A strategy for creating ultrafine-grained microstructure in magnesium alloy sheets

초록

An Mg-3Al-1Zn alloy with fully recrystallized microstructure and a mean grain size of 1 mu m has been produced by high-ratio differential speed rolling under the condition that the cold sheet is subjected to rolling with hot rolls preheated to 473 K, resulting in a total thickness reduction of 68% after two-step rolling. No surface or internal cracks were developed. The microstructure was homogenous along the thickness direction. A bimodal grain size distribution was obtained in which approximately 40% of the grains were ultrafine with submicron size coexisting with other grains with a size of several microns. The proposed processing method holds great potential for continuous production of ultrafine-grained magnesium alloy sheets. (C) 2009 Elsevier B.V. All rights reserved.

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