The influence of the reinforcing particle shape and interface strength on the fracture behavior of a metal matrix composite

A numerical analysis of the reinforcing particle shape and interface strength effects on the deformation and fracture behavior of an Al/Al2O3 composite is performed. Three-dimensional calculations are carried out for five elastic–brittle particles embedded into the elastic–plastic matrix, the reinforcing particle shape being varied from spherical to strongly irregular. It is shown that microstructural heterogeneity of the composite gives rise to a complex stress–strain state in the vicinity of particle boundaries and hence to near-interface areas undergoing tensile deformation both in tension and compression. Within the strain range under study, compressive strength is not achieved, either in compression or in tension, i.e., all cracks grow only under tensile stress. Particle fracture is found to occur by two mechanisms: interface debonding and particle cracking. Individual and combined effects of the particle shape, interface strength, and loading conditions on the fracture mechanisms are analyzed.