Slow relaxations in deeply undercooled metallic liquids

Temperature-modulated calorimetry measurements on bulk glass forming Pd-rich alloys are reported that are unaffected by the structural glass transition or by irreversible relaxation phenomena, and that measure the relaxation time spectrum near the glass transition directly. The comparison of the temperature dependencies of the average relaxation times for two Pd-rich alloys with different thermal stability shows that the more stable alloy is more fragile, indicating that vitrification for these alloys is strictly governed by nucleation control. The comparison of the present data with results from static equilibrium measurements indicates further, that near the caloric glass transition the description of equilibrium thermodynamic properties, rheological quantities and relaxation times can be based on a common divergence limit.