An investigation to the hot deformation characteristics of AZ31 alloy through continuous cooling compression testing method

The design and control of thermomechanical processing (TMP) schedule are substantially facilitated by a thorough understanding of the dominant deformation mechanisms and phase transformations which occur in the alloy system under consideration. In this regards due to the effects of deformation history, the results of conventional methods such as dilatometry and thermal analysis are insufficient. In the present work, the hot deformation characteristics of AZ31 magnesium alloy has been studied through applying a series of continuous cooling compression (CCC) tests. The compression tests were conducted as the temperature was continuously reduced from 500 °C to 100 °C. The variations of true stress with true strain (or temperature) were extracted and the critical temperatures were determined. The derived true stress-true strain curves revealed five deviations at 440 ± 5 °C, 350 ± 5 °C, 300 ± 5 °C, 215 ± 5 °C and 150 ± 5 °C, which were properly addressed considering the related microstructural evolutions.

► Occurrence of several deviations from the ideal behavior during continuous cooling compression.
► Hardening behavior at first deviation due to the inverse eutectic reaction.
► Increasing the CRSS of the first-order pyramidal slip system below 350 °C.
► Changing the recrystallization mechanism by decreasing temperature to 215 °C.
► The reduction of non-basal slip systems activity below 150 °C.