Interactions between dislocations and twins in deformed titanium aluminide crystals

Guang Yang^1,2，Shang-Yi Ma²，Kui Du²，Dong-Sheng Xu³，Sen Chen^1,2，Yang Qi⁴，Heng-Qiang Ye^1,2

1. School of Materials Science and Engineering, Northeastern University2. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences3. Division of Titanium Alloys, Institute of Metal Research, Chinese Academy of Sciences4. Department of Materials Physics and Chemistry, School of Materials Science and Engineering, Northeastern University

摘 要：Using scanning, transmission electron microscopy and aberration-corrected scanning transmission electron microscopy, we have studied the interactions between dislocations and twins in impact deformed polysynthetic twinned TiAl crystal. The 1/3 < 111] and 1/6 < 211] step dislocations on coherent twin boundaries reveal the interactions of glissile 1/2 < 101> dislocations with the coherent twin boundaries.An abnormal stacking fault was found adjacent to the coherent twin boundary. It has the same stacking sequence but different atom species in the [110] direction with an additional displacement of 1/4[110]in two neighboring {111} layers, and is likely induced by the slip of a 1/12[112]（i.e. 1/4[110] + 1/6[211]）dislocation.

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