Grain growth in sintering of clustered powder compacts

A theoretical model of grain growth in sintering of clustered powder compac ts is outlined, showing that the microstructure evolution is stepwise conti nuous in time and its general trends can be predicted independently of the particular system and process being considered. The dependence of coarsenin g on densification can be accounted for by introducing a densification-scal ed time variable (intrinsic time). The theory is successively applied to sy stems where particular local mechanisms of matter transport are supposed to operate, respectively in the initial/intermediate and the intermediate/fin al stage of sintering. The obtained mathematical models are solved numerica lly to follow the evolution of three regularly packed clusters. The model p redictions are in good agreement with experimental data obtained by other r esearchers. (C) 2000 Kluwer Academic Publishers.