Evolution of Microstructure during Low Temperature superplastic Deformation of Bulk Nanostructured Ni-Cr-Fe-Nb Base Superalloy

摘要

Ultrafine-grained and nanocrystalline structure have been obtained in Ni-Cr-Fe-Nb based alloy (INCONEL^? 718) by multiple isothermal forging. The ultrafine-grained and nanostructured samples demonstrated low temperature (T=700 °C) superplastic behavior. Nanostructured alloy showed larger uniform elongation and reduced cavitation than those of Inconel 718 with microcrystalline structure. Electron backscatter diffraction was employed to reveal characteristics of structure, second particles distribution and grain boundary statistics.