Twinning-induced dislocation and coordinated deformation behavior of a high-Nb TiAl alloy during high-cycle fatigue

•The high-cycle rotating bending fatigue limit of the high-Nb TiAl alloy is close to 400 MPa.•The deformation in the γ phase is dominated by superlattice dislocations [0 1 1¯] and twinning.•Dislocations in the B2 phase can be induced by twins in adjacent γ phase with a low stacking fault energy due to high Nb addition.•The local stresses at the phase interface were accommodated by continuous dislocation slip of B2 phase, deformation twins, and twin intersections in the γ phase.