A mesoscale model to predict the effect of microstructural heterogeneities on superplastic deformation Original Research Article

A two-dimensional approach is proposed to describe superplastic deformation at a mesoscopic scale in order to predict the effect on the mechanical behaviour of microstructural heterogeneities, like grain size distribution or spatial distribution of grains. The grains in the microstructure may slide and plastically deform, the extent of each mechanism depending on the applied conditions. The degree of homogeneity of deformation through the material is estimated by the predictions of differences in shear rates along bands specifically oriented in reference to the stress axis. It is shown that the superplastic behaviour not only depends on the grain size distribution but also on the degree of dispersion of the large grains through the microstructure, despite a same mean grain size. This dependence may concern the macroscopic behaviour as well as the extent of localisation of deformation through the sample.