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Lazarus, David Jackson, Mark Sennett 2011-07-05T18:16:05Z 2011-07-05T18:16:05Z 10000-01-01 1976 The isotope effect for diffusion of in Ti has been measured at five temperatures in the bcc G-phase. Separation of the Sn isotopes was effected by 3-spectroscopy on electroplated sources. The effect is small and highly temperature-dependent, varying from 0.18 ± 0.03 at 9720 C to 0.37 ± 0.03 at 15250 C. When corrected for the mass difference between the Sn tracers used and the Ti solvent, the magnitude of the effect seems to be consistent with a relaxed vacancy mechanism as observed in normall bcc metals. Between 1100 and 12000 C the isotope effect parameter increases quite rapidly. The temperature variation seems to be inconsistent with the hypothesis that two competing mechanisms of bulk diffusion operate over the bee temperature range. The data do seem to be consistent with three possible mechanisms for diffusion: enhancement by dislocation networks which anneal out at higher temperatures, enhancement due to the presence of w-embryos at low temperatures, and diffusion by highly relaxed vacancies with a large coefficient of thermal expansion and specific heat of formation. The last explanation is preferred. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-05T18:16:05Z No. of bitstreams: 1 1976_jackson.pdf: 1923770 bytes, checksum: 3123a4e11af36cedd6fb945f607fdd6b (MD5) Made available in DSpace on 2011-07-05T18:16:05Z (GMT). No. of bitstreams: 1 1976_jackson.pdf: 1923770 bytes, checksum: 3123a4e11af36cedd6fb945f607fdd6b (MD5) Previous issue date: 1976 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-05T18:16:05Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:32:40-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 1940732 http://hdl.handle.net/2142/25657 en 1976 Mark Sennett Jackson isotope effect diffusion of tin beta-titanium bcc tin isotopes Isotope effect for diffusion of tin in beta-titanium Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.