Doctoral Dissertations
Date of Award
12-2024
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Major
Data Science and Engineering
Major Professor
Russell Zaretzki
Committee Members
Vincent Paquit, Hairong Qi, Mingzhou Jin
Abstract
Before metal powder bed fusion additive manufacturing may be deployed on a wide scale, the reliability and repeatability of the process must be improved. Currently additively manufactured components suffer from mechanical anisotropy and often-poor performance due to the presence heterogeneities in microstructure and defects throughout the component. Work must be undertaken to help determine how the process itself contributes to the evolution of these heterogeneous structures. This is true for both electron beam and laser powder bed fusion technologies. The dynamism of the process is largely driven by the scan path that the heat source traverses to fuse feedstock into solid material - introducing nuanced thermal cycling and histories to different regions. The complexity of the process, time and space scales under consideration, and the increasing availability of data necessitate development of additional process-structure analyses to complement those in existence already. Two distinct tasks will be performed to explore localized heterogeneities and their connection to the powder bed process utilizing scan path data. The first task will investigate how the scan path itself may be manipulated in order to induce desired location specific microcstructure in electron beam powder bed fusion utilizing genetic algorithm and concurrent greedy line search optimization algorithms. The second task will leverage scan path data to localize temporal process data. Specifically, the scan path data will be utilized to spatially map temporal data about gas flow and oxygen content of laser powder bed fusion builds. The data, in its new format, will then be used to predict the local prevalence of soot which has been shown to lead to mechanical anisotropy.
Recommended Citation
Halsey, William Henry, "Localized Heterogeneities in Metal Powder Bed Additive Manufacturing – Investigating Process-Structure Relationships Leveraging Scan Path Data. " PhD diss., University of Tennessee, 2024.
https://trace.tennessee.edu/utk_graddiss/11358