Influence of initial texture on twinning and slip behaviors in rolled AZ31 magnesium alloy during three-point bending deformation

Abstract

This study investigates the influence of initial crystallographic texture on the deformation mechanisms during three-point bending of AZ31 Mg alloy sheets. Three distinct orientations are examined by using the following bending specimens: (i) the normal direction (ND) sample, where the c-axes are predominantly aligned along the specimen thickness, (ii) the rolling direction (RD) sample, where the c-axes are mostly aligned along the longitudinal direction, and (iii) the 45 sample, where the c-axes are tilted at approximately 45° from both the thickness and longitudinal directions. The bending properties vary significantly depending on the initial texture, thereby affecting the strain accommodation and dominant deformation modes. The ND sample exhibits the lowest bendability due to its unfavorable orientation for {10–12} extension twinning and basal slip, which results in poor strain accommodation and early crack initiation in the outer tensile side. By comparison, the RD sample demonstrates an approximately 22.1 % improvement, with extensive {10–12} extension twinning in the outer tensile zone. Meanwhile, the 45 sample exhibits the highest bendability (approximately 75.7 % greater than that of the ND sample) due to sustained activation of both basal slip and {10–12} extension twinning, promoting uniform strain distribution and delaying fracture. Detailed electron backscatter diffraction analysis reveals that the 45 sample retains favorable crystallographic orientations for basal slip throughout bending, minimizing strain localization and enhancing the bendability. These findings highlight the importance of tailoring the initial texture in order to optimize the bending properties of Mg alloy sheets, and provide valuable insights for improving the manufacturability of Mg-based structural components.