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Data rich imaging approaches assessing fatigue crack initiation and early propagation in a DS superalloy at room temperature

Data rich imaging approaches assessing fatigue crack initiation and early propagation in a DS superalloy at room temperature
Data rich imaging approaches assessing fatigue crack initiation and early propagation in a DS superalloy at room temperature
Crack initiation and early propagation behavior of the directionally solidified (DS) superalloy CM247LC has been assessed by data rich imaging approaches. These include conventional characterization methods such as replica record analysis, 3D optical surface imaging, optical and scanning electron microscopy (SEM) as well as more recent techniques like digital image correlation (DIC) and synchrotron radiation computed tomography (SRCT). Three modes of secondary crack behaviors were found during evaluation of the fatigue process. The early stages
of fatigue damage were controlled by microstructure-induced cracking, mainly consisting of carbide cracking. Fatigue damage was then promoted via slip band cracking and opening mode controlled carbide-cracking. The mechanisms of these different cracking behaviors are associated with the plastic zone of the main crack tip. Even though the early localized strain levels were of the same intensity within slip bands and at the intersection siteswith carbides, carbide-induced cracking occurred prior to slip band cracking, characterized by SEM-DIC. This indicated that carbide-induced cracking was more likely to occur in the early stages of the fatigue process. Early crack growth behaviors were further investigated in situ at the microstructural scale via SRCT. The effect of
carbides on crack initiation and propagation processes were evaluated in 3D. This revealed the phenomenonaround pores, that cracks simultaneously grew on different slip planes in 3D, contrary to previous theories that
such cracks tend to grow on a single favourable slip plane (in polycrystalline alloys). The SRCT result demonstrates the importance and necessity of 3D characterization of the crack propagation behavior at sub-surface,
which is not fully analyzed by 2D characterization.
Directionally solidified Ni-Based superalloyFatigue crack initiationShort crackDigital image correlationSynchrotron radiation computed tomography
Tan, Yuanguo
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Bull, Daniel John
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Jiang, Rong
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Evangelou, Angelos
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Chaudhuri, Somsubhro
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Octaviani, Sari
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Pierron, Fabrice
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Gao, Nong
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Toda, H.
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Sinclair, Ian
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Reed, Philippa
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Tan, Yuanguo
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Bull, Daniel John
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Jiang, Rong
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Evangelou, Angelos
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Chaudhuri, Somsubhro
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Octaviani, Sari
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Pierron, Fabrice
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Gao, Nong
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Toda, H.
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Sinclair, Ian
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Reed, Philippa
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Tan, Yuanguo, Bull, Daniel John, Jiang, Rong, Evangelou, Angelos, Chaudhuri, Somsubhro, Octaviani, Sari, Pierron, Fabrice, Gao, Nong, Toda, H., Sinclair, Ian and Reed, Philippa (2021) Data rich imaging approaches assessing fatigue crack initiation and early propagation in a DS superalloy at room temperature. Materials Science & Engineering: A, 805 (140592), [140592]. (doi:10.1016/j.msea.2020.140592).

Record type: Article

Abstract

Crack initiation and early propagation behavior of the directionally solidified (DS) superalloy CM247LC has been assessed by data rich imaging approaches. These include conventional characterization methods such as replica record analysis, 3D optical surface imaging, optical and scanning electron microscopy (SEM) as well as more recent techniques like digital image correlation (DIC) and synchrotron radiation computed tomography (SRCT). Three modes of secondary crack behaviors were found during evaluation of the fatigue process. The early stages
of fatigue damage were controlled by microstructure-induced cracking, mainly consisting of carbide cracking. Fatigue damage was then promoted via slip band cracking and opening mode controlled carbide-cracking. The mechanisms of these different cracking behaviors are associated with the plastic zone of the main crack tip. Even though the early localized strain levels were of the same intensity within slip bands and at the intersection siteswith carbides, carbide-induced cracking occurred prior to slip band cracking, characterized by SEM-DIC. This indicated that carbide-induced cracking was more likely to occur in the early stages of the fatigue process. Early crack growth behaviors were further investigated in situ at the microstructural scale via SRCT. The effect of
carbides on crack initiation and propagation processes were evaluated in 3D. This revealed the phenomenonaround pores, that cracks simultaneously grew on different slip planes in 3D, contrary to previous theories that
such cracks tend to grow on a single favourable slip plane (in polycrystalline alloys). The SRCT result demonstrates the importance and necessity of 3D characterization of the crack propagation behavior at sub-surface,
which is not fully analyzed by 2D characterization.

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fatigue_crack_initiation_and_early_propagation_1_ - Accepted Manuscript
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Accepted/In Press date: 21 November 2020
e-pub ahead of print date: 1 December 2020
Published date: 23 February 2021
Additional Information: Funding Information: The authors would like to thank the EPSRC (Grant no: EP/M000710/1) for funding support and the China Scholarship Council, China, for financial support. Dr. R. Jiang would like to thank the National Natural Science Foundation of China [Grant no: 51805251] for financial support. S. Octaviani gratefully acknowledges support from Schlumberger Faculty for the Future Programme and the Roberto Rocca Education Programme. The synchrotron radiation experiments were performed at the BL20XU beamline in SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal number 2016A1278). The authors are grateful for the travel funding provided by the Great Britain Sasakawa Foundation and the Global Partnership Award from University of Southampton to visit Spring-8. The authors also would like to thank the MatchID team for provision of the MatchID software. The authors also would like to acknowledge Prof. Liguo Zhao at Loughborough University, Dr. Mark Hardy at Rolls-Royce, Dr. Matthew Lunt at Defence Science and Technology Laboratory, Dr. Gordon McColvin at GE Power, Prof Michael Preuss and Dr. Jo?o Quinta da Fonseca at University of Manchester and Prof. Scott Lockyer at Uniper Technologies Ltd for several useful discussions and comments of the results presented in this paper. Funding Information: The authors would like to thank the EPSRC (Grant no: EP/M000710/1 ) for funding support and the China Scholarship Council , China, for financial support. Dr. R. Jiang would like to thank the National Natural Science Foundation of China [Grant no: 51805251 ] for financial support. S. Octaviani gratefully acknowledges support from Schlumberger Faculty for the Future Programme and the Roberto Rocca Education Programme. The synchrotron radiation experiments were performed at the BL20XU beamline in SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal number 2016A1278 ). The authors are grateful for the travel funding provided by the Great Britain Sasakawa Foundation and the Global Partnership Award from University of Southampton to visit Spring-8. The authors also would like to thank the MatchID team for provision of the MatchID software. The authors also would like to acknowledge Prof. Liguo Zhao at Loughborough University, Dr. Mark Hardy at Rolls-Royce, Dr. Matthew Lunt at Defence Science and Technology Laboratory, Dr. Gordon McColvin at GE Power, Prof Michael Preuss and Dr. João Quinta da Fonseca at University of Manchester and Prof. Scott Lockyer at Uniper Technologies Ltd for several useful discussions and comments of the results presented in this paper. Publisher Copyright: © 2020 Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
Keywords: Directionally solidified Ni-Based superalloyFatigue crack initiationShort crackDigital image correlationSynchrotron radiation computed tomography

Identifiers

Local EPrints ID: 448864
URI: http://eprints.soton.ac.uk/id/eprint/448864
PURE UUID: 7a78e44f-ff25-4c9e-9ede-32f619e53707
ORCID for Somsubhro Chaudhuri: ORCID iD orcid.org/0000-0001-9849-5766
ORCID for Fabrice Pierron: ORCID iD orcid.org/0000-0003-2813-4994
ORCID for Nong Gao: ORCID iD orcid.org/0000-0002-7430-0319
ORCID for Philippa Reed: ORCID iD orcid.org/0000-0002-2258-0347

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Date deposited: 07 May 2021 16:31
Last modified: 17 Mar 2024 06:22

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Contributors

Author: Yuanguo Tan
Author: Daniel John Bull
Author: Rong Jiang
Author: Angelos Evangelou
Author: Somsubhro Chaudhuri ORCID iD
Author: Sari Octaviani
Author: Fabrice Pierron ORCID iD
Author: Nong Gao ORCID iD
Author: H. Toda
Author: Ian Sinclair
Author: Philippa Reed ORCID iD

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