Superplasticity in high temperature magnesium alloy WE43

Severe plastic deformation of the magnesium alloy WE43 (Mg-4%Y-2.3%Nd-0.5%Zr) has been carried out by multi-axial forging (MAF) in order to refine the grain size from 25 mu m to 6 mu m. Deformation behaviour of the as processed material has been investigated. Compression tests were carried out in the temperature range 250-450 degrees C and in the strain rate range 10(-3)-10 (s-1). Strain-rate sensitivity values were calculated from the stress strain curves. A high value of strain rate sensitivity was noticed in the temperature range 350-400 C-o and the strain rate range 10(-4)-10 (s-1), which indicated the possibility of superplastic forming after multi-axial forging. The superplastic behaviour of MAF processed samples was further investigated by carrying out tensile tests. An excellent superplastic elongation of 470% was obtained at the temperature 375 C-o and strain rate 3*10(-4) s(-1). The material also exhibited superplasticity at higher strain rates at this temperature.