Atomistic simulation of chemical ordering phenomena in nanostructured intermetallics

Title : Atomistic simulation of chemical ordering phenomena in nanostructured intermetallics

Abstract:

Vacancy-mediated chemical ordering phenomena were studied by means of Monte Carlo (MC) simulations in nanostructured B2-ordering NiAl and L10-ordering FePt. The (100)-oriented NiAl films were modeled with an Ising-type Hamiltonian with pair-interaction energy parameters yielding the effect of “triple-defect disordering”. While the Semi Grand Canonical MC (SGCMC) simulations provided equilibrium defect concentration and configuration in the films, the Kinetic MC (KMC) ones enabled modelling of the sample relaxations towards equilibrium configurations. Specific effects of free surfaces on both the defect concentration and ordering kinetics were revealed.

MC simulations of free-surface-induced L10 chemical long-range ordering phenomena in nanolayers, nanowires and cubic nanoparticles of FePt modelled with nearest-neighbor and nextnearest-neighbor interatomic pair interactions deduced from ab initio calculations were focused on the surface-induced nucleation and growth of domains of particular L10 variants. The phenomenon is of great technological importance. Due to the specific competition between the three kinds of (100)-type free surfaces, the initial c-L10 variant long-range order appeared the most stable in the cubic nanoparticles.

Biography:

Prof. Rafal Kozubski completed his Ph.D. and D.Sc. at the Jagiellonian University in Kraków. He was a post-doc at the Strasbourg Institute of Physics and Chemistry of Materials (IPCMS), France, an academic visitor in the Institute for Applied Physics, Swiss Federal Institute of Technology, Zurich, Switzerland and a Lise-Meitner Fellow at the Vienna University, Austria. His international experience includes also an International Fellowship at the Queen’s University in Belfast, a visiting professorship at the University of Strasbourg, France and the Honorary Professorship at the University of Newcastle, Australia. He published over 100 scientific papers in international reviewed journals and is an author of over 150 communications on international conferences.