Grain morphology and plasticizing mechanism of AZ31 magnesium alloy curved profiles by staggered extrusion

Abstract

Traditional manufacturing processes for lightweight curved profiles are often associated with lengthy procedures, high costs, low efficiency, and high energy consumption. In order to solve this problem, a new staggered extrusion (SE) process was used to form the curved profile of AZ31 magnesium alloy in this paper. The study investigates the mapping relationship between the curvature, microstructure, and mechanical properties of the formed profiles by using different eccentricities of the die. Scanning electron microscopy (SEM) and electron backscatter diffraction techniques are employed to examine the effects of different eccentricity values (e) on grain morphology, recrystallization mechanisms, texture, and Schmid factors of the products. The results demonstrate that the staggered extrusion method promotes the deep refinement of grain size in the extruded products, with an average grain size of only 15% of the original billet, reaching 12.28 µm. The tensile strength and elongation of the curved profiles after extrusion under the eccentricity value of 10 mm, 20 mm and 30 mm are significantly higher than those of the billet, with the tensile strength is increased to 250, 270, 235 MPa, and the engineering strain elongation increased to 10.5%, 12.1%, 15.9%. This indicates that staggered extrusion enables curvature control of the profiles while improving their strength.

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Central South University