Dynamic strain aging (DSA) in solid solubilized Mg-Gd alloys under compression at intermediate temperatures

Abstract

The Mg-Gd alloys compressed at intermediate temperatures exhibit flow serrations which present a significant dependence on strain rate and compression temperature. The apparition of this phenomenon is due to the dynamic strain ageing effect, that basically consists in the simultaneous and competitive movement of diffusing solute atoms, mobile dislocations and twin boundaries during deformation. Compression tests have been carried out at temperatures between 25–300 °C and strain rates in a range of 4×10−5 - 8×10−3 s−1 to analyze the apparition of serrations and, implicitly, the DSA effect. A relation between the activation energy for serrated flow and the concentration of gadolinium was determined and indicates that there would be an inversely proportional relation between these two parameters.