Investigation of Microstructure and Deformation Behavior of a Mg-Gd-Y Alloy Processed by ECAP and Aging Treatment

The combined strengthening effect of grain refinement by equal channel angular pressing (ECAP) and aging on a wrought Mg-12Gd-3Y-0.5Zr (mass fraction, %) alloy was investigated. The resulting mechanical properties and microstructures were examined by uniaxial tensile test, optical microscope (OM) and transmission electronic microscope (TEM). It is found that ECAP for 4 passes at 673K followed by aging treatment at 523K for 16h is the optimum condition to strengthen the selected alloy Microstructure analysis reveals that precipitates appear at grain boundaries, accompanies by a few precipitates in grain interior after ECAP and aging treatment. By contrast of as-annealed sample, the strength and elongation were improved which revealed that grain boundaries and precipitation hardening were the main contributor to the high tensile strength of the experimental alloy.