Mechanical properties and strain-hardening behavior of Mg alloy AZ31B-H24 thin sheet

The strain-hardening behavior of Mg alloy AZ31B-H24 deformed in tension was analyzed using the Kocks-Mecking phenomenological approach. The relationship between strain-hardening behavior and dynamic recrystalliztion at elevated temperatures was investigated in this work. At room temperature, stage II strain-hardening consistent with the forest hardening mechanism, which was similar to that observed in face-centered cubic metals, was observed. The specimens tested at temperatures above 250 °C did not show stage II strain-hardening, and their stage III with a decreasing of strain-hardening rate took place immediately after yielding. The absence of stage II strain-hardening should be related to the dynamic recovery and recrystallization, causing the softening effects. The onset of dynamic recovery occurred earlier than that of the dynamic recrystallization (DRX).