The effect of added oversized elements on the microstructure of binary alloy nanoparticles

Abstract

Molecular dynamics simulations are used to investigate the microstructures of Cu–Ninanoparticles with different concentrations of oversized atoms added to them. A manybody second moment tight binding approximation potential is adopted to model theinteratomic interactions. The Honeycutt–Anderson (HA) pair analysis technique is adoptedto analyse in detail the transformation between local structures at different temperatures.From the simulation results, at temperatures higher than the melting point, thenanoparticles are in a liquid state and an icosahedral local structure is most frequentlyfound inside the nanoparticles. At temperatures beneath the melting point, the fraction ofFCC local structure increases with decreasing concentrations of the larger size atoms,whereas a larger fraction of amorphous structure still remains in the solid state for higherconcentrations of oversized atoms. This is because the effects of distortion and misfit aremore significant for a nanoparticle having a higher concentration of oversizedatoms.