β Scribed by Z. Chen; A.V. Kazantzis; J.Th.M. De Hosson
No coin nor oath required. For personal study only.
The coarseβgrained Al alloy AA5182 exhibits poor superplasticity with a maximum elongation to failure not exceeding 220β% at 450βΒ°C and at 10^β2^ s^β1^. The low values of the strain rate sensitivity indicate that the dislocation velocity is quite high and necking is developed quite soon during extension. The size (often exceeding 1 ΞΌm) and the distribution of the precipitates render them incapable of pinning the subgrain boundaries efficiently. As a result recovery and reconstruction by grain refinement occurs only within the necking region where the applied stress is concentrated. A fabrication method which will be able to introduce a large number of submicron sized precipitates will most likely result in sufficient pinning of the subgrain boundaries. This will promote recovery and reconstruction to take place more uniformly in the material rendering it appreciably superplastic.
π SIMILAR VOLUMES
## Abstract Despite decades of study, the fundamental mechanisms of superplasticity, particularly relating to the accommodation of grain boundary sliding, are still widely disputed. This is partly due to a lack of information on individual grain deformation and sliding events. Previous studies of s