Effect of Temperature on the Superplasticity of AZ81 Magnesium Alloy Processed by Hot Extrusion
An AZ81 magnesium alloy, which was processed by hot extrusion in advance, was tested in the temperature range of 473 ~ 623 K and at various initial strain rates, ranging from 1×10-1 to 1×10-4 s-1. True stress-true strain curves under various temperatures and activation energy within different temperature range were investigated for the analysis of effect of temperature on superplastic behaviors. Elongation of the as-extruded AZ81 alloy increased with temperature when tested at the same initial strain rate. Elongation values, obtained at the same initial strain rate of 1×10-3 s-1, were 94% at 473K and 446% at 623K, respectively. Deformation mechanisms varied with increasing temperature, from the grain boundary sliding (GBS) accommodated by grain boundary diffusion to the GBS accommodated by lattice diffusion, transition temperature was 573 K.
W.Ke, E.H.Han, Y.F.Han, K.Kainer and A.A.Luo
L. Lin et al., "Effect of Temperature on the Superplasticity of AZ81 Magnesium Alloy Processed by Hot Extrusion", Materials Science Forum, Vols. 488-489, pp. 585-588, 2005