Date of Award

2020

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Materials Science and Engineering (MS)

Administrative Home Department

Department of Materials Science and Engineering

Advisor 1

Paul Sanders

Committee Member 1

Stephen Kampe

Committee Member 2

Douglas Swenson

Abstract

Dissimilar castings are under investigation due to their light-weighting opportunities within the automotive industry. In this case, dissimilar castings consist of a solid steel core and a poured aluminum component. The strength and integrity of the casting relies on the coherency of the bond between the two components; by optimizing the metallurgical component of the bonding phenomena, the weight and complexity of the insert can be reduced, further increasing the light-weighting opportunities. An interface comprised of intermetallics, generally Fe4Al13 and Fe2Al5, forms between the two components with the latter forming nearest the steel. Cerium and magnesium additions to the aluminum component of the casting were investigated to increase the integrity of the metallurgical bond. Five alloys, 99.99wt%Al, Al-5Mg, Al-6Ce, Al-10Ce, and Al-10Ce-5Mg, were utilized to study the effect of cerium and magnesium on the intermetallic growth through an immersion experiment. Three alloys, Al-6Ce, Al-10Ce, and Al-10Ce-5Mg, were used to investigate the interfacial shear strength through a pin extraction experiment. The magnesium containing alloys showed a large decrease in total intermetallic compound layer thickness and an increase in the interfacial shear strength. A possible mechanism for the thickness reduction was magnesium reducing the lattice parameters of Fe4Al13 and Fe2Al5 reducing the diffusion of aluminum through the layer.

Included in

Metallurgy Commons

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