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Evolution of microstructure and microtexture during hot deformation in an advanced P/M nickel base superalloy
S.S.S. Kumar, T. Raghu, , G. Appa Rao, U. Borah
Published in Elsevier Inc.
2018
Volume: 146
   
Pages: 217 - 236
Abstract
In the present study, the effect of hot deformation parameters on the microstructural evolution is investigated for an experimental powder metallurgy nickel superalloy. The hot isostatically pressed (HIPed) alloy is isothermally hot compressed at constant true strain rate over wide temperatures (1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.001 s−1, 0.01 s−1, 0.1 s−1, 1 s−1) regimes. Electron Back-Scattered Diffraction (EBSD) characterization of the hot deformed samples is carried out to evaluate the microstructural evolution, grain boundary characteristics, and microtextural behaviour. The strong dependence of dynamic recrystallization characteristics on the hot deformation conditions is divulged through EBSD derived colour inverse pole figure maps endorsed by grain/twin boundary characteristics and misorientation gradient. Dynamic recrystallization (DRX) is maximized at higher deformation temperatures, whereas limited DRX is observed at lower deformation temperatures, especially at higher strain rates. The dominance of discontinuous dynamic recrystallization (DDRX) is manifested through bulged/serrated grain boundaries resulting in the formation of necklace microstructure corroborated by grain boundary cumulative misorientation gradient. Although random microtexture is revealed in both deformed and recrystallized microstructures, the tendency towards the formation of 〈110〉 fiber compression texture is apparently evident. © 2018 Elsevier Inc.
About the journal
JournalData powered by TypesetMaterials Characterization
PublisherData powered by TypesetElsevier Inc.
ISSN10445803