Alternative Length Scales for Polycrystalline Materials

Abstract

AbstractIt is well established from studies of bicrystals that the properties of a grain boundary depend on the atomic structure of the boundary. However, constitutive relations for the properties of polycrystalline materials do not currently take into account this boundary-toboundary variability. Instead, such relations depend on a single length scale, typically the average grain diameter. We extend the traditional viewpoint by proposing that boundaries may be divided into two distinct categories, depending on their misorientation angle. The relevant length scale in constitutive relations for polycrystals is then the average cluster size, where clusters consist of grains connected by boundaries in the same misorientation category. A brief discussion of this additional length scale and how it may be reflected in various constitutive relations for physical and mechanical properties of polycrystals is given.