Effect of bending and tension deformation on the texture evolution and stretch formability of Mg–Zn–RE–Zr alloy

Bending and tension deformations were performed on Mg–1.3wt%Zn–0.2wt%RE–0.3wt%Zr (ZEK100) alloy sheets that initially had a transverse direction (TD)-split texture. The effects of bending and tension deformations on the texture formation and room-temperature formability of specimens were investigated. The specimen subjected to 3-pass bending and tension deformations exhibited an excellent Erichsen value of 9.6 mm. However, the Erichsen value deterioration was observed in the specimen subjected to 7-pass deformations. The rolling direction-split texture developed on the surface with an increasing pass number of deformations. Conversely, the clear TD-split texture remained at the central part. As a result, a quadrupole texture was macroscopically developed with an increasing pass number of deformations. The reduction in anisotropy by the formation of the quadrupole texture is suggested to be the main reason for the improvement in stretch formability. By contrast, the generation of coarse grains near the surface is suggested to be the direct cause for the deterioration of the stretch formability of the specimen subjected to 7-pass deformations.