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arXiv · 2109.02402

Low-cycle fatigue of a nickel-based superalloy at high temperature: Simplified micromechanical modelling

Valerie Brien·L. Kubin·B. Décamps
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Abstract

This work is focused on the micromechanical modelling of the low cycle fatigue of the nickel based $γ/γ'$ superalloy AM1 at high temperature. The nature of the activated slip systems in the different types of channels of the $γ$ phase is analysed, taking into account the combined effects of the applied and internal stresses. The latter are split into two contributions, misfit stresses and compatibility stresses between the elastic $γ'$ phase and the elasto-plastic $γ$ phase, which are estimated within a simplified composite approach. Internal stresses may induce slip activity and/or be relaxed by it, which results in a complex sequence of slip activation events in the different channels under increasing applied stress. The consideration of these effects leads to a prediction of the nature and distribution of the active slip systems within the channels in [001] tension, compression and during low cycle fatigue. The resulting microstructural behaviour and its consequences regarding the anisotropic nature of the coalescence of the $γ'$ precipitates are discussed with respect to the available experimental data.

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Valerie Brien, L. Kubin, B. Décamps. 2021-09-06. Low-cycle fatigue of a nickel-based superalloy at high temperature: Simplified micromechanical modelling. https://doi.org/10.1080/01418610108217148

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