Constitutional and thermal defects in B82-SnTi2

被引：11

作者：

Colinet, Catherine ^{[1
]}

Tedenac, Jean-Claude ^{[2
]}

机构：

[1] Inst Natl Polytech Grenoble, UJE, CNRS, UMR 5266, F-38402 St Martin Dheres, France

[2] Univ Montpellier 2, CNRS, ICG, Inst Chim Mol & Mat,UMR 5253, F-34095 Montpellier, France

来源：

INTERMETALLICS | 2009年 / 17卷 / 05期

关键词：

Intermetallics; Phase diagram; Point defects; Site occupancy; Ab initio calculations; EFFECTIVE FORMATION ENERGIES; AB-INITIO CALCULATION; POINT-DEFECTS; ATOMIC DEFECTS; INTERMETALLIC PHASES; DIFFUSION; SIMULATION; VOLUMES; SYSTEM; NI3AL;

D O I：

10.1016/j.intermet.2008.11.014

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Vacancy and antisite defect formation energies in B8(2)-SnTi2 are calculated by an ab initio approach. Three sublattices are introduced to account for the B8(2) structure. A statistical model based on a mean-field approximation is developed in the canonical ensemble. The defect concentrations are calculated as function of temperature and deviation from stoichiometry. For stoichiometric B8(2)-SnTi2 alloys, the dominant thermal defects are composed of one antisite Ti atom and three Ti vacancies. In the Sn-rich B8(2)-SnTi2, the constitutional defects are Ti vacancies; the thermal defect below 1000 K is an interbranch where Ti vacancies are replaced by Sn antisites; at high temperatures, it is a four point-defect comprising one Ti antisite and three Ti vacancies. In the Ti-rich B8(2)-SnTi2, the constitutional defects are antisite Ti atoms and the thermal defect is a four point defect comprising one Ti antisite and three Ti vacancies. The effective defect formation enthalpies are derived at low temperature. The Gibbs energy as well as the Sn and Ti chemical potentials in B8(2)-SnTi2 phase are obtained as function of composition for various temperatures. The extension of the one-phase domain of B8(2)-SnTi2 in the Sn-Ti phase diagram is discussed. (C) 2008 Elsevier Ltd. All rights reserved.

引用

页码：291 / 304

页数：14

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