The evolution of damage in tritium exposed copper

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Journal of Materials Research; (USA)

DOI:https://doi.org/10.1557/JMR.1991.0303· OSTI ID:6196629

Goods, S H ^[1]

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1. Tritium Effects Research Division, Sandia National Laboratories, Livermore, California 94550 (US)

Severe microstructural damage has been observed in polycrystalline OFHC copper specimens thermally exposed to high pressure tritium gas at temperatures {le}200 {degree}C, but not at 300 {degree}C. No such damage occurs in single crystal specimens exposed under identical conditions, regardless of temperature. In the polycrystals, the damage takes the form of very flat, crack-like intergranular cavities. It is found that the cavitation evolves slowly with time. For short exposure times, cavities as small as 0.1 {mu}m are observed. In specimens subjected to the longest aging times, the cavities grow and link until entire grain boundary facets fail. The driving force for the growth of these cavities is attributed to the internal gas pressure of helium-3 generated by the decay of tritium. The growth kinetics of cavity microstructure are described by a coupled grain boundary, surface self-diffusion process. The tritium exposure profoundly affects the mechanical properties of the polycrystalline material, inducing a severe loss in ductility. In concert with the observed ductility loss is a change in fracture morphology from transgranular ductile rupture to intergranular fracture. Examination of the resulting grain boundary facets reveals a dimple structure. The spacing of these dimples can be correlated with the spacing of the exposure-induced grain boundary cavities.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6196629
• Journal Information: Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 6:2; ISSN JMREE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360106* -- Metals & Alloys-- Radiation Effects
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CAVITATION
COPPER
CRYSTAL STRUCTURE
CRYSTALS
DAMAGE
ELEMENTS
FLUIDS
GASES
GRAIN BOUNDARIES
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
NUCLEI
ODD-EVEN NUCLEI
POLYCRYSTALS
RADIOISOTOPES
TIME DEPENDENCE
TRANSITION ELEMENTS
TRITIUM
YEARS LIVING RADIOISOTOPES