MICROSTRUCTURAL FACTORS CONTROLLING THE STRENGTH AND DUCTILITY OF PARTICLE-REINFORCED METAL-MATRIX COMPOSITES

A micromechanical model is developed to simulate the mechanical respon se in tension of particle-reinforced metal-matrix composites. The micr ostructure of the composite is represented as a three-dimensional arra y of hexagonal prisms with one reinforcement at the centre of each pri sm. The shape, volume fraction and state (either intact or broken) of the reinforcement is independent for each cell, so the interaction amo ng all these factors could be studied. The tensile response of the com posite is determined from the behaviour of the intact and damaged cell s, the fraction of damaged cells being calculated on the assumption th at the reinforcement strength follows the Weibull statistics. The mode l is used to determine the microstructural factors which provide optim um behaviour from the point of view of the tensile strength and ductil ity. The analyses included the effect of the matrix and reinforcement properties, the reinforcement volume fraction, the interaction between reinforcements of different shape and the heterogeneous distribution of the reinforcements within the composite. (C) 1997 Elsevier Science Ltd. All rights reserved.