We report on a study on the influence of Plasma activated sintering (PAS) parameters on the microstructure and mechanical properties of aluminum matrix composites (AMCs). In this paper a commercial Al alloy (7075) reinforced with 7.5 wt.% B4C were synthesized using PAS. Specifically, we studied the influence of temperature, in the range of 450 °C to 540 °C, and holding time on the densification behavior of Al-7075/B4C composites. Moreover, the influence of residual porosity on mechanical properties of Al-7075/B4C composites was established via measurements of Vickers hardness, bending and compressive strength. High mechanical properties including Vickers hardness 181.6 HV, bending strength 1100.3 MPa, high compression yield strength 878.0 MPa and fracture strength 469.3 MPa of the consolidated Al-7075/B4C composite sintered at 530 °C for 3 min were achieved and attributed to a fully dense microstructure and a strong interface between matrix and reinforcement.