An HVEM study of hydrogen effects on the deformation and fracture of nickel

Journal Article · Sat Mar 01 04:00:00 EST 1986 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(86)90071-4· OSTI ID:6977356

Robertson, I M; Birnbaum, H K

The mechanisms of hydrogen embrittlement of nickel have been investigated. The generation rate and velocity of dislocations and the crack propagation rate were increased by the presence of hydrogen. The advance of transgranular cracks, in both vacuum and hydrogen, occurs by either the direct emission of dislocations from the crack tip or by a complex process of hole nucleation and growth ahead of the crack. Intergranular cracks also propagate by these mechanisms; these cracks advance along the deformation zone that follows the contour of the boundary rather than along the boundary interface. The effect of hydrogen is to decrease the stress required for crack advance and to localize the deformation. When viewed macroscopically, this confinement of plastic deformation to a narrow zone gives the impression of a brittle type feature. Hydrogen embrittlement therefore occurs by a mechanism whereby hydrogen locally enhances plastic processes rather than by a decohesion mechanism.

• Research Organization: Dept. of Metallurgy and Mining Engineering, and Materials Research Lab., Univ. of Illinois, Urbana, IL (US)
• DOE Contract Number: AC02-76ER01198
• OSTI ID: 6977356
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 34:3; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
CRACK PROPAGATION
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DEFORMATION
DISLOCATIONS
ELEMENTS
EMBRITTLEMENT
FAILURES
FRACTURE PROPERTIES
FRACTURES
HYDROGEN EMBRITTLEMENT
LINE DEFECTS
MECHANICAL PROPERTIES
METALS
NICKEL
STRAINS
STRESS ANALYSIS
STRUCTURAL CHEMICAL ANALYSIS
TRANSITION ELEMENTS