Modelling the orientation and direction dependence of the critical resolved shear stress of nickel-base superalloy single crystals

Österle, Werner; Bettge, Dirk; Fedelich, Bernard; Klingelhöffer, Hellmuth

doi:10.1016/s1359-6454(99)00404-8

Cited by 89 publications

(36 citation statements)

References 17 publications

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“…Therefore, only a small fraction of the simulated volume is deformed plastically and a significant strain incompatibility is expected. [7,10,19]. Two distinct stages can be observed.…”

Section: Loading Conditionsmentioning

confidence: 99%

“…for crystals oriented with one of the h1 1 1i axes along the loading direction, {1 0 0} slip traces have been observed within the channels. Activation of cube slip systems has important consequences for the models of the orientation-dependence of the mechanical response [14][15][16][17][18][19]. Adopting cube slip is a convenient scheme to account for the softer plastic response of nonh0 0 1i oriented specimens.…”

Section: Introductionmentioning

confidence: 99%

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Orientation dependence of plastic deformation in nickel-based single crystal superalloys: Discrete–continuous model simulations

2010

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“…Therefore, only a small fraction of the simulated volume is deformed plastically and a significant strain incompatibility is expected. [7,10,19]. Two distinct stages can be observed.…”

Section: Loading Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Orientation dependence of plastic deformation in nickel-based single crystal superalloys: Discrete–continuous model simulations

2010

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“…room temperature, and high volume fractions of small y7 precipitates, plastic deformation has been suggested to begin in the y'-phase [9]. Several studies have demonstrated that the break down of Schmid law is a characteristic feature not only for the y'-phase with the L12 structure, but also for all superalloys containing a high, medium or even low volume fraction of the 7'-phase [10,11]. It has been shown that the degree of anisotropy depends on the test temperature as well as the size and shape of the y'-precipitates [2,12] The yielding anisotropy of the superalloys has been attributed to the non-Schmid effect of the y'-precipitates [13].…”

Section: Introductionmentioning

confidence: 99%

Slip analysis in a Ni-base superalloy

2005

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A Ni-base superalloy single crystal with y/y' structure was tested at room temperature along the , <110> and <111> directions. Consistent with previously reported investigations, this alloy did not obey the Schmid law and the CRSS (critical resolved shear stress) was noticeably lower for the < 1 1 1 >-oriented samples. Furthermore, the strain hardening rate decreased and the degree of deformation localization increased in the order of <111>, and <110> orientations. The appearance and orientation of deformation traces were found to depend on the loading orientation as well as the amount of strain. In general, when y'-particles were sheared, the traces followed the expected octahedral shear planes. It is demonstrated that the wavy deformation traces that do not follow the { 11 1 ] planes are associated with changes in the y-channels width and the falling off of the ;/'-particles. In this paper the evolution of deformation bands are discussed in terms of plastic localization at microscopic, mesoscopic and macroscopic levels.

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“…Cube slip for the γ matrix is included primarily to reflect zig-zag cross slip, as noted by Osterle and Bettge (2000). The structure of the evolution equation for dislocation density is similar to that of the precipitate phase, except that no locking or unlocking terms are present.…”

Section: Model Frameworkmentioning

confidence: 99%

Effects of Microstructure Variability on Intrinsic Fatigue Resistance of Nickel-base Superalloys – A Computational Micromechanics Approach

2006

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Understanding the effects of microstructure variability on fatigue resistance is a key to selection and design of materials for fatigue applications. The traditional empirical approach rooted in experiments is being increasingly combined with systematic computational modeling. This work is concerned with demonstrating the feasibility of linking effects of microstructure variability on cyclic plasticity at the scale of intrinsic microstructure of a single crystal nickel-base superalloy. The precipitate and the matrix phases of the alloy are modeled explicitly using a physically based crystal viscoplasticity constitutive framework with appropriate scale and spacing effects to reflect dislocationprecipitate interactions. The model is implemented as a user material subroutine within a finite element code. Various realizations of different microstructures are generated using a constrained Poisson point process. Statistical volume elements (SVEs) with random-periodic boundary conditions are simulated under fully reversed cyclic loading at 650 • C. Primary cooling γ precipitate size and volume fraction are considered in terms of their effects on the macroscopic stress-strain response and on distributed cyclic microplasticity within the SVE. To compare various microstructures in terms of probability of fatigue crack formation, an appropriate nonlocal measure of cyclic plastic shear strain range is proposed based on percolation of cyclic microplasticity at the scale of the SVE.

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Modelling the orientation and direction dependence of the critical resolved shear stress of nickel-base superalloy single crystals

Cited by 89 publications

References 17 publications

Orientation dependence of plastic deformation in nickel-based single crystal superalloys: Discrete–continuous model simulations

Orientation dependence of plastic deformation in nickel-based single crystal superalloys: Discrete–continuous model simulations

Slip analysis in a Ni-base superalloy

Effects of Microstructure Variability on Intrinsic Fatigue Resistance of Nickel-base Superalloys – A Computational Micromechanics Approach

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