Physical mesomechanics of grain boundary sliding in a deformable polycrystal
The temperature-rate dependences of strain resistance and the mechanisms of grain boundary sliding in Pb polycrystals and Pb-based alloys under active tension were investigated. The activation energies of plastic deformation and grain boundary sliding were determined. The structural mechanisms of grain boundary sliding were studied in a wide temperature range. The conclusion was made that self-consistency of grain boundary sliding and intragranular plastic flow has its origins in rotational deformation modes, with the grain boundary sliding being a primary process. Theoretical analysis of rotational deformation modes involved in grain boundary sliding was performed. It is shown that the dependence of deforming stress on the polycrystal grain size is impossible to describe only by the universal Hall–Petch equation.