Term of Award

Spring 2024

Degree Name

Master of Science in Applied Engineering (M.S.A.E.)

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Digital Commons@Georgia Southern License


Department of Manufacturing Engineering

Committee Chair

Jingjing Qing

Committee Member 1

Mingzhi Xu

Committee Member 2

Haijun Gong


The iron matrix is a major component of the gray iron (GI) microstructure, which is the transformation product of austenite during solidification. It is generally accepted that the structure of the austenite will impact the final grain structure and thus the properties of GI. Refinement of the austenite grain structure has the potential to increase the strength of GI. Knowledge of controlling austenite grain size with common alloy additions in GI is very limited and is investigated in this research. Utilizing the DAAS heat treatment process, the austenite grain boundaries can be retained and observed directly. The observations were correlated to the microstructure (graphite, matrix, and nonmetallic inclusions), macrostructure (austenite), and mechanical properties of an inoculant addition (Foundry Grade or Superseed®) or an element addition (Al, Ca, Ce, Sr, or Ti), in reference to a pure Si addition as a baseline. The analysis showed that refining the austenite grains will also lead to refined eutectic cell size. TiCN showed potential for refining the austenite. The in-mold addition of Al showed negative impacts on the austenite grain size (larger equiaxed zone grains) and changed the distribution of inclusion composition. However, the in-mold element additions (Ca, Ce, Sr, Ti) reduced the size of austenite grains. The inoculant additions (Foundry Grade and Superseed®) also showed negative effects on the structure of austenite grain size by enlarging the grains and reducing the size of the equiaxed zone.

OCLC Number


Research Data and Supplementary Material


Available for download on Sunday, May 03, 2026

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