Prediction of crystallographic cracking planes in single-crystal nickel-base superalloys

Busse, Christian; Palmert, Frans; Sjödin, Björn; Almroth, Per; Gustafsson, David; Simonsson, Kjell; Leidermark, Daniel

doi:10.1016/j.engfracmech.2018.04.047

Cited by 13 publications

(29 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The calibration parameter necessary to predict the correct crystallographic cracking plane after a transition from Mode I cracking, as described in [14], was initially set to a value of 0.1 based on experimental results. In the referenced study, the RSIF was calculated along a Mode I crack and not along crystallographic crack fronts as in the current study.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Crystallographic crack propagation rate in single-crystal nickelbase superalloys

et al. 2018

View full text Add to dashboard Cite

Single-crystal nickel-base superalloys are often used in the hot sections of gas turbines due to their good mechanical properties at high temperatures such as enhanced creep resistance. However, the anisotropic material properties of these materials bring many difficulties in terms of modelling and crack growth prediction. Cracks tend to switch cracking mode from Mode I cracking to crystallographic cracking. Crystallographic crack growth is often associated with a decrease in crack propagation life compared to Mode I cracking and this must be taken into account for reliable component lifing. In this paper a method to evaluate the crystallographic crack propagation rate related to a crystallographic crack driving force parameter is presented. The crystallographic crack growth rate is determined by an evaluation of heat tints on the fracture surface of a specimen subjected to fatigue loading. The complicated crack geometry including two crystallographic crack fronts is modelled in a three dimensional finite element context. The crack driving force parameter is determined by calculating anisotropic stress intensity factors along the two crystallographic crack fronts by finite-element simulations and post-processing the data in a fracture mechanics tool that resolves the stress intensity factors on the crystallographic slip planes in the slip directions. The evaluated crack propagation rate shows a good correlation for both considered crystallographic cracks fronts.

show abstract

Section: Resultsmentioning

confidence: 99%

“…The superscript denotes that the stress tensor is scaled to account for Burgers' direction from which the crack front is approached, which does not necessarily lie in the plane orthogonal to the crack front. Further information and the definition of the tensor ′ is given in the submitted manuscript by Busse et al [14].…”

Section: The Equivalent Rsifmentioning

confidence: 99%

Crystallographic crack propagation rate in single-crystal nickelbase superalloys

et al. 2018

View full text Add to dashboard Cite

show abstract

“…The fatigue crack growth experiments were performed according to the test conditions shown in Table 2. Further details of the experimental procedure can be found in [25]. Note…”

Section: Materials and Experimentsmentioning

confidence: 99%

Evaluation of the crystallographic fatigue crack growth rate in a single-crystal nickel-base superalloy

Busse

Palmert

Sjödin

et al. 2019

International Journal of Fatigue

Self Cite

View full text Add to dashboard Cite

Cracks in single-crystal nickel-base superalloys have been observed to switch cracking mode from Mode I to crystallographic cracking. The crack propagation rate is usually higher on the crystallographic planes compared to Mode I, which is important to account for in crack growth life predictions. In this paper, a method to evaluate the crystallographic fatigue crack growth rate, based on a previously developed crystallographic crack driving force parameter, is presented. The crystallographic crack growth rate was determined by evaluating heat tints on the fracture surfaces of the test specimens from the experiments.Complicated crack geometries including multiple crystallographic crack fronts were modelled in a three dimensional finite element context. The data points of the crystallographic fatigue crack growth rate collapse on a narrow scatter band for the crystallographic cracks indicating a correlation with the previously developed crystallographic crack driving force.

show abstract

“…Modelling and test data evaluation for crystallographic crack growth is more complex than for Mode I crack growth. A crack driving force parameter for crystallographic crack growth has recently been proposed by Busse et al 40,41 .…”

Section: Crystallographic Crack Growthmentioning

confidence: 99%

Thermomechanical fatigue crack growth in a single crystal nickel base superalloy

Palmert

Gustafsson

2019

International Journal of Fatigue

View full text Add to dashboard Cite

Thermomechanical fatigue crack growth in a single crystal nickel base superalloy was studied. Tests were performed on single edge notched specimens, using in phase and out of phase thermomechanical fatigue cycling with temperature ranges of 100-750°C and 100-850°C and hold times at maximum temperature ranging from 10s to 6h. Isothermal testing at 100°C, 750°C and 850°C was also performed using the same test setup. A compliancebased method is proposed to experimentally evaluate the crack opening stress and thereby estimate the effective stress intensity factor range ΔKeff for both isothermal and nonisothermal conditions. For in phase thermomechanical fatigue, the crack growth rate is increased if a hold time is applied at the maximum temperature. By using the compliance-based crack opening evaluation, this increase in crack growth rate was explained by an increase in the effective stress intensity factor range which accelerated the cycle dependent crack growth. No significant difference in crack growth rate vs ΔKeff was observed between in phase thermomechanical fatigue tests and isothermal tests at the maximum temperature. For out of phase thermomechanical fatigue, the crack growth rate was insensitive to the maximum temperature and also to the length of hold time at maximum temperature. The crack growth rate vs ΔKeff during out of phase thermomechanical fatigue was significantly higher than during isothermal fatigue at the minimum temperature, even though the advancement of the crack presumably occurs at the same temperature.Dissolution of γ′ precipitates and recrystallization at the crack tip during out of phase thermomechanical fatigue is suggested as a likely explanation for this difference in crack growth rate.

show abstract

Prediction of crystallographic cracking planes in single-crystal nickel-base superalloys

Cited by 13 publications

References 40 publications

Crystallographic crack propagation rate in single-crystal nickelbase superalloys

Crystallographic crack propagation rate in single-crystal nickelbase superalloys

Evaluation of the crystallographic fatigue crack growth rate in a single-crystal nickel-base superalloy

Thermomechanical fatigue crack growth in a single crystal nickel base superalloy

Contact Info

Product

Resources

About