Selective laser melting 316L/CuSn10 multi-materials: Processing optimization, interfacial characterization and mechanical property.

• The 316 L/CuSn10 bimetallic multi-material lattice structures were successfully fabricated by SLM process. • Re-melting and recrystallization refinement promoted mechanical strengthening of the fusion zone. • Difference in physical properties of materials and copper penetration caused crack initiation. • The 316 L/CuSn10 composites have good interfacial bonding strength proven by mechanical tests. Adopting selective laser melting (SLM), a typical technology of additive manufacturing (AM), to form multi-material metallic composites is a challenging and promising field. In this study, SLM 316 L/CuSn10 multi-material composites was an innovative attempt to develop functional and structural materials with excellent properties of steel and copper alloys. Dense 316 L/CuSn10 specimens with no interfacial macrocracks were successfully fabricated. Results showed that the Vickers microhardness gradually decreased from 329.5 ± 12.5 HV in 316 L region to 172.8HV ± 7.4 in CuSn10 region. The ultimate tensile strength and flexural strength of 316 L/CuSn10 specimen were between 316 L and CuSn10. The shear stress of 316 L/CuSn10 sample was 210 MPa, which was higher than the steel/copper alloys fabricated by other methods. It indicated an ideal interfacial bonding condition of 316 L/CuSn10 multi-material, which was benefited from sufficient agitation of the molten pools and elements diffusion in the term of continuous distribution of elements and the enrichment of the heterogeneous alloy phases. Also, the grain refinement by re-melting and recrystallization upgraded the bonding performance at the interface. Finally, the 316 L/CuSn10 lattice structure was formed by SLM, hinting at the prospects for industrial applications of steel/copper multi-material by SLM in future. [ABSTRACT FROM AUTHOR]