Superplasticity in a magnesium alloy prepared with bimodal grain size distributions developed by dynamic recrystallisation

In the present work the influence of bimodal grain size distributions on superplastic behavior, of a magnesium alloy, was investigated. Samples with different volume fraction of fine grains have been prepared, and their strain rate-stress relation during superplasticity has been measured. Additionally, the predictions of two deformation models, based on the isostrain and the isostress conditions, were compared with the experimental data. The isostrain model allows the major experimental observations to be readily explained and predicted. (C) 2008 Elsevier B.V. All rights reserved.