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

摘要

Alumina fiber (Al_2O_(3f)) and alumina particle (Al_2O_(3p)) 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 Al_2O_(3f) and Al_2O_(3p) 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.% Al_2O_(3f) and 7.5 vol.% Al_2O_(3p) has better wear resistance compared with PRMMC with 20 vol.% Al_2O_(3p) and FRMMC with 20 vol.% Al_2O_(3f). The excellent Hybrid-MMC is attributable to a synergy effect of Al_2O_3 particles and Al_2O_3 fibers having a 3-D distribution, which protects Al_2O_3 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.