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Title: TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS

Abstract

A transmission electron microscopy (TEM) study was conducted to characterize the helium bubble distributions in tritium-charged-and-aged 304L and 21Cr-6Ni-9Mn stainless steel fusion welds containing approximately 150 appm helium-3. TEM foils were prepared from C-shaped fracture toughness test specimens containing {delta} ferrite levels ranging from 4 to 33 volume percent. The weld microstructures in the low ferrite welds consisted mostly of austenite and discontinuous, skeletal {delta} ferrite. In welds with higher levels of {delta} ferrite, the ferrite was more continuous and, in some areas of the 33 volume percent sample, was the matrix/majority phase. The helium bubble microstructures observed were similar in all samples. Bubbles were found in the austenite but not in the {delta} ferrite. In the austenite, bubbles had nucleated homogeneously in the grain interiors and heterogeneously on dislocations. Bubbles were not found on any austenite/austenite grain boundaries or at the austenite/{delta} ferrite interphase interfaces. Bubbles were not observed in the {delta} ferrite because of the combined effects of the low solubility and rapid diffusion of tritium through the {delta} ferrite which limited the amount of helium present to form visible bubbles.

Authors:
;
Publication Date:
Research Org.:
SRS
Sponsoring Org.:
USDOE
OSTI Identifier:
945005
Report Number(s):
SRNS-STI-2008-00079
TRN: US200902%%1174
DOE Contract Number:  
DE-AC09-08SR22470
Resource Type:
Conference
Resource Relation:
Conference: International Hydrogen Conference 2008
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 36 MATERIALS SCIENCE; AUSTENITE; BEARINGS; BUBBLES; DIFFUSION; DISLOCATIONS; FERRITE; FRACTURE PROPERTIES; GRAIN BOUNDARIES; HELIUM; HELIUM 3; HYDROGEN; SOLUBILITY; STAINLESS STEELS; TRANSMISSION ELECTRON MICROSCOPY; TRITIUM

Citation Formats

Tosten, M, and Michael Morgan, M. TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS. United States: N. p., 2008. Web.
Tosten, M, & Michael Morgan, M. TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS. United States.
Tosten, M, and Michael Morgan, M. Fri . "TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS". United States. https://www.osti.gov/servlets/purl/945005.
@article{osti_945005,
title = {TRANSMISSION ELECTRON MICROSCOPY STUDY OF HELIUM BEARING FUSION WELDS},
author = {Tosten, M and Michael Morgan, M},
abstractNote = {A transmission electron microscopy (TEM) study was conducted to characterize the helium bubble distributions in tritium-charged-and-aged 304L and 21Cr-6Ni-9Mn stainless steel fusion welds containing approximately 150 appm helium-3. TEM foils were prepared from C-shaped fracture toughness test specimens containing {delta} ferrite levels ranging from 4 to 33 volume percent. The weld microstructures in the low ferrite welds consisted mostly of austenite and discontinuous, skeletal {delta} ferrite. In welds with higher levels of {delta} ferrite, the ferrite was more continuous and, in some areas of the 33 volume percent sample, was the matrix/majority phase. The helium bubble microstructures observed were similar in all samples. Bubbles were found in the austenite but not in the {delta} ferrite. In the austenite, bubbles had nucleated homogeneously in the grain interiors and heterogeneously on dislocations. Bubbles were not found on any austenite/austenite grain boundaries or at the austenite/{delta} ferrite interphase interfaces. Bubbles were not observed in the {delta} ferrite because of the combined effects of the low solubility and rapid diffusion of tritium through the {delta} ferrite which limited the amount of helium present to form visible bubbles.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Dec 12 00:00:00 EST 2008},
month = {Fri Dec 12 00:00:00 EST 2008}
}

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