Metal Matrix Composites as Potential Armour Materials

To defeat a kinetic energy projectile the armour needs to be extremely hard on the surface, so as to blunt the projectile on initial impact. A ceramic material may be an ideal choice. However, to absorb and dissipate the complete kinetic energy of the projectile, the subsequent material has to be extremely tough with a very high work of fracture. It also needs to be a light weight material to keep the overall weight to a minimum possible value. A fibre reinforced polymer matrix composite can meet the requirement. The innermost laver needs to have a very high ductility so as to avoid any fracture and fragment formation which could be lethal. So it has to be a metallic material. Thus, the application requires a range of properties starting from that of a ceramic and ending with that of a metal. Metal matrix composites (MMCs) are essentially metals reinforced with ceramic reinforcements, which exhibit a combination of properties of both the constituents and could be tailored to suit the requirements. Discontinuously reinforced MMCs also have the added advantage of being amenable to conventional metal forming operations, which makes it easier to produce them in the required shapes. This paper would provide an introduction to MMCs and review the available literature on their evaluation for possible applications as armour materials.It would also present the results of the preliminary studies on the dynamic hardness measurements of discontinuously reinforced aluminium alloy composites which gives a good indication of their potential use as armour materials