A non-Schmid crystal plasticity finite element approach to multi-scale modeling of nickel-based superalloys

This paper develops non-Schmid crystal plasticity constitutive models at two length scales, and bridges them in a multi-scale framework. The constitutive models address thermo-mechanical behavior of Nickel-based superalloys for a large temperature range, viz. 300 K–1223 K, and include orientation de...

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Bibliographic Details
Published in:Acta materialia 2016-08, Vol.114, p.106-115
Main Authors: Keshavarz, Shahriyar, Ghosh, Somnath, Reid, Andrew C.E., Langer, Stephen A.
Format: Article
Language:English
Subjects:
Computer simulation
Constitutive relationships
Crystal plasticity
Crystals
Homogenization
Homogenizing
Mathematical models
Morphology
Ni-based superalloys
Non-Schmid
Orientation
Plasticity
Superalloys
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Summary:This paper develops non-Schmid crystal plasticity constitutive models at two length scales, and bridges them in a multi-scale framework. The constitutive models address thermo-mechanical behavior of Nickel-based superalloys for a large temperature range, viz. 300 K–1223 K, and include orientation dependencies and tension-compression asymmetry. The orientation dependencies result in tension-compression asymmetry for almost all orientations on the standard unit triangle. However simulations show different trends for the stronger direction (tension or compression) in terms of yield stress and hardening. The multi-scale framework includes two sub-grain and homogenized grain scales. For the sub-grain scale, a size-dependent, dislocation density-based FEM model of the representative volume element (RVE) with explicit depiction of the γ-γ′ morphology is developed as a building block for homogenization. For the next scale, an activation energy based crystal plasticity (AE-CP) model is developed for single crystal Ni-based superalloys. The homogenized AE-CP model develops functional forms of constitutive parameters in terms of characteristics of the sub-grain γ-γ′ microstructural morphology including γ′ shape, volume fraction and γ channel-width in the sub-grain microstructure. This homogenized model can significantly expedite crystal plasticity FE simulations due to the parametrized representation, while retaining accuracy. [Display omitted]
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2016.05.016