CHANGEMENTS DE PHASES ET MICROSTRUCTURES
J. Phys. IV France 04 (1994) C3-65-C3-73
Weak beam study of antiphase boundaries in Fe-27%Al as a function of temperatureC. BARRETEAU1, A. LOISEAU2, C. RICOLLEAU2 and F. DUCASTELLE1
1 Office National d'Etudes et de Recherches Aérospatiales, ONERA, Direction des Matériaux, BP. 72, 92322 Chatillon cedex, France
2 Office National d'Etudes et de Recherches Aérospatiales, ONERA, Direction des Matériaux et Laboratoire d'Etude des Microstructures, CNRS-ONERA, BP. 72, 92322 Chatillon cedex, France
The study by electron microscopy of the fringes due to planar defects such as antiphase boundaries (APB) is not a new problem, and the equations describing this phenomenon are well-known, but the effect on electron diffraction of the broadening with temperature of these boundaries close to order-disorder transitions is a new field of investigation. We show here that a careful study of the behaviour of the fringes generated by the APB in dark field images is a good method to analyze the different order-disorder transitions. In particular we describe in detail a quantitative method that allows us to determine the correlation length ξ below a second order transition.
© EDP Sciences 1994