Doctoral Dissertations
Keywords and Phrases
Additive Manufacturing; Domain Decomposition; Melt Spinning; Parallel Computation; Phase Field; Rapid Solidification
Abstract
"Many advanced manufacturing processes such as additive manufacturing utilize rapid solidification of alloys, as it enables the formation of exotic non-equilibrium microstructure and thus improved properties. However, the interrelationship between the processing parameters and the resulting microstructure in rapid solidification is yet to be fully understood. We aim to investigate the microstructure evolutions during the rapid solidifications using phase-field modeling. The phase-field method assumes a diffuse interface, which avoids tracking the moving interface and hence enables efficient numerical simulations for complex microstructure evolution. A phase-field model with coupled solute-thermal diffusion and solute trapping effect is developed to investigate the rapid solidification of alloys. First a one-dimensional version is applied to investigate additive manufacturing and melt spinning. The variation of key variables of the solid-liquid interface throughout the rapid solidification of both processes are analyzed. It is found that the onset of nucleation determines the selection of solidification pathways and consequently the evolution of temperature and interface velocity. To capture the complex solidification patterns and morphologies that cannot be fully described in one dimension, a two-dimensional (2D) phase-field model is developed using domain decomposition method to leverage the capabilities of parallel computing. This model can be employed to simulate anisotropic growth patterns like columnar, and cellular/dendritic morphologies. The impact of thermal diffusion on the rapid solidification of a dilute alloy is examined through the study of isothermal holding and continuous cooling conditions. The results demonstrate that the effect of thermal diffusion depends strongly on the growth velocity"-- Abstract, p. iii
Advisor(s)
Gu, Yijia
Committee Member(s)
Emdadi, Arezoo
Newkirk, Joseph William
O'Malley, Ronald J.
He, Xiaoming
Department(s)
Materials Science and Engineering
Degree Name
Ph. D. in Materials Science and Engineering
Publisher
Missouri University of Science and Technology
Publication Date
Spring 2025
Pagination
ix, 96 pages
Note about bibliography
Includes_bibliographical_references_(pages 91-95)
Rights
©2024 Nima Najafizadeh , All Rights Reserved
Document Type
Dissertation - Open Access
File Type
text
Language
English
Thesis Number
T 12466
Recommended Citation
Najafizadeh, Nima, "Phase-Field Modeling Of Rapid Solidification Processes" (2025). Doctoral Dissertations. 3363.
https://scholarsmine.mst.edu/doctoral_dissertations/3363
