Abstract
The use of lightweight arc-shaped products is one of the effective ways to realize the lightweight of material and structure. Staggered extrusion (SE) is a new method for short process forming of arc-shaped materials. Due to step-like stem, it has an important influence on extrusion flow behavior and microstructure. Herein, the AZ31 magnesium alloy microstructure evolution during the SE is focused on. By means of metallographic microstructure analysis and electron backscatter diffraction, the microstructure of bending products with staggered distance h of 16 mm and extrusion ratio of 11.11 was analyzed. The results show that with the change of stem structure, the order and amount of shear deformation change at each part, resulting in the difference of average grain size. Compared with the initial billet, the average grain size is refined from 68.38 to 17.15 μm. Complete dynamic recrystallization takes place to form fine and uniform grains. Basal texture {0001} tends to be perpendicular to the extrusion direction (ED) in regions A, B and C. The texture of region A in forward extrusion is shifted counterclockwise, and that of regions B and C in backward extrusion is shifted clockwise. However, the texture in the region D turns parallel to the ED, but there is a small deflection angle α. It provides scientific guidance for the shape control and precision manufacturing of high-quality arc-shaped products.