It was noted that ordinary dislocations in γ-TiAl frequently cross-slipped onto various non-primary slip planes at high temperatures, and that anomalous hardening was

attributed to such cross-slip behavior. The stability of ordinary dislocations, and the interaction energy of kink pairs or jog pairs, on these cross-slip planes were therefore examined in order to understand cross-slip. The energy factors and line tensions for ½<110] screw dislocations were calculated on the basis of the sextic formalism. Inverse Wulff plots were used to determine the instability of dislocations on (111), (110) and (001) glide planes. The dislocations were stable, due to the convexity of the plots, and always had a positive line tension. The interaction energy of kink pairs on the cross-slip planes was calculated. The results showed that the interaction energy was highly anisotropic in the cross-slip planes, and was minimum on the (110) plane. This was consistent with published transmission electron microscopic observations. The effects of temperature on the stability and interaction energy were also investigated by using 6 independent elastic constants at various temperatures.

Stability of Ordinary Dislocations on Cross-Slip Planes in γ-TiAl. Z.Jiao, S.H.Whang, M.H.Yoo, Q.Feng: Materials Science and Engineering A, 2002, 329-331, 171-6