Processing routes leading to superplastic behaviour of magnesium alloy ZK60

Abstract

There has recently been discussion on processing of magnesium alloys by equal channel angular extrusion (ECAE) to achieve a high elongation-to-failure under superplastic tensile deformation. A two-step processing route was suggested to improve superplastic capabilities of such alloys. In this work, superplastic behaviour of ZK60 processed by ECAE alone was compared with that for the material that was rolled prior to the ECAE processing. It was shown that deformation preceding the ECAE step does not bring any benefit with regard to superplastic behaviour in the low temperature range around 200 °C. An important finding is that ECAE processing by itself leads to a record elongation of 1400 and 2040% at the strain rates of 3 × 10 −3 and 3 × 10 −4 s −1, respectively.