Understanding creep in nanocrystalline materials

Only a limited number of creep investigations have been carried out on nanocrystalline materials to-date. These studies have remained largely inconclusive in establishing the mechanisms of creep in nanocrystalline materials. The stress exponent and activation energy values obtained from nanocrystalline materials do not correlate well with conventional well established creep models. Furthermore discrepancies between experimentally determined deformation rates and theoretical predictions suggest that an entirely new mechanism of creep could be operational in these exotic materials. In this work we aim to develop an understanding of the creep behavior of nanocrystalline materials by considering a stress assisted grain growth mechanism that has been recently identified in these materials. In turn a model has been developed that provides a quantitative understanding of some of the observations made in creep literature.