Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97

The novel reduced activation ferritic/martensitic steel Eurofer 97 is employed by many concept designs for the plasma-facing first wall of the EU DEMO fusion reactor. These designs feature precision joints between Eurofer 97 coolant piping, for which an advanced laser-keyhole welding technique is pr...

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Main Authors: J. Hargreaves, S. Moore, G. Yuan, D. Liu, H. Tipping, R. Abbott, J. Tufnail, H. Dawson, T.L. Martin
Format: Article
Language:English
Published: Elsevier 2023-02-01
Series:Materials & Design
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0264127523000291
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author J. Hargreaves
S. Moore
G. Yuan
D. Liu
H. Tipping
R. Abbott
J. Tufnail
H. Dawson
T.L. Martin
author_facet J. Hargreaves
S. Moore
G. Yuan
D. Liu
H. Tipping
R. Abbott
J. Tufnail
H. Dawson
T.L. Martin
author_sort J. Hargreaves
collection DOAJ
description The novel reduced activation ferritic/martensitic steel Eurofer 97 is employed by many concept designs for the plasma-facing first wall of the EU DEMO fusion reactor. These designs feature precision joints between Eurofer 97 coolant piping, for which an advanced laser-keyhole welding technique is proposed. In this work the microstructure of these novel laser-keyhole Eurofer 97 welds is modelled by combining finite element thermal analysis with precipitate kinetics modelling. Microanalysis of a representative specimen via scanning electron and high-speed atomic force microscopy techniques is also conducted, complimented by electron backscatter diffraction, energy-dispersive X-ray spectroscopy, and nanoindentation hardness testing. Models of the weld microstructure agree well with the results of microanalysis although the precipitate diameters predicted are slightly underestimated. Several large void defects were discovered within the weld fusion zone, the cause of which is suspected to arise from the evaporation of cerium-rich oxide inclusions present in the as-cast Eurofer 97 during welding.
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spelling doaj.art-b29dced25c2d4e869fa46dc320fcd1252023-03-08T04:13:31ZengElsevierMaterials & Design0264-12752023-02-01226111614Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97J. Hargreaves0S. Moore1G. Yuan2D. Liu3H. Tipping4R. Abbott5J. Tufnail6H. Dawson7T.L. Martin8University of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UK; Corresponding author.University of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UKUniversity of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UKUniversity of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UKUniversity of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UKUniversity of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UKUniversity of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UKUKAEA, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB, UKUniversity of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UKThe novel reduced activation ferritic/martensitic steel Eurofer 97 is employed by many concept designs for the plasma-facing first wall of the EU DEMO fusion reactor. These designs feature precision joints between Eurofer 97 coolant piping, for which an advanced laser-keyhole welding technique is proposed. In this work the microstructure of these novel laser-keyhole Eurofer 97 welds is modelled by combining finite element thermal analysis with precipitate kinetics modelling. Microanalysis of a representative specimen via scanning electron and high-speed atomic force microscopy techniques is also conducted, complimented by electron backscatter diffraction, energy-dispersive X-ray spectroscopy, and nanoindentation hardness testing. Models of the weld microstructure agree well with the results of microanalysis although the precipitate diameters predicted are slightly underestimated. Several large void defects were discovered within the weld fusion zone, the cause of which is suspected to arise from the evaporation of cerium-rich oxide inclusions present in the as-cast Eurofer 97 during welding.http://www.sciencedirect.com/science/article/pii/S0264127523000291MicrostructureWeldingPrecipitation kineticsAnalytical electron microscopyAtomic force microscopy
spellingShingle J. Hargreaves
S. Moore
G. Yuan
D. Liu
H. Tipping
R. Abbott
J. Tufnail
H. Dawson
T.L. Martin
Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97
Materials & Design
Microstructure
Welding
Precipitation kinetics
Analytical electron microscopy
Atomic force microscopy
title Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97
title_full Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97
title_fullStr Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97
title_full_unstemmed Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97
title_short Microstructural modelling and characterisation of laser-keyhole welded Eurofer 97
title_sort microstructural modelling and characterisation of laser keyhole welded eurofer 97
topic Microstructure
Welding
Precipitation kinetics
Analytical electron microscopy
Atomic force microscopy
url http://www.sciencedirect.com/science/article/pii/S0264127523000291
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