Doctoral Dissertations

Keywords and Phrases

304L Stainless Steel; Aluminum Alloys; AM Metal Parts; Laser Additive Manufacturing; Laser Foil Printing; Laser Welding Modes

Abstract

"This work presents research conducted on a novel metal additive manufacturing process, called Laser Foil Printing (LFP), to fabricate metal parts with various geometries layer by layer using metal foil as the feedstock. To investigate the processability and characteristics of LFP for fabricating metal parts, the materials included 304L stainless steel and Al-1100 aluminum alloy. The LFP process parameter windows for both 304L and Al-1100 were determined, and the optimal process parameters with stable formation of the melt pools were selected to fabricate dense metal parts. The microstructure and properties of LFP-fabricated parts were characterized and analyzed using tensile testing, scanning electron microscopy, electron backscattered diffraction, and ANOVA analysis. The mechanical properties of fabricated parts were compared with those of parts fabricated by the Laser Powder Bed Fusion (L-PBF) process. The results showed that the 304L parts fabricated by LFP were 10-20% higher in strength and ductility than those fabricated by L-PBF due to the finer grains formed by faster cooling in LFP. Also, oxidation in LFP-fabricated parts was less compared with that in L-PBF fabricated parts because of smaller surface area in metal foil compared with metal powder. The density ( > 99.3%) of Al-1100 aluminum alloy parts fabricated by LFP was much higher than the density ( < 90%) of Al-1100 parts fabricated by L-PBF because of no air gaps in foil like those in powder particles. A fully automated LFP system was constructed and used to automatically fabricate 304L parts with various geometries. The parts’ dimensional accuracies and their mechanical properties were measured. These parts exhibited higher tensile strength than those fabricated by other laser additive manufacturing technologies"--Abstract, page iv.

Advisor(s)

Leu, M. C. (Ming-Chuan)

Committee Member(s)

Liou, Frank W.
Chandrashekhara, K.
Pan, Heng
O'Malley, Ronald J.

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Comments

This work was supported by the Department of Energy [grant number DE- FE0012272], the Intelligent Systems Center at the Missouri University of Science and Technology, and the Keith and Pat Bailey Professorship fund from the Missouri University of Science and Technology.

Research Center/Lab(s)

Intelligent Systems Center

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2021

Journal article titles appearing in thesis/dissertation

  • Enhanced mechanical properties for 304L stainless steel parts fabricated by laser-foil-printing additive manufacturing
  • Aluminum parts fabricated by laser-foil-printing additive manufacturing: Processing, microstructure, and mechanical properties
  • The effect of laser welding modes on mechanical properties and microstructure of 304L stainless steel parts fabricated by laser-foil-printing additive manufacturing
  • Development and experimental study of an automated laser-foilprinting additive manufacturing system

Pagination

xiv, 107 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2021 Chia-Hung Hung, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11837

Electronic OCLC #

1262050462

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