Author

Pawel Okrutny

Date of Award

1-2011

Degree Type

Thesis

Degree Name

Master of Science (MSc)

Department

Materials Science and Engineering

Supervisor

Hatem Zurob

Co-Supervisor

Shahrzad Esmaeili

Language

English

Abstract

Through the study of recovery, precipitation and their effects on recrystallization at various annealing temperatures, a physically based model was developed to describe recrystallization kinetics of Mg AZ31. Based on Zener drag calculations, precipitates in AZ31 had little effect on recrystallization. Recovery activation energy and activation volume were determined from yield stress vs. time experiments. Recovery kinetics were used to determine the stored energy remaining within the material throughout the annealing process. Recrystallization experiments showed that contraction twins were preferred regions of recrystallization and in-situ recrystallization experiments showed that twin/twin and twin/GB intersections were ideal locations for nuclei growth outside of the twinned volume. Given the deformation and the annealing temperature, the proposed model is able to predict the recrystallized fraction as a function of time. Future versions of the model may be used to construct recrystallization-time-temperature (RTT) maps as well as predict recrystallized grain size after a time of anneal. The model predictions are in excellent qualitative agreement with experimental observations and can capture nucleation growth within both the twins and matrix.

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