The size and content of SiC particles play crucial roles in determining the metallurgical quality and mechanical properties of particle-reinforced aluminum matrix composites (PAMCs) fabricated via laser powder bed fusion (LPBF). TiB2/AlSi10Mg prealloyed powder was used as the matrix, and SiC particles with different sizes and volume fractions

(5 μm-5 vol.%, 5 μm-10 vol.%, and 20 μm-10 vol.%) were incorporated through mechanical mixing. The effects of the SiC particle size and content on the densification behavior, process window, metallurgical defects, and mechanical properties were systematically investigated. The results show that increasing the SiC content or particle size reduces densification and narrows the processing window. The maximum relative densities of the 5 μm-5 vol.%, 5 μm-10 vol.%, and 20 μm-10 vol.% samples are 99.1%, 98.2%, and 96.9%, respectively. Excessive addition or larger SiC particles tend to induce porosity, cracking, and agglomeration defects, deteriorating the forming quality. The 5 vol.% SiC sample exhibits a microhardness of 170 HV and a Young's modulus of 113.8 GPa, whereas those of the 10 vol.% SiC sample increase to 200 HV and 130.6 GPa, respectively. A moderate SiC content combined with smaller particle size is beneficial for achieving high densification and superior mechanical properties.