Doctoral Dissertations

Tianju Chen

Keywords and Phrases

Crystal Plasticity; Crystallographic orientation; Dislocations; Finite Element Model; Strength; Superalloys

Abstract

“Ni-based superalloy is considered as a good candidate due to its excellent resistance to elevated temperature deformation for long term period application. Understanding the deformation and failure mechanisms of Ni-Based superalloys is very helpful for providing design guidelines for processing Ni-based superalloys. Experimental characterization indicates that the deformation mechanisms of Ni based superalloy is strongly microstructure dependent. Besides, damage transform from the void nucleation to the macro cracks by voids growth leading to the failure of the Ni-based superalloys are also showing strong microstructure sensitivity. Therefore, this work focuses on the prediction and comprehension of the deformation and void growth behavior in Ni based superalloy at different working conditions via crystal plasticity finite element modeling and simulation.

Physically based crystal plasticity frameworks were developed for newly Ni-based superalloy Haynes 282. It was found that dislocation shearing through the precipitates were acting as the main contributor to the strength of Haynes 282 at room temperature and 8150⁰ C. Our analysis of the creeping behavior of Haynes 282 exhibited that resistance of general climb replaced by the resistance induced by the deposited climb dislocation density. In addition, in the study of void growth behavior, our simulation results demonstrated that as the main loading axis perpendicular to the grain boundary (GB), voids grow more slowly on tilt GBs in bicrystals than those in single and bicrystals with twist GBs. And tilt GBs would promote the void grow into irregular shape”--Abstract, page iv.

Advisor(s)

Zhou, Caizhi

Committee Member(s)

Wen, Haiming
Bartlett, Laura
Newkirk, Joseph William
Gao, Stephen S.

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Materials Science and Engineering

Comments

This work was supported by the grants from DOE-NETL Crosscutting Research Program (No. FE0031554).

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2020

Journal article titles appearing in thesis/dissertation

  • Predicting the high temperature deformation behavior of Ni-based superalloys by a dislocation-density based crystal plasticity model
  • Crystal plasticity modeling of void growth on grain boundaries in Ni-based superalloys

Pagination

xvi, 89 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2020 Tianju Chen, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11739

Electronic OCLC #

1198498985

Download

Share

 
COinS