Microstructure evolution and tensile properties of hot rolled Mg-6Al-3Sn alloy sheet at elevated temperatures

摘要

A fine-grained (～3.6 μm) Mg-6Al-3Sn (AT63) alloy prepared by a hot rolled method is subjected to uniaxial tensile tests within the temperature range of 25-250 ℃. Mg_2Sn and Mg_(17)Al_(12) precipitates at grain boundaries effectively retard the growth of dynamically recrystallized (DRXed) grains. Grain boundary sliding (GBS) is activated at 250 ℃, which is indicated by the stable DRXed grain size and agglomeration of the precipitates at grain boundaries. Moreover, Mg_2Sn and Mg_(17)Al_(12) precipitates promote the formation of dynamic recrystallization (DRX). Both the DRX and GBS result in the high elongation (151.4%) of the AT63 alloy at 250 ℃. Results obtained here will shed some light on elevated temperature deformation mechanisms of a new type of Mg-Al-Sn system, which is critical to the development of new Mg alloys with potential for applications at elevated temperatures.