Fracture Mechanics and Corrosion Fatigue

McEvily, A.J.; Wei, Robert P.

doi:10.1520/stp44804s

Cited by 28 publications

(8 citation statements)

References 12 publications

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“…The assumption given by (5) has been successfully applied to corrosion fatigue cracking of fcc materials: an aluminium alloy 12 and an austenitic stainless steel. 4 In bcc materials, as structural steels, the hydrogen diffusion is relatively too fast to be the rate-determining step.…”

Section: A I N a S S U M P T I O N O F T H E M O D E Lmentioning

confidence: 99%

A model of corrosion fatigue crack growth in ship and offshore steels

Jakubowski

2007

Fatigue Fract Eng Mat Struct

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A B S T R A C T A model describing corrosion fatigue crack growth rate da/dN has been proposed. The crack growth rate is assumed to be proportional to current flowing through the electrolyte within the crack during a loading cycle. The Shoji formula for the crack tip strain rateε has been assumed in the model. The obtained formula for the corrosion fatigue crack growth rate is formally similar to the author's empirical formulae established previously. The different effects of K and the fatigue loading frequency f on da/dN, in region I as compared to region II of the corrosion fatigue crack growth rate characteristics can be described by a change of one parameter only: the crack tip repassivation rate exponent.Keywords a model; corrosion fatigue; ship and offshore steels. N O M E N C L A T U R E a = crack nominal-length (i.e. including the notch length) a n = crack net-length (i.e. measured from the notch root) a * f = a constant in the Shoji relation forε A' = a constant in the Gangloff's model B = specimen thickness C = the Paris Law constant C 1 ; C 2 ; C 3 ; C V = constants C II = constant in Eq. (2) da d N air = fatigue crack growth rate in air da d N CF = crack length increment per cycle due to interaction of cyclic deformation and chemical reactions da d N e = corrosion fatigue crack growth rate da d N m = pure mechanical fatigue crack growth rate E tip = the crack tip electrochemical potential E x = electrochemical potential within the crack at the point of coordinate x f = loading frequency i A = anodic current density i(t) = the transient current after the crack tip surface film rupture K max ; K = respectively: the maximum and the range of stress intensity factor m = the Paris Law exponent n = exponent in Eq.(2) n i = the crack tip repassivation exponent P; P = respectively: load and the load range Q = electric charge passed through the crack per load cycle Q r = electric charge passed through the crack per rupture event of the crack tip filmCorrespondence: M. Jakubowski.

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Section: A I N a S S U M P T I O N O F T H E M O D E Lmentioning

confidence: 99%

A model of corrosion fatigue crack growth in ship and offshore steels

Jakubowski

2007

Fatigue Fract Eng Mat Struct

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“…In that context, the range of the stress intensity factor has been used 16 , 17 , 29 to account for the role of pitting in defining threshold using linear elastic fracture mechanics (LEFM), viz.…”

Section: Discussionmentioning

confidence: 99%

“…Lifetime prediction is complex because of the need to account for pit initiation, pit growth, crack initiation, short crack growth and long crack growth 13 . Several models have been proposed for life prediction of cracking initiated from pits, based on the kinetics of pit growth and crack growth 14 –16 . The condition for the transition of cracks from pits is generally defined phenomenologically using a LEFM approach, i.e.…”

Section: Introductionmentioning

confidence: 99%

Influence of pitting on the fatigue life of a turbine blade steel

Zhou

Turnbull

1999

Fatigue Fract Eng Mat Struct

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The role of pits as stress raisers and their influence on fatigue life has been investigated for a 12Cr turbine blade material. A particular feature of this work was the establishment of an electrochemical procedure for generating pits with ‘controlled’ pit depth and low density. Pits grown under laboratory conditions were partially spherical in shape and simulated, in general appearance, those observed in service. In terms of the threshold stress intensity factor, the results supported the concept of pits acting as effective cracks of the same depth, provided that a short crack model based on an effective crack length is used.

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“…1.6 x 10-6 (a) 36.0 1.2 X 10-7 39.2 6.5 X 10-6 41.8 4.0 X 10-6 43. 7 6.5 X 10-6 46.8 4.9 X 10-6 52.0 3.9 X 10-5 57. 3 3.1 X 10-5 • Homogeneity of variance was also assumed for most analyses.…”

Section: Discussionmentioning

confidence: 99%

Corrosion and environmental-mechanical characterization of iron-base nuclear waste package structural barrier materials. Annual report, FY 1984

Westerman¹,

Haberman²,

Pitman³

et al. 1986

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The disposal of high-level nuclear waste in deep underground repositories may require the development of waste packages that will keep the radioisotopes contained for time periods up to 1000 years. The primary geologic media currently being considered in the United States for repository siting are salt, basalt, tuff, and granite. sidered for the structrual A number of iron-base materials are being conbarrier members of waste packages. Their uniform and nonuniform (pitting and intergranular) corrosion behavior and their resistance to stress-corrosion cracking in aqueous environments relevant to salt media are under study at Pacific Northwest Laboratory {PNL). The purpose of the work is to provide data for a materials degradat1on model that can ultimately he used to predict the effective lifetime of a waste package overpack in the actual repository environment. This report summarizes the results of the studies conrlucted at PNL during the FY 1983-FY 1984 time period in support of the Salt Repository Project of the Department of Energy. The corrosion behavior of the candidate materials was investigated in simulated intrusion brine (essentially NaCl) in flowing autoclave tests at 150°C, and in combinations of intrusion/inclusion (high-Mg) brine environments in moist salt tests, also at 150°C. Studies utilizing a 6°co irradiation facility were performed to determine tne corrosion resistance of the candidate materials to products of brine radiolysis at dose rates of 2 x 103 and 1 x 105 rad/h and a temperature of 150°C. These irradiation-corrosion tests were "overtests," as the irradiation intensities employed were 10 to 1000 times as high as those expected at the surface of a thick-walled waste package. Slow-strain-rate (SSR) tests and corrosion fatigue tests conducted in intrusion brine environments at 150°C and, in the case of some SSR tests, with a superimposed radiation field of 3 x 10 5 rad/h, were used to determine the resistance of the candidate alloys to environmentally enhanced crack propagation. With the exception of the high general corrosion rates found in the tests using moist salt containing high-Mg brines, the ferrous materials exhibited a degree of corrosion resistance that indicates a potentially satisfactory application to waste package structural barrier members in a salt repository environment.

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Fracture Mechanics and Corrosion Fatigue

Cited by 28 publications

References 12 publications

A model of corrosion fatigue crack growth in ship and offshore steels

A model of corrosion fatigue crack growth in ship and offshore steels

Influence of pitting on the fatigue life of a turbine blade steel

Corrosion and environmental-mechanical characterization of iron-base nuclear waste package structural barrier materials. Annual report, FY 1984

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