Studying Stability of Atom Packing for Ti Nanoparticles on Heating by Molecular Dynamics Simulations

Molecular dynamics simulations using an embedded atom method (EAM) potential shows that melting behaviors of Ti nanoparticles are strongly dependent on their size. For the particles having the diameter of less than 2.5nm, their structures are preferred with the icosahedron of geometric shell closures, and there are multi-structures' transitions. With the increase in size, while most atoms in the particles can hold their HCP packing patterns, there exist movements and structural rearrangements of the atoms in the surface. At a high temperature, the accumulation of structural disorder can quickly extend into the entire particle, which resembles the melting of bulk Ti. In the HCP particles with sizes of less than 4nm, the surface atoms still have important influence on their melting.