Correlation between liquid structure and glass forming ability in glassy Ag-based binary alloys

Abstract

The atomic structures of liquid Ag-based binary alloys have been investigated in the solidification process by means of X-ray diffraction. The results of liquid structure show that there is a break point in the mean nearest neighbor distance r 1 and the coordination number N min for glass-forming liquid, while the correlation radius r c and the coordination number N min display a monotone variational trend above the break point. It means glass-forming liquids have a steady changing in structure above liquidus and more inhomogeneous state at liquidus. We conclude that there is a strong correlation between liquid structure and glass forming ability in Ag-based binary alloys. liquid structure, glass forming ability, Ag-based binary alloys PACS: 81.05.Bx, 07.85.Nc, 61.20.-PThe liquid structure is known to be more complicated and mysterious in the three states of matter. As people's understanding of liquid structures has stagnated, it remains an open question in condensed state physics that has attracted investigations into the liquid structure through the methods of X-ray diffraction, neutron diffraction, X-ray absorption spectroscopy, and computer simulations [1][2][3][4]. Bulk metallic glass is generally obtained by rapid quenching from melts, and consequently its atomic distribution is very close to that of the liquid state. Whether the liquid structure of melt affects glass forming ability or not attracts the attention of researchers. Due to its theoretical and applied values, many researchers looked into this matter [5][6][7][8][9]. Mattern et al.[10] found a continuous development of structural change between liquid state and glass state. However, the direct relationship between liquid structure and glass forming ability has not been reported by now.In this paper, we study the differences in liquid structure between glass and crystal in Ag-based binary alloys, in which Ag 50 Cu 50 , Ag 60 Cu 40 and Ag 70 Ge 30 are glasses reported in refs. [11][12][13], while Ag 70 Cu 30 is crystal, aiming to give insight into the effect of liquid structure on glass forming ability.