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By employing a containerless high-temperature high-vacuum electrostatic levitation technique, the thermophysical properties, including the ratio between the specific heat capacity and the hemispherical total emissivity, the specific volume, and the viscosity, of Cu 50 Zr 50 and ͑Cu 50 Zr 50 ͒ 95 Al 5 bulk-metallic-glass ͑BMG͒-forming liquids have been measured. Compared with Cu 50 Zr 50 , the improved glass-forming ability of ͑Cu 50 Zr 50 ͒ 95 Al 5 can be attributed to its dense liquid structure and its high value of viscosity. Additionally, the relationship between the viscosity of various BMG forming liquids at the melting temperature and the elastic properties of the corresponding glasses at room temperature will be compared. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2408634͔The processing, the thermophysical, and mechanical properties of low-cost Cu-based bulk-metallic glasses ͑BMGs͒ have been intensively studied recently. [1][2][3][4][5] The Cubased BMGs exhibit extraordinarily high strength and good compressive ductility, which are comparable with the Zrbased BMGs. In order to frustrate the crystal formation during the copper-mold casting process, previous studies indicate that BMG alloys should typically consist of at least three components, which have varying atomic sizes. 6 However, it was reported recently that binary Cu-Zr alloys can be cast into bulk amorphous structures with sample diameters up to 2 mm. 7-10 Subsequent studies reveal that small amounts of Al additions ͑several at. %͒ further increase its glass-forming ability ͑GFA͒ in the ternary Cu-Zr-Al alloys. 11 Das et al. 12 reported that both Cu 50 Zr 50 and ͑Cu 50 Zr 50 ͒ 95 Al 5 BMGs exhibit good compressive ductility at room temperature. Most strikingly, the Cu 50 Zr 50 and ͑Cu 50 Zr 50 ͒ 95 Al 5 BMGs exhibit "strain hardening" effects during the compressive tests, which were not expected for the BMG alloys since there is no dislocation activities in the amorphous structure. Strain hardening is a desirable factor for the prevention of the strain localization. Nevertheless, the localized deformation within the shear bands was still primarily responsible for the observed plasticity in both Cu 50 Zr 50 and ͑Cu 50 Zr 50 ͒ 95 Al 5 BMGs. 12 Therefore, the precise mechanisms responsible for the plastic deformation of the Cu 50 Zr 50 and ͑Cu 50 Zr 50 ͒ 95 Al 5 BMGs require further investigations. 13,14 Recently, it was reported that the ductility of BMGs was closely related to their Poisson's ratio. [15][16][17] For example, Ptbased BMG with high Poisson's ratio of about 0.41 shows an excellent compressive ductility. 15 Nivikov and Sokolov 18 reported that Poisson's ratio of a glass at room temperature correlates with the fragility of liquids at high temperature. This correlation was recently challenged by Yannopoulos and Johari 19 by compiling extensive experimental data covering various glass-forming systems. In this letter, in an effort to further understand the relationship between the fragility and the elastic properties of glass-...

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