The Size Effect on Solidification in Eutectic Bismuth-Tin (Bi-Sn) Nanowires by In-Situ Annealing Processes

Abstract

The size effects on solidification and the formation mechanism of the segmented eutectic Bi-43Sn nanowires during in situ annealing have been investigated. A directional solidification along the wire axis limits the segmented eutectic nanowire to arrange axially during the in situ annealing processes due to directional solidification. In 70 nm nanowires, the small size confines the convection in liquid, which results in differences in the microstructure and composition profiles between 70 and 200 nm nanowires. In the vacuum hydraulic pressure injection process, the directional cooling helps the formation of single crystal, and the isotropic solidification leads to polycrystalline microstructure.