Nanoscience and Nanotechnology Commons^™

Failure Simulations At Multiple Length Scales In High Temperature Structural Alloys, Chao Pu

Doctoral Dissertations

A number of computational methodologies have been developed to investigate the deformation and damage mechanism of various structural materials at different length scale and under extreme loading conditions, and also to provide insights in the development of high-performance materials.

In microscopic material behavior and failure modes, polycrystalline metals of interest include heterogeneous deformation field due to crystalline anisotropy, inter/intra grain or phase and grain boundary interactions. Crystal plasticity model is utilized to simulate microstructure based polycrystalline materials, and micro-deformation information, such as lattice strain evolution, can be captured based on crystal plasticity finite element modeling (CPFEM) in ABAQUS. The comparison …

Ion Irradiation-Induced Microstructural Change In Sic, Chien-Hung Chen

Doctoral Dissertations

The high temperature radiation resistance of nuclear materials has become a key issue in developing future nuclear reactors. Because of its mechanical stability under high-energy neutron irradiation and high temperature, silicon carbide (SiC) has great potential as a structural material in advanced nuclear energy systems.

A newly developed nano-engineered (NE) 3C SiC with a nano-layered stacking fault (SFs) structure has been recently considered as a prospective choice due to enhanced point defect annihilation between layer-type structures, leading to outstanding radiation durability.

The objective of this project was to advance the understanding of gas bubble formation mechanisms under irradiation conditions in …

Atomistic Modeling Of Hydrogen Storage In Nanostructured Carbons, Lujian Peng

Doctoral Dissertations

Nanoporous carbons are among the widely studied and promising materials on hydrogen storage for on-board vehicles. However, the nature of nanoporous carbon structures, as well as the relationship between local structure and hydrogen adsorption are still unclear, and hinder the design of carbon materials for optimum hydrogen storage. This dissertation presents a systematic modeling effort of hydrogen storage in nanoporous carbon materials. Tight binding molecular dynamics simulations are utilized to simulate the amorphous carbons over a wide range of density. The resulting structures are in good agreement with experimental data of ultra-microporous carbon (UMC), a wood-based activated carbon, as indicated …