Effects of texture and stress sequence on twinning, detwinning and fatigue crack initiation in extruded magnesium alloy AZ31

Several types of cyclic stress were applied to specimens made an extruded magnesium alloy, AZ31, elucidate twinning, detwinning, and fatigue crack initiation mechanisms by electron backscattered diffraction analysis. In both the texture random orientation, twinning occurred under compressive exceeding yield strength. Detwinning only in upon subsequent application tensile less than strength monotonic loading, whereas detwinning did not occur structure with orientation. Under compression–compression test, successive occurred, which changed orientation basal plane. As a result, grains normal plane was parallel loading direction. Cracks formed along boundary high Schmid factor slip system misfit grain on sides large. Near site, twin bands observed; however, after compression loading.