Fig. 1. Microstructure of as-extruded Mg-9Li-3Al-2.5Sr alloys: (a) optical micrograph, (b) secondary electron SEM micrograph.

Fig. 2. Compressive true stress-true strain curves of Mg-9Li-3Al-2.5Sr alloy at different strain rates and temperatures.

Fig. 3. Peak stress of Mg-9Li-3Al-2.5Sr alloy under different hot compression conditions.

Fig. 4. Linear relationship fitting: (a) ln ε ? -lnσ; (b) ln ε ? -σ; (c) ln ε ? -ln[sinh(ασ)]; (d) ln[sinh(ασ)]-1000/Tln[sinh(ασ)]-1000/T. Data points are from Fig. 3.

Fig. 5. Relationship between lnZ and ln[sinh(ασ).

Fig. 6. Comparison between the calculated peak stresses based on hyperbolic sine function and the measured peak stresses.

Fig. 7. Hot processing maps of Mg-9Li-3Al-2.5Sr alloy at different strains (the contour numbers represent power dissipation efficient and the shaded areas correspond to the regimes of flow instability): (a) ε = 0.1; (b) ε = 0.4; (c) ε = 0.6.

Fig. 8. Microstructure of Mg-9Li-3Al-2.5Sr alloy in the low temperature-low strain rate area (strain rate 0.001 s-1, temperature 200 °C) with peak efficiency in percent of power dissipation: (a) SEM image; (b) TEM image.

Fig. 9. Microstructure of Mg-9Li-3Al-2.5Sr alloy in the medium temperature-low strain rate area (strain rate 0.001 s-1, temperature 300 °C) with peak efficiency in percent of power dissipation: (a) SEM image; (b) TEM image.

Fig. 10. Microstructure of Mg-9Li-3Al-2.5Sr alloy in the high temperature-medium strain rate area (strain rate 0.01 s-1, temperature 350 °C) with peak efficiency in percent of power dissipation: (a) SEM image; (b) TEM image.