Synthesis, Consolidation, and Mechanical Testing of Nanophase Metals

Indentation creep experiments were performed on nanocrystalline copper and palladium specimens and also on sinterforged Ti-48Al specimens. The copper and palladium specimens showed a higher creep rate than their microcrystalline counterparts, exhibiting creep even at room temperature. The activation energies for both specimens are lower than activation energy for grain boundary diffusion in microcrystalline materials. A model is proposed to explain the higher creep rate. It assumes that the specimens produced from vapor condensed powders have a higher grain boundary energy due to a higher disorder in their grain boundary structure. Contrary to the pure metal specimens, the sinterforged Ti-48Al specimens exhibited an activation energy close to that for lattice diffusion in the microcrystalline alloy and also the activation energy determined from the sinterforging experiments.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science and Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Kim, Lisa Sungwoon

Contributors dc:contributor

• Averback, R.S.

• Engineering, Metallurgy

Language dc:language

eng

Identifier

(MiAaPQ)AAI9812654

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/82888