2007 Volume 48 Issue 6 Pages 1406-1411
Superplasticity was studied in a fine-grained magnesium alloy AZ31 processed by multidirectional forging (MDF) under decreasing temperature conditions. Tensile tests were carried out at temperatures from 393 K to 473 K and at various strain rates. Superplasticity appears even at a low temperature of 393 K with a stress exponent of around 5.6 and a total elongation of over 370%. The relative large stress exponent can be connected with grain coarsening or refinement taking place during deformation. The initial deformation texture introduced by MDF hardly changes during superplasticity. These suggest that grain boundary sliding can take place during superplasticity, while grain rotation hardly occurs as a whole.
