Multi-material laser powder bed fusion additive manufacturing of a bimodal laminate heterostructure with Cu-base and Ni-base alloys

A bimodal laminate heterostructure consisting of alternating copper-base (CuCrZr) and nickel-base (Hastelloy X) alloy layers was carefully fabricated via multi-material laser powder bed fusion (MM-LPBF) additive manufacturing approach, employing a custom-designed multi-powder delivery device system and proprietary process-control software. The heterostructure shows a hierarchical architecture with periodically alternating coarse-grained (predominantly Hastelloy X) and fine-grained (primarily CuCrZr) layers, interconnected by transition zones containing mixed grain morphologies. The heterostructural material demonstrates exceptional mechanical performance under building-direction loading, achieving a yield strength of 674.2 MPa, ultimate tensile strength of 756.4 MPa (∼92 % of monolithic LPBF-processed Hastelloy X), and elongation of 19.9 %. Crystal plasticity simulations elucidate deformation coordination and strength-ductility synergy mechanisms, while microstructural characterization confirms the bimodal grain structure originates from the LPBF-laser-induced melt pool dynamics and heterogeneous nucleation during the rapid solidification. This study establishes MM-LPBF as a viable approach for manufacturing high-performance, architecturally graded multi-material systems.