Near-threshold fatigue crack growth behavior in copper

Liaw, Peter K.; Leax, T.R.; Williams, Robert; Peck, M.G.

doi:10.1007/bf02644801

Cited by 98 publications

(20 citation statements)

References 25 publications

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“…This difference in the fatigue-crack-growth rate at different R ratios can be attributed to the crack-closure effect. [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] At the low R ratio, the effective stress-intensity range experienced by the alloy at the fatigue-crack tip will decrease due to crack-closure effects, and, consequently, slower crackgrowth rates are observed at the low R ratio than at the high R ratio. However, the monotonic crack-tip openings are large at the high R ratio, and, thus, the crack-closure effects are virtually eliminated, although, in this case, the change in R ratio did not cause any alteration in failure mechanisms.…”

Section: Influence Of Load Ratio and Temperature On Crackgrowth Bementioning

confidence: 99%

The low-cycle fatigue and fatigue-crack-growth behavior of HAYNES® HR-120 alloy

Chen

Liaw

McDaniels

et al. 2003

Metall Mater Trans A

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The low-cycle fatigue and fatigue-crack-growth behavior of the HAYNES HR-120 alloy was investigated over the temperature range of 24°C to 980°C in laboratory air. The result showed that increasing the temperature usually led to a substantial decrease in the low-cycle fatigue life. The reduction of fatigue life could be attributed to oxidation and dynamic strain-aging (DSA) processes. The strain vs fatigue-life data obtained at different temperatures were analyzed. It was also found that the fatigue-crack-growth rate per cycle generally increased with increasing temperature and R ratio (R ϭ min / max , where min and max are the applied minimum and maximum stresses, respectively). The relationship between the stress-intensity-factor range and fatigue-crack-growth rate was determined. Scanning-electron-microscopy (SEM) examinations of the fracture surfaces revealed that the fatigue cracks initiated and propagated predominantly in a transgranular mode.

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Section: Influence Of Load Ratio and Temperature On Crackgrowth Bementioning

confidence: 99%

The low-cycle fatigue and fatigue-crack-growth behavior of HAYNES® HR-120 alloy

Chen

Liaw

McDaniels

et al. 2003

Metall Mater Trans A

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“…At least in the near-threshold and Paris law regimes, fatigue crack growth rates are relatively independent of the yield strength of the material but scale with the elastic modulus. This rather surprising observation has been borne out in numerous studies on a variety of metallic alloys including for example steels [3], copper [4] and aluminum [5]. Experimental data for the effective fatigue threshold ⌬K eff th reported by Liaw et al [5] and Hertzberg [6] indicates that (⌬K eff th / E) 2 Ϸb, where b is the Burgers vector magnitude and E is the Young's modulus.…”

Section: Introductionmentioning

confidence: 99%

Scaling of discrete dislocation predictions for near-threshold fatigue crack growth

2003

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Analyses of the growth of a plane strain crack subject to remote mode I cyclic loading under small scale yielding are carried out using discrete dislocation dynamics. Plastic deformation is modelled through the motion of edge dislocations in an elastic solid with the lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and dislocation annihilation being incorporated through a set of constitutive rules. An irreversible relation is specified between the opening traction and the displacement jump across a cohesive surface ahead of the initial crack tip in order to simulate cyclic loading in an oxidizing environment. Calculations are carried out with different material parameters so that values of yield strength, cohesive strength and elastic moduli varying by factors of three to four are considered. The fatigue crack growth predictions are found to be insensitive to the yield strength of the material despite the number of dislocations and the plastic zone size varying by approximately an order of magnitude. The fatigue threshold scales with the fracture toughness of the purely elastic solid, with the experimentally observed linear scaling with Young's modulus an outcome when the cohesive strength scales with Young's modulus.

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“…The threshold stress intensity factor ranges, DKth, are obtained 2.3MPa m, 3.3 MPa m and 3.5 MPa m for the aluminum, the copper and the titanium films, respectively. The value of DKth is smaller for the copper film than for the bulk one with the comparable poof stress (Liaw, et al, 1982 andMarchand, et al, 1988). On the other hand, the DKth for the titanium film has about the same value with the bulk one (Ogawa et al, 1988).…”

Section: Crack Propagation Ratementioning

confidence: 77%

Development of <i>ΔK</i>-decreasing test method of the metal film by displacement constraint along the elliptical through hole-edge

Shimizu

Kato

Sakata

2016

Mechanical Engineering Journal

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A new DK-decreasing test method of the metal film was developed. The film was adhered to a through elliptical hole in a base plate and was fatigued in accordance with the displacement constraint along the hole -circumference in the base plate subjected to a cyclic stress. Commonly, a stress intensity factor range was increased with a crack propagation under a constant stress amplitude but was decreased toward the hole-edge because of the difference in thickness between the film and the base plate in this DK-decreasing test method.The decrease in a stress intensity factor with a crack propagation was calculated by FEM analysis and the optimum aspect ratio of an elliptical hole was determined. Using the DK-decreasing test method, the crack propagation test was conducted for metal films. As a result, the fatigue crack propagation rate was decreased and was arrested near the hole-edge under the constant stress amplitude to the base plate. The threshold stress intensity factor ranges were obtained for some kinds of metal film and the accuracy of the testing method was discussed.

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Near-threshold fatigue crack growth behavior in copper

Cited by 98 publications

References 25 publications

The low-cycle fatigue and fatigue-crack-growth behavior of HAYNES® HR-120 alloy

The low-cycle fatigue and fatigue-crack-growth behavior of HAYNES® HR-120 alloy

Scaling of discrete dislocation predictions for near-threshold fatigue crack growth

Development of <i>ΔK</i>-decreasing test method of the metal film by displacement constraint along the elliptical through hole-edge

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