Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Mechanical Engineering
Characterization Of Dislocation - Grain Boundary Interactions Through Electron Backscatter Diffraction, Landon Thomas Hansen
Characterization Of Dislocation - Grain Boundary Interactions Through Electron Backscatter Diffraction, Landon Thomas Hansen
Theses and Dissertations
Further understanding of dislocation-GB interactions is critical to increasing the performance of polycrystalline metals. The research contained within this dissertation aims to further dislocation-GB interaction understanding through three research studies. First, the effect of noise in EBSPs on GND calculations was evaluated in order to improve dislocation characterization via HR-EBSD. Second, the evolution of GNDs and their effects on back stress was studied through experimental and computational methods applied to tantalum oligo specimens. Third, statistical analysis was used to evaluate grain parameters and current GB transmission parameters on their correlation with dislocation accumulation.
An Atomistic Approach For The Survey Of Dislocation-Grain Boundary Interactions In Fcc Nickel, Devin William Adams
An Atomistic Approach For The Survey Of Dislocation-Grain Boundary Interactions In Fcc Nickel, Devin William Adams
Theses and Dissertations
It is well known that grain boundaries (GBs) have a strong influence on mechanical properties of polycrystalline materials. Not as well-known is how different GBs interact with dislocations to influence dislocation movement. This work presents a molecular dynamics study of 33 different FCC Ni bicrystals subjected to mechanical loading to induce incident dislocation-GB interactions. The resulting simulations are analyzed to determine properties of the interaction that affect the likelihood of transmission of the dislocation through the GB in an effort to better inform mesoscale models of dislocation movement within polycrystals. It is found that the ability to predict the slip …
An Examination Of The Indentation Size Effect In Fcc Metals And Alloys From A Kinetics Based Perspective Using Nanoindentation, David Earl Stegall
An Examination Of The Indentation Size Effect In Fcc Metals And Alloys From A Kinetics Based Perspective Using Nanoindentation, David Earl Stegall
Mechanical & Aerospace Engineering Theses & Dissertations
The indentation size effect (ISE) in metals is described as the rise in hardness with decreasing depth of indentation and contradicts conventional plasticity behavior. The goal of this dissertation is to further examine the fundamental dislocation mechanisms that may be contributing to the so-called indentation size effect. In this work, we examined several metals and alloys including 99.999% Aluminum (SFE ~200 mJ/m2), 99.95% Nickel (SFE ~125 mJ/m2), 99.95% Silver (SFE ~22 mJ/m2), and three alloys, alpha brass 70/30 (SFE >10 mJ/m2), 70/30 nickel copper (SFE ~100 mJ/ …