DISLOCATIONS IN AS-CAST AND DEFORMED SAMPLES OF TI3AL AND TI-25AL-4NB

The observations reported show that the dissociation of 1/3 112 OVER BAR 0 direction dislocations in dipoles in Ti//3Al is on the order of 6nm if it is assumed, as is reasonable for deformation carried out at 300 degree C, that the dissociation occurs by glide on left brace 11 OVER BAR 00 right brace . In order to derive a value for the antiphase boundary energy from such observations, detailed calculations and image simulation are underway. The apparent separation observed both here and in the earlier work of Thomas et al. of between 8 and 15nm in dislocation networks lying on high index planes in as-cast and homogenized samples is not fully understood.