CHANGE IN THE STRUCTURE OF TITANIUM NANOCLUSTERS UNDER THERMAL EXPOSURE: MOLECULAR DYNAMIC SIMULATION

Abstract

Investigation of the structure of nanoclusters at different temperatures is an urgent task of modern materials science. This fact is due to the prospect of their application in the creation of materials with unique physical, mechanical, chemical and operational properties. Computer simulation was carried out by the method of classical molecular dynamics in the LAMMPS software package. To describe the interatomic interaction in the cluster, a modification of the Finnis-Sinclair many-body potential was used. The structure of titanium nanoclusters of various sizes has been studied. They are obtained at various cooling rates from the liquid state. An increase in the cooling rate leads to the formation of a subblock structure and an increase in the number of atoms with a disordered environment. They are due to the fact that high cooling rates impede the equilibrium process of rearrangement of the atomic structure with the formation of long-range order. No regions with an icosahedral structure were found. It is shown that the crystallization temperature and binding energy decrease with decreasing nanocluster size. An increase in the cooling rate increases the temperature difference between the start and end points of crystallization, respectively. The simulation results indicate a less pronounced dimensional dependence of the crystallization temperature – its estimated value for a macroscopic system (810K) is much lower than the value for bulk titanium (1940K).

Keywords

• nanocluster
• binding energy
• crystallization temperature
• cooling rate
• structure
• molecular dynamics method