Model of high-temperature plastic deformation of nanocrystalline materials: Application to yttria tetragonal zirconia

Abstract

The possibility of the influence of segregation-induced local electric fields in the bulk diffusion of the species controlling the plastic deformation of nanocrystalline materials has been pointed out. Until now, there is only a model applicable to the case of a monodimensional system. In spite of its simplicity, it predicts a significative influence of a local electric field in creep. Our work develops a different model applicable to three-dimensional systems. It takes as a starting point the diffusional model, and it can be generalized to those systems in which the grain-boundary sliding model accommodated by diffusional processes accurately describes plasticity in the submicron range of grain size. The range of validity, as well as the different behavior of nanocrystalline materials from the submicron ones is discussed. Preliminary results are in good agreement with the published data for yttria tetragonal zirconia (YTZP) nanocrystalline ceramics.