Polyamorphic Transitions In Ce-Based Metallic Glasses By Synchrotron Radiation

We report here on a polyamorphic-phase transition upon application of pressure on a Ce-based metallic glass, Ce(70)Al(10)Ni(10)Cu(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 gamma-Ce and alpha-Ce under pressure.