This study presents an effective approach to assess the machinability of 6351 aluminum alloy matrix, reinforced with 5wt.% silicon carbide (SiC) and (0, 5, and 10wt.%) boron carbide (B4C) particles. The turning tests are carried out with a polycrystalline diamond (PCD) tool to identify the effect of the B4C particles addition to the composite, with an objective to improve the material removal rate (MRR) and to reduce the surface roughness (Ra) and power consumption (P). The significant level of each factor, which contributes to affect the output response, is found through analysis of variance (ANOVA). The results show that the inclusion of B4C particles in the hybrid composite significantly affects the machinability, with a contribution to the surface roughness by 7.87% and P by 6.36%. The increase in MRR affects the quality of the material, irrespective of the composites.