Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °C

Creep degradation behaviour of service-exposed P91 steel is evaluated during interrupted creep tests at 660 °C and 80 MPa using a number of material characterization techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron backscattered diffraction (E...

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Main Authors: R. Bonetti, N.C. Neate, A. Morris, P.H. Shipway, W. Sun
Format: Article
Language:English
Published: Elsevier 2024-11-01
Series:Journal of Materials Research and Technology
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2238785424023159
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author R. Bonetti
N.C. Neate
A. Morris
P.H. Shipway
W. Sun
author_facet R. Bonetti
N.C. Neate
A. Morris
P.H. Shipway
W. Sun
author_sort R. Bonetti
collection DOAJ
description Creep degradation behaviour of service-exposed P91 steel is evaluated during interrupted creep tests at 660 °C and 80 MPa using a number of material characterization techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), energy dispersive spectroscopy (EDS) and optical microscopy (OM) to identify the microstructural evolution and the associated deformation mechanisms. Microhardness has also been measured in order to evaluate the softening mechanism. Under the creep conditions examined, microstructural degradation is found to be governed by the disappearance of the lath sub-structure, lath widening and recrystallization, as well as dislocation density reduction, coarsening of M23C6 and creep cavitation while MX and Laves phases are stable. Hardness evolution, extrapolated from hardness data obtained from uniaxial creep tests, is used to characterize the softening of the material. On this basis, hardness decrease is justified in term of the aforementioned microstructural changes. Implications of the findings for specific in-service life management in thermal plant piping systems are addressed.
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spelling doaj-art-28c64e6c393d4eb8aa870e2829f253c52024-12-26T08:54:26ZengElsevierJournal of Materials Research and Technology2238-78542024-11-013335293549Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °CR. Bonetti0N.C. Neate1A. Morris2P.H. Shipway3W. Sun4Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK; Corresponding author.Nanoscale and Microscale Research Centre, University of Nottingham, Nottingham, NG7 2RD, UKEDF Energy (UK), Coal and Gas Operations, Central Technical Organisation, Barnwood, Gloucester, GL4 3RS, UKFaculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UKFaculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UKCreep degradation behaviour of service-exposed P91 steel is evaluated during interrupted creep tests at 660 °C and 80 MPa using a number of material characterization techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), energy dispersive spectroscopy (EDS) and optical microscopy (OM) to identify the microstructural evolution and the associated deformation mechanisms. Microhardness has also been measured in order to evaluate the softening mechanism. Under the creep conditions examined, microstructural degradation is found to be governed by the disappearance of the lath sub-structure, lath widening and recrystallization, as well as dislocation density reduction, coarsening of M23C6 and creep cavitation while MX and Laves phases are stable. Hardness evolution, extrapolated from hardness data obtained from uniaxial creep tests, is used to characterize the softening of the material. On this basis, hardness decrease is justified in term of the aforementioned microstructural changes. Implications of the findings for specific in-service life management in thermal plant piping systems are addressed.http://www.sciencedirect.com/science/article/pii/S2238785424023159P91 steelInterrupted creep testsMicrostructure evolutionSoftening mechanismHardness and life fraction
spellingShingle R. Bonetti
N.C. Neate
A. Morris
P.H. Shipway
W. Sun
Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °C
Journal of Materials Research and Technology
P91 steel
Interrupted creep tests
Microstructure evolution
Softening mechanism
Hardness and life fraction
title Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °C
title_full Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °C
title_fullStr Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °C
title_full_unstemmed Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °C
title_short Microstructure evolution and deformation mechanisms of service-exposed P91 steel via interrupted uniaxial creep tests at 660 °C
title_sort microstructure evolution and deformation mechanisms of service exposed p91 steel via interrupted uniaxial creep tests at 660 °c
topic P91 steel
Interrupted creep tests
Microstructure evolution
Softening mechanism
Hardness and life fraction
url http://www.sciencedirect.com/science/article/pii/S2238785424023159
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