Grain boundary mobility - a brief review

This brief review describes the major features of grain boundary mobility in metals and current limitations in our theoretical understanding. Although thermally activated exchange of atoms across boundaries provides a basic picture of grain boundary correct to within an order of magnitude, no refinement of this theory is available that. accounts for the experimental characteristics of grain mobility as it depends on crystallographic type. An example is given of a simple extension involving density of kinks on the two surfaces that comprise a boundary to show that the resulting estimate of mobility is essentially different from the experimentally observed dependence.