Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés
J. Phys. IV France 03 (1993) C7-435-C7-440
"Optimisation" of imaging conditions for weak beam studies of dislocation core structures in Ti3AlJ.M.K. WIEZOREK
Department of Materials Science & Metallurgy, University of Cambridge, Pembroke St., Cambridge CB2 3QZ, U.K.
The imaging conditions for weak bearn (WB) studies of dislocations in Ti3A1 with intermediate voltage transmission electron microscopes have been derived following a theoretical examination of the traditional criteria for WB-microscopy. The cores of <2c+a>-dislocations in room temperature deformed Ti3Al have been characterised in a case study with 300kV electrons by experimental WB-microscopy, which used imaging conditions not satisfying the traditional WB criteria. Image simulations facilitated the determination of the corrected dislocation dissociation widths for dissociated edge character dislocations. A superpartial separation of 19.5nm has been deterrnined from experimentally observed image peak separations of (21±1)nm for the edge dislocation cores.
© EDP Sciences 1993