Localized twin bands in sheet bending of a magnesium alloy

Three-point bending tests were performed at room temperature on Mg–Al–Zn sheet material (∼8.0 μm initial grain size). In situ electron backscatter diffraction and optical microscopy examinations revealed a highly localized twinning pattern during bending. In the compression zone, {101¯2}〈101¯1¯〉 twins were localized in bands, each band comprising high-density twins, but twins were absent between the bands. As the bending angle increased, the twin bands grew across the center line. Possible mechanisms for such localized twin bands are discussed.