Slip behavior during tension of rare earth magnesium alloys processed by different rolling methods

Abstract

To expand the practical application of rare earth magnesium alloys, rare earth magnesium alloy sheets with no cracks and good plasticity were prepared by cross rolling. The plastic deformation behavior and fracture mechanism of cross rolling and conventional rolling were investigated, and the results showed that the twins after cross rolling have a certain effect on stimulating the activation of the slip systems with lower Schmid factor. The basal slip was dominant in conventional-rolled sheets. However, the plastic deformation process of cross-rolled magnesium alloys is dominated by both basal slip and non-basal slip, especially the second-order pyramidal slip. This is because cross-rolling reduces the critical shear stress of non-basal slip. Although the slip transfer between ordinary rolling grains is good, the activated slip cannot coordinate the c-axis strain. At the same time, the slender precipitation hinders the movement of dislocations and aggravates the strain concentration, which is likely to cause the generation of ledges and further develop into cracks. In the cross-rolling process, the short and flocculent precipitation decreases the resistance of dislocation movement, and the activated non-basal slip can coordinate the strain of the c-axis, which can better coordinate the deformation and reduce the possibility of cracking.