Time: 02:30 p.m.
Place: 15th International Conference on Creep and Fracture of Engineering Materials and Structures
Creep resistance of superalloys at high temperature is one of the most important parameters defining the range of applicability of superalloys. A combination of thermodynamics and material diffusion with elasto-plasticity within the framework of phase-field allows us a depth and systematic analysis of creep behavior of superalloys. In order to investigate the creep properties of single crystal Ni-based superalloys during the evolution of microstructure, a dislocation-based strain gradient crystal plasticity model  is implemented. The model is calibrated against the experimental results of a creep test at a high temperature and low stress. Then, it is used to predict the kinetics of the microstructure up to 1% creep strain, in which diffusion is assumed to be controlled by the slowest diffusing element Rhenium Re . It is demonstrated that the loss of coherency between the matrix and the precipitate is crucial for the coalescence of the γ precipitate and initiation of rafting [3,4,5] and rotation of the γ matrix. It is further observed that highly localized shear bands were formed under high stresses and a tendency of rafting direction toward 45 degrees . Finally, sensitivity of microstructural topology and evolution kinetics towards creep properties of superalloys was analyzed [4,5]. The effect of pre-strained matrix on the evolution of γ precipitates is highlighted.
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