Synergy effect of reinforcement particle, fiber and matrix on wear resistance of hybrid metal matrix composite fabricated by low pressure infiltration process

Alumina fiber (Al2O3f) and alumina particle (Al2O3p) reinforced Al-4mass%Cu alloy matrix composites (Hybrid-MMC) have been fabricated by a low pressure infiltration process. Total amount of reinforcements is fixed to be 20 vol.% and the range of the amounts of Al2O3f and Al2O3p is varied from 7.5 vol.% to 12.5 vol.%. When the ratio of fiber vol.% to particle vol.% is increased, the soundness of casting has improved. The Hybrid-MMC with 12.5 vol.% Al2O3f and 7.5 vol.% Al2O3p has better wear resistance compared with PRMMC with 20 vol.% Al2O3p and FRMMC with 20 vol.% Al2O3f. The excellent Hybrid-MMC is attributable to a synergy effect of Al2O3 particles and Al2O3 fibers having a 3-D distribution, which protects Al2O3 particles from dropping out. A superior wear resistance has been observed in the MMC with an age-hardened Al-Cu matrix and another synergy effect of reinforcements and matrix is observed.