About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
|
Bulk Metallic Glasses XVII
|
Presentation Title |
Anelastic Relaxation as a Probe of Structural Evolution of Metallic Glasses |
Author(s) |
Michael Atzmon, Tianjiao Lei |
On-Site Speaker (Planned) |
Michael Atzmon |
Abstract Scope |
Using a combination of measurement methods, we have observed anelastic relaxation of metallic glasses over ten orders of magnitude of time. Reliable relaxation-time spectra could be computed from the data. These exhibit distinct peaks, which are consistent with an atomically-quantized hierarchy of shear transformation zones (STZs). The methodology we developed allows for detailed characterization of the effect of structural evolution. In La-based alloys, room-temperature ageing decreases the number of the slowest potential shear transformation zones, associated with the main (alpha) relaxation. It also increases their corresponding time constants, which is a result of the increasing shear modulus. Cryogenic cycling reverses the effect of ageing on the time constants, but not that on the number of potential STZs. While the secondary (beta) relaxation is also consistent with the STZ model and is part of the atomically-quantized hierarchy of STZs, it is not affected by room-temperature ageing for the durations probed. |
Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |