Hot deformation behavior and workfability of the homogenized Mg-5.8Zn-1.2Y–1Mn alloy containing I and W phases

Abstract

In the present study, a thermo-mechanical simulator (Gleeble-1500D) is applied to conduct compression tests on homogenized Mg–6Zn-1.2Y–1Mn (wt.%) alloy and investigate features of this alloy in terms of flow behavior, dynamic recrystallization (DRX) evolution and hot workability. Different strain rates varying from 0.005 to 5 s−1 and different temperatures within the range of 200–400 °C are used in the experiments. An apparent mean deformation activation energy of 216.027 kJ/mol with a stress exponent of 10.88964 are achieved by regression analysis of Arrhenius type flow behavior equation. Using true stress-true strain data analysis, a kinetic model of dynamic recrystallization is presented as: XDRX=1−exp[−1.41((ε−εc)/ε∗)1.51]. Furthermore, the processing maps are developed and analyzed according to the dynamic material model (DMM). Based on the processing maps, the flow stability and instability domains are determined. It is found that the optimal hot working region of the alloy is temperature of 325–400 °C and strain rate of 0.005–0.05 s−1. Finally, a finite element analysis is carried out, and the reasonability of the optimal deformation parameters are verified.

Keywords

• Mg–Zn–Y–Mn alloy
• Constitutive equation
• Kinetic model
• Processing map