Multiscale modelling of radiation effects in MgAl2O4 spinel and general oxides (2014 - 2020)
Project coordinator Dr. habil. phys. Eugene Kotomin
- Dr.habil. phys. V. Kuzovkov
- Dr. phys. A. Popov
- Dr.phys. G. Zvejnieks
- Dr.phys. S. Piskunov
- Dr.phys. Y. Mastrikov
- Dr.phys. O. Dumbrajs
- Ph.D. A. Chesnokov
Duration (years) 2014-2020
Radiation resistant insulating materials are important components of the future fusion reactors, including elements of diagnostics, coating etc. Study of radiation damage in these functional materials are of special importance. In this project related to topic of MATERIALS (WPMAT) in Eurofusion activities, we focus on several promising materials, first of all, Al2O3 (sapphire) and spinels. Our multiscale activities combine first principles atomistic modeling of primary radiation defects and their basic properties, and the kinetics of radiation damage and metal colloid formation under powerful radiation.
Radiation resistivity of oxide materials depends critically on created defects. We performed first principles calculations of hole and interstitial defects in MgAl2O4 spinel, in order to understand the role of anti-site defects. We calculated the atomic, electronic structure and charge redistribution and suggested interpretation to experimental data obtained by partners in Estonia and Spain. Calculations of the interstitial oxygen migration in spinel shows that the activation energy is smaller in a charged state rather as a neutral atom. A similar conclusion was drawn earlier for sapphire.
We analysed experimental data for radiation defect annealing in MgAl2O4 spinel – both single crystals and ceramics with different grain sizes - and demonstrated strong correlation between the effective diffusion energy and pre-exponential factor which depends strongly on the radiation dose. This is a new important factor, which has to be taken into account in the future analysis of experimental data. The effects of different types of irradiation (neutrons, protons, swift heavy ions) on radiation damage in spinels were carefully analysed.