The effect of pretorsional deformation on the creep properties of tin 0.5 at.% bismuth alloy

Pretorsional deformation was found to have considerable effect on the steady state creep rate of polycrystalline tin 0.5 at.% bismuth alloy. Low degrees of pretorsional deformation decreased the steady state creep rate to a minimum followed by an increase at higher degrees. The critical degree of pretorsional deformation ( ND/ L) c = θ c , causing minimum steady state creep rate was found to depend on the working temperature as well as on the applied stress. The results were interpreted in terms of dislocation density and stability of preinduced substructures. The energy Q activating the creep process was found to be 0.37 eV which agreed quite well with that available in literature.