Dynamic grain growth in Al-6Ni: Modelling and experiments

The dynamic grain growth of the eutectic Al-6Ni alloy, processed to give a spheroidal particle morphology, has been investigated. Despite a fine grain size, this material is not superplastic. It shows significant grain growth during deformation, which is essentially strain controlled down to a temperature of about 250 °C with a strain rate of 10^-3 s^-1. It is suggested that the dynamic growth is due to geometric perturbation of the Zener pinned structure, and this has been modelled using the Monte Carlo-Potts method. This modelling gave a reasonably good prediction of the dynamic growth and of the transition temperature to strain controlled growth. Differences between dynamic grain growth in plane strain and uniaxial tension may also be consistent with a geometric mechanism.