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 degrees 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 similar to 970% at 473 K when using an initial strain rate of 1.0 X 10(-4) s(-1). The strain rate sensitivities under the optimum superplastic conditions were measured as m approximate to 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. (c) 2005 Elsevier B.V. All rights reserved.