[SY-F6] Symposium F-6

[SY-F6] 3D modeling of microstructure evolution in Ni-based superalloys under creep loading

^○Maeva Cottura¹, Benoît Appolaire¹, Alphonse Finel², Yann Le Bouar² (1.Institut Jean Lamour , France, 2.LEM - CNRS/Onera, France)

Many materials used in everyday life have a complex internal structure organized at different scales with a texture of grains, and a complex pattern of thermodynamic phases at lower scale. This microstructure strongly impacts the movement of crystalline defects in the materials and therefore controls the mechanical behaviour. The phase field method has emerged as a well-suited method for tackling microstructure evolutions during phase transformations when elastic coherency stresses are generated. In addition, in many materials and especially at high temperature, the microstructure evolution is coupled with plasticity, and there is currently a great research effort to extend the phase field method to take this coupling into account.
In this context, we will show how to couple a classical phase field model (for the description of the phase transformation) with a crystal plasticity model based on dislocation densities. The latter model uses a storage-recovery law for the dislocation density of each glide system and a hardening matrix to account for the short-range interactions between dislocations. The proposed model will be applied to study rafting of ordered precipitates observed in Ni-based superalloys. We will present 3D calculations of microstructure evolution under [100], [110] and [111] creep loading as well as different shear creep tests.