Influence mechanism of staggered distance on grain morphology evolution and texture state of AZ31 curved profile formed by staggered extrusion (SE)

There are some bottlenecks in the traditional lightweight curved forming manufacturing, such as long process flow, high cost, low efficiency, and large energy consumption. This is undoubtedly contrary to the development concept of green forming manufacturing, and the staggered extrusion rule is one of the effective ways to solve this problem. In this paper, the distribution characteristics of flow velocity on the cross section of extrusion die and its mapping relationship with the curvature change of curved material are analyzed by finite element simulation. The effects of different staggered distance h values on grain morphology, recrystallization behavior, and texture of AZ31 magnesium alloy extruded by staggered extrusion were studied by metallographic microscope and electron backscatter technology. The results show that the staggered extrusion method can promote the deep refinement of grain size of extruded products. When h = 16 mm, the average grain size is only 1/10 of the original billet, reaching 11.40 μm. At the same time, the recrystallization behavior is more fully, reaching 87.02%, and the texture strength is as low as 9.74, indicating that DRX is one of the main reasons for weakening texture. It provides scientific guidance and technical support for the formulation and industrial application of the magnesium alloy curved material staggered extrusion process scheme.