A model for superplastic flow induced texture annihilation

A phenomenological model that simulates the frequently observed texture annihilation during superplastic deformation is presented using the random walk process as an analogy. This phenomenon has been described as `orientation diffusion'. The model has been validated by considering the texture changes accompanying superplastic deformation in the alloy SUPRAL 100 (Al-6.5%Cu-0.4%Zr). The resulting `orientation diffusion coefficient' is given physical significance in terms of two processes present during superplastic flow, namely grain boundary sliding and grain rotation.