THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Wednesday, May 2, 2018

3:30 PM
in MRDC 3515

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Jordan Walker Key

"Developing structure-property relations for the global and local corrosion of the AA5083 alloy"

Committee Members:

Prof. Josh Kacher, Advisor, MSE

Prof. Preet Singh, MSE

Prof. Matthew McDowell, MSE

Prof. Hamid Garmestani, MSE

Prof. Andrew Medford, CHBE

Abstract:

In order to accelerate advanced materials design, experimental investigations across several length scales must be combined with computational and data science methods. This combination will allow materials scientists and data scientists to collaborate in order to generate sophisticated and invertible processing-structure-property relations that can be used to tailor materials for many different applications. Some promising data science methods using spatial statistics have been demonstrated in the literature. This dissertation work will develop structure-property relations for the local and global corrosion of AA5083. This material is of particular interest for naval applications for its corrosion resistance and the phenomenon of sensitization, in which its corrosion resistance is greatly jeopardized. Better understanding of the corrosion of AA5083 and the sensitization process could lead to reduced cost and increased lifetime for naval vessels.

Investigations into the corrosion of AA5083 will be performed at both the local and global scale. Mesoscale statistical characterization using electron microscopy techniques will be performed on different microstructures generated by various thermal and mechanical treatments. Local pitting corrosion will be characterized by SEM analysis, while global corrosion will be measured through nitric acid mass loss testing (NAMLT). Data science techniques involving spatial statistics and principal component analysis will be used to develop the global structure-property relation between mass-loss and system microstructure. Locally, pitting characteristics will be directly evaluated with respect to local microstructural properties such as dislocation density and grain boundary character to search for correlations. Additionally, nanoscale in situ TEM investigations will provide additional insight: in situ heating will be used to study the impact of microstructure on sensitization behavior and in situ liquid cell TEM will be used to study the corrosion process in order to learn more about influence of microstructure on corrosion in the AA5083 system.