High-Resolution TEM Observations of Superdislocations in Ni3(Al, Ti)

Abstract

End-on images of dislocations in Ni3(Al, Ti) single crystals deformed at 683 and 293 K were observed by high-resolution transmission electron microscopy. They showed a superlattice intrinsic stacking fault (SISF) type of dissociation on a {111} plane and an antiphase boundary (APB) type of dissociation on a {001} plane. SISF and APB energies were calculated to be 133 and 560 mJ/m2, respectively, using an isotropic elasticity theory, and they were compared with the other results obtained by field ion microscopy, weak-beam technique and high-resolution electron microscopy. It is considered that a decrease of dissociation distance due to the Ti addition results in an increase of strength anomaly. © 1992, The Japan Institute of Metals. All rights reserved.