INTERFACES IN DISCONTINUOUSLY REINFORCED METAL-MATRIX COMPOSITES - ANOVERVIEW

The fundamental and engineering aspects pertaining to the matrix-reinf orcement interfaces in discontinuously reinforced metal matrix composi tes are presented in this overview. The interfaces play a key role in determining mechanical properties, namely Young's modulus, yield stren gth, elongation, creep and fracture behaviour, as well as physical pro perties like coefficient of thermal expansion, thermal conductivity an d damping characteristics of metal matrix composites; these are discus sed in detail. The ratio of the experimental value of the Young's modu lus to that predicted from the rule of mixtures has been used as a mea sure of interfacial bond strength. Various issues such as the nature o f the interfacial bond, chemical reaction at the interfaces, and effec t of alloying acid processing on the structure of the interfaces and t he properties of the composite are examined. In order to exploit the f ull potential of reinforcing the. metallic matrix, the suggested strat egies include creation; of metallic bonding at the interface, use of i n situ processing, choice of right type of alloying elements, and heat treatments and engineering of interfaces.