Les intermétalliques : des superalliages aux quasicristaux
J. Phys. IV France 06 (1996) C2-15-C2-20
EXAFS Study of the Local Atomic Order in Ti2AlX (X=Nb, Mo) B2 Intermetallic CompoundsT. Sikora1, G. Hug1, M. Jaouen2 and A.-M. Flank3
1 Laboratoire d'Etudes des Microstructures, ONERA-CNRS, BP. 72, 92322 Châtillon, France
2 Laboratoire de Métallurgie Physique, URA 131 du CNRS, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France
3 Laboratoire d'Utilisation du Rayonnement Electromagnétique, CNRS-CEA-MEN, Centre Universitaire de Paris Sud, Bât. 209D, 91405 Orsay cedex, France
Extended X-ray absorption fine-structure (EXAFS) has been used to study the local atomic order in Ti2AlMo and Ti2AlNb in the B2 phase. It is found that the Mo and Nb atoms have different behaviors. Whereas the Ti2AlMo alloy is ordered as a pseudo-B2 structure in which the Mo and Al atoms are localized on one site and Ti atoms on the other, the Ti2AlNb alloy exhibits a more disordered behavior since the Nb and the Ti atoms are distributed on both sites. EXAFS experiments allowed us to quantify the fraction of Nb on each site in Ti2AlNb as well as the bond lengths in both alloys.
© EDP Sciences 1996