The plastic deformation of alloys based on aluminum titanide

The thermal stability of a dispersion of rare-earth oxide particles in Ti and Ti$\sb3$Al matrices has been considered analytically and determined experimentally. The solubility product for the formation of erbia (Er$\sb2$O$\sb{3)}$ in a Ti matrix has been calculated using known thermodynamic data which allows the concentration terms in the Lifshitz, Slyozov and Wagner coarsening equation to be calculated. Predictions show that a dispersion will exhibit a greater thermal stability when in a matrix with an excess concentration of oxygen (with respect to that necessary to form the stoichiometric Er$\sb2$O$\sb3$) compared with an excess concentration of erbium. The diffusivity of Er in Ti$\sb3$Al has been approximated on the basis of known thermodynamic and elastic data. This result has been used to estimate the thermal stability of erbia in Ti$\sb3$Al. A model has been developed which describes accelerated Ostwald ripening at moving interfaces. Isothermal and isochronal annealing experiments have been executed on rapidly solidified materials with results which are consistent with the presented predictions.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Lofvander, Jan Per Axel

Contributors dc:contributor

• Fraser, Hamish L.

• Engineering, Metallurgy

Statement dc:rights

• Copyright 1989 Lofvander, Jan Per Axel

Language dc:language

eng

Identifier

AAI9010940
(UMI)AAI9010940

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/20756