Stability and mobility of small vacancy and copper-vacancy clusters in bcc-Fe: An atomistic kinetic Monte Carlo study

Mobility and stability of small vacancy (V) and copper-vacancy (Cu-V) clusters determine the microstructural evolution of Fe-Cu alloys under irradiation, but these are largely unknown, experimentally unmeasurable parameters. They have therefore been determined using atomistic kinetic Monte Carlo simulations, where the vacancy jump activation energies vs local atomic environment was previously calculated using a molecular dynamics (MD) code and tabulated . This method allowed relaxation effects to be implicitly included and possible differences between the predictions of different potentials to be evaluated. In this work the mobility, lifetime and mean free path of clusters containing up to six Vs and Cu-V complexes containing up to four components has been studied. In the case of the VV and CuV pairs, the results obtained with different many-body potentials are compared with ab initio results. All results are briefly discussed in terms of their impact on microstructure evolution in irradiate FeCu alloys.