The effects of reinforcement particle to matrix powder size ratio (R-s/M-s) and volume fraction of reinforcement particle on the microstructure, densification and tribological properties of SiCp reinforced aluminium (Al-SiCp) metal matrix composites manufactured via hot-pressing method were investigated for high ratios of R-s/M-s (1 <= R-s/M-s <= 4). Central composite design (CCD) method was used for experimental design. Based on the results obtained in this study, density of 99% could be reached and a uniformly distribution of reinforcement particles in microstructure could be observed for the composite with the volume fraction of 15% and R-s/M-s ratio of 3.5. Also, the relative density increased as R-s/M-s ratio increased up to the reinforcement volume fraction of 17.5%. However, an increase in R-s/M-s ratio had an unfavourable effect on the density at the high volume fractions (>= 17.5). Results also showed that there was no direct correlation between hardness and wear resistance as a function of volume fraction and R-s/M-s ratio. The wear tests were performed under adhesive wear condition using pin-on-ring test machine. The results showed that R-s/M-s ratio had a strong influence on the microstructure and wear behaviour of Al-SiCp composites. Up to the volume fraction of 15%, as the reinforcement particle size or reinforcement particle to matrix powder size ratio increased, the wear loss decreased; however, at the volume fractions higher than 17.5%, wear loss increased with increasing the reinforcement particle to matrix powder size ratio. Both adhesive and abrasive wear mechanisms were the dominant failure mechanisms at the low volume fractions (<= 15%) while delamination wear was the most dominant failure mechanism for the composites with higher volume fractions (>= 20%). (C) 2015 Elsevier Ltd. All rights reserved.