Interfacial characterization of SLM parts in multi-material processing: Intermetallic phase formation between AlSi10Mg and C18400 copper alloy

Multi-material processing in selective laser melting (SLM) using AlSi10Mg and UNS C18400 copper alloy was carried out. The interfacial characteristics were analyzed with FIB, SEM, XRD, EDS and EBSD techniques. Al2Cu intermetallic compound was formed at the Al/Cu bond interface after the SLM process. The tensile strength of Al/Cu SLM parts was evaluated to be 176 ± 31 MPa and flexural strength under a 3 point bending test was evaluated to be around 200 MPa for Cu at root and 500 MPa for Al at root. Further analysis suggested that the formation of intermetallic compounds translated the fracture mechanism at the interface from ductile to brittle cleavage. The microhardness values also varied along the interface with high microhardness at the interface due to the intermetallic compounds.