| During severe plastic deformation (isothermal multiple forging with low strain rate) of Alloy 718 at the temperature of 0.6Tm, the initial submicrocrystalline structure transforms to the nanocrystalline one with grain size 0.08 µm. The thermal stability of nanocrystalline structure is investigated at heating and superplastic deformation. The refinement of structure up to nanocrystalline one (0.08 µm) provides the reduction of the lower temperature limit for superplasticity to 0.57Tm (550 °C) |
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