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.
Highlights
Ni-based single crystal superalloys (NSCS) is the most commonly used material for turbine blades of advanced aero-engines today [1,2,3,4,5,6], and most single crystal turbine blades are produced by casting that entails controlling the growth direction of the principal stress axis [7]
Wang et al [19] further studied the effects of secondary orientations on thermal fatigue behavior of an NSCS turbine blade and found that fatigue cracks initiate from stress concentration regions which are affected by the secondary orientation
Both have a bilinear characteristic before and after yielding, and it is found that secondary orientation has a significant influence on the deformation behavior of NSCS in the elastic stage, and the plastic stage
Summary
NSCS is the most commonly used material for turbine blades of advanced aero-engines today [1,2,3,4,5,6], and most single crystal turbine blades are produced by casting that entails controlling the growth direction of the principal stress axis [7]. The prediction and optimization of secondary orientation may be a potential way to further improve the mechanical properties of single crystal blades. Wang et al [19] further studied the effects of secondary orientations on thermal fatigue behavior of an NSCS turbine blade and found that fatigue cracks initiate from stress concentration regions which are affected by the secondary orientation. Most above research has all shown that MD was an effective way to simulate the damage process Those MD models developed with NSCS were mainly based on a two-layer or a sandwich structure simulation [30,31], without considering the actual structure (γ’ phase embedded in γ matrix) characteristic of NSCS, leading to inaccurate mechanical properties and difficulty predicting the real deformation behavior. This work will be meaningful to understand the secondary orientation effection and deformation mechanism in NSCS
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
