Mechanical response of discontinuous ceramic fiber reinforced metal matrix composites under quasi-static and dynamic loadings

The quasi-static mechanical properties and ballistic impact performance of several discontinuous ceramic fiber (Saffil) reinforced Al-2% Cu metal matrix composites (MMC) are characterized. The ballistic penetration resistance of the materials are determined against a fragment simulating projectile and compared to the performance of the baseline matrix alloy. Digital image correlation with high speed photography is used to measure the full field deflection of the materials during impact. Mechanical behavior and post-mortem fracture analysis are used to relate material properties to performance in penetrating and non-penetrating impact events. It is demonstrated that the MMC materials exhibit a strong asymmetry in their tensile and compressive responses. The MMC materials are stronger in compression and the asymmetry in response increases with increasing volume fraction of fiber. It was found that the ballistic performance (V50BL) decreases when the volume fraction of fiber is greater than 3% due to the decrease in tensile strain to failure at higher volume fractions. In non-penetrating impacts the increased stiffness and strength with higher volume fractions greatly reduces the magnitude and distribution of plate deflection.