A microstructural study of phosphorus segregation and intergranular fracture in neutron irradiated submerged-arc welds

Bischler, P J.E.; Wild, R K

Title: A microstructural study of phosphorus segregation and intergranular fracture in neutron irradiated submerged-arc welds

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Abstract

Accelerated irradiation experiments have been carried out on submerged-arc welds to obtain validation of trend curves built up from surveillance results. This was done by withdrawing surveillance specimens and re-irradiating them in higher flux positions. One batch, from weld HS, showed a significantly higher increase in the Charpy {Delta}T{sub 40J} value than that for weld LS at a similar dose. Work done to explain this difference is described in this paper. Selected Charpy specimens were examined using a shielded scanning electron microscope to determine the fracture modes present. Regions of mixed cleavage, micro-void coalescence (MVC) and intergranular failure (IGF) were found on HS weld specimens fractured in the transition region. The IFG was confined to certain regions within each weld bead. Significantly less IGF was found on LS weld specimens. Sub-fracture surface matchstick specimens were removed from embrittled regions and fractured within a scanning Auger microscope. IGF occurred in these specimens, and phosphorus was found to be the main grain boundary segregant. The levels of phosphorus increased with increasing neutron dose. No other embrittling element was consistently found at any significant level, but carbon was also found on grain boundary surfaces in some cases. The grain boundary coverage of phosphorusmore »« less

Authors:

Bischler, P J.E. ^[1]; Wild, R K ^[2]

Nuclear Electric plc, Berkeley (United Kingdom). Berkeley Technology Centre
Univ. of Bristol (United Kingdom). Interface Analysis Centre

Publication Date:: Tue Dec 31 00:00:00 EST 1996

OSTI Identifier:: 524806

Report Number(s):: CONF-940657-
Journal ID: ISSN 1050-7515; TRN: 97:016788

Resource Type:: Conference

Resource Relation:: Conference: 17. symposium on effects of radiation on materials, Sun Valley, ID (United States), 20-23 Jun 1994; Other Information: PBD: 1996; Related Information: Is Part Of Effects of radiation on materials: 17. international symposium; Gelles, D.S. [ed.] [Pacific Northwest National Lab., Richland, WA (United States)]; Nanstad, R.K. [ed.] [Oak Ridge National Lab., TN (United States)]; Kumar, A.S. [ed.] [Univ. of Missouri, Rolla, MO (United States)]; Little, E.A. [ed.] [University College of Swansea (United Kingdom)]; PB: [1175] p.; ASTM special technical publication, 1270

Country of Publication:: United States

Language:: English

Subject:: 22 NUCLEAR REACTOR TECHNOLOGY; PRESSURE VESSELS; WELDED JOINTS; PHYSICAL RADIATION EFFECTS; SUBMERGED ARC WELDING; EMBRITTLEMENT; MICROSTRUCTURE; PHOSPHORUS; FRACTURES

Citation Formats


                    Bischler, P J.E., and Wild, R K. A microstructural study of phosphorus segregation and intergranular fracture in neutron irradiated submerged-arc welds.  United States: N. p., 1996. 
        Web.

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                    Bischler, P J.E., & Wild, R K. A microstructural study of phosphorus segregation and intergranular fracture in neutron irradiated submerged-arc welds.  United States.

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                    Bischler, P J.E., and Wild, R K. 1996.  
        "A microstructural study of phosphorus segregation and intergranular fracture in neutron irradiated submerged-arc welds".  United States.

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@article{osti_524806,

  title        = {A microstructural study of phosphorus segregation and intergranular fracture in neutron irradiated submerged-arc welds},

  author       = {Bischler, P J.E. and Wild, R K},

  abstractNote = {Accelerated irradiation experiments have been carried out on submerged-arc welds to obtain validation of trend curves built up from surveillance results. This was done by withdrawing surveillance specimens and re-irradiating them in higher flux positions. One batch, from weld HS, showed a significantly higher increase in the Charpy {Delta}T{sub 40J} value than that for weld LS at a similar dose. Work done to explain this difference is described in this paper. Selected Charpy specimens were examined using a shielded scanning electron microscope to determine the fracture modes present. Regions of mixed cleavage, micro-void coalescence (MVC) and intergranular failure (IGF) were found on HS weld specimens fractured in the transition region. The IFG was confined to certain regions within each weld bead. Significantly less IGF was found on LS weld specimens. Sub-fracture surface matchstick specimens were removed from embrittled regions and fractured within a scanning Auger microscope. IGF occurred in these specimens, and phosphorus was found to be the main grain boundary segregant. The levels of phosphorus increased with increasing neutron dose. No other embrittling element was consistently found at any significant level, but carbon was also found on grain boundary surfaces in some cases. The grain boundary coverage of phosphorus was determined for each weld at several neutron dose levels.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/524806},
  journal      = {},

  issn         = {1050-7515},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Tue Dec 31 00:00:00 EST 1996},

  month        = {Tue Dec 31 00:00:00 EST 1996}

}

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