Improving the superplastic properties of a two-phase Mg–8% Li alloy through processing by ECAP

Significant grain refinement was achieved in a cast Mg–8 mass% Li alloy through processing by equal-channel angular pressing (ECAP) using a die having an internal channel angle of 110° and a pressing temperature of 473 K. Following extrusion and subsequent ECAP through two passes, the alloy exhibited excellent superplastic properties including a maximum elongation of ∼970% at 473 K when using an initial strain rate of 1.0 × 10−4 s−1. The strain rate sensitivities under the optimum superplastic conditions were measured as m ≈ 0.4–0.6. The maximum elongation achieved in this investigation is very high by comparison with other Mg alloys tested in tension at similar temperatures and strain rates.