Modeling dislocation cutting the precipitate in nickel-based single crystal superalloy via the discrete dislocation dynamics with SISF dissociation scheme

摘要

In order to fully capture dislocation cutting the precipitate (γ′ phase) in the nickel-based single crystal superalloy servicing in a wide range of temperatures, the superlattice intrinsic stacking fault (SISF) dissociation scheme is introduced into the three-dimensional discrete dislocation dynamics (3D-DDD) simulation framework by employing a total energy-based criterion for the transition from anti-phase boundary (APB) dissociation scheme to SISF one. The computational results show that the present 3D-DDD extension can successfully capture two key stages of the transition from APB to SISF dissociation. This extended 3D-DDD framework is also used to predict the overall stress-strain response of nickel-based single crystal superalloys at two typical temperatures 293 K and 873 K. Compared with the stress-strain curves predicted by the 3D-DDD framework only with consideration of APB dissociation scheme, the results by this extended 3D-DDD framework with consideration of both SISF and APB dissociations are closer to experimental data.