Fig. 8: Experimental evidence of twinning nucleation in grain with a low twinning SF in sample S90.

a IPF-Z map of grain G1 and its neighboring grains before deformation. Based on the mean orientation for each grain, the crystal lattice as well as the basal plane trace were determined and overlaid in this figure as a red line. b <a> basal slip Schmid factor map of the same grains under the tension along the horizontal direction. c IPF-Z map of grain G1 and formed Twin1 after deformation. The rotation of the crystal lattice and basal plane trace reveals a possible twinning behavior. d Projections of the orientation of grain G1 and Twin1 on the (0002) pole figure before (blue) and after (black) deformation. Based on the mean orientation of grain G1 before deformation, the orientations of all six possible extension twin variants were obtained, with their projections added in the pole figure.