Effect of SiC particle size on densification behavior and mechanical properties of SiCp/AlSi10Mg composites fabricated by laser powder bed fusion

The effect of SiC particle size (300, 600 and 1200 mesh) on the properties of 15 wt% SiC particles reinforced AlSi10Mg matrix composites fabricated by laser powder bed fusion (LPBF) was investigated. The results showed that the laser absorptivity of blended powder increased as the SiC particle size decreased, which was useful to improve the densification of the LPBFed composites. The highest relative density of 98.9% was obtained at 1200 mesh of SiC particle. The amount of the interfacial reaction products, including Al4SiC4 and Si, was increased by reducing the SiC particle size. For all types of composites, SiC particles had a good wettability with the aluminum matrix owing to the high temperature and the interfacial reaction during the LPBF process. The mechanical properties were significantly improved by decreasing the SiC particles size. The microhardness of 316.1 HV0.2 and the ultimate compressive strength of 764.1 MPa were achieved using SiC particle having 1200 mesh size. The existence of the pores in the aluminum matrix and the SiC particle’s cracking were the primary reasons for the failure of the composites. Furthermore, large SiC particles were more easily cracked. When the SiC particle size decreased from 300 mesh to 1200 mesh, the average coefficient of friction (COF) distinctly reduced from 0.45 to 0.18 and wear rate decreased from 9.09 to 2.02 × 10−4 mm3N−1m−1, respectively. The abrasive and adhesive wear were the dominant wear mechanism of the LPBFed composites with 300 mesh of SiC particle. However, as the SiC particle decreased to 1200 mesh, the main wear mechanism was transferred to the delamination and abrasive mechanism. These results have contributed to understanding the characteristics of LPBFed SiCp/AlSi10Mg composites. •The 15 wt% SiCp/AlSi10Mg composites with different SiC particles size were fabricated by laser powder bed fusion.•The densification was improved by the increase of the laser absorptivity of blended powder as the size decreases.•The good interfacial bonding was achieved due to the good wettability and the interfacial reaction.•Decreasing size provided a significant enhancement of the mechanical properties.