The densification rate of pores located at grain corners was obtained by constructing and analyzing a simple model with a transport mechanism of grain-boundary diffusion. The densification rate obtained for a microstructure of tetrakaidecahedral grains decreased with densification and was nearly consistent with the Wilkinson model at low porosities. The effect of grain-size distribution upon the densification rate was also estimated under the two limiting conditions of constant stress and constant strain rate. At constant strain rate, the densification rate with grain-size distribution was lower than the value for the average grain size, whereas it was identical to the value at constant stress.

Shrinkage of Pores Located at Grain Corners by Grain-Boundary Diffusion. B.N.Kim, K.Hiraga, K.Morita, H.Yoshida, H.Zhang: Journal of the American Ceramic Society, 2011, 94[4], 982-4