High speed dynamic deformation of polysynthetic twinned titanium aluminide intermetallic compound

Research paper by Guang Yang, Kui Du; Dongsheng Xu; Hui Xie; Wenqing Li; Dingming Liu; Yang Qi; Hengqiang Ye

Indexed on: 05 May '18Published on: 01 May '18Published in: Acta Materialia


Publication date: 15 June 2018 Source:Acta Materialia, Volume 152 Author(s): Guang Yang, Kui Du, Dongsheng Xu, Hui Xie, Wenqing Li, Dingming Liu, Yang Qi, Hengqiang Ye Impact deformed TiAl polysynthetic twinned crystal was investigated by scanning and transmission electron microscopy including aberration-corrected scanning transmission electron microscopy. Shear bands, deformation twins and dislocations were observed in γ-TiAl phase. Deformation twins were identified on both primary (11 1 ¯ ) and secondary (1 1 ¯ 1 ¯ ) twin planes, and dislocation structures were resolved on the coherent {111} twin boundaries. Among them, 1/6 < 211] pseudo-twin dislocations were observed on the coherent twin boundaries co-existing with 1/2 < 101] super-partial dislocations. Two types of shear bands were identified, one was composed of (11 1 ¯ ) twin lamellae inclined to the propagation direction of shear bands, while the other was composed of curved (1 1 ¯ 1 ¯ ) twin lamellae and its propagation is nearly parallel to the (1 1 ¯ 1 ¯ ) twin plane. Graphical abstract