Effect of Double Aging on Microstructure and Mechanical Properties of Ag Added magnesium Alloys

To improving the mechanical properties of Mg alloys at high temperature, we investigated the mechanical properties at high temperature and the change of microstructure of Mg-6 wt%Zn-0.4 wt%Mn and Mg-6 wt%Zn-0.4 wt%Mn-1 wt%Ag alloys on age treatment that have a stable MgZn phase at high temperature and AgMg4 improving yield stress. In order to predict thermodynamic data of Mg alloys, a phase diagram and precipitation phase were calculated using a thermodynamic program, and it was confirmed that the MgZn and AgMg4 phase existed as main precipitation in this alloys. The experimental data examined using DSC and XRD were comparable with the calculated data for reliability. In order to analysis the microstructure and precipitate phase during aging treatment, it was measured by SEM/EDS and TEM. Lastly, mechanical properties of the MgZn and AgMg4 phase were measured by a tensile test at high temperature.