Influence of SiC Reinforcement and Laser Energy Density on AlSi10Mg Parts via LPBF

This study investigates the effect of 10 wt.% SiC ceramic reinforcement and laser energy density on the structural, mechanical, and thermal performance of AlSi10Mg components fabricated via Laser Powder Bed Fusion. Samples of both unreinforced and SiC-reinforced AlSi10Mg were produced across a broad energy density range (35–200 J/mm³). The base alloy achieved optimal density (2.63 g/cm³) and tensile strength (246.5 MPa) at 100 J/mm³, while the composite reached peak performance at 140 J/mm³ with a density of 2.62 g/cm³ and tensile strength of 204.6 MPa. Despite a 17% drop in strength, the composite exhibited a > 30% hardness increase. XRD confirmed in-situ formation of Al₄C₃, indicating chemical reactivity between Al and SiC. Higher energy densities led to increased surface roughness and porosity in the composite due to melt pool instability. The thermal expansion behavior of the composite was more stable, with a peak CTE of 18 µm/m·°C, reflecting a 28% reduction compared to the base alloy (25 µm/m·°C). Thermal conductivity decreased from 170 to 100 W/m·K upon SiC addition. These results underscore the dual role of SiC as a strengthening agent and a thermal disruptor, necessitating precise energy control. The findings establish clear process–structure–property relationships and provide guidelines for fabricating dimensionally stable, high-performance AlSi10Mg–SiC parts for demanding thermal environments.