Isothermal Relaxation Behavior in a Pd_42.5Cu₃₀Ni_7.5P₂₀ Metallic Glass

Abstract

The structural relaxation process was investigated for a Pd_42.5Cu₃₀Ni_7.5P₂₀ metallic glass (bulk and ribbon samples) isothermally annealed at 566 and 573 K just below glass transition temperature T_g = 576 K. The relaxation process was examined by differential scanning calorimetry (DSC) and electrical resistmetry. Then, the resistivity of bulk glass was exactly estimated from the resistance and the geometry of the sample. Although the DSC absorption peak appeared just after glass transition became larger with the progress of the relaxation, the growth was terminated after annealing for 6 × 10³ s at 566 K or 6 × 10² s at 573 K, meaning that the free volume content reached a constant value and a fully relaxed state was attained. The corresponding change was also seen in the room temperature residual resistivity ρ(300) during relaxing at 566 K. Then, the ρ(300) increased with time for initial 6 × 10³ s and was constant during further 6 × 10⁴ s.