The microstructure and plastic deformation of Al-rich single crystals which contained 54.7 or 58.0at%Al were examined. Attention was focussed upon the effect of chemical ordering, of an Al5Ti3 superstructure, upon anomalous strengthening. Fine precipitates with the Al5Ti3 superstructure developed in the L10 matrix of the Ti-58.0at%Al alloy. The size and volume fraction of the precipitates varied, depending upon the temperature. An anomalous increase in the yield stress of the 2 alloys occurred at about 800C. The strengthening mechanism was explained on the basis of a difference in antiphase boundary energies on the (111), (110) and (001) planes of the Al5Ti3 phase.

Stress Anomaly in Al-Rich Ti-Al Single Crystals Deformed by the Motion of ½<110] Ordinary Dislocations T.Nakano, K.Hagihara, T.Seno, N.Sumida, M.Yamamoto, Y.Umakoshi: Philosophical Magazine Letters, 1998, 78[5], 385-91