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Abstract

The 3D discrete dislocation dynamics (DDD) method has been used to investigate the creep behavior of cobalt-base superalloy single crystal in different temperature and stress regions. In the simulation a representative volume element has been generated to consider the characteristic γ/γ’ microstructure of superalloys. Based on this RVE, the internal stress due to the lattice misfit between γ and γ’ phase has been calculated by the fast Fourier transformation approach. Through considering the external load and the internal stress at the same time, dislocation patterns in the phase boundary, dislocation density evolutions inside different γ channels, γ’ precipitate cutting by dislocation pairs, and rafting formation have been carried out. With the help of the 3D-DDD simulation, the creep properties of cobalt-base and nickel-based superalloy single crystals have been compared.