Evolution of microstructure and microtexture during hot deformation in an advanced P/M nickel base superalloy
- Near Net Shape Group, Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500058 (India)
- Department of Materials Science & Metallurgical Engineering, Indian Institute of Technology, Hyderabad 502285 (India)
- Powder Processing Group, Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500058 (India)
- Materials Technology Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)
Highlights: • Microstructural evolution of PM superalloy sensitive to temperature and strain rate. • Highest DRX with finer grained structure at higher temperatures and strain rates. • Dominance of DDRX showed by serrated grain boundaries and misorientation gradient. • Weak microtextural evolution inclined towards [110] fiber compression texture seen. 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{sup −1}, 0.01 s{sup −1}, 0.1 s{sup −1}, 1 s{sup −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.
- OSTI ID:
- 23118134
- Journal Information:
- Materials Characterization, Vol. 146; Other Information: Copyright (c) 2018 Elsevier Inc. All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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