Structural fragility and Curie-Weiss behavior distinguishing glass forming ability in Ti-based metallic alloys

The results of synchrotron x-ray scattering studies of glass forming Ti₄₀Zr₁₀Cu₃₆Pd₁₄ and Ti₃₄Zr₁₁Cu₄₇Ni₈ (Vit101) liquids and glasses are presented. Containerless experiments on the liquids were made using electrostatic levitation, while the corresponding glasses were thermally cycled to measure and account for structural relaxation. The total structure factor and total pair-distribution functions were measured as a function of temperature for the two equilibrium and supercooled Ti-based liquids, and for the corresponding glasses from room temperature to their respective glass transition temperatures. The rate of structural ordering was determined from the rate of increase in the magnitude of the first peak in the X-ray structure factors with decreasing temperature. Structural fragility is observed in these systems, with the magnitude of the fragility factor inversely correlated with the glass forming-ability. The amplitude of the first peak in the x-ray static structure factor in both alloys displays evidence for a Curie-Weiss type behavior. A proposed order parameter distinguishing glass-forming ability, (S(T,q₁)−1)⁻¹, shows a peak in the effective Curie temperature. This peak is at a higher temperature for the better glass former, consistent with a liquid that is closer to the ideal glass structure at a higher temperature.