Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 263171
Loughborough University

Loughborough University Institutional Repository

Please use this identifier to cite or link to this item: https://dspace.lboro.ac.uk/2134/18364

Title: Evolution of sigma phase in 321 grade austenitic stainless steel parent and weld metal with duplex microstructure
Authors: Green, Graham
Higginson, Rebecca L.
Hogg, Simon C.
Spindler, Sarah
Hamm, Christopher
Keywords: Sigma phase
Stainless steel
Microstuctural development
Particle size
Issue Date: 2014
Publisher: Maney Publishing / © Institute of Materials, Minerals and Mining
Citation: GREEN, G. ... et al, 2014. Evolution of sigma phase in 321 grade austenitic stainless steel parent and weld metal with duplex microstructure. Materials Science and Technology, 30 (12), pp. 1392 - 1398.
Abstract: Samples of 321 stainless steel from both the parent and welded section of a thin section tube were subjected to accelerated ageing to simulate long term service conditions in an advanced gas cooled reactor (AGR) power plant. The initial condition of the parent metal showed a duplex microstructure with approximately 50% ferrite and 50% austenite. The weld metal showed three distinct matrix phases, austenite, delta ferrite and ferrite. This result was surprising as the initial condition of the parent metal was expected to be fully austenitic and austenite+delta ferrite in the weldment. The intermetallic sigma phase formed during the accelerated ageing was imaged using ion beam induced secondary electrons then measured using computer software which gave the particle size as a function of aging time. The measurements were used to plot particle size, area coverage against aging time and minimum particle spacing for the parent metal. During aging the amount of ferrite in the parent metal actually increased from ∼50 to ∼80% after aging for 15 000 h at 750°C. Sigma has been observed to form on the austenite/ferrite boundaries as they may provide new nucleation sites for sigma phase precipitation. This has resulted in small sigma phase particles forming on the austenite/ferrite boundaries in the parent metal as the ferrite transforms from the austenite.
Description: This article was published in the journal, Materials Science and Technology [Maney Publishing / © Institute of Materials, Minerals and Mining] and the definitive version is available at: http://dx.doi.org/10.1179/1743284713Y.0000000452
Sponsor: The authors would like to thank EDF Energy and Loughborough University for providing the funding and the materials for this project.
Version: Accepted for publication
DOI: 10.1179/1743284713Y.0000000452
URI: https://dspace.lboro.ac.uk/2134/18364
Publisher Link: http://dx.doi.org/10.1179/1743284713Y.0000000452
ISSN: 0267-0836
Appears in Collections:Published Articles (Materials)

Files associated with this item:

File Description SizeFormat
Green G, Higginson R, Hogg S, Spindler S and Hamm C, Materials Science and Technology, 2014.pdfAccepted version926.87 kBAdobe PDFView/Open


SFX Query

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.