The study of coupled diffusive-displacive processes like dislocation climb at the atomic scale is inherently challenging due to the vastly different time scales involved in the individual processes. One way to address this challenge is to extend the possible simulation timescales while keeping proper atomistic description of a system by using diffusive molecular dynamics (DMD). The method combines classical atomistic interaction potentials in the variational Gaussian method with a numerical solver for the diffusion equation on a variable grid given by the atom positions. Recently, various computational implementations of DMD were presented. Here we apply the DMD method to get an insight into the diffusion-based processes in Ni-based superalloys. To do this, we describe in detail the different implementations of DMD and provide benchmarks for their accuracy and efficiency based on simulations of vacancy diffusion at dislocations and dislocation climb processes in single crystal Ni. 

The authors gratefully acknowledge the financial support under the scope of the project SFB/Transregio 103 (project C3).