On the formation of {112̄2} boundary via {101̄2}-{011̄2} twin–twin interaction in magnesium

{ 10 1 2 } twinning occurs extensively in Mg to accommodate plastic deformation. With multiple active twin variants, twin–twin interaction occurs and this often forms twin–twin boundaries. In this work, the { 11 2 2 } twin–twin boundary is studied using electron backscatter diffraction (EBSD) analysis and atomistic simulations. EBSD data show that many of the twin–twin boundaries align well with { 11 2 2 } or { 11 2 6 } planes. Further, atomistic simulations reveal dynamically the formation of { 11 2 2 } boundary via the interaction of two non-co-zone { 10 1 2 } twin variants. Moreover, the twinning mode of the { 11 2 2 } boundary is found to be an extension twin with second undistorted plane of { 11 2 6 } . In addition, the { 11 2 2 } boundaries contribute significantly to the 60 ° 〈 01 1 0 〉 peak in the misorientation histogram; they also play an essential role in the unique strong strain hardening under c -axis tension. Our findings are crucial for completing the twinning theories for Mg.