Effect of corrugated-flat rolling on the microstructure evolution and mechanical properties of AZ31 magnesium alloy plate

This study proposes a hybrid processing technique integrating corrugated rolling (CR) with flat rolling (FR) to alleviate the pronounced basal texture in AZ31 magnesium alloy sheets during rolling. Finite element simulations based on the developed CR model show that the von Mises stress distribution exhibits a peak spacing of 10 mm, consistent with the geometric periodicity of the corrugated rolls. Microstructural characterization reveals that increasing the CR reduction from 10% to 50% significantly increases the dynamic recrystallization (DRX) fraction from 13.1% to 61.7% and refines the average grain size from 16.49 μm to 3.07 μm. Meanwhile, the Schmid factors for prismatic 〈a〉 and pyramidal 〈a〉 slip systems increase from 0.391 to 0.401 and from 0.435 to 0.443, respectively. After subsequent FR, the basal texture intensity of the 50% CR+FR sheet decreases to 11.41 mrd, markedly lower than the 18.74 mrd of the 10% CR+FR sheet. The periodic shear strain introduced by CR promotes dynamic recrystallization, grain refinement, and basal texture weakening, while FR stabilizes the modified microstructure. In addition, the tensile properties improve markedly with increasing pre-CR reduction: the ultimate tensile strength and yield strength increase from 223 MPa and 178.4 MPa in the 10% CR+FR sample to 282.9 MPa and 243.3 MPa in the 50% CR+FR sample, while the elongation remains 17.1%. These results demonstrate the feasibility of the CR-FR process for producing high-performance AZ31 magnesium alloy sheets.