An evaluation of the macro damage on metal matrix composites after high velocity impact

The ballistic impact failures and damages on metal matrix composites reinforced by SiC and alumina are studied. AA 6063 aluminum alloy is reinforced with SiC and alumina particles in different sizes and percentages by casting method. Ballistic tests are carried out by two different projectile types, AP (armor piercing) 7.62 and 9 mm. The macrography of the craters and holes created by high velocity projectiles impact are analyzed by light and scanning electron microscopy studies. The projectile type strongly influences the damage formation. When the high velocity projectile (AP 7.62, 7.9g, 710 m/s) impacts the 30% SiC or Al2O3 reinforced composite, it leads to deep craters and then a hole by passing the thickness of the composite target thoroughly. Brittle cracking on the target and on the reinforcing particles are also observed after impact. If this impacting carried out on the composite is relatively tough (i.e., having 15% SiC), swelling and petalling on the entrance and back sides of the hole are also created without any cracking or breaking. In case of impacting by a lower velocity projectile (9 mm, 7.47 g, 400 m/s) on the 15% SiC composite target, it can pass the thickness with or without its jacket. This projectile cannot pass the composites reinforced by 30% SiC and Al2O3. Besides some damages such as plastic deformation and craters occur on the projectile tip