Rapid Solidification and Undercooling of Aluminum-Germanium Alloys: Characterization and Control of Microstructure (Metastability, Metallic Glass, Electron Microscopy)

A determination of the importances of undercooling and cooling rate in the microstructural development of Al-Ge alloys during rapid solidification has been carried out. A new technique has been developed which allows for such determinations to be performed directly in a transmission electron microscope. This technique involves the in-situ melting and solidification of submicron powders, where it is possible to vary the cooling rate from the liquid or semi-solid state over a fairly large range while observing directly the various solidification microstructures. Further, a heating stage may be used either to measure the liquid undercoolings achieved upon slowly cooling or to select substrate temperatures (and so affect the nucleation temperatures) during rapid quenching experiments. In this manner it has been shown that certain combinations of phases form over rather specific ranges of undercooling (substrate temperature).

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Metallurgical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Kaufman, Michael Joseph

• Engineering, Metallurgy

Identifier

(UMI)AAI8422095

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/71810