Cyclic deformation and fatigue damage in single-crystal magnesium under fully reversed strain-controlled tension–compression in the [1 0 1¯ 0] direction

 Cyclic deformation and the resulting fatigue are experimentally investigated in single-crystal magnesium subjected to fully reversed strain-controlled tension–compression in the [1 0 1¯ 0] direction at room temperature. Plastic instability is found near the end of the first detwinning reversal. Twin–twin boundaries and secondary twins are induced by interaction of primary {1 0 1¯ 2} twins. Microcracks are developed at primary twin boundaries and twin–twin interaction sites. Final fracture is most likely caused by cleavage-cracking on the {1 0 1¯ 1}–{1 0 1¯ 2} double twin and shearing fracture on the basal plane.