|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Bulk Metallic Glasses XIX
||Assessment of Excess Entropy in Extremely Fragile Glasses
||Hillary Smith, Claire Saunders, Camille Bernal, Stefan Haegeli Lohaus, Marios Demetriou, Brent Fultz
|On-Site Speaker (Planned)
A new series of ultra-fragile bulk metallic glasses (BMGs) Pt80-xCuxCu20 were recently reported with Angell fragility parameters ranging from 73 to more than 90. The structure of these ultra-fragile BMGs was observed to collapse discontinuously at the glass transition, resembling a first order melting transition . We report measurements of the excess entropy for two compositions, x=57 and x=60 with Angell fragilities of 73 and 82 for respectively. Inelastic neutron scattering measurements were performed while heating through the glass transition and crystallization. The difference in vibrational entropy between the glass/liquid and crystal is approximately 0.05kB per atom. The change in phonon spectrum across the glass transition was even smaller. This work is discussed in the context of our previous report on of the vibrational entropy through the glass transition in Cu50Zr50 and Cu46Zr46Al8.  Na, J.H., et al., P.N.A.S. 117, 2779 (2020).