Impact of compressive hold on out‐of‐phase thermomechanical fatigue crack growth in <scp>IN</scp> 718

Radzicki, Andrew T.; Johnson, WS; Neu, Richard W.; Annigeri, Balkrishna S.; Ziegler, B.

doi:10.1111/ffe.12584

Cited by 9 publications

(8 citation statements)

References 25 publications

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“…Using the consortium spectrum, shown in Figure 7, compressive holds at elevated temperature were shown to have no accelerating effect on FCGR [23]. Additionally, using the isothermal spectrum, shown in Figure 5, tensile holds at 75% of the prior cyclic maximum load or less did not show development of a TAZ.…”

Section: Spectrum Effects On Taz Developmentmentioning

confidence: 97%

Predictive Modeling of Arbitrary Loaded TMF Crack Growth in Superalloys

Johnson

Neu

Radzicki³

et al. 2018

MATEC Web Conf.

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Abstract. Hot sections in turbine engines are subjected to large variations in temperatures and mechanical/thermal loadings. As such, accurate predictions of fatigue crack growth must account for many physical phenomena: temperature dependent crack growth behavior, load interaction history effects, time at temperature effects, temperature history effects, and the effects of stress/temperature/time on the materials. Through extensive experimental work on superalloys, a very definite "temperature history effect" on the resulting crack growth behavior has been identified and modeled. This work also identified a Temperature Affected Zone (TAZ) that occurs ahead of the crack tip and affects subsequent crack growth rates. The size of the TAZ is dependent on temperature, hold time, and stress state. Measurements of the TAZ were made under various conditions. The changes that occur in this TAZ are a combination of oxidation and material microstructure evolution. Various simplified "hot section" engine spectra (changing temperatures and stress levels) were tested to determine resulting crack growth behavior. Correlation between the experiments and model predictions were good and generally conservative.

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Section: Spectrum Effects On Taz Developmentmentioning

confidence: 97%

Predictive Modeling of Arbitrary Loaded TMF Crack Growth in Superalloys

Johnson

Neu

Radzicki³

et al. 2018

MATEC Web Conf.

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“…When it comes to TMF crack growth testing of single crystal superalloys, no previous publications were found. Some research has however been done regarding the crack growth behaviour of polycrystalline nickel base alloys under TMF conditions 58,59,60,61,62,63,64 . There are numerous publications regarding isothermal fatigue crack growth in single crystal nickel base super alloys.…”

Section: Fatigue Crack Propagation Of Single Crystal Superalloysmentioning

confidence: 99%

“…TMF of nickel base superalloys has been studied previously, but the majority of the work has been concerning the cyclic deformation behaviour and crack initiation life 15,16,17,18,19,20,21,22,23,24,25,26,27,28 . Only limited work has been done to study the crack growth behaviour under TMF conditions 29,30,31,32,33,34 . In the present work, TMF crack growth testing is performed and a method is developed to experimentally evaluate the crack opening stress under TMF conditions.…”

Section: Part 1 Background and Metodology 1 Introductionmentioning

confidence: 99%

Crack growth in single crystal nickel base superalloys under isothermal and thermomechanical fatigue

Palmert

2019

Linköping Studies in Science and Technology. Licentiate Thesis

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This work concerns the fatigue crack growth behaviour of nickel base single crystal superalloys. The main industrial application of this class of materials is in gas turbine blades, where the ability to withstand severe mechanical loading in combination with high temperatures is required. In order to ensure the structural integrity of gas turbine blades, knowledge of the fatigue crack growth behaviour under service-like conditions is of utmost importance. The aim of the present work is both to improve the understanding of the crack growth behaviour of single crystal superalloys and also to improve the testing and evaluation methodology for crack propagation under thermomechanical fatigue loading conditions. Single crystal superalloys have anisotropic mechanical properties and are prone to localization of inelastic deformation along the close-packed planes of the crystal lattice. Under some conditions, crystallographic crack growth occurs along these planes and this is a complicating factor throughout the whole chain of crack propagation life simulation; from material data generation to component calculation. Fatigue crack growth testing has been performed, both using conventional isothermal testing methods and also using thermomechanical fatigue crack growth testing. Experimental observations regarding crystallographic crack growth have been made and its dependence on crystal orientation and testing temperature has been investigated. Quantitative crack growth data are however only presented for the case of Mode I crack growth under isothermal as well as thermomechanical fatigue conditions. Microstructural investigations have been undertaken to investigate the deformation mechanisms governing the crack growth behaviour. A compliance based method for the evaluation of crack opening force under thermomechanical fatigue conditions was developed, in order to enable a detailed analysis of the test data. The crack opening force evaluation proved to be of key importance in the understanding of the crack driving force under different testing conditions. vi vii

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“…TMF of nickel base superalloys has been studied previously, but the majority of the work has been concerning the cyclic deformation behaviour and crack initiation life [17][18][19][20][21][22][23][24][25][26][27][28][29][30] . Only limited work has been done to study the crack growth behaviour under TMF conditions [31][32][33][34][35][36] . In the present work, TMF crack growth testing is performed, and a method is developed to experimentally evaluate the crack opening stress under TMF conditions.…”

Section: Introductionmentioning

confidence: 99%