Multi-Scale Computer Simulation of Dislocation Motion in Nickel Base Superalloy

Abstract

Multi-scale computer simulation technique is applied to the study of the dislocation behavior in nickel base superalloys. The keys of this simulation are the modeling of the interactions of dislocations with γ' precipitates, and the treatment of complicated behavior of dislocations in complex microstructure of nickel base superalloy. The strength of a γ' particle as an obstacle to dislocation motion is calculated by means of molecular dynamics (MD) simulations. The strength of a γ' cube is modeled basing on the consideration of the energy increase by the formation of anti-phase boundary due to cut of the γ' phase by a dislocation. These models are implemented into the dislocation dynamics (DD) code, which is very successfully applied in this study to the simulations of the evolution of the dislocation microstructures with different γ' obstacle arrangements. The present simulations clearly demonstrate that the multi-scale computer simulation strategy has capability to predict mechanical property such as stress-strain relationship starting from atomistic-level information on the dislocation-obstacle interaction. This technique should be very promising to understand the fundamental mechanisms of dislocation behavior in other materials.