Document Type
Dissertation - Open Access
Award Date
2026
Degree Name
Doctor of Philosophy (PhD)
Department / School
Mechanical Engineering
First Advisor
Yucheng Liu
Abstract
Metallic materials exhibit process–structure–property relationships that arise from physical mechanisms operating across multiple length and time scales. Atomistic processes control diffusion, thermal response, and interfacial behavior; mesoscale mechanisms govern grain morphology, interface migration, and microstructure evolution; full-field crystal-plasticity calculations resolve heterogeneous mechanical fields; and continuum-scale finite-element (FE) models connect material response to component-level deformation, damage, and performance. Because no single simulation method can resolve all of these mechanisms, predictive modeling requires a framework in which information obtained at one scale can be transferred to the next. This dissertation develops a multiscale computational framework that bridges molecular dynamics (MD), phase-field (PF) modeling, and elasto-viscoplastic fast Fourier transform-based (EVPFFT) crystal plasticity simulations for metallic materials. At the atomistic scale, MD simulations of the aluminum–silicon (Al–Si) system are used to compute thermophysical, interfacial, and kinetic quantities relevant to aluminum foam systems, including self-diffusion coefficients, specific heat capacity, solid–liquid interfacial energy, and grain-boundary mobility. These quantities provide physically informed inputs for PF formulations and establish the atomistic-to-mesoscale connection within the framework. The PF method is then used to describe grain growth and recrystallization and is coupled with EVPFFT-based crystal plasticity to simulate static recrystallization (SRX) in three-dimensional polycrystalline copper. In the coupled formulation, the PF model describes nucleation, grain growth, and grain-boundary migration, while the EVPFFT solver computes the heterogeneous stress, strain, and stored deformation-energy fields generated during plastic deformation. A subcycling strategy exchanges grain identity, crystallographic orientation, and mechanical-field information between the two solvers as the simulation proceeds, allowing the mechanical response to be updated as recrystallization proceeds and the microstructure evolves. Overall, this dissertation demonstrates how atomistic, mesoscale, and full-field mechanical modeling approaches can be integrated into a unified computational framework for the design and analysis of metallic materials. The Al–Si system is used to establish the MD-informed PF parameterization, while copper is used to develop and validate the coupled PF–EVPFFT recrystallization model. The framework provides a foundation for studying microstructural evolution, recrystallization kinetics, mechanical-field redistribution, and process–structure–property relationships, with future extensions toward texture evolution, dynamic recrystallization (DRX), and thermomechanical processing.
Publisher
South Dakota State University
Recommended Citation
Jouhari, Chaimae, "A Multiscale Computational Framework Bridging Molecular Dyanmics, Phase-Field, and Elasto–Viscoplstic Fast Fourier Transform: Applications to Process–Structure–Property Relationships in Metallic Materials" (2026). Electronic Theses and Dissertations. 2125.
https://openprairie.sdstate.edu/etd2/2125
Rights Statement
