A model for surface reaction and transport controlled fatigue crack growth

Weir, T. W.; Simmons, G.W.; Hart, R. G.; Wei, Robert P.

doi:10.1016/0036-9748(80)90359-2

Cited by 67 publications

(24 citation statements)

References 3 publications

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“…This correspondence in fatigue crack growth rates has been observed also by other investigators [4][5][6]. These observations strongly suggested that corrosion fatigue crack growth in this region is controlled by a common reaction process; namely, the dissociative chemisorption of water on the bare metal surfaces to produce hydrogen [7][8][9]. With decreases in frequency, further increases in crack growth rates in the aqueous environments towards a second plateau were observed.…”

Section: Introductionsupporting

confidence: 82%

Corrosion fatigue and electrochemical reactions in modified HY130 steel

Shim

Wei

1987

Materials Science and Engineering

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Section: Introductionsupporting

confidence: 82%

Corrosion fatigue and electrochemical reactions in modified HY130 steel

Shim

Wei

1987

Materials Science and Engineering

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“…The present results for 7475-T651 and those of Br'adshaw and Wheeler [2] and Weiet al [BJ for the Al-Cu-Mg alloys OTO 5070A and 2219-T851 showed a crack growth rate transition that occurred at relatively low water vapor pressures. Mathematical models [14] have been developed for the limiting cases of gas phase transport control and surface reaction rate control with the assumption that these processes are slower than hydrogen diffusion within the plastic zone. Predictions from the gas phase transport control model have shown reasonable correlation [8,15] with the data for DTD 5070A and 2219-T851.…”

Section: ! -13 Mechanismsmentioning

confidence: 99%

Effect of Water Vapor on Fatigue Crack Growth in 7475-T651 Aluminum Alloy Plate

Dicus

1984

Environment-Sensitive Fracture: Evaluation and Comparison of Test Methods

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An investigation was performed to assess the effects of water vapor on fatigue crack growth in 7475-T651 aluminum alloy plate at frequencies of 1 and 10 Hz. Twenty-five mm thick compact specimens were subjected to constant amplitude fatigue testing at a load ratio of 0.2. Fatigue crack growth rates were calculated from effective crack lengths determined by using a compliance method. Tests were conducted in hard vacuum and at water vapor partial pressures ranging from 94 Pa to 3.8 kPa. Fatigue crack growth rates were frequency-insensitive under all environmental conditions tested. For constant stress intensity factor ranges, crack growth rate transitions occurred at low and high water vapor pressures. Crack growth rates at intermediate pressures were relatively constant and showed reasonable agreement with published data for two Al-Cu-Mg alloys. The existence of two crack growth rate transitions suggests either a change in rate-controlling kinetics or a change in corrosion fatigue mechanism as a function of water vapor pressure. Reduced residual deformation and transverse cracking on specimens tested in water vapor versus vacuum may be evidence of embrittlement within the plastic zone due to environmental interaction.

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“…In the model, 5 environmental enhancement of fatigue crack growth is assumed to result from embrittlement by hydrogen that is produced by the reaction of hydrogenous gases (e.g., water vapor) with the freshly produced fatigue crack surfaces. More specifically, (da/dN)cf is assumed to be proportional to the amount of hydrogen produced by the surface reaction during each cyc3e, which is proportional in turn to the "effective" crack area 1 !/produced during the prior loading cycles and to the extent of surface reaction.…”

Section: Modeling Of Fatigue Crack Growth In One Compontnt Gasmentioning

confidence: 99%

“…The time available for reaction is assumed to be equal to one-half of the fatigue cycle. 5 Transport of gaseous environments to the-crack tip is assumed to be by Knudsen flow 1 3 at low pressures.…”

Section: Modeling Of Fatigue Crack Growth In One Compontnt Gasmentioning

confidence: 99%