Modelling materials driven far from equilibrium

Materials driven from equilibrium offer a challenging field for both time and space multiscale modelling. In materials under irradiation the elementary damaging process, that is, the nuclear collision leading to the displacement cascade, is modelled by molecular dynamics (≈ 10 ps, 103 nm3), whereas the later stage recovery process is modelled by kinetic Monte Carlo (≈ years, 104 nm3); at still a coarser scale, grain boundary segregations are modelled by a meanfield approximation of the very same atomistic model as used in kinetic Monte Carlo modelling. Connecting this broad range of time scales helps to elucidate basic issues on the criteria for alloy stability under irradiation. Irradiation effects on plasticity are beginning to be modelled in the same spirit; a first molecular dynamics study of the interaction of cascade debris with gliding dislocations has been reported together with the first results of mesoscale modelling of dislocation dynamics in the course of a nanoindentation test. Such studies can be extended to materials processed by ball milling.