|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||In Situ Analysis of Microstructural Evolution during the Devitrification of Amorphous Tantalum Films
||Olivia Donaldson, Khalid Hattar, Jason Trelewicz
|On-Site Speaker (Planned)
Engineering nanocrystalline structures into refractory metals has gained significant attention as a pathway to improving the performance of next-generation nuclear reactor materials. In this study, in situ transmission electron microscopy (TEM) was used to characterize microstructural evolution during the devitrification of amorphous tantalum films prepared by pulsed laser deposition. Films were deposited to a thickness of 20 nm and confirmed amorphous through bright field imaging and selected area diffraction (SAD) analysis. In situ heat treatments at temperatures of 800 – 1200°C were employed to crystallize the amorphous films. Quantitative image analysis of the SAD patterns revealed a multi-phase nanostructure following crystallization that contained nanocrystalline tantalum grains as well as a series of metastable oxide precipitates. These nanoscale grains and precipitates exhibited limited growth following ex situ TEM analysis of films subjected to isothermal anneals for up to 100 hours, thus demonstrating stable multi-phase nanostructures in refractory metals.
||Planned: A print-only volume