Fatigue Crack Initiation In WASPALOY at 20 °C

Davidson, D. L.; Tryon, Robert; Oja, M.; Matthews, Robert; Chandran, K.S. Ravi

doi:10.1007/s11661-007-9178-6

Cited by 59 publications

(31 citation statements)

References 18 publications

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“…The PSBs are observed to transverse through low-angle grain boundaries (LAGBs) with misorientations less than 15° [21,51], thereby resulting in an overall PSB length that can stretch over multiple connected grains [21,52]. Failure (e.g., fatigue crack initiation) would occur when the energy of the PSB would attain its stable, minimum value, that is as follows:…”

Section: Design For Fatigue Enhancementmentioning

confidence: 99%

Tailoring the Properties of a Ni-Based Superalloy via Modification of the Forging Process: an ICME Approach to Fatigue Performance

Detrois

Rotella

Hardy

et al. 2017

Integr Mater Manuf Innov

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Traditionally, material design and property modifications are usually associated with compositional changes. Yet, subtle changes in the manufacturing process parameters can also have a dramatic effect on the resulting material properties. In this work, an integrated computational materials engineering (ICME) framework is adopted to tailor the fatigue performance of a Ni-based superalloy, RR1000. An existing fatigue model is used to identify microstructural features that promote enhanced fatigue life, namely a uniform, fine grain size distribution, random orientation, a distinct grain boundary distribution (specifically high twin boundary density and limited low-angle grain boundaries). A deformation mechanism map and process models for grain boundary engineering of RR1000 are used to identify the optimal thermo-mechanical processing parameters to realize these desirable microstructural features. For validation, small-scale forgings of RR1000 were produced and heat-treated to attain fine grain and coarse grain microstructures that represent the conventionally processed and grain boundary engineered (GBE) conditions, respectively. For each of the four microstructural variants of RR1000, the twin density and grain size were characterized and were in agreement with the desired microstructural attributes. In order to validate the deformation mechanisms and fatigue behavior of the material, high-resolution digital image correlation was performed to generate strain maps relative to the microstructural features. The high density of twin boundaries was confirmed to inhibit the length of slip bands, which is directly attributed to extended fatigue life. Thus, this study demonstrated the successful role of models, both process and performance, in the design and manufacture of Ni-based superalloy disk forgings.

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Section: Design For Fatigue Enhancementmentioning

confidence: 99%

Tailoring the Properties of a Ni-Based Superalloy via Modification of the Forging Process: an ICME Approach to Fatigue Performance

Detrois

Rotella

Hardy

et al. 2017

Integr Mater Manuf Innov

View full text Add to dashboard Cite

show abstract

“…Grain refinement increases the fatigue limit, while reducing the microcrack initiation threshold, but it also increases the fatigue crack growth rate. Based on a study on waspaloy [5,6], it was also pointed out that the crack initiation sites tend to be larger than the average grain size, but not necessarily the largest grain size. The crack initiation grains normally are located within some cluster of grains with misorientations less than 15 o , which act similar to a large single grain.…”

Section: Introductionmentioning

confidence: 99%

Material characterisation and finite element modelling of cyclic plasticity behaviour for 304 stainless steel using a crystal plasticity model

Sun

Becker

2016

International Journal of Mechanical Sciences

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Abstract: Low cycle fatigue tests were carried out for a 304 stainless steel at room temperature. A series of experimental characterisations, including SEM, TEM, and XRD were conducted on for the 304 stainless steel to facilitate the understanding of the mechanical responses and microstructural behaviour of the material under cyclic loading including nanostructure, crystal structure and the fractured surface. The crystal plasticity finite element method (CPFEM) is a powerful tool for studying the microstructure influence on the cyclic plasticity behaviour. This method was incorporated into the commercially available software ABAQUS by coding a UMAT user subroutine. Based on the results of fatigue tests and material characterisation, the full set of material constants for the crystal plasticity model was determined. The CPFEM framework used in this paper can be used to predict the crack initiation sites based on the local accumulated plastic deformation and local plastic dissipation energy criterion, but with limitation in predicting the crack initiation caused by precipitates.

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“…Li et al [9] found that large grains and favorably orientated local texture might promote fatigue crack initiation in IN100 nickelbase superalloy. Recently, Davidson et al [10,11] reported that in Waspaloy at 20°C fatigue cracks initiated from clusters of surface grains, termed supergrains, that were favorably orientated for slip transmission across grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Crack Initiation in Nickel-Based Superalloy Ren� 88 DT at 593�C

Miao¹,

Pollock²,

Jones³

2008

Superalloys 2008 (Eleventh International Symposium)

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Fatigue crack initiation in the polycrystalline nickel-based superalloy, René 88 DT, was investigated at 593 °C in air using an ultrasonic fatigue testing instrument. Within the testing stress range of 500 -760MPa, all fatigue failures initiated from internal regions. Large crystallographic facets were observed at the crack initiation sites in most failed fatigue samples. Critical microstructure features controlling fatigue crack initiation and the early stage of small crack growth were identified by the combination of serial sectioning, orientation imaging microscopy (OIM) and quantitative fractographic analysis. Large crystallographic facets at crack initiation sites were formed in regions close to Σ 3 annealing twin boundaries within favorably oriented large grains. The facet planes are parallel to Σ 3 annealing twin boundaries and are of {111} type. Cyclic deformation substructures were studied by transmission electron microscopy. At the low cyclic stresses and long lives examined, fatigue failure at 593°C is controlled by strain localization in large, favorably oriented grains and subsequent propagation of small cracks through neighborhoods of favorably oriented grains. Annealing twin boundaries, prevalent in the microstructure, appear to be important in cyclic strain localization.

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Fatigue Crack Initiation In WASPALOY at 20 °C

Cited by 59 publications

References 18 publications

Tailoring the Properties of a Ni-Based Superalloy via Modification of the Forging Process: an ICME Approach to Fatigue Performance

Tailoring the Properties of a Ni-Based Superalloy via Modification of the Forging Process: an ICME Approach to Fatigue Performance

Material characterisation and finite element modelling of cyclic plasticity behaviour for 304 stainless steel using a crystal plasticity model

Fatigue Crack Initiation in Nickel-Based Superalloy Ren� 88 DT at 593�C

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