|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Bulk Metallic Glasses XIX
||Surface Mobility of Metallic Glass Thin Films Controls Glass Phase Stability and Crystallization
||Debaditya Chatterjee, Ajay Annamareddy, Chengrong Cao, Yuhui Li, John Perepezko, Lian Yu, Dane Morgan, Paul Voyles
|On-Site Speaker (Planned)
Metallic glass surfaces have much higher mobility than the interior of the glass at the same temperature in both experiments and simulations. Electron correlation microscopy experiments show that surface dynamics, like bulk dynamics, are spatially heterogeneous. Surface diffusivity and surface relaxation time slow down with cooling in a way similar to the bulk glass transition at a temperature Tg,s well below the bulk glass transition temperature Tg,b. The surface and bulk diffusivities near these temperatures scale such that Ds(Tg,s / T) = Db(Tg,b / T). High surface mobility enables physical vapor deposition of highly stable metallic glass films with increased structural order, and helps determine which combinations of deposition rate and substrate temperature result in amorphous films and which result in crystalline films. Metallic glasses fit into a general trend connecting surface mobility to bulk liquid fragility that cuts across many different types of glasses.
||Characterization, Thin Films and Interfaces,