High Temperature Elastic Constants of Pd- and Zr-Based Bulk Metallic Glasses Studied by Electromagnetic Acoustic Resonance

Abstract

Elastic constants C_ij of Pd₄₀Ni₄₀P₂₀ and Zr₅₅Al₁₀Ni₅Cu₃₀ bulk metallic glasses (BMGs) has been investigated by MHz frequency range electromagnetic acoustic resonance (EMAR) from ambient temperature to their glass transition point T_g. With increasing in temperature the BMGs show elastically plateau region in C_ij(T) curves which is due to two competitive processes; elastic softening by anharmonicity and stiffening by structural relaxation. Significant elastic softening in C_ij(T) curves was confirmed around T_g without any precursor phenomena. Our theoretical analysis revealed that elastic inhomogeneity can explain the characteristic elastic behaviors around T_g.