The stability of interconnected pores in materials of non-uniform grain size

Abstract

An existing model of the equilibrium morphology of interlinked grain-edge porosity in materials of uniform grain size is generalized to investigate polycrystals containing bimodal distributions of tetrakaidecahedral grains. The results of the calculations are used to discuss the influence of the spread in grain size, which is inevitably present in any real material, on swelling during fission-gas release from UO 2 nuclear fuel and on sintering of powder compacts. The behaviour of the model suggests that the intermediate stage of sintering is likely to end at appreciably higher pore volumes than was supposed on the basis of the original theory.