Deformation behaviour of silicon carbide reinforced Al-7Si composite after balistic impacts

The deformation after ballistic impact loading of silicon carbide reinforced aluminium alloy composite is investigated in this research. The composite consists of 10 % volume fraction of silicon carbide particulate in a matrix of Al-7Si-Mg-Zn alloy and were produced through the squeeze casting process with a pressure of 1 MPa at semi-solid melting temperatures of 590-610 °C. The mechanical property of the composite was examined with hardness test. The ballistic tests were performed with two types of projectiles, 9 mm and 5.56 mm calibre of projectiles. Furthermore the deformed surfaces were studied with optical microscopy. During ballistic testing, the 9 mm projectile did not pierce the composite plate although the test resulted in significant cracks on the backside of the plate. The cross section observation of the plate showed ductile deformation in the matrix and silicon carbide particulates give significant rule in withstanding the penetration of the projectile. By contrast, the 5.56 mm projectile pierced through the composite and caused a brittle fracture of the matrix.