Unveiling the effect of Gd content on the dynamic recrystallization behavior and resultant mechanical property of magnesium

Abstract

The dependence of dynamic recrystallization (DRX) behavior of Mg on the Gd content was studied using Mg-3wt %Gd and Mg-13 wt%Gd alloys in this work. After solution treatment, the two alloys labeled as the AS-3Gd and AS-13Gd samples, were hot-compressed at 480 °C to the true strain of ε = 1.3. As a comparison, the AS-13Gd sample was peak-aged and labeled as the AA-13Gd sample, which was also subjected to hot-compression under the same condition. The results showed that adding Gd content significantly delayed the DRX progress and affected the dominant DRX mechanism. Specifically, continuous DRX dominated the AS-3Gd sample while discontinuous DRX controlled the AS-13Gd sample. For the AA-13Gd sample, continuous DRX started easily during low straining but discontinuous DRX become dominant during high straining. Consequently, the DRX fractions were 91%, 61%, and 67% for the AS-3Gd, AS-13Gd, and AA-13Gd samples, respectively. Besides, the AS-13Gd sample achieved the best combination of strength and ductility, due to the successful collaboration of strong solution strengthening and obvious texture weakening. On the other hand, the insufficient solution strengthening failed in improving the strength of AS-3Gd sample, and the strong texture hardening deteriorated the ductility of AA-13Gd sample.