Separating the configurational and vibrational entropy contributions in metallic glasses
- California Inst. of Technology (CalTech), Pasadena, CA (United States. Dept. of Applied Physics and Materials Science
- Univ. of California, Riverside, CA (United States). Dept. of Mechanical Engineering
- Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States)
- California State Univ. Channel Islands (CI), Camarillo, CA (United States). Dept. of Applied Physics
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Data Analysis and Visualization Division
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
Glassy materials exist in nature and play a critical role in technology, but key differences between the glass, liquid and crystalline phases are not well understood. Over several decades there has been controversy about the specific heat absorbed as a glass transforms to a liquid—does this originate from vibrational entropy or configurational entropy? We report direct in situ measurements of the vibrational spectra of strong and fragile metallic glasses in the glass, liquid and crystalline phases. For both types of material, the measured vibrational entropies of the glass and liquid show a tiny excess over the crystal, representing less than 5% of the total excess entropy measured with step calorimetry. These results reveal that the excess entropy of metallic glasses is almost entirely configurational in origin, consistent with the early theories of Gibbs and co-workers describing the glass transition as a purely configurational transition.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- Grant/Contract Number:
- AC05-00OR22725; FG02-03ER46055; DMR-0520547
- OSTI ID:
- 1471839
- Journal Information:
- Nature Physics, Vol. 13, Issue 9; ISSN 1745-2473
- Publisher:
- Nature Publishing Group (NPG)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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