Achieving high ductility and low in-plane anisotropy in magnesium alloy through a novel texture design strategy

Texture regulation is a prominent method to modify the mechanical properties and anisotropy of magnesium alloy. In this work, the Mg-1Al-0.3Ca-0.5Mn-0.2Gd (wt.%) alloy sheet with TD-tilted and circular texture was fabricated by unidirectional rolling (UR) and multidirectional rolling (MR) method, respectively. Unlike generating a strong in-plane mechanical anisotropy in conventional TD-tilted texture, the novel circular texture sample possessed a weak in-plane yield anisotropy. This can be rationalized by the similar proportion of soft grains with favorable orientation for basal <a> slip and {1012} tensile twinning during the uniaxial tension of circular-texture sample along different directions. Moreover, compared with the TD-tilted texture, the circular texture improved the elongation to failure both along the rolling direction (RD) and transverse direction (TD). By quasi-in-situ EBSD-assisted slip trace analysis, higher activation of basal slip was observed in the circular-texture sample during RD tension, contributing to its excellent ductility. When loading along the TD, the TD-tilted texture promoted the activation of {1012} tensile twins significantly, thus providing nucleation sites for cracks and deteriorating the ductility. This research may shed new insights into the development of formable and ductile Mg alloy sheets by texture modification.