Effects of Yttrium Addition on Bending Deformation Behavior of Magnesium

Pure magnesium and Mg-(0.2-0.9 at.%) Y rolled sheets were subjected to three-point bending tests to individually investigate the effects of texture and yttrium addition on bending deformation behavior. Yttrium addition increased bending yield stress in both Specimen TR with the neutral plane parallel to the rolled plane and Specimen TN with the neutral plane perpendicular to the rolled plane, resulting from the increase in critical resolved shear stresses (CRSSs) for basal slip and {1012} twinning with yttrium addition. Bending ductility increased with increasing yttrium addition until 0.5 at.% yttrium addition, and then decreased at 0.9 at.% yttrium addition in Specimen TN. On the other hand, bending ductility increased until 0.9 at.% yttrium addition in Specimen TR since non-basal slip activities increased with increasing yttrium addition. Since neutral planes in Specimen TN with 0.9 at.% yttrium addition moved more to the center than those in Specimen TN with 0.5 at.% yttrium addition, resulting in the higher tensile strain at the tension side. Therefore, the bending ductility in 0.9 at.% yttrium addition was lower than that in 0.5 at.% yttrium addition.