Detection of phase and antisite structure of Ti-Al alloys by Al-27 solid state nuclear magnetic resonance

Smith, M.E. and Gibson, M.A. and Forwood, C.T. and Bastow, T.J. (1996) Detection of phase and antisite structure of Ti-Al alloys by Al-27 solid state nuclear magnetic resonance. Philosophical Magazine a-Physics of Condensed Matter Structure Defects and Mechanical Properties, 74 (3). pp. 791-809. ISSN 0141-8610. (The full text of this publication is not available from this repository)

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Abstract

Static room-temperature Al-27 nuclear magnetic resonance (NMR) spectra for Tit-xAlx alloys in the range 0.25 less than or equal to x less than or equal to 0.55 are reported for the first time. The main resonances associated with the alpha(2) and gamma phases are clearly identified. The spectra follow the phase distribution in that, for samples annealed at 1473 K for 6h in the range 0.43 less than or equal to x less than or equal to 0.48, resonances from both alpha(2) and gamma are observed. Careful quantitative analysis of the Al-27 NMR spectra indicates that from single-phase samples all aluminium nuclei from the central transition are recorded, whereas for two-phase samples there is a loss of signal that is a consequence of the two-phase alloy microstructure. For the gamma-phase the NMR centre band shows a distinctive, largely second-order quadrupolar line shape together with associated satellite transitions which yield a quadrupolar coupling constant C-Q = 8.15 MHz and an axial Knight shift anisotropy of 130 ppm. For the alpha(2) phase the centre-band simulation requires only an axial Knight shift anisotropy of 270 ppm and no quadrupolar interaction. An additional resonance associated with the gamma-phase is also detected and quantified, and this is attributed to aluminium on antisites.

Item Type: Article
Subjects: Q Science > Q Science (General)
Divisions: Faculties > Science Technology and Medical Studies > School of Computing > Applied and Interdisciplinary Informatics Group
Depositing User: P. Ogbuji
Date Deposited: 27 May 2009 07:56
Last Modified: 30 May 2012 08:31
Resource URI: http://kar.kent.ac.uk/id/eprint/18510 (The current URI for this page, for reference purposes)
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