Hot compression behavior of GZ31 magnesium alloy

Highlights: • Study the hot deformation behavior of Mg–3Gd–1Zn (GZ31) magnesium alloy. • Determination of activation energy for hot deformation of this alloy. • Determination of material's constants of constitutive equations for this material. - Abstract: Hot deformation behavior of Mg–3Gd–1Zn (GZ31) magnesium alloy was studied by hot compression tests over the temperature range of 300–500 °C under strain rates of 0.0001–0.1 s⁻¹. This material exhibited typical broad single-peak dynamic recrystallization behavior followed by a gradual drop towards the steady state stress. The constitutive behavior of the tested alloy was studied by the power, exponential, and hyperbolic sine laws. The stress multiplier and the hyperbolic sine exponent were calculated as 0.024 MPa⁻¹ and 3.42, respectively. The deformation activation energy was found to be about 173.2 kJ/mol, which is higher than the lattice self-diffusion activation energy of magnesium (135 kJ/mol). The latter can be ascribed to the presence of gadolinium, which shows the importance of rare earth elements in increasing the deformation resistance at high temperatures