Introducing chemistry in atomistic kinetic Monte Carlo simulations of Fe alloys under irradiation

Abstract

The evolution of alloy microstructures under non-equilibrium conditions such as irradiation is an important academic as wellindustrial issue. Atomistic kinetic Monte Carlo is one of the most versatile method which can be used to simulate the evolution of a complex microstructure at the atomic scale, dealing with elementary atomic mechanisms. It was developed more than 40 years ago to investigate diffusion events via the motion of a single vacancy, and the introduction of heterointerstitials or self-interstitials in the models is yet under development. This paper presents the key ingredients of the model, i.e. the algorithm, and some methods implemented to determine the cohesive energy as well as the activation energy. For purpose of simplicity and speed of calculations, most of the models developed so far apply to idealized lattices and model alloys, for example binary alloys. The extension of the models to more complex alloys is recent and an example of the simulation of multi-component Fe-CuNiMnSi alloys representative of pressure vessel steels is thus presented in more details. In particular, the adjustment procedures of the cohesive model are demonstrated as well as the validation of the model for vacancies and self-interstitials on thermal ageing and isochronal annealing experiments.

Transport properties in dilute UN(X) solid solutions (X=Xe,Kr)

“…Binding energies are considered up to the 6NN, and all jump frequencies that were computed are used in the calculations (Table III). Of course, this DFT-computed set of migration barriers is not exhaustive, and all missing migration barriers needed as input in the SCMF formalism (mainly dissociation frequencies) are obtained via the commonly used kinetically resolved activation (KRA) barrier approximation 46,47 …”

Multiscale Modelling of Microstructure Evolution under Radiation Damage of Steels Based on Atomistic to Mesoscale Methods

“…Multi-scale modelling 1nm 3 0 -ps ns (10-30nm) 3 cm 3 µm 3 h-year The microstructure evolution under irradiation is obtained starting from the neutron spectrum to obtain the primary damage (displacement cascades), followed by the evolution of the point defects formed and their accumulation (Fig. 2).…”

“…In these atomic KMC simulations, both self interstitials and vacancies, isolated or in clusters, as well as carbon atoms are modelled [3]. The short term evolution of the microstructure is simulated.…”

On the interaction between radiation-induced defects and foreign interstitial atoms in α-iron

“…[4][5][6][7][8][9][10][11][12][13][14]). The ab initio calculations obtained the values of binding energy of V-C pairs ranging from 0.41 to 0.6 eV [10,12], while for V-N they were significantly higher, 0.7-0.85 eV [5,10].…”