Molecular Dynamics Simulation of the Evolution of Interfacial Dislocation Network and Stress Distribution of a Ni-Based Single-Crystal Superalloy
YL Li and WP Wu and ZG Ruan, ACTA METALLURGICA SINICA-ENGLISH LETTERS, 29, 689-696 (2016).
The evolution of misfit dislocation network at gamma/gamma' phase interfaces and the stress distribution characteristics of Ni-based single-crystal superalloys under different temperatures of 0, 100 and 300 K are studied by molecular dynamics (MD) simulation. It was found that a closed three-dimensional misfit dislocation network appears on the gamma/gamma' phase interfaces, and the shape of the dislocation network is independent of the lattice mismatch. Under the influence of the temperature, the dislocation network gradually becomes irregular, a/2 110 dislocations in the c matrix phase emit and partly cut into the gamma' phase with the increase in temperature. The dislocation evolution is related to the local stress field, a peak stress occurs at gamma/gamma' phase interface, and with the increase in temperature and relaxation times, the stress in the c phase gradually increases, the number of dislocations in the c phase increases and cuts into gamma' phase from the interfaces where dislocation network is damaged. The results provide important information for understanding the temperature dependence of the dislocation evolution and mechanical properties of Ni- based single-crystal superalloys.
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