Rotary extrusion forming method for magnesium alloy plate with weak anisotropy and high toughness

Abstract

The invention discloses a rotary extrusion forming method for a low-anisotropy high-toughness magnesium alloy plate, which comprises the following steps of: placing a blank from an extrusion section cavity, rotating a male die under the driving of a rotating mechanism, carrying out axial feeding motion together with a base plate under the driving of an axial moving mechanism, and meanwhile, carrying out axial feeding motion on a helical rack at the edge part of the base plate, the helical rack is meshed with the second helical gear to enable the helical rack to rotate, the second helical gear is meshed with the first helical gear to enable the first helical gear to rotate and drive the inner female die to rotate, the male die enters from an extrusion-in section cavity, and the blank is pushed to an extrusion working belt through axial feeding and the male die. And the two ends of the blank are simultaneously subjected to rotation of the male die and the inner female die in two opposite directions, and the blank is continuously extruded from the extrusion-in section cavity to the extrusion-out section cavity in the axial direction along with continuous axial extrusion of the male die, so that a plate is obtained. By means of the method, the magnesium alloy plate which is more uniform in ultra-fine grain structure, high in strength and toughness and weak in anisotropy can be obtained.

Description

technical field [0001] The invention belongs to the technical field of metal plastic deformation, and in particular relates to a rotary extrusion forming method for a weakly anisotropic, high-strength and tough magnesium alloy sheet. Background technique [0002] Sheets are widely used in military, aerospace, automotive, marine and electronic fields. The complex service environment requires them to have high strength, toughness and weak anisotropy. At present, the traditional sheet forming methods are mainly rolling, twin-roll casting and extrusion forming, among which the sheet manufacturing of magnesium alloys mostly adopts the process path combining extrusion billet and rolling. Magnesium alloy has a close-packed hexagonal structure, which has poor plasticity at room temperature and is difficult to deform. During the low-temperature rolling process, there are few activated slip systems, and the basal plane slip is dominant, forming a strong basal plane texture and showing...

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Problems solved by technology

Magnesium alloy has a close-packed hexagonal structure, poor plasticity at room temperature, and difficult deformation; during low-temperature rolling, there are few movable slip systems, and the base surface slip is the main one, forming a strong base surface texture and showing high anisotropy , it is easy to cause defects such as edge cracks; in the process of thermal deformation, due to the restriction of recrystallization fine grain and strengthening phase effect, it is difficult for the traditional large plastic deformation process to obtain ultra-fine grain structure and improve toughness

Rotary extrusion can accumulate a large amount of strain, and obtain magnesium alloy sheets with ultra-fine grain structure, high strength and toughness, and weak anisotropy. However, traditional rotary extrusion can only provide a single torque, and provide shear under certain deformation conditions. The amount of strain is limited. In view of this, the existing technology needs to be improved, and this case proposes

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