Mechanical Behavior and Constitutive Modeling of the Mg-Zn-Y Alloy in an Electrically Assisted Tensile Test.

The Mg-Zn-Y alloy containing the LPSO phase has excellent mechanical properties and functional application prospects. In an effort to clarify the electrically assisted deformation behavior of the Mg-Zn-Y alloy, electrically assisted tensile tests of MgZnY alloy sheets were carried out at different temperatures, current densities, duty ratios, and frequencies. The experimental results showed that, after the pulse current was applied (26.58 A·mm), the peak stress of the sample deformed at 200 °C decreased by 8 MPa. The peak stress of the material decreased with the increase in current density. It is noticeable that the changes in duty ratios and frequencies have a small effect on the peak stress and strain. When the current was applied, more recrystallized grains appeared in the alloy and the basal texture was weakened. According to the experimental results, the Arrhenius model was derived based on the Zener-Hollomon parameter. Owing to the appearance of the stacking fault structure (LPSO), the activation energy Q of the MgZnY alloy was 389.41 KJ/mol, which is higher than conventional Mg alloys. Moreover, the constitutive equation of the electro plastic effect coupled with temperature and pulse current parameters was established by introducing electrically assisted characteristics. By comparing the experimental and predicted values, the established model can effectively predict the variation trend of flow stress under electrically assisted deformation. Moreover, the constitutive model was incorporated into the UHARD subroutine of ABAQUS software to study the deformation behavior of the MgZnY alloy.