Role of twinning and transformation in hydrogen embrittlement of austenitic stainless steels
Internal hydrogen embrittlement may be viewed as an extreme form of environmental embrittlement that arises following prolonged exposure to a source of hydrogen. Smooth bar tensile specimens of three stainless steels saturated with deuterium (approximately 200 mol D/sub 2//m/sup 3/) were pulled to failure in air at 200 to 400/sup 0/K or in liquid nitrogen at 78/sup 0/K. In Type 304L stainless steel and Tenelon ductility losses are a maximum around 200 to 273/sup 0/K; Type 310 stainless steel is not embrittled at this hydrogen concentration. A distinct change in fracture mode accompanies hydrogen embrittlement, with fracture proceeding along coherent boundaries of pre-existing annealing twins. This fracture path is observed in Tenelon at 78/sup 0/K even when hydrogen is absent. There is also a change in fracture appearance in specimens with no prior exposure to hydrogen if they are pulled to failure in high-pressure hydrogen. The fracture path is not identifiable, however. Magnetic response measurements and changes in the stress-strain curves show that hydrogen suppresses formation of strain-induced ..cap alpha..'-martensite at 198/sup 0/K in both Type 304L stainless steel and Tenelon, but there is little effect in Type 304L stainless at 273/sup 0/K.
- Research Organization:
- Du Pont de Nemours (E.I.) and Co., Aiken, S.C. (USA). Savannah River Lab.
- DOE Contract Number:
- EY-76-C-09-0001
- OSTI ID:
- 7087751
- Report Number(s):
- DP-MS-77-46; CONF-771010-1; TRN: 77-018011
- Resource Relation:
- Conference: Conference on environmental degradation of engineering materials, Blacksburg, Virginia, USA, 10 Oct 1977
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
08 HYDROGEN
HYDROGEN
METALLURGICAL EFFECTS
STAINLESS STEEL-304L
EMBRITTLEMENT
STAINLESS STEEL-310
STAINLESS STEELS
LOW TEMPERATURE
MEDIUM TEMPERATURE
PHASE TRANSFORMATIONS
TWINNING
VERY LOW TEMPERATURE
ALLOYS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
CRYOGENIC FLUIDS
ELEMENTS
FLUIDS
HEAT RESISTING ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
NICKEL ALLOYS
NONMETALS
STEELS
360105* - Metals & Alloys- Corrosion & Erosion
080800 - Hydrogen- Properties & Composition