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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, Ce 70Al 10Ni 10Cu 10, 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. © 2011 American Physical Society.