Thermodynamic and mechanical stabilities of α- and β-Ta{sub 4}AlC{sub 3} via first-principles investigations
- Department of Materials Science and Engineering, Texas A and M University, College Station, Texas 77843-3123 (United States)
Recently, it has been predicted that Ta{sub 4}AlC{sub 3} is likely to exhibit an (α–β) polymorphic transformation at temperatures above 1873 K. However, recent X-ray diffraction and transmission electron microscopy experiments suggest on the other hand that the α phase remains stable up to temperatures close to the limit of experimental capabilities and no transition has yet been observed. While the matter has already been settled experimentally, in this work, we re-investigate the phase stability problem in Ta{sub 4}AlC{sub 3} by using first-principles methods. The study was carried out by considering both thermodynamic and mechanical stabilities of the Ta{sub 4}AlC{sub 3} polymorphs. Particularly, finite-temperature Gibbs free energies and elastic properties of the polymorphs were calculated using density functional theory. Calculation results reveal that the α phase continue to be stable even at temperatures exceeding 1875 K, which is in agreement with experimental results reported in literature.
- OSTI ID:
- 22258689
- Journal Information:
- Journal of Applied Physics, Vol. 114, Issue 21; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mysterious SiB 3 : Identifying the Relation between α- and β-SiB 3
MAX phase – Alumina composites via exchange reaction in the M{sub n+1}AlC{sub n} systems (M=Ti, V, Cr, Nb, or Ta)