Journal article
High-temperature neutron diffraction and the temperature-dependent crystal structures of the MAX phases Ti3SiC2 and Ti3GeC2
Physical review. B, v 82(17)
10 Nov 2010
Abstract
Herein, we report on the crystal structures of the isostructural Ti3SiC2 and Ti3GeC2 phases determined by Rietveld analysis of neutron diffraction data in the 100 to 1100 degrees C temperature range. The results show that the Si and Ge atoms vibrate anisotropically with the highest amplitudes and within the basal planes. The equivalent isotropic thermal motion behavior does not differ significantly between the two phases; the anisotropic thermal motion, interatomic distances, and bond angles, however, show strikingly different behavior. Furthermore, while the Ti- Si bonds increase linearly with increasing temperature, the Ti- Ge bonds apparently do not. The anisotropic motion of the Ge atoms in the basal plane with the correlated motion between the Ti and the Ge atoms is invoked as a possible explanation. The volume expansions are 9.0(+/- 0.1) X 10(-6) K-1 and 8.7(+/- 0.1) X 10(-6) K-1 for Ti3SiC2 and Ti3GeC2, respectively; the expansions along the a and c axes are alpha(a) = 8.9 (+/- 0.1) X 10(-6) K-1 and alpha(c)= 9.4 (+/- 0.1) X 10(-6) K-1 for Ti3SiC2 and alpha(a) = 8.5(+/- 0.1) X 10(-6) K-1 and alpha(c) = 9.2(+/- 0.1) X 10(-6) K-1 for Ti3GeC2. A dramatic increase in error bars and a discontinuity in thermal motion parameters of the Ti-II atoms in Ti3GeC2 were also observed between 300 and 500 C during both heating and cooling. This discontinuity may in turn explain why the internal friction rises dramatically in that temperature range.
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Details
- Title
- High-temperature neutron diffraction and the temperature-dependent crystal structures of the MAX phases Ti3SiC2 and Ti3GeC2
- Creators
- Nina J. Lane - Drexel Univ, Dept Mat Sci & Engn, Philadelphia, PA 19104 USASven C. Vogel - Los Alamos Natl Lab, Los Alamos Neutron Sci Ctr, Los Alamos, NM 87545 USAMichel W. Barsoum - Drexel University
- Publication Details
- Physical review. B, v 82(17)
- Publisher
- Amer Physical Soc
- Number of pages
- 11
- Grant note
- U.S. Department of Energy's Office of Basic Energy Sciences; United States Department of Energy (DOE) DE-AC52-06NA25396 / Department of Energy's Office of Basic Energy Sciences under DOE P200A060117 / Graduate Assistance in Areas of National Need for Drexel Research and Education in Advanced Materials (GAANN-DREAM) under the U. S. Department of Education DE-AC52-06NA25396 / DOE; United States Department of Energy (DOE) DMR 0503711 / Ceramics Division of the National Science Foundation
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Materials Science and Engineering
- Web of Science ID
- WOS:000284045600004
- Scopus ID
- 2-s2.0-78649677894
- Other Identifier
- 991019168085804721
InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Materials Science, Multidisciplinary
- Physics, Applied
- Physics, Condensed Matter