The structural relaxation behavior around glass transition temperature in Pd-Cu-Ni-P metallic glasses

The structural relaxation behavior in the Pd₄₀Cu₃₀Ni₁₀P₂₀ and the Pd₄₃Cu₂₇Ni₁₀P₂₀ metallic glasses was examined by the differential scanning calorimetry and the electrical resistivity experiment. A sharp endothermic peak in the DSC thermogram appeared just before the supercooled liquid region for the sample annealed at 540 K during a given time ranged from 864 to 2940 ks. Although the peak area, ΔH_g, increased with annealing time, it did not saturate within the experiment. The room temperature Mossbauer experiment was performed to examine the change in the amorphous structure of the Pd₄₀Cu₃₀Ni₉⁵⁷Fe₁ P₂₀ glass accompanied with the structural relaxation at 540 K. A Mossbauer spectrum showed an asymmetrical doublet peculiar to the paramagnetic metallic glass. The average isomer shift and quadrupole splitting decreased with time up to 1440 ks and thereafter increased. The behavior of these parameters was interpreted within the framework of the free volume theory.