Helium 3 precipitation in AISI 316L stainless steel induced by radioactive decay of tritium: Microstructural study of helium bubble precipitation

Journal Article · Sat Oct 01 00:00:00 EDT 1994 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02652313· OSTI ID:6821595

Brass, A M; Chene, J ^[1]; Chanfreau, A ^[2]

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1. Univ. of Paris-South, Orsay (France). Lab. of Structural Metallurgy
2. CEA-DAM, Bruyeres Le Chatel (France)

The development of the thermonuclear technology has given rise to a renewed interest in the study of the behavior of helium in metals. A great amount of work is still required for the understanding of the role of helium on the mechanical properties of structural materials for fusion technology, especially austenitic stainless steels. This article deals with the study of the influence of thermomechanical heat treatments, aging conditions (temperature and time), and helium concentration of helium bubble precipitation in a 316L austenitic steel. Helium was generated by the radioactive decay of tritium (tritium trick). Helium bubbles impede the grain growth in 316L steel aged at 1,373 K and also the recrystallization reaction at this temperature if cold working is performed prior to aging. Transmission electron microscopy (TEM) observations indicated a weak helium precipitation at 1,073 and 1,223 K, presumably due to the presence of trapping sites for tritium, and no bubble growth after aging up to 100 hours. Precipitation sites are mainly dislocations in the matrix at 1,073 K and grain boundaries and individual dislocations in the matrix at 1,223 K. The large bubble size (50 nm) observed at 1,373 K, even for short aging times (0.083), can partly be attributed to bubble dragging by dislocations toward the grain boundaries. Cold deformation prior to aging leads to a larger bubble size due to growth enhancement during recrystallization. Decreasing the helium content leads to a smaller helium bubble size and density. Tritium trapping at helium bubbles may favor helium 3 accumulation on defects such as grain boundaries, as observed by tritium autoradiography.

• OSTI ID: 6821595
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Vol. 25:10; ISSN 0360-2133
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Ma
STAINLESS STEEL-316L
INTERSTITIAL HELIUM GENERATION
CRYSTAL DEFECTS
MICROSTRUCTURE
THERMOMECHANICAL TREATMENTS
THERMONUCLEAR REACTOR MATERIALS
ALLOYS
AUSTENITIC STEELS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-MOLYBDENUM STEELS
CHROMIUM-NICKEL STEELS
CHROMIUM-NICKEL-MOLYBDENUM STEELS
CRYSTAL STRUCTURE
FABRICATION
HEAT TREATMENTS
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MATERIALS WORKING
MOLYBDENUM ALLOYS
NICKEL
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
STAINLESS STEELS
STEEL-CR17NI12MO3-L
STEELS
360106* - Metals & Alloys- Radiation Effects
700480 - Fusion Technology- Component Development
Materials Studies- (1992-)