Twin intersections in TiAl alloy compressed at room temperature were investigated by high-resolution electron microscopy. One incident twin was observed to divide into three thin twin bands and leave several superlattice intrinsic stacking faults in the barrier twin. It was a process related to the dislocation dissociation: ½[112] → (1/6)[112] + SISF + (1/6)[112] + SESF + (1/6)[112] The nucleation of type-I twin intersection was also observed. The incident twin was found to be a bundle of superlattice intrinsic stacking faults, instead of a perfect twin lath. In addition, a triangular striated structure around type-I twin intersection was examined by high-resolution electron microscopy. The formation mechanism of this triangular striated structure and the related dislocation reactions were considered.

TEM Observations of Twin Intersections in a Ti–47Al–2Cr–2Nb–0.1Y Alloy Compressed at Room Temperature. C.L.Chen, W.Lu, Y.Y.Cui, L.L.He, H.Q.Ye: Journal of Alloys and Compounds, 2008, 454[1-2], 201-5