Date of Award
2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Materials Science
Committee Chair
Judy Schneider
Committee Member
Sherri Messimer
Committee Member
Luke Brewer
Committee Member
Michael Banish
Committee Member
Seyed Sadeghi
Research Advisor
Judy Schneider
Subject(s)
Additive manufacturing, Gas tungsten arc welding, Carbon steel--Microstructure, Metals--Heat treatment
Abstract
Additively manufactured (AM) parts are subjected to rapid and repeated localized melting, solidification, and reheating, which produces a heterogeneous microstructure. To homogenize the resulting heterogeneous microstructure that results from this non-equilibrium thermal cycling, ex-situ heat treatments can be used. However, this is intended to provide homogenous properties to the printed part, thereby not realizing one of the potential benefits of AM in providing site-specific properties such as fatigue resistance, wear resistance or high strength. This study explores the use of in-situ heat treatments to spatially control microstructure evolution, thereby controlling the location of specific mechanical properties. To guide the processing parameters, numerical models were used to predict the thermal histories and the corresponding desired microstructures and properties. To achieve this goal, a Gas Tungsten Arc Welding (GTAW) based AM process has been designed and built for spatial control of microstructures in a carbon steel. The GTAW process is selected due to the ability to separate the heat flux from the material deposition, providing the ability for in-situ heat treatments.
Recommended Citation
Beeker, Benjamin M., "Microstructure control through the use of gas tungsten arc welding based additive manufacturing" (2024). Dissertations. 401.
https://louis.uah.edu/uah-dissertations/401