CNT-reinforced AlSi10Mg composite by selective laser melting: Microstructural and mechanical properties

Carbon nanotube (CNT)-AlSi10Mg composites were fabricated by selective laser melting (SLM). The influence of CNTs on the density, microstructure, and strength of SLM CNT-AlSi10Mg composites was investigated. The addition of CNTs over 0.1 wt-% significantly damaged the density due to the high surface energy of the CNTs. The network Si eutectic had no significant difference in either the SLM AlSi10Mg alloy or the CNT-AlSi10Mg composite. Reserved CNTs with a short scale were observed in the SLM CNT(0.5 wt-%)-AlSi10Mg composite. The ultimate tensile strength of the 0.05 wt-% CNT-AlSi10Mg composite was 441.2 ± 0.9 MPa, which was higher than that of AlSi10Mg alloy. The grain boundary strengthening played an important role in the reinforcement of CNT-AlSi10Mg composite because of the refined grain.