Modeling of the Effect of Secondary Orientation on the Micro Deformation Behavior of Ni-Based Single Crystal Superalloys

Abstract

In this paper, a supercell modeling of secondary orientation was established using 90 cubic mosaic units made up of γ’ phase embedded in γ matrix, in accordance with an actual structure of Ni-based single crystal superalloys (NSCS). The effects of secondary orientation on the deformation behavior and microstructure evolution of NSCS under uniaxial tensile were studied by a three-dimensional molecular dynamics (MD) simulation. Simulation results showed that secondary orientation had a significant effect on mechanical properties of NSCS, that is, a big fluctuation was found in tensile strength which dropped down almost 50% from a peak (corresponding to the secondary orientations of 18° and 45°) to a trough (those of 34° and 63°). Mechanisms of secondary orientation affecting the deformation behavior were further discussed systematically. The deformation of NSCS under uniaxial tensile was a process tending towards amorphization of microstructure, together with the dislocation formation, merging and break-up. On a micro viewpoint, this work for us will be useful to apprehend the tensile deformation conduct of NSCS.

Keywords

• Ni-based single crystal superalloys
• secondary orientation
• dislocations
• tensile properties
• molecular dynamics (MD)