Doctoral Dissertations

Jingwei Zhang

Keywords and Phrases

Additive Manufacturing; Cellular Automaton; Finite Element; Mechanical Properties; Microstructure; Simulation

Abstract

"Microstructure and properties of Direct Metal Deposition (DMD) parts are very crucial to meeting industrial requirements of parts quality. Prediction, and control of microstructure and mechanical properties have attracted much attention during conventional metal manufacturing process under different conditions. However, there is few investigations focused on microstructure simulation and mechanical properties control under different process parameters during DMD process. This dissertation is intended to develop a multiscale model to investigate Ti6Al4V grain structure development and explore Ti6Al4V based functionally graded material (FGM) deposit properties during DMD process. The first research topic is to investigate and develop a cellular automaton-finite element (CA-FE) coupled model to combine with thermal history and simulate nucleation sites, grain growth orientation and rate, epitaxial growth of new grains, remelting of preexisting grains, metal addition, and grain competitive growth. The second research topic is to develop grain growth algorithm, which is appropriate for highly non-uniform temperature field and high cooling rate, to control grain structure under real-time changing process parameters. The third research topic is to investigate the influence of process parameters on microstructure and properties of Ti6Al4V-based FGMs, which are fabricated with different TiC volume fraction from 0 to 30vol%. The microstructure, Vickers hardness, phase identification, tensile properties of FGM are measured to investigate the fabricated FGM qualities. The Digital Image Correlation (DIC) is developed to analyze Young's modulus versus composition of FGM parts"--Abstract, page iv.

Advisor(s)

Liou, Frank W.

Committee Member(s)

Homan, Kelly
Newkirk, Joseph William
Chandrashekhara, K.
Pan, Heng

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Sponsor(s)

Laser Aided Manufacturing Processes (LAMP) Laboratory
Langley Research Center

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2018

Journal article titles appearing in thesis/dissertation

  • A coupled finite element cellular automaton model to predict thermal history and grain morphology of Ti6Al4V during direct metal deposition (DMD)
  • A two-dimensional simulation of grain structure growth within substrate and fusion zone during direct metal deposition
  • Microstructure and properties of functionally graded materials Ti6Al4V/TiC fabricated by direct laser deposition

Pagination

xii, 82 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2018 Jingwei Zhang, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11329

Electronic OCLC #

1041858921

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