The study of hot deformation behavior of an Mg-10Li-1Zn alloy by Arrhenius constitutive equations

Hot deformation of an extruded Mg–10Li–1Zn alloy was studied by compression testing in the temperatures range of 250- 450 ˚C and strain rates of 0.001–0.1 s−1. During the hot compressive deformation of the Mg-10Li-1Zn alloy, flow stress curves reach a maximum value and then reach a steady state which is indicative of the occurrence of dynamic recrystallization. Because of the activation of softening mechanisms at higher temperatures and lower strain rates, this phenomenon is more pronounced at lower temperatures and higher strain rate.
The flow stress of the Mg–10Li–1Zn alloy at elevated temperatures was modeled via an Arrhenius-type constitutive equation. The values for the activation energy of about
103 kJ mol–1 and the power-law stress exponents in the range of 5.2–6.0 obtained from the Arrhenius-type model indicate that the dominant mechanism during hot deformation of the Mg–10Li–1Zn alloy is dislocation climb which is controlled by the lattice
self-diffusion of Li atoms.