The role of grain boundary orientation and secondary phases in creep cavity nucleation of a 316h boiler header

Tomas L. Martin, Siqi He, Alexander D. Warren, Hao Shang, David M. Knowles, Peter E.J. Flewitt

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

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Cavity formation during creep of steels at high temperatures and stresses is closely related to the original and evolved microstructure, particularly the orientation between grains and precipitation at the grain boundaries. Understanding the initiation, growth and coalescence of creep cavities is critical to determining the operational life of components in high temperature, high stress environments such as an advanced gas-cooled nuclear reactor. However, accelerated laboratory-based testing frequently shows another kind of void within the microstructure, caused by plastic damage and ductile failure, particularly if a specimen fails during a test. This paper compares the type of voids and cavities observed in an AISI 316 stainless steel after extensive service in a gas-cooled nuclear reactor boiler header and after uniaxial creep testing of a similar material at higher stresses. The differences between the features observed and their potential mechanistic origins are discussed.

Original languageEnglish
Title of host publicationProceedings of the ASME 2020 Pressure Vessels & Piping Conference
Subtitle of host publicationVol 6: Materials and Fabrication
PublisherAmerican Society of Mechanical Engineers (ASME)
Number of pages7
ISBN (Electronic)978-0-7918-8386-0
Publication statusE-pub ahead of print - 28 Oct 2020
EventASME 2020 Pressure Vessels and Piping Conference, PVP 2020 - Virtual, Online
Duration: 3 Aug 2020 → …

Publication series

NameProceedings of the Pressure Vessels and Piping (PVP) Conference
PublisherAmerican Society of Mechanical Engineers,
ISSN (Print)0277-027X


ConferenceASME 2020 Pressure Vessels and Piping Conference, PVP 2020
CityVirtual, Online
Period3/08/20 → …

Bibliographical note

Funding Information:
Dr Mike Spindler and EDF Energy are thanked for providing the 316H material and performing the strain-controlled creep test (specimen 2). Edward Hares and Mahmoud Mostafavi are thanked for performing the creep relaxation test for specimen 3. This work was supported by the EDF High Temperature Centre and ESPRC grant EP/R026076/1.

Publisher Copyright:
© 2020 ASME


  • Cavitation
  • Creep
  • Plastic deformation
  • Voids


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