| Superplastic behaviors have been investigated in Duralumin 2017 alloy at 280-450℃ over the strain rate range 10^(-4)/min-10^(-1)/min. The usual method of measuring the strain rate sensitivity m of superplastic materials showed that m and flow stress in 2017 alloy are dependent upon temperature, strain rate, and grain size of recrystallized grains. The flow stress of 2017 alloy at 450℃ was proportional to L^a (a∼1) at the different strain rate and the apparent activation energy for superplastic deformation was estimated to be about a half of the one for lattice diffusion of Al. It may be concluded that the structural requirements for superplasticity in 2017 Al alloy can be produced by appropriate combination of severe hot-extrusion, coldrolling, and recrystallization, and that grain boundary slip is the rate controlling process for the superplastic deformation of this alloy. |
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