Effects of deformation conditions on the superplastic deformation behavior of LZ91 Mg-Li alloy under electric field

Abstract. The electro-superplastic effect (ESP effect) can enhance the superplastic deformation ability of alloy, and can also make alloy with poor plasticity have superplastic properties. Diverse grain sizes of LZ91 Mg-Li alloy were successfully prepared through equal channel angular pressing (ECAP) process. In order to explore the superplastic deformation behavior of LZ91 Mg-Li alloy under the electric current, an electric field assisted superplastic uniaxial tensile test platform was designed and fabricated. A decreasing constant voltage electrification scheme was proposed, and the experiments under different current densities, initial strain rates and grain sizes were carried out. The results indicate that the true strain-stress curve of LZ91 Mg-Li alloy gradually comes to steady with the increase of current density, presenting a steady-state rheological characteristic. The initial strain rate has a significant effect on the superplastic deformation behavior of LZ91 Mg-Li alloy under high voltage condition. For the fine-grained LZ91 Mg-Li alloy, the electric field can effectively reduce the superplastic deformation temperature and considerably enhance the elongation. This paper enriches the understanding of the superplastic deformation behavior of LZ91 Mg-Li alloy under the action of electric field.