The structure and dynamic viscosity of molten metal In in the temperature range from 280 to 750℃ and investigated by using a high-temperature X-ray diffractometer and a torsional oscillation viscometer. The experiments show that the nearest interatomic distance r1 and the corrdination number Ns of In melt decrease with increasing temperature from 280 to 750℃. The viscosity of In melt drops as temperature increases and meets on the whole the whole the exponential relation. Thermal contraction of atom clusters can be found in the heating process. The sudden change in structure or noticeable contraction occurs in the range of 390-550℃. The anomalous change of viscosity is measured at about 430 and 470℃, which is in good accordance with that of structure. A theoretical discussion on the correlation of struture and viscosity of In melt is given in this paper.

Investigations of the thermal evolution of the structural and dynamic properties of small cobalt clusters in melt are performed using molecular-dynamics simulations with a Finnis-Sinsclaire potemtial. The mean square displacements, atomic volume, and inernal energy, as well as the pair correlation function and bonded pairs, are obtained from quick and slow cooling simulations, respectively. The splitting of a second peak of pair correlation funcion is due to the presence of icosahedron-type clusters. The results demonstrate that the transition from a supercooled-liquid to a crystal is a discontinuous transition in structure, while the supercooled-liquid to glass transition is a continuous transiton in tructure. The physical picture of the tructure of metallic glass is a disrdered entanglement with a lot of icosahedar.

The effects of thermkal-rate treatment technique on the critical thickness of glass formation for an Al85Ni10Ce5 alloy melt have been investigated. The amorphous ribbon of the alloy with a thickness of 300μm is obtained using a single-roller melt-spinning technique by the thermal-rate tteatment, while that of 50μm is obtained at conventional melt superheavitn condition. The experiment shows that the coordiantion numbers of the Al85Ni10Ce5 alloy melt decreases from 12 to 9 with increasing melt temperature from 900 to 1200℃. The relationship between the corrdination numbers, the first position of the main peak of the alloy melt and the critical cooling rate for getting amorphous alloys has been discussed.

The structrues of molten Cu-23% Sn alloy at different temperatures have determined by using a high-teperature X-ray diffractometer. It has been found that there exist not only short-range order (SRO) structure but also medium-range order (MRO) structure in the molten alloy. The medium-range order structure in the alloy melt is a function of temperature. There exist obvious medium-range order structure at the range of temperatures from 900 to 1200℃. The medium-range order structure disappears when the temperature reaches 1300℃. the temperature dependence of the dynamic viscosity of the alloy melt has been measured using a torsional oscillation viscometer. It has been found that there is an abnormal change in the relationship between the temperature and the viscosity of the alloy melt. The abnormity change is consistent with the transformation from medium-range order to short-range order in the alloy melt.