DEVELOPMENT OF METAL-DIAMOND COMPOSITES FOR LIGHT-WEIGHT ARMOUR

Metal Diamond Composites (Me-CD) are a new class of metal matrix composites that are exciting the interest of designers and engineers because of their unique combination of physical, thermal, electrical and mechanical properties. In general, due to the high volume fraction of diamonds inside the matrix, the mechanical behavior of such materials is always brittle with low level of fracture stress and strain. However, with advanced innovations in the sintering processes, it is possible to obtain composite materials with a good level of strength and toughness even in high strain-rate conditions. The great advantage of these materials is the possibility to combine the high hardness and low density of diamonds with the strength and toughness of metals. This class of materials could be used in every case in which the material requirements are hardness combined with ductility and lightness: military protection devices instead of synthetic alumina or carbides are potential applications. Due to the composite nature, the strain and stress distribution in the material is quite complex and, as a consequence, the mechanical behavior is different from a homogeneous one. The elastic properties, which are fundamental in case of wave propagation, were calculated using the mixture law and then compared with that of other ceramic materials usually used in military protection. Preliminary impact tests were conducted using a single bar SHPB setup in order to qualitatively investigate the fracture mechanism. SEM analyses were also performed to examine the interface between diamond and aluminium.