Hydrogen and interfacial cohesion
Hydrogen effects on interfacial cohesion are discussed in relation to models for atomistically brittle cracking. An analysis is presented of the condition for stability against dislocation blunting of a critically stressed, atomistically sharp interfacial crack tip configuration, the satisfaction of which is viewed as a pre-condition for the occurrence of brittle interfacial separation. Results are applied to estimate the necessary effect of dissolved H on cohesive energies, so as to allow brittle grain boundary cracking of fcc metals, in which grain interfaces are not normally capable of sustaining such cracks. In addition, a new approach is presented to the thermodynamics of interfacial separation in presence of a segregated mobile species such as H, and some generalizations of the Gibbs adsorption relation are derived expressing the dependence of critical fracture parameters, namely the interfacial separation energy and cohesive strength, on the equilibrating potential and surface concentration of the segregant.
- Research Organization:
- Brown Univ., Providence, R.I. (USA). Div. of Engineering
- OSTI ID:
- 7347953
- Report Number(s):
- COO-3084/40; CONF-750925-8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
080800 -- Hydrogen-- Properties & Composition
36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ADSORPTION
CRACKS
CRYOGENIC FLUIDS
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DISLOCATIONS
ELEMENTS
EMBRITTLEMENT
FAILURES
FCC LATTICES
FLUIDS
FRACTURES
GRAIN BOUNDARIES
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
INTERFACES
LINE DEFECTS
METALLURGICAL EFFECTS
METALS
MICROSTRUCTURE
NONMETALS
SORPTION
STRESSES