Cyclic deformation and fatigue damage in single-crystal magnesium under fully reversed strain-controlled tension-compression in the [10(1)over-bar0] 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) over bar 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) over bar 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) over bar 1}-{1 0 (1) over bar 2} double twin and shearing fracture on the basal plane. Published by Elsevier Ltd. on behalf of Acta Materialia Inc.