Strong-Superstrong Transition in Glass Transition of Metallic Glass

Dynamic fragility of bulk metallic glass (BMG) of Zr₆₄Cu₁₆Ni₁₀Al₁₀ alloy is studied by three-point beam bending methods. The fragility parameter mfor Zr₆₄Cu₁₆Ni₁₀Al₁₀ BMG is calculated to be 24.5 at high temperature, which means that the liquid is a "strong" liquid, while to be 13.4 at low temperature which means that the liquid is a "super-strong" liquid. The dynamical behavior of Zr₆₄Cu₁₆Ni₁₀Al₁₀ BMG in the supercooled region undergoes a strong to super-strong transition. To our knowledge, it is the first time that a strong-to-superstrong transition is found in the metallic glass. Using small angle x-ray scattering experiments, we find that this transition is assumed to be related to a phase separation process in supercooled liquid.