Atomistic simulation of strength properties of conventional and nano-structured materials

Abstract

State-of-the-art supercomputing technologies allow addressing the problem of materials design and their properties change due to processing, storage and exploitation to direct large-scale Molecular Dynamics (MD) simulations. In the first part of the paper, by the example of fission materials we demonstrate the chain of MD simulation techniques developed to evaluate material properties change due to self-irradiation (so-called ageing). Starting from detailed microscopic Monte Carlo + MD calculations of damage cascade development and annealing resulting in a system of Primary Radiation Defects (PRD), the problems of PRD and radiogenic products accumulation and clustering are resolved by the application of Thermodynamic Integration Method. Finally, virtual samples of a material containing defects of determined morphology corresponding to a given age are subjected to a ‘mechanical loading’ to evaluate the effect of self-irradiation on mechanical strength properties. In the second part we consider issues of MD simulations of nano-structured materials, including effects of samples processing history (dislocation density) on mechanical properties, solidification and thermal recrystallization, as well as resistance to radiation loading. In conclusion the prospects of application of the techniques to structural materials which are, as a rule, multi-component aggregates are discussed with a number of straightforward examples.