title: Temperature-dependent elastic stiffness constants of α- and θ-Al2O3 from first-principles calculations.
abstract: Temperature-dependent elastic stiffness constants (c(ij)s), including both the isothermal and isoentropic ones, have been predicted for rhombohedral α-Al(2)O(3) and monoclinic θ-Al(2)O(3) in terms of a quasistatic approach, i.e., a combination of volume-dependent c(ij)s determined by a first-principles strain versus stress method and direction-dependent thermal expansions obtained by first-principles phonon calculations. A good agreement is observed between the predictions and the available experiments for α-Al(2)O(3), especially for the off-diagonal elastic constants. In addition, the temperature-dependent c(ij)s predicted herein, in particular the ones for metastable θ-Al(2)O(3), enable the stress analysis at elevated temperatures in thermally grown oxides containing α- and θ-Al(2)O(3), which are crucial to understand the failure of thermal barrier coatings in gas-turbine engines.
authors.affiliation: Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, USA. sus26@psu.edu
authors.forename: Shun-Li
authors.initials: SL
authors.lastname: Shang
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Zi-Kui
authors.initials: ZK
authors.lastname: Liu
mesh_terms: D000465:Algorithms; D000537:Aluminum Oxide / Q000737:chemistry*; D003460:Crystallization / Q000379:methods; D004548:Elasticity; D013696:Temperature
chemical_list: D000537:Aluminum Oxide