Superplastic forming characteristics of AZ41 magnesium alloy

Abstract

An AZ41 magnesium alloy in the hot-rolled condition without further thermomechanical processing to modify its microstructure was investigated to establish its suitability for use within a superplastic forming process and to establish optimum forming parameters. Formability was assessed using elevated temperature tensile testing and hot gas bulging, across a range of strain rates (1×10 −1 −1×10 −3 s −1 ) and temperatures (350−450 °C). Circle grid analysis with GOM Aramis cameras was used to understand peak strains and material thinning in relation to industrial forming processes. Post forming EBSD and STEM analysis was conducted to understand the mechanisms responsible for the materials formability, with dynamic recrystallization being clearly evident. Peak elongation of 520% was achieved at 450 °C and 1×10 −3 s −1 ; industrially relevant elongation was achieved at 1×10 −2 s −1 at both 450 °C (195%) and 400 °C (170%).