The evolution of grain size distribution during deformation of superplastic materials

摘要

Grain size distribution and its evolution duringsuperplastic deformation have been studied for two materials-ultrahigh carbon steel, which has a two phase microstructure, and acopper alloy, which has a quasi-single phase microstructure. Forboth materials, the distribution of initial grain sizes is veryaccurately represented by a lognormal function. As the materialsare superplastically deformed, the distributions retain theirlognormality throughout the deformation history. The evolution ofthe parameters characterizing the lognormal distribution (mean andstandard deviation) have also been studied and found to vary in asystematic manner. Results can be used to specify the grain sizedistribution as a function of strain during superplastic deformationand thus should prove useful for computational studies in whichgrain size distribution is evaluated.