Shear deformation of amorphous and nanocrystalline copper microstructures via atomistic simulation

In the well-known Hall-Petch behavior, yield and flow stresses in polycrystalline metals increase with a decrease in grain size. As grain size continues to decrease, mechanical strength peaks. As grain size further decreases, mechanical strength begins to decrease. As grain size approaches zero, the total structure is composed of an increasingly high percentage of grain boundaries, which exhibit the properties of an amorphous structure. Molecular dynamics simulations, with the goal of exploring this behavior, were performed on nanocrystalline and amorphous microstructures using the embedded atom potential developed by Mishin et al. A 0.2 shear strain was applied to each of the nanocrystalline and amorphous samples. From these simulations, we have observed the inverse Hall-Petch behavior of nanocrystalline structures. We have also shown that the amorphous structure as zero grain size is reasonable as the limiting case for the inverse Hall-Petch trends in nanocrystalline structures.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Gandy, David R

Advisor dc:contributor.advisor

• Sidney Yip.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/40424

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/40424