Modelling of ion beam mixing with phase separation - Simulation of damage formation and thermally activated relaxation

Until now, damage formation and thermally activated relaxation are calculated by different atomistic methods like Binary Collision Approximation (BCA) and kinetic Monte Carlo (kMC), respectively. However, frequently damage formation and relaxation happens simultaneously. Molecular Dynamics (MD), which treats both processes, can not describe them on experimental spatiotemporal scales due to insufficient computer power. Here, an unified BCA-kMC simulation method will be presented and applied to ion-induced mixing and phase separation of intermetallic compounds. In particular we will show the importance of employing these two approaches into one algorithm by studies of two contrary systems. We irradiate Al/Pb with He ions causing ballistic interface mixing. Additionally, creation of Al and Pb clusters can be observed due to the bulk thermal diffusion driving the system to the equilibrium. On the other hand, strongly enhanced intermixing in an ordering compound, like PtCo, after the He irradiation is observed. This effect cannot be understood by purely collisional results alone, and therefore the high miscibility of the system has to be taken into account.