Simulation study and experiment verification of the creep mechanism of a nickel-based single crystal superalloy obtained from microstructural evolution
JG Yu and SM Zhang and QX Zhang and R Liu and MK Tang and XW Li, RSC ADVANCES, 6, 107748-107758 (2016).
Molecular dynamics (MD) simulations and experiments were used to understand the creep properties and microstructural evolution of a nickel-based single crystal superalloy. By observing the microstructural evolution using MD simulations, we have found a P-type rafting in the 001 crystal orientation owing to dislocations cutting into the gamma' phase. The deflected gamma phases lead to an L-type rafting, indicating it is an inferior creep property in the 011 crystal orientation. Unlike the 001 and 011 crystal orientations, dislocations climb over to the gamma' phase without rafting in the 111 crystal orientation, which manifests a superior creep property. In addition, by comparing the effect between temperature and stress on the creep properties, the results suggest that the creep of the 111 crystal orientation was strongly influenced by stress, whereas the creep properties of the 001 and 011 crystal orientations were significantly affected by temperature. Furthermore, the experimental results are consistent with the MD simulations. This study provides fundamental guidance for the rational design and testing of nickel base single crystal superalloy for structural applications.
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