[SY-K4] Grain boundary sliding within the entropy production rate theory
It is a challenging task to clarify the underlying principle of deformation behavior of an alloy. In high temperatures, an alloy undergoes various deformation modes driven by dislocations movement, grain boundary sliding etc. Under a given strain rate (tensile test) or a given stress (creep test), how does an alloy adjust internal structures to accommodate externally imposed deformation conditions such as deformation rate and applied stress? This is the question the author addresses in the present paper. By taking a grain boundary sliding as an example, we formulated deformation behavior in terms of average rotation rate of a grain and density of rotating grains based on entropy production rate theory within the linear regime. The physical implications of grain boundary sliding at an extremum of entropy production rate are main focus of the discussion, and thermodynamic similarity between grain boundary sliding and dislocations driven deformation is addressed. Furthermore, it will be briefly touched upon how to extend the formulation of grain boundary sliding for an alloy to larger scale deformation phenomena.