Atomic simulation of the effect of orientation on tensile/compressive properties in nickel-based single crystal superalloys

Abstract

Nickel-based single crystal superalloys reveal obvious anisotropy and orientation correlation. Choosing the orientation with the best mechanical properties is beneficial to prolong its service life. In this paper, the effects of crystal orientation on the plastic deformation and mechanical properties of the nickel-based single crystal two-phase model under uniaxial tension/compression were simulated by molecular dynamics. The microstructure evolution and dislocation movement are studied through stress-strain response and structural changes of the two phases with different crystal orientations. In addition, the typical dislocation structures are analyzed, it is found that the yield stress of different orientation models is: [111] > [001] > [011]. Different orientation models all show tension/compression asymmetry and the [001] orientation is the most obvious. The results showed that the evolution of dislocation and stacking faults is one of the reasons which causes the crystal anisotropy.