The Shear Modulus of Glassy and Supercooled Liquid Pd₄₀Ni₄₀P₂₀

Abstract

We have measured the shear modulus and its temperature dependence of Pd40Ni40P20 using an EMAT technique. The room temperature value of 3.92(1011) d/cm2 is in fair agreement with that of 3.66(1011) d/cm2 given earlier by He and Schwarz, using a resonant ultrasound spectroscopy technique. The relative change with temperature coefficient for T << Tg is 3.4(10−4) K−1. For the heating rate of ∼1 K/min used here, Tg = 565 K compared with a value of 575 K reported earlier. The shear modulus is continuous at Tg , but its temperature coefficient is larger by a factor of 6.5 for T >> Tg. During temperature cycling near but below Tg , irreversible aging effects are found showing that the amorphous state is not an equilibrium state. Near but above Tg, the cycling effects are reversible for time scales of the order of hours but not for time scales of the order of days, showing that metastable equilibrium states have not yet been fully attained. The results are in overall agreement with the predictions of the Interstitialcy Theory.