The wear behaviour of two different MMCs, namely AA5083 and AA6063 reinforced by 45, 30 and 15% SiCp, respectively, are investigated under condition of high-velocity impact. The tests are carry out by firing 7.62 armour piercing rounds into these composite materials. The wear and failure mechanisms are evaluated by examining the projectile tips and the hole surfaces produced by high-velocity impact using SEM and optical microscopy. The hardness differences of the two regions on the hole surfaces, i.e. the plastically compressed regions surrounding the projectile hole is higher than unaffected matrix. The wear mechanisms on the friction surfaces of the matrix are predominantly abrasion and melt wear. It is observed that the projectile nose is plastically deformed when it impacts the armour. The projectile surface is also scratched by the SiC particles on the hole surface produced by the impact. The wear mechanism on the projectile surface is predominantly abrasive. (C) 2003 Elsevier Science Ltd. All rights reserved.