Author

Jared Stone

Date of Award

2020

Document Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Mechanical Engineering

Committee Chair

Judith Schneider

Committee Member

Sherri L. Messimer

Committee Member

Michael Banish

Committee Member

D. Keith Hollingsworth

Subject(s)

Three-dimensional printing., Manufacturing processes--Mathematical models.

Abstract

Additive Manufacturing (AM) is a fabrication process that provides a cost effective alternative to conventional subtractive methods for small volume, complex parts. To accelerate development, numerical modeling methods are being evaluated to establish processing parameters thereby reducing the current trial and error methods. Resulting microstructure of an AM build is determined by the thermal profile it undergoes in-situ. This study uses a nominal approach to verify modeling predictions with metallurgical analysis of an as-built AM part. The finite difference additive thermal model (DATM) was used to construct temperature gradients from its generated temperature and time data simulated for a single bead plate build using 4340 steel. Predicted temperature gradients were overlaid onto time-temperature-transformation (TTT) and continuous cooling transformation (CCT) diagrams. Images from metallurgical evaluation of the actual build are compared with the predicted microstructures as a function of the cooling rate to verify results.

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