Interest in titanium for mass-scale applications has driven an exploration for rapid, cost-effective consolidation of titanium powders. The effects of electric current and pressure on binary diffusion in beta phase titanium niobium are studied to enhance understanding of Spark Plasma Sintering (SPS), an advanced powder consolidation technology. Binary diffusion couples were annealed in the SPS system, as well as a custom-fabricated load-free furnace, for one hour to elucidate the influences of pressure and current at 1000, 1100, and 1150 °C. The results show Ti-Nb interdiffusion coefficient dependence on composition, temperature, current, and pressure. Compared to published results, the activation energy for low concentration Nb, 10-22 at%, has shown to be reduced in the SPS by an average 38kJ/mol at 15MPa and 70kJ/mol at 80MPa. The effect on activation energy of direct current without pressure, at a similar current density as the SPS, shows an average decrease of 105kJ/mol. The possible mechanisms for these changes are discussed, and concepts for subsequent studies are provided.
|Advisor:||Lavernia, Enrique J.|
|Commitee:||Earthman, James C., Mumm, Daniel R.|
|School:||University of California, Irvine|
|Department:||Materials Science and Engineering|
|School Location:||United States -- California|
|Source:||MAI 58/01M(E), Masters Abstracts International|
|Subjects:||Engineering, Materials science|
|Keywords:||Interdiffusion, Niobium, Spark plasma sintering, Titanium|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be