Polyamorphic transitions in Ce-based metallic glasses by synchrotron radiation

Abstract

We report here on a polyamorphic-phase transition upon application of pressure on a Ce-based metallic glass, Ce70Al10Ni10Cu10, investigated by x-ray diffraction and inelastic x-ray scattering. This alloy is found to display a strong hysteresis in volume per atom upon application and subsequent release of pressure. The observed structural changes are correlated with changes observed by inelastic x-ray scattering in the elastic constants, acoustic mode frequencies, and sound speed. The results reported here point toward three different amorphous phases for this alloy existing in the 0–25 GPa pressure region: low- and high-density states and an intermediate mixed state that displays a hysteresis behavior. Finally, we discuss the impact of Ce concentration on the polyamorphic transition for a series of Ce-based metallic glass alloys and link it to the phase transformation between γ-Ce and α-Ce under pressure.