MODELING THE DENSIFICATION OF POWDER COMPOSITES BY POWER-LAW CREEP

A model describing the densification under isotropic pressure of a powder composite, consisting of viscoplastic particles deforming by power law creep mixed with rigid inclusions of the same size, is presented. A description of the behaviour of each type of contacts is first proposed, from which an expression for the densification rate of the mixture is deduced. The evolution of particle coordination numbers and contact areas during densification is then estimated from an extension of Arzt's model [Acta metall. 30, 1883 (1982)] to powder composites. The model can be used up to a density corresponding to the formation of a supportive inclusion network. Finally the validity of the model is discussed in relation with experimental data.