Orientation dependence of microstructure deformation mechanism and tensile mechanical properties of Nickel-based single crystal superalloys: A molecular dynamics simulation

Abstract

In this paper, molecular dynamics (MD) simulations are performed to investigate the tensile deformation mechanisms and mechanical properties of superalloys with different orientations. The research results show that the superalloys exhibit anisotropy of mechanical properties and are consistent with previous experimental research results. The anisotropy of mechanical properties is related to the differences of stability at the interfacial dislocation network and the 1/6〈112〉{111} slip system startup of superalloys with different orientations. When the yield point is reached, dislocations and stacking faults on both sides of the slip plane will contact each other and merge into a stacking fault band to penetrate into the γ' precipitates. Meanwhile, the dislocation density and the proportion of face-centered cubic (FCC) structure with different orientation models have a sudden change at the yield point. As the temperature increases, the yield strength and elastic modulus decrease in the (110) and (111) orientation models, whereas the (100) orientation model has an anomalous yield behavior. This is mainly related to the destruction of dislocation network, the change of deformation mechanism and the thermally activated cross-slip mechanism when the temperature increases.