Structure-dependent sliding and grain boundary engineering for superplasticity

Bicrystal work on grain boundary sliding has revealed that sliding strongly depends on the type and structure of grain boundary. Strong structural effect on sliding suggests the possibility of grain boundary engineering for higher superplasticity. Some optimal condition may exist for the grain boundary character distribution which defines the type and the frequency of grain boundaries, and for geometrical configuration of the boundaries in polycrystals. The contribution of sliding to deformation and fracture may be compromised. Several important factors which can affect grain boundary deformation and fracture have been discussed in connection with structural transformation and grain boundary connectivity.