Effect of oxidation kinetics on the near threshold fatigue crack growth behavior of a nickel base superalloy

Yuen, J.L.; Roy, Prodyot; Nix, William D.

doi:10.1007/bf02666360

Cited by 37 publications

(7 citation statements)

References 19 publications

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“…transgranular or intergranular slip, 8 cracking of precipitates, 9 shrinkage 10 as well as interior fracture under surface oxide films at elevated temperature, 11 indicating that the mechanism of a fatigue crack initiation changes with the alloy composition, stress levels and environmental conditions. Particularly at elevated temperature, the behaviour of a fatigue crack becomes more complicated because of the effect of oxidation, 11 –14 which must be taken into account besides the variation of mechanical properties. Therefore, knowledge of the influence of temperature on the initiation and growth behaviour of a fatigue small crack in each alloy is necessary when considering material selection for practical applications.…”

Section: Introductionmentioning

confidence: 99%

Fatigue strength of Inconel 718 at elevated temperatures

Kawagoishi

Chen

Nisitani

2000

Fatigue Fract Eng Mat Struct

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The strength of Inconel 718 under rotary bending fatigue is investigated at room temperature, 300, 500 and 600 °C in air. It is found that in the long‐life region, the fatigue strength of a plain specimen is much higher at elevated temperatures than at room temperature, though the static strength decreases with the increase in temperature. The effect of temperature on the fatigue strength is examined in terms of the initiation and early growth behaviour of a small crack. The results are discussed in relation to the competition between the softening of the nickel matrix (γ phase) and the surface oxidation at elevated temperatures.

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Section: Introductionmentioning

confidence: 99%

Fatigue strength of Inconel 718 at elevated temperatures

Kawagoishi

Chen

Nisitani

2000

Fatigue Fract Eng Mat Struct

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“…6. At elevated temperatures, oxidation kinetics play an important role in determining the oxide thickness [20] rather than the oxide fretting mechanism, which was important at room temperature. Oxide thicknesses at 538°C in air are about 50% less than the maximum oxide thickness produced in the room temperature tests.…”

Section: Discussionmentioning

confidence: 99%

Effects of Air and Inert Environments on the Near Threshold Fatigue Crack Growth Behavior of Alloy 718

Yuen

Schmidt

Roy

1985

Fatigue Fract Eng Mat Struct

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The near threshold fatigue crack growth behavior of alloy 718 was studied in air and helium environments at room temperature and at 538°C. Tests were performed at 100 Hz and at load ratios of 0.1 and 0.5. At room temperature and at 538"C, the AK,, values in helium were lower than in air. The AK,, values in air decreased with increasing load ratio. These results can be explained with a model that involves the accumulation of oxide in the crack which enhances crack closure. In the air tests, the oxide build-up on the fatigue fracture surfaces at AKlh was of the order of magnitude as the crack tip opening displacement. In the helium tests, no significant build-up of oxide on the fracture surface at threshold was found. NOMENCLATURE da/dN = fatigue crack growth rate K,, = stress intensity factor to close the crack K,,, = maximum stress intensity factor K,,, = minimum stress intensity factor AK = alternating stress intensity factor equal to K,,, -K,,, AKerr= effective AK equal to K, , , -KcI AKth = threshold alternating stress intensity factor R = load ratio equal to K,,/K,,, uys = yield stress E = elastic modulus Kthmax=AKth/(l -R ) CTOD = crack tip opening displacement SIMS = secondary ion mass spectrometry.

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“…This effect is related to very slow coarsening rate [5]. The propagation of long cracks in conventionally manufactured Inconel 718 at ambient and high temperatures was studied intensively in the past [15][16][17], because this alloy is often used for fabrication of components exposed to long term cyclic loading at high temperatures. Also the mechanism of the crack growth was a subject of investigation.…”

Section: Fatigue Fracture Profilesmentioning

confidence: 99%

Fatigue crack growth behavior of Inconel 718 produced by selective laser melting

Konečná¹,

Kunz²,

Nicoletto³

et al. 2015

Frattura Ed Integrità Strutturale

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Additive layer manufacturing has recently gained a lot of interest due to the feasibility of producing metallic components directly from a computer-aided design file of the part. Selective laser melting, one of the main additive layer manufacturing technologies, is currently capable of producing nearly ready-to-use parts made of metallic materials. Their microstructure, however, differs substantially from that produced by conventional manufacturing. That is why a detailed study and knowledge of the relation of specific microstructure, parameters of the selective laser melting process and mechanical properties is of utmost significance. This study reports on the investigation of the fatigue crack growth behavior in Inconel 718 superalloy produced by selective laser melting. The fatigue crack growth curve and the threshold values of the stress intensity factor for propagation of long cracks were experimentally determined on compact-tension specimens fabricated using a RENISHAW A250 system and the recommended processing parameters. The fatigue crack growth rates and the fatigue crack paths both in the threshold and in the Paris region were investigated. The crack propagation curves and the crack propagation threshold were compared with literature data describing the behavior of conventionally manufactured material. The mechanism of fatigue crack growth was discussed in terms of the specific microstructure produced by selective laser melting.

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Effect of oxidation kinetics on the near threshold fatigue crack growth behavior of a nickel base superalloy

Cited by 37 publications

References 19 publications

Fatigue strength of Inconel 718 at elevated temperatures

Fatigue strength of Inconel 718 at elevated temperatures

Effects of Air and Inert Environments on the Near Threshold Fatigue Crack Growth Behavior of Alloy 718

Fatigue crack growth behavior of Inconel 718 produced by selective laser melting

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