Structural study of Zr-Cu-Ag bulk metallic glasses using the anomalous X-ray scattering method

The structures of Zr45Cu45Ag10 and Zr40Cu40Ag20 bulk metallic glasses (BMGs) were investigated using the anomalous x-ray scattering and reverse Monte Carlo simulation (AXS-RMC) method. The fundamental structural features of Zr45Cu45Ag10 and Zr40Cu40Ag20 can be properly demonstrated through the common dense random packing of the hard spheres, and the addition of Ag appeared to result in no prominent formation of the particular chemical ordering units. A Voronoi analysis indicated that the fraction of the icosahedron-like coordination was the largest around the Cu in Zr45Cu45Ag10 BMG, where the best glass-forming ability was realized. The improvement in the glass-forming ability in a Zr-Cu-Ag system appears to be associated with the icosahedron-like local coordination.