Role of Grain Boundaries
Grain boundaries have very important role in plastic deformation of polycrystalline materials.
We outline below the important aspects of the role of grain boundaries.
1. At low temperature (Tɘ.5Tm, where Tm is the melting point in K), the grain boundaries act as strong obstacles to dislocation motion. Mobile dislocations can pile up against the grain boundaries and thus give rise to stress concentrations that can be relaxed by initiating locally multiple slip.