Thermodynamic stability and implications of anisotropic boundary particles

(cont.) Generally, a boundary is nonplanar in the neighborhood of an attached particle--even when anisotropic interfacial free energies do not produce faceting-and maintains a icKy = 0 while the boundary particles maintain a nonzero ,Ky. This is consistent with independent observations of Pb-rich particles at grain boundaries in dilute Pb-AI alloys. Predicted particle/boundary morphologies give a trade-off between boundary and particle interface-a particle replaces some boundary but also produces boundary area through local distortions. This result has several implications. The transition to perfect wetting requires a larger boundary energy density. The steady-state heterogeneous nucleation rate is increased when facets appear on the nucleus, but the increase is diminished if the boundary distorts. A corollary result presented in this thesis, that particles can induce rotations or ser- ration through torques, has implications in microstructural stability and illustrates avenues for future research.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Siem, Ellen J. (Ellen Jane), 1979-

Advisor dc:contributor.advisor

• W. Craig Carter and Samuel M. Allen.

• Materials Science and 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

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/27874

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/27874