Fig. 1. (a) Inverse pole figure (IPF) map, (0002) and (10-10) pole figures (PF) on the RD-TD plane and (b) test specimens with various geometries and shapes of rolled AZ31B alloy.

Fig. 2. (a) Engineering stress-strain curves and (b) strain distribution on the specimens T, ST, and S just before fracture analyzed by DIC.

Fig. 3. IPF maps of sample T: (a) at the strain of 2.0%, (b) at the strain of 4.0%, (c) after fracture. The {10-12} extension twin boundaries (86° <1-210> ±5°) are shown in red, the {10-11} contraction twin boundaries (56° <1-210> ±5°) in green and the {10-11}-{10-12} double-twin boundaries (38° <1-210> ±5°) in blue.

Fig. 4. IPF maps of sample S: (a) at the strain of 2.0%, (b) at the strain of 4.0%, (c) after fracture. The {10-12} extension twin boundaries (86° <1-210> ±5°) are shown in red, the {10-11} contraction twin boundaries (56° <1-210> ±5°) in green and the {10-11}-{10-12} double-twin boundaries (38° <1-210> ±5°) in blue.

Fig. 5. IPF maps of sample ST: (a) at the strain of 2.0%, (b) at the strain of 4.0%, (c) after fracture. The {10-12} extension twin boundaries (86° <1-210> ±5°) are shown in red, the {10-11} contraction twin boundaries (56° <1-210> ±5°) in green.

Fig. 6. Misorientation angle distributions of samples at different strains: (a) T sample, (b) S sample, (c) ST sample.

Fig. 7. Twin volume fraction (TVF) developed with increasing the plastic strain (Horizontal axis is logarithmic).

Fig. 8. Schematic of the proposed mechanism for the different deformations: (a) tension, (b) compression and (c) shear loading.

Fig. 9. Fracture surface of the samples under different stress triaxiality: (a) 1/3 (sample T), (b) 0 (sample S) and (c) 1/6 (sample ST).