Surface structure and properties of NiZr model metallic glasses: A molecular dynamics simulation

A systematic study of the surface structure and properties of NiZr model metallic glasses is reported using atomistic simulations. It is found that at low temperatures below the glass transition temperatures, the surface retains the amorphous structure and the surface energy γ is significantly lower (∼50%) than that of the corresponding crystalline alloy constituents. The variation of alloy concentration has little effect on γ; but increase in cooling rate and annealing temperature can lead to large decrease in γ. At elevated temperatures, γ increases with temperature and surface melting occurs at a temperature about 30% below T_g. At all temperatures up to T_g, the surface remains atomically smooth.