only addresses the challenge of interfacial integrity but also offers considerable potential for the development of large-scale heterogeneous components in industrial applications, such as aerospace and biomedical fields.