Wear characteristics of Al−Si−Mg−(Cu)/Al2O3 composites fabricated by thermit reaction

Al^sub 2^O^sub 3^ particles could be formed by a thermit reaction in an Al-12Si-4Mg-1.5Cu/Al^sub 2^O^sub 3^ composite due to thein-situ reaction between Al-12Si-4Mg-(1.5Cu) molten metal and SiO^sub 2^ particles in preform, which took place at 1173 K for 24 hours, resulting in the decomposition of SiO^sub 2^ particles and the formation of Al^sub 2^O^sub 3^ particles simultaneously. The mechanically mixed layers (MMLs) consisting of α-Fe and Fe oxides existed on the subsurface layers beneath the worn surface in composites or mother alloys, which improved the wear resistance. The characteristics of wear resistance and hardening of an Al-12Si-4Mg-1.5Cu/Al^sub 2^O^sub 3^ composite are superior to those of the Al-12Si-4Mg/Al^sub 2^O^sub 3^ composite and Al-12Si-4Mg-1.5Cu alloy.[PUBLICATION ABSTRACT]