Mechanism Governing the Effect of Roller Straightening of a Pure Magnesium Strip on the Tensile Stress–Strain Curve Shape

A roller straightening process of a pure magnesium strip, accompanied by alternating elastic-plastic deformation, was performed through one and three passes, where one pass corresponded to 19 bending events. It was discovered that roller straightening leads to the appearance of a kink in the specimen’s tensile stress–strain curve as well as an almost twofold decrease in the yield stress. This effect was observed only on longitudinal specimens. The conducted EBSD analysis confirmed the previously stated hypothesis about the influence of twinning on the change in the shape of the roller-straightened magnesium alloy specimen’s stress–strain curve. The tensile twins {101¯2} formed during roller straightening facilitate the detwinning process during subsequent tensile deformation, which, along with the basal sliding, is the reason for the decrease in yield stress. The scaling factor of the tensile specimens was investigated.