J. Phys. IV France 11 (2001) Pr10-21-Pr10-25
Calcul ab initio des enthalpies de formation des composés ZrAl3 et HfAl3C. Colinet1 and A. Pasturel2
1 Laboratoire de Thermodynamique et Physico-Chimie Métallurgiques, CNRS/INPG/UJF, ENSEEG, BP. 75, 38402 Saint-Martin-d'Hères, France
2 Laboratoire de Physique et Modélisation des Milieux Condensés, Maison des Magistères, CNRS, BP. 166, 38042 Grenoble cedex 09, France
The relative stabilities of L12, D022, and D023 structures in ZrAl3 and HfAl3 compounds are investigated employing the Vienna ab initio simulation package (VASP). In ZrAl3 and HfAl3 compounds, the energetic effects related to the tetragonal distortion are important and lead to the stabilization of the D022 and D023 structures with respect to the L12 structure. The effect of the cell internal displacements of the atoms in the D023 structure is studied. In the case of the HfAl3 compound, the D023 structure appears as the most stable structure after this last stage of relaxations. In the case of ZrAl3 compound, the D023 structure is the most stable structure in both distorted and fully relaxed stages of the relaxation. The results are discussed in the framework of an antiphase boundary model.
© EDP Sciences 2001