Open AccessOn the small angle twist sub-grain boundaries in Ti3AlC2
Author(s) -
Hui Zhang,
Chao Zhang,
Tao Hu,
Xun Zhan,
Xiaohui Wang,
Yanchun Zhou
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep23943
Subject(s) - grain boundary , twist , materials science , dislocation , stacking fault energy , deformation (meteorology) , crystallography , atomic units , condensed matter physics , grain boundary strengthening , tilt (camera) , stacking , phase (matter) , deformation mechanism , partial dislocations , geometry , microstructure , composite material , physics , chemistry , nuclear magnetic resonance , mathematics , quantum mechanics
Tilt-dominated grain boundaries have been investigated in depth in the deformation of MAX phases. In stark contrast, another important type of grain boundaries, twist grain boundaries, have long been overlooked. Here, we report on the observation of small angle twist sub-grain boundaries in a typical MAX phase Ti 3 AlC 2 compressed at 1200 °C, which comprise hexagonal screw dislocation networks formed by basal dislocation reactions. By first-principles investigations on atomic-scale deformation and general stacking fault energy landscapes, it is unequivocally demonstrated that the twist sub-grain boundaries are most likely located between Al and Ti4 f (Ti located at the 4 f Wyckoff sites of P 6 3 / mmc ) layers, with breaking of the weakly bonded Al–Ti4 f . The twist angle increases with the increase of deformation and is estimated to be around 0.5° for a deformation of 26%. This work may shed light on sub-grain boundaries of MAX phases, and provide fundamental information for future atomic-scale simulations.