Deep drawability and drawing behaviour of AZ31 alloy sheets with different initial texture

Repeated unidirectional bending (RUB) process was carried out to improve the texture of AZ31 alloy sheets. Compared to the as-received sheet with a strong basal texture, the RUB processed sheet with a weaker basal texture can be successfully drawn at a larger limiting drawing ratio (LDR) of 1.7. For both the drawn cups, the c-axis of some grains tends to rotate toward the transverse direction (TD) of the sheet in the inner regions of the shoulders due to the occurrence of extension twinning and the basal texture dramatically changes to the c-axis//TD texture in the walls and the edges. Compared with the drawn cup of the as-received sheet, the drawn cup of the RUB processed sheet maintains a weaker texture intensity in the shoulder, which results in a larger Schmid factor of basal slip and thus contributes to the sheet thinning. Further, for the drawn cup of the RUB processed sheet, a finer grain microstructure resulting from the twin dynamic recrystallization (TDRX) is observed in the edge. The TDRX plays an important role in the softening during plastic deformation and consequently favours the further deformation. The changed Schmid factor of basal slip is caused by the rotation of the c-axis of grains and the texture evolution. (C) 2014 Elsevier B.V. All rights reserved.