Superplasticity at elevated temperature of an Mg–8%Li–2%Zn alloy

An Mg–8%Li–2%Zn (LZ82) alloy was prepared by melt casting and then extruded and rolled, the superplasticity at elevated temperature of the specimens of obtained alloy at the temperature range of 423 K–523 K under the initial strain rate of 1.6 × 10−4–1.0 × 10−2 s−1 was investigated. The results indicate that the alloy exhibits significant superplasticity with a maximum elongation of 430% at the temperature of 498 K, even when the temperature decrease to 423 K, the maximum elongation exceed 100%, reached 120%. The activation energy under the optimum condition is 99.24 kJ/mol, and the strain rate sensitivity m is measured as 0.55, indicating that the dominant deformation mechanism in the alloy is grain-boundary sliding controlled by grain-boundary diffusion.

► Superplasticity at relatively low temperature in Mg–Li alloy.
► Measurement of the activation energy and strain rate sensitivity, superplastic deformation mechanism of the alloy.
► Microstructure discussion after tensile test.