Stress-corrosion crack growth by film-induced cleavage: some kinetic considerations

Conference · Tue Jan 01 04:00:00 EST 1985

OSTI ID:7008829

Newman, R C; Kim, J S; Sieradzki, K

Transgranular stress-corrosion cracking (TGSCC) is now widely believed to be an essentially brittle process. The debate has shifted from the reality of the stepwise brittle fracture to the role of the environment in nucleating it. However, published correlations of ''bare surface'' electrochemical kinetics with the rate of TGSCC continue to be successful, notably for alpha brass in sodium nitrite solution. By comparing the results of two techniques (scratching and rapid straining) it is shown that the published bare surface anodic current densities in this system are at least one order of magnitude too high. The revised values fit neatly into the ''film-induced cleavage'' picture of TGSCC. In another system (alpha brass in cuprous ammonia solution) the anodic process is dezincification to a depth of 20 to 40 nm, followed by cleavage on the order of 1 ..mu..m; here the inadequacy of the anodic process to account for the cracking is more obvious. Some suggestions are made as to how one can incorporate cleavage into a kinetic model of SCC, with the objective of harmonizing film-induced cleavage with earlier electrochemical models.

• Research Organization: Brookhaven National Lab., Upton, NY (USA); University of Manchester Inst. of Science and Technology (UK). Corrosion and Protection Centre
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7008829
• Report Number(s): BNL-38541; CONF-8510160-20; ON: DE87001369
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALKALI METAL COMPOUNDS
ALLOYS
AMMONIA
AQUEOUS SOLUTIONS
BRASS
CHEMICAL REACTIONS
CLEAVAGE
COPPER ALLOYS
COPPER BASE ALLOYS
CORROSION
CRACK PROPAGATION
CRYSTAL STRUCTURE
CURRENT DENSITY
DISPERSIONS
FILMS
HYDRIDES
HYDROGEN COMPOUNDS
KINETICS
MICROSTRUCTURE
MIXTURES
NITRITES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXYGEN COMPOUNDS
SODIUM COMPOUNDS
SOLUTIONS
STRESS CORROSION
ZINC ALLOYS