In pure D03 ordered Fe3Al single crystals with low C content the yield stress showed a pronounced drop in a narrow range around 375K, connected with the movement of single partial dislocations with extended antiphase boundaries at lower, and of complete super-dislocations at higher temperatures. This was supported by measurements of the temperature and strain rate dependence of the critical resolved shear stress in the lower temperature regime and their quantitative analysis according to Seeger’s kink-pair nucleation theory. The rapid transition between these two regimes was explained by positive feedback mechanisms which stabilize the different situations, based on the relative frequencies of kink-pair nucleation and motion.

Yield Stress and Dislocation Mechanisms in the D03 Ordered Intermetallic phase Fe3Al in the Temperature Range, 240–500K. A.Brinck, H.Neuhäuser: Materials Science and Engineering A, 2004, 387-389, 969-72