Laser powder bed fusion of oxidized microscale SiC-particle-reinforced AlSi10Mg matrix composites: Microstructure, porosity, and mechanical properties

Laser powder bed fusion (LPBF)-fabricated Al matrix composites reinforced with SiC particles are strongly influenced by SiC particle features. In this study, the microstructural features, mechanical properties, and porosity of moderate volume fraction (10 vol%) microscale SiC-particle-reinforced AlSi10Mg composites fabricated by LPBF under different oxidation temperatures of SiC particles were investigated. The results demonstrate that LPBF-deposited SiCp/AlSi10Mg composites mainly exhibited laser track segments in macroscale and fine cellular-like dendrite grains and (Al + Si) eutectic phases within the melt pool on a microscale. The transition layer of MgAl2O4 was present around the SiC particles in the oxidized-SiCp reinforced AlSi10Mg composites. In addition, the pore spatial distribution of the deposited composites using the microcomputed tomography test and the microstructural formation mechanism using Thermal Calc software were also studied. Using the finite element to model the deposited composites, it was found that the stress and strain distribution presented higher values than those without long-stripe precipitation phases in the deposited parts with long-stripe precipitation phases. The LPBF-fabricated oxidized-10 vol% SiCp/AlSi10Mg composite part with a relatively large ultimate tensile strength (∼405.3 MPa), relative density (∼98.89%), compressive strength (∼1046 MPa) and friction coefficient (0.32) were obtained. In particular, the ultimate tensile strength was larger than that of the other reported SiCp/AlSi10Mg composites with similar volume fractions and particle sizes.