Development and Characterization of a Damage Tolerant Microstructure for a Nickel Base Turbine Disc Alloy

Kearsey, Rick; Koul, A. K.; Beddoes, J.; Cooper, Christopher R.

doi:10.7449/2000/superalloys_2000_117_126

Cited by 3 publications

(2 citation statements)

References 9 publications

(1 reference statement)

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“…Traditionally, turbine disks are designed for a finite life using low-cycle fatigue (LCF) criterion under the safe-life design approach. The safe-life approach considers components to be automatically exhausted after 0.1% of the components have initiated a crack of 0.79 mm (1/32 in) in length [1]. However, some premature material damage may occur due to handling, machining damage, fretting, or inherent defects, causing cracks to propagate and become critical during the predicted "safe-life" [2].…”

Section: Introductionmentioning

confidence: 99%

Probabilistic Risk Assessment for Life Extension of Turbine Engine Rotors

Carter

Goswami

2022

Metals

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Maintaining the component service life beyond its historical limits requires the ability to accurately quantify component reliability and address the uncertainties in material responses. A probabilistic method for predicting the total fatigue life was developed and applied to determine the probability of failure of a Ti-6Al-4V turbine disk component. The total fatigue life incorporates a dual mechanism approach including the crack initiation life and propagation life while simultaneously determining the associated initial flaw sizes. A microstructure-based model was employed to address the uncertainties in material response and relate the crack initiation life with crack size. The propagation life was characterized using both small and large crack growth models to ensure accurate fatigue life prediction. Fatigue life predictions were found to correlate with experimental data at high stress levels. The risk assessment can be used to estimate the expected initial crack sizes from variability in material properties, which can further be used to establish an enhanced inspection planning.

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Section: Introductionmentioning

confidence: 99%

Probabilistic Risk Assessment for Life Extension of Turbine Engine Rotors

Carter

Goswami

2022

Metals

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“…Past results of researches carried out on PWA1113 have shown that the complex flowery γ ′ morphology was beneficial to improve the mechanical properties. 22,23 Therefore, it is of great importance to study the flowery γ ′ evolution during aging in wrought superalloys.…”

Section: Introductionmentioning

confidence: 99%

Morphology evolution of unstable γ′ in Ni–Co based superalloy

Tian

Cui

et al. 2014

Materials Science and Technology

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The evolution of γ′ morphology was investigated during cooling and isothermal aging in a newly developed Ni–Co based wrought superalloy. The results showed that unstable flowery γ′ precipitated at a cooling rate of 5°C min−1 and became stable during isothermal aging, and its shape was either spherical or cuboidal depending on the aging temperatures. The evolution mechanism of γ′ morphology was discussed in terms of the diffusion effects, the elastic strain energy and the γ′/ γ interface energy.

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Prediction of creep properties for two nickel-base superalloys from stress relaxation testing

Beddoes

2011

The Journal of Strain Analysis for Engineering Design

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The creep properties derived from stress relaxation tests are compared to those from creep tests in the temperature range from 705 °C to 800 °C and stresses from 200 MPa to 750 MPa for the nickel base superalloys IN738LC and modified Waspaloy. The creep behaviour of IN738LC exhibits an extended period of steady state strain rate, while creep of modified Waspaloy exhibits only a minimum creep strain rate. The results indicate that stress relaxation tests can be used to estimate the creep steady state or minimum strain rates, time to 1 per cent creep strain, and the creep stress exponent for both superalloys. Stress relaxation tests can generate these properties in a significantly more time-efficient and specimen-efficient manner than creep tests, regardless of whether the superalloy creep behaviour exhibits a steady state or minimum creep strain rate.

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Development and Characterization of a Damage Tolerant Microstructure for a Nickel Base Turbine Disc Alloy

Cited by 3 publications

References 9 publications

Probabilistic Risk Assessment for Life Extension of Turbine Engine Rotors

Probabilistic Risk Assessment for Life Extension of Turbine Engine Rotors

Morphology evolution of unstable γ′ in Ni–Co based superalloy

Prediction of creep properties for two nickel-base superalloys from stress relaxation testing

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