| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
O-31: Surface Diffusion in Metallic Glasses Using Atomistic Simulations |
| Author(s) |
Ajay Annamareddy, Paul M Voyles, John H Perepezko, Dane Morgan |
| On-Site Speaker (Planned) |
Ajay Annamareddy |
| Abstract Scope |
Atoms on the surface are loosely bonded to their neighbors, leading to their non-localization and accompanying high surface mobility even in the condensed phase. Here, we study the enhancement of surface diffusion (DS) in model metallic glasses by MD simulations. First, we focus on the prefactor and activation energy in Arrhenius fits to glassy-state diffusion. The activation energies of the surface (QS) and bulk (QV) diffusion are related, as expected, by QS ≈ 0.5 × QV, contributing to the observed increase in DS compared to DV. However, the surface also has orders of magnitude lower pre-exponential factors than the bulk. We explore how structural and cooperative motion changes between the bulk and surface might explain the changes in prefactor. We also investigate the suppression of the surface glass-transition-temperature from variations in D and relaxation times. Finally, we present an estimate of the thickness of the region of enhanced surface diffusion. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |