Size effects on the structural and physical properties of Cu50Zr50 metallic glass nanoparticles

Abstract

The large surface area to volume ratio of metallic glass on the nanoscale imparts unique properties that are active areas of research in material science. We performed extensive calculations to investigate the structural properties, vibrational properties and low-temperature heat capacity of the Cu 50 Zr 50 metallic glass nanoparticles. The low-frequency vibrational density of states was lower in the core region of the nanoparticles than that of the bulk metallic glass. Furthermore, the potential energy of the core region was lower than that of the bulk metallic glass, which confirms that the stability of the core region of the nanoparticles was different from the bulk. The fast dynamics of the surface atoms and curvature effects enhanced the stability of the core region. The fraction of Cu-centered icosahedral clusters increased in the core region of the nanoparticles and it was the structural origin of the enhanced stability. The low-temperature heat capacity of the metallic glass depended on the nanoparticle size and there was an obvious boson peak in nanoparticles with a radius of 54.9 Å. Our investigations are helpful for understanding the structural and vibrational properties of metallic glass nanoparticles. • We performed extensive calculations to explore the structure properties, vibrational properties and low-temperature heat capacity of Cu 50 Zr 50 MGNs. • The core region of the metallic glass nanoparticles have a lower potential energy, higher density and higher fraction of icosahedral clusters. • Fast surface dynamics and curvature effect benefited to the suppressed low-frequency VDOS of the core region of the nanoparticles. • An obvious boson peak was observed in the Cu 50 Zr 50 metallic glass nanoparticle.