Effect of cyclic deformation on strain enhanced grain growth during superplastic flow

Generally, superplastic deformation is accompanied by concurrent grain growth. In this paper, the effect of strain reversals on this process is investigated using two materials. In the first, Coronze 638, a precipitate strengthened copper alloy, no effect is found. In the second, Zn–22Al (wt-%) eutectoid, a distinct retardation of grain growth occurs after each strain reversal. A new model based on the ability of grain boundary sliding to overcome the Zener drag process is developed and found to be consistent with the experimental results. MST/731