Effect of Initial Microstructure under Different Solidification Conditions on Hot Working Behavior of AZ31 Alloy
In order to investigate the effect of the as-cast microstructure on the hot working behavior of an AZ31 magnesium alloy, specimens were cast in copper moulds with and without water cooling. A series of compression tests were performed at a temperature of 350 °C, a strain rate of 0.01 s-1, and at strains up to 1.0. It was found that as-cast microstructure is very sensitive to the solidification conditions, which leads to a significant difference in flow behavior and dynamic recrystallization (DRX) characteristics. It appears that more uniform and refined as-cast grain size promotes dynamic recrystallization and reduces the flow stress. It is also possible that second phases (>1+m in size) contribute to DRX by acting as nuclei.
Young Won Chang, Nack J. Kim and Chong Soo Lee
L. Shang et al., "Effect of Initial Microstructure under Different Solidification Conditions on Hot Working Behavior of AZ31 Alloy", Materials Science Forum, Vols. 561-565, pp. 325-328, 2007