Actions for 3D Spatial Reconstruction of Thermal Characteristics in Directed Energy Deposition through Optical Thermal Imaging

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3D Spatial Reconstruction of Thermal Characteristics in Directed Energy Deposition through Optical Thermal Imaging

Author
Kriczky, Dennis
Published
[University Park, Pennsylvania] : Pennsylvania State University, 2014.
Physical Description
1 electronic document
Additional Creators
Michaleris, Pan and Reutzel, Edward W., 1969-
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Graduate Program
Restrictions on Access
Open Access.
Summary
An application to visualize thermal metrics extracted from coaxial thermal images in three dimensions during directed energy deposition is presented in this thesis. The extraction of thermal metrics is useful for correlation of microstructure for process monitoring and control of additive manufacturing. The thermalmetrics attained from the coaxial images include the thermal gradient at the solidus to liquidus region, the maximum temperature in the melt pool, the melt pool pixel area, and the length-to-width ratio of the melt pool. The current procedure for part qualification in additive manufacturing is through destructive methods. The use of thermal metrics in a 3D spatial reconstruction allows for a non-destructive means to distinguish material microstructure. For this reconstruction, two Ti-6Al-4V L-shaped parts were deposited with a 1-bead wide deposition on one leg of the build and 3-bead wide deposition on the second leg of the build. A filtering scheme of the coaxial thermal images is utilized to produce melt pools with distinguishable solidus to liquidus regions. The acquisition of laser location during deposition is used to create a threedimensional representation of the calculated thermal metrics. Differences in thermal metric values between separate legs of the L-shaped parts express changes in the thermal history and hence the microstructure development for the transient and steady state regions of melt pool movement. For process monitoring, the crosssectional cuts of the three dimensional representation of thermal metrics can correlate to variations in material microstructure from the cross sectional cuts of actual L-shaped builds.
Other Subject(s)
Dissertation Note
M.S. Pennsylvania State University 2014.
Reproduction Note
Library holds archival microfiches negative and service copy. 2 fiches. (Micrographics International, 2015)
Technical Details
The full text of the dissertation is available as an Adobe Acrobat .pdf file ; Adobe Acrobat Reader required to view the file.
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