Type of Document Dissertation Author Castello Branco, Gilberto URN etd-07182005-163551 Title Effect of Thermo-Mechanical Treatment on Texture Evolution of Polycrystalline Alpha Titanium Degree Doctor of Philosophy Department Mechanical Engineering, Department of Advisory Committee
Advisor Name Title Hamid Garmestani Committee Chair Chiang Shih Committee Member Chuck Zhang Committee Member Justin Schwartz Committee Member Keywords
- Cold and Warm Rolling
Date of Defense 2005-05-16 Availability unrestricted AbstractThe present work attempts to establish a unified path model for characterization as well as prediction of microstructure evolution, in terms of texture, in commercially pure titanium that have undergone thermo-mechanical processing. Two deformation temperatures, room temperature (cold rolling) and 260°C (warm rolling), and five different degrees of deformation, 20%, 40%, 60%, 80% and 95% were used in this investigation. X-ray measurements (texture measurements and peak profile analysis) have been used to characterize the texture and to evaluate the relative activity of the various slips systems activated during the process. Simulations of the resultant textures after each mode of deformation were performed using a crystal plasticity self-consistent scheme, and comparisons, in the form of pole figures, between the experimental results and the predicted deformation textures were performed in order to validate the results obtained from peak profile analysis.
The experimental texture results show that excepting for the samples 95% deformed, the warm rolling has shown to develop a deformed texture different from the cold rolling.
The results of peak profile analysis carried out for the 40%, 60% and 80% warm rolled samples show that the type of dislocation was prevalent in all samples while the
type of dislocation was only marginal. The X-ray peak profile analysis, based on the dislocation model of anisotropic peak broadening, show the dislocation densities, distributions and type during the rolling processing in good agreement with the texture evolution.
Even though twining was not taken into account during simulation of the cold rolled samples, there is a reasonable agreement between the experimental and the predicted pole figures with a small divergence on the distribution of in the TD-RD plane for the higher deformed samples.
The results of simulated deformation texture of warm rolled CP-Ti are in good agreement with the experimental results and with the peak profile analysis findings.
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