Correlation between Modulus Relaxation and Excess Entropy in Pd-Based Metallic Glasses

The correlation between structural disorder and relaxation behavior in metallic glasses (MGs) plays a key role in governing their glass transition and viscoelastic response. In this work, differential scanning calorimetry and dynamic mechanical analysis were employed to systematically investigate the thermodynamic and relaxation behaviors of Pd₄₀Ni₄₀P₂₀ and Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ MGs. The temperature dependent evolutions of the excess entropy, complex modulus, and relaxation modulus analyzed over a wide temperature range. A dimensionless disorder parameter ξ was introduced, and its correlation with relaxation kinetics was demonstrated. The results show that, compared with Pd₄₀Ni₄₀P₂₀ MG, Pd₂₀Pt₂₀Cu₂₀Ni₂₀P₂₀ MG exhibits higher structural disorder and more active relaxation kinetics. This study contributes to understanding the relationship between structural disorder and relaxation behavior in MGs and their connection to compositional design.