关键词: nickel-based single crystal superalloys, elastic-plastic behavior, dislocations, molecular dynamics simulation

Abstract: The effects of temperature and Re content on the mechanical properties, dislocation morphology, and deformation mechanism of $\gamma $-$\gamma ' $ phases nickel-based single crystal superalloys are investigated by using the molecular dynamics method through the model of $\gamma $-$\gamma ' $ phases containing hole defect. The addition of Re makes the dislocation distribution tend towards the $\gamma $ phase. The higher the Re content, the earlier the $\gamma $ phase yields, while the $\gamma '$ phase yields later. Dislocation bends under the combined action of the applied force and the resistance of the Re atoms to form a bend point. The Re atoms are located at the bend points and strengthen the alloy by fixing the dislocation and preventing it from cutting the $\gamma '$ phase. Dislocations nucleate first in the $\gamma $ phase, causing the $\gamma $ phase to deform plastically before the $\gamma '$ phase. As the strain increases, the dislocation length first remains unchanged, then increases rapidly, and finally fluctuates and changes. The dislocation lengths in the $\gamma $ phase are larger than those in the $\gamma ' $ phase at different temperatures. The dislocation length shows a decreasing tendency with the increase of the temperature. Temperature can affect movement of the dislocation, and superalloys have different plastic deformation mechanisms at low, medium and high temperatures.

Key words: nickel-based single crystal superalloys, elastic-plastic behavior, dislocations, molecular dynamics simulation