Crystal plasticity phase-field simulation of rafting and creep properties with a continuous change of the mismatch strain in a Co-Al-W superalloy

Abstract The lattice mismatch strain between the precipitates and matrix has an essential effect on the creep morphology and properties of Co-based superalloys. The rafting morphology with a continuous change of the mismatch strain is clearly presented in a Co-10Al-8W at.% alloy by utilizing crystal plasticity phase-field simulation. The large mismatch strain accelerates the rafting of γ′-Co3(Al, W) phases, the hardening effect caused by eigenstrain elevates the creep properties in the initial creep stage, while the accumulation of damage variable induced by large eigenstrain reduces the creep life in tertiary creep stage. These results suggest that the suitable lattice mismatch is beneficial for the creep properties of superalloys.