H. Emori et al., HIGH-RESOLUTION ELECTRON-MICROSCOPY OF GRAIN-BOUNDARIES IN NI-3(AL0.8TI0.2) BICRYSTALS .1. [001]SMALL-ANGLE TILT BOUNDARIES, Philosophical magazine. A. Physics of condensed matter. Structure, defects and mechanical properties, 75(5), 1997, pp. 1403-1416
The grain-boundary structure of [001] small-angle tilt boundaries in L
l(2)Ni(3)(Al0.8Ti0.2) bicrystals prepared by hot pressing was investig
ated by high-resolution transmission electron microscopy. Dislocations
with a Burgers vector a[100] which are dissociated into two superpart
ials with Burgers vectors (a/2)[110] and (a/2)[<1(1)over bar0>] connec
ted by an antiphase boundary (APE) were found. The dissociated superpa
rtials and the corresponding APE lie along the grain-boundary plane. T
he cores of the dissociated superpartials extend (or spread) over a fe
w (011) atomic planes. Also, the preferred configuration of the disloc
ation array observed was discussed on energy considerations.