Hybrid additive manufacturing of high performance Ti/Al dissimilar metal structure: Interfacial design and strengthening mechanisms

To address the challenge of low joint strength induced by brittle intermetallic compounds (IMCs) in Ti/Al dissimilar metal components (DMCs), this study proposes a hybrid additive manufacturing (AM) strategy. This approach integrates laser powder bed fusion ( L -PBF) with low-heat-input metal inert gas directed energy deposition (MIG-DED) to fabricate a dual-scale reinforced Ti/Al structure (DSR-TAS). Initially, a Ti64 lattice scaffold featuring mortise cavities was fabricated via L -PBF. Subsequently, 5183 aluminum alloy was deposited into these cavities using low-heat-input MIG-DED, establishing robust metallurgical connection and mechanical interlocking. Finally, the bulk aluminum matrix was built up using conventional MIG-DED with standard heat input to complete the DSR-TAS. The resulting structure exhibits a tensile strength of 222.3 ± 9 MPa, reaching 81% of the base 5183 Al alloy strength (275 ± 4 MPa). This enhancement is attributed to a dual-scale synergistic mechanism: at the macroscopic level, the mortise-and-tenon architecture converts tensile loads into shear stress, effectively inhibiting interfacial peeling; at the microscopic level, surface roughness facilitates capillary penetration of the molten aluminum, creating micro-mechanical locks that strengthen interfacial bonding. Furthermore, the controlled low heat input restricts the IMC layer thickness to 3–13 μm, preventing the formation of extensive brittle phases. This work offers a promising method for the integrated manufacturing of high-performance heterogeneous metal components.