ROLE OF DAMAGE ON THE FLOW AND FRACTURE OF PARTICULATE-REINFORCED ALLOYS AND METAL-MATRIX COMPOSITES

A large number of models exist to predict the tensile behaviour of two -phase materials. They fail, however, to predict the behaviour at high strain because they do not properly account for the role which damage accumulation plays during plastic flow. A new model is proposed here which incorporates damage. It uses an incremental self-consistent meth od developed previously. In the new application, the model treats dama ged and undamaged regions as distinct continuous ''phases'' and allows the relative volume fraction of each phase to vary during deformation . The stress redistribution due to damage during the evolution is care fully analysed. The model considers the influence of particle size via a Weibull analysis and incorporates the results of existing FEM calcu lations. The model agrees well with existing experimental data and pro vides a new method to evaluate the role of microstructural parameters. (C) 1997 Acta Metallurgica Inc.