Mechanisms Operating During Continuous Dynamic Recrystallization in an Aluminum-4magnesium-0.3scandium Alloy

In-situ TEM experiments were used to directly observe the mechanisms operating during continuous static and continuous dynamic recrystallization. The static process was observed to occur much more rapidly than the dynamic process. The dominant mechanism of continuous static recrystallization appears to be the rapid generation of dislocations at sources in grain boundaries and at grain boundary triple points. These dislocations slip across the subgrains and either interact with other dislocations or enter nearby grain boundaries. Low-angle grain boundaries were observed to disintegrate, but the mechanism by which this occurred was unclear. The primary mechanism of continuous dynamic recrystallization appears to be the process of subgrain rotation, manifested as the migration and disintegration of dislocation structures and the disintegration of subgrain boundary triple points. Subgrain rotation resulting in increased boundary misorientation was not observed; however, the restraints imposed by the thin foil geometry of the tensile TEM samples may be the reason for this.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science and Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Dougherty, Lisa Marie

Contributors dc:contributor

• Robertson, Ian M.

• Engineering, Materials Science

Language dc:language

eng

Identifier

(MiAaPQ)AAI3023043

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/82701