Effect of strain level on the evolution of microstructure in a recently developed AD730 nickel based superalloy during hot forging

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Abstract

Design and control of microstructure of engineering parts made from nickel based superalloys with superior mechanical properties for high temperature applications, require the parts to be subjected to certain thermo-mechanical processing during forging. This often includes sequential straining and annealing at elevated temperatures followed by subsequent aging heat treatments at lower temperatures. In this study, the effect of strain magnitude on the evolution of microstructure during hot forging of a recently developed AD730 nickel based superalloy has been investigated. Microstructural heterogeneity was observed in a forged material manifested in a form of large non-recrystallized grains within the recrystallized matrix that is observed to be dependent on the level of deformation (i.e. strain magnitude). Analyses of microstructure indicated significant reduction in the fraction of low-angle grain boundaries and sub-structures with an increase in the applied strain, suggesting higher fraction of recrystallization with higher levels of strains. It was concluded that the lower strain levels were insufficient to provide enough driving force for complete recrystallization throughout the entire microstructure of the forged material.
LanguageEnglish
Pages437-445
Number of pages9
JournalMaterials Characterization
Volume139
Early online date21 Mar 2018
DOIs
Publication statusPublished - 31 May 2018

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forging
heat resistant alloys
Forging
Nickel
Superalloys
nickel
microstructure
Microstructure
High temperature applications
heat treatment
grain boundaries
engineering
mechanical properties
Grain boundaries
Aging of materials
annealing
Heat treatment
Annealing
matrices
Mechanical properties

Keywords

  • nickel-based superalloy
  • hot forging
  • electron backscatter diffraction
  • grain structure
  • recrystallization

Cite this

@article{a9000e1e4917494db35c7d0a0ac92142,
title = "Effect of strain level on the evolution of microstructure in a recently developed AD730 nickel based superalloy during hot forging",
abstract = "Design and control of microstructure of engineering parts made from nickel based superalloys with superior mechanical properties for high temperature applications, require the parts to be subjected to certain thermo-mechanical processing during forging. This often includes sequential straining and annealing at elevated temperatures followed by subsequent aging heat treatments at lower temperatures. In this study, the effect of strain magnitude on the evolution of microstructure during hot forging of a recently developed AD730 nickel based superalloy has been investigated. Microstructural heterogeneity was observed in a forged material manifested in a form of large non-recrystallized grains within the recrystallized matrix that is observed to be dependent on the level of deformation (i.e. strain magnitude). Analyses of microstructure indicated significant reduction in the fraction of low-angle grain boundaries and sub-structures with an increase in the applied strain, suggesting higher fraction of recrystallization with higher levels of strains. It was concluded that the lower strain levels were insufficient to provide enough driving force for complete recrystallization throughout the entire microstructure of the forged material.",
keywords = "nickel-based superalloy, hot forging, electron backscatter diffraction, grain structure, recrystallization",
author = "T. Konkova and S. Rahimi and S. Mironov and T.N. Baker",
year = "2018",
month = "5",
day = "31",
doi = "10.1016/j.matchar.2018.03.027",
language = "English",
volume = "139",
pages = "437--445",
journal = "Materials Characterization",
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}

TY - JOUR

T1 - Effect of strain level on the evolution of microstructure in a recently developed AD730 nickel based superalloy during hot forging

AU - Konkova, T.

AU - Rahimi, S.

AU - Mironov, S.

AU - Baker, T.N.

PY - 2018/5/31

Y1 - 2018/5/31

N2 - Design and control of microstructure of engineering parts made from nickel based superalloys with superior mechanical properties for high temperature applications, require the parts to be subjected to certain thermo-mechanical processing during forging. This often includes sequential straining and annealing at elevated temperatures followed by subsequent aging heat treatments at lower temperatures. In this study, the effect of strain magnitude on the evolution of microstructure during hot forging of a recently developed AD730 nickel based superalloy has been investigated. Microstructural heterogeneity was observed in a forged material manifested in a form of large non-recrystallized grains within the recrystallized matrix that is observed to be dependent on the level of deformation (i.e. strain magnitude). Analyses of microstructure indicated significant reduction in the fraction of low-angle grain boundaries and sub-structures with an increase in the applied strain, suggesting higher fraction of recrystallization with higher levels of strains. It was concluded that the lower strain levels were insufficient to provide enough driving force for complete recrystallization throughout the entire microstructure of the forged material.

AB - Design and control of microstructure of engineering parts made from nickel based superalloys with superior mechanical properties for high temperature applications, require the parts to be subjected to certain thermo-mechanical processing during forging. This often includes sequential straining and annealing at elevated temperatures followed by subsequent aging heat treatments at lower temperatures. In this study, the effect of strain magnitude on the evolution of microstructure during hot forging of a recently developed AD730 nickel based superalloy has been investigated. Microstructural heterogeneity was observed in a forged material manifested in a form of large non-recrystallized grains within the recrystallized matrix that is observed to be dependent on the level of deformation (i.e. strain magnitude). Analyses of microstructure indicated significant reduction in the fraction of low-angle grain boundaries and sub-structures with an increase in the applied strain, suggesting higher fraction of recrystallization with higher levels of strains. It was concluded that the lower strain levels were insufficient to provide enough driving force for complete recrystallization throughout the entire microstructure of the forged material.

KW - nickel-based superalloy

KW - hot forging

KW - electron backscatter diffraction

KW - grain structure

KW - recrystallization

UR - https://www.sciencedirect.com/journal/materials-characterization

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DO - 10.1016/j.matchar.2018.03.027

M3 - Article

VL - 139

SP - 437

EP - 445

JO - Materials Characterization

T2 - Materials Characterization

JF - Materials Characterization

SN - 1044-5803

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