Anisotropic in-plane fatigue behavior of rolled magnesium alloy with {10-12} twins

초록

The effects of initial {10-12} twins on the in-plane fatigue characteristics of a rolled Mg alloy were investigated by introducing these twins through precompression along the rolling direction of the material and then performing strain-controlled low-cycle fatigue tests along the rolling direction, 45 to the rolling direction, and transverse direction. The as-rolled sample with a strong basal texture was found to exhibit the same fatigue behavior in all the loading directions, whereas the precompressed samples exhibited anisotropic in-plane fatigue behaviors because the specific crystallographic orientation of the twinned region resulted in a variation in the active deformation modes during cyclic loading in the applied loading directions. An increase in the amount of precompression was also found to enhance the anisotropy of the in-plane fatigue behavior via an increase in the area fraction of the twinned region. The variation in the dominant deformation mechanism with a change in the loading direction was investigated by analyzing the crystallographic angle relationship and activation stresses, and the resultant evolutions of the cyclic flow curve and fatigue life were discussed in detail.

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