Thermal Expansion and Specific Volume of Pd₄₀Cu₃₀Ni₁₀P₂₀ Alloy in Various States

Abstract

We measured the thermal expansion and specific volume of the Pd₄₀Cu₃₀Ni₁₀P₂₀ alloy by thermomechanical analyzer (TMA), fluid (H₂O) displacement and volume dilatometric methods. At room temperature (293 K), the specific volumes of the Pd₄₀Cu₃₀Ni₁₀P₂₀ alloy in the relaxed glassy and crystalline states are 0.1070 and 0.1065 m³/Mg, respectively. The average linear coefficients of thermal expansion are 17.0×10⁻⁶ K⁻¹ at 323 to 523 K in the relaxed glassy state (α_relax), 14.2×10⁻⁶ K⁻¹ at 323–673 K in the crystalline state (α_cry) and 39.9×10⁻⁶ K⁻¹ at 873–1223 K in the liquid (α_liq). Based on these results, the specific volume of the Pd₄₀Cu₃₀Ni₁₀P₂₀ alloy as a function of temperature, V(T), is estimated. The extrapolation line of the specific volume for the equilibrium liquid is smoothly connected to the specific volume for the supercooled liquid. On the other hand, the intersection point of the specific volume between the extrapolation of equilibrium liquid and crystal is evaluated at 527 K. In the assumption that the temperature of the intersection point corresponds to the entropic stability limit for the undercooled liquid, it is much lower than that of previous thermodynamic study.