Incorporating strain gradient effects in a multiscale constitutive framework for nickel-base superalloys

Abstract

An efficient multiscale constitutive framework for nickel-base superalloys is proposed that enables the incorporation of strain gradient effects. Special interface regions in the unit cell contain the plastic strain gradients that govern the development of internal stresses. The model is shown to accurately simulate the experimentally observed size effects in the commercial alloy CMSX-4. The limited complexity of the proposed unit cell and the micromechanical simplifications make the framework particularly efficient in a multiscale approach. This is demonstrated by applying the model in a gas turbine blade finite element analysis.

Keywords:

• crystal plasticity
• strain gradients
• superalloys
• dislocations
• size effects

Acknowledgements

The authors want to acknowledge the National Aerospace Laboratory NLR for facilitating this research and the Ministry of Defence for funding part of this research under contract NTP N02/12.