Using

in situ

optical microscopy

electron backscatter diffraction analysis

and atomistic simulations

we studied co-zone {1¯012} twin interaction in magnesium single crystal under compression–tension along the [101¯0

]

direction. Two co-zone twins are activated and interact with each other

resulting in two types of tilt boundaries that have habit planes (0001) and (101¯0) and prevent twin-across-twin transmission but facilitate the propagation of a basal slip band. Upon strain reversal

the unfavorable dissociation of dislocations in the formed tilt boundaries hinder de-twinning.