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Session: Poster pitches day 2
Session starts: Tuesday 27 June, 10:00
Presentation starts: 10:00
Room: Theatre room: plenary

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Pin Lu ()
Xiaochao Jin ()
Xueling Fan ()

Abstract:
Ni-based single crystal has been used as the critical hot-end components of aeroengine due to the excellent mechanical properties. In addition, the finite element method is widely used in performance assessment of hot-end components in engineering applications. Therefore, it is of great significance to construct a constitutive model that can accurately capture the mechanical response of Ni-based single crystals for simulation analysis. In this work, a dislocation density-based single crystal plasticity constitutive model was developed to capture the temperature dependent anomalous yield and tension/compression asymmetry behaviour of Ni-based single crystals. Firstly, thermally activated cross-slip mechanism, which was considered as the main inducement of anomalous yield behaviour, was introduced into the hardening model. Secondly, the transformation of dislocation motion mode from shearing to by-passing was described using a temperature dependent function. Thirdly, non-Schmid stress tensors were introduced into the constitutive model to describe the tension/compression asymmetric phenomenon. The model considers the contributions of various strengthening mechanisms, including solid solution, precipitates and base metal. Furthermore, the evolution of microstructural features (such as dislocation density, etc.) and contribution of each mechanism to yield stress with increasing temperature were further analyzed. The model has been implemented via crystal plasticity framework and can accurately predict the temperature dependent anomalous characteristics of yield stress of Ni-based single crystal. This work provides a basis for accurately describing and predicting the cyclic loading behaviour of Ni-based single crystals.