Separate contributions of texture and grain size on the creep mechanisms in a fine-grained magnesium alloy

The influence of texture and grain size on the creep behavior of a fine-grained magnesium alloy, over the temperature range 423-723 K was investigated. Equal channel angular pressing and rolling were used to produce samples with different textures. Two deformation regimes could be distinguished by their stress exponents. A stress exponent close to 2 and activation energy of 91 kJ mol(-1), close to that for grain boundary diffusion, were found at the lower strain rates. In this range, there is no detectable effect of texture. In the high stress exponent regime, within the range 3 < n < 12, a noticeable effect of texture and grain size has been found. The texture effect is related to the orientation of the basal planes. The influence of grain size distribution on flow stress is satisfactorily explained by modeling the deformation as a combination of grain boundary sliding and slip creep. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.