Stress anomaly in Al-rich Ti-Al single crystals deformed by the motion of 1/2 <110> ordinary dislocations

摘要

The microstructure and plastic deformation behaviour of Al-rich Ti-Al single crystals containing 54.7 and 58.0 at.% Al have been examined, focusing on the effect of chemical ordering of a Al_5Ti_3 superstructure on anomalous strengthening. Fine precipitates with the Al_5Ti_3 superstructure were developed in the L1_0 matrix of the Ti-58.0 at.% Al alloy. The size and volume fraction of the precipitates varied depending on temperature. An anomalous increase in the yield stress of the two alloys appeared at around 800 ℃. This strengthening mechanism is discussed on the basis of the difference in antiphase-boundary energies on (111), (110) and (001) planes in the Al_5Ti_3 phase.