|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Bulk Metallic Glasses XIX
||Measuring Metallic Glass Viscosities over Wide Composition Ranges
||Sebastian A. Kube, Sungwoo Sohn, Theo Evers, Will Polsky, Rodrigo Ojeda-Mota, Kevin Ryan, Sean Rinehart, Yong Sun, Jan Schroers
|On-Site Speaker (Planned)
||Sebastian A. Kube
Amongst the most fundamental properties of metallic glass (MG) forming liquids are the viscosity and its temperature dependence, the fragility. Measuring these is challenging and data have only been reported for few compositions and systems. Here, we present a new experimental method to measure the viscosity and fragility across wide composition ranges: Using co-sputtering and silicon etching, we prepare compositionally graded wafers, which are then cleaved out into individual chips with freely suspended circular MG thin film membranes. Applying gas pressure, these membranes are thermoplastically deformed between Tg and Tx. As the membranes expand into spherical shape, we track the deformation rate as function of the temperature and pressure difference, from which we compute viscosities for the full temperature range. We map out and discuss the fragility behavior for ~200 compositions in the Mg-Cu-Y system with elemental concentrations ranging over 20 at.%.