A method for preparing fine-grained magnesium alloy by alternate reverse extrusion

Abstract

The invention discloses a method for manufacturing a fine-grain magnesium alloy through alternate inverted extrusion and belongs to the technical field of magnesium alloy processing. The method includes the steps that a magnesium alloy cylindrical bar is obtained through cutting; secondly, the bar is heated; thirdly, a die is preheated; fourthly, alternate inverted extrusion is conducted, wherein the magnesium alloy cylindrical bar is subjected to 3-6 passes of inverted extrusion, and a magnesium alloy deformation part is manufactured; the operation sequences of all passes of inverted extrusion are the same; one time of blank remelting heating is conducted between every two adjacent passes of inverted extrusion, and a blank is overturned to be subjected to the next pass of inverted extrusion; and in the first time of inverted extrusion, the magnesium alloy cylindrical bar is placed at the bottom of a female die, a center male die descends and is then unloaded, and then a hollow male die descends; and fifthly, the final pass of forging is conducted, wherein the center male die and the hollow male die descend to conduct extrusion at the same time, and the fine-grain magnesium alloy is obtained. According to the method, the fine-grain magnesium alloy with the manufacturing strength and plasticity obviously improved and with the average grain size being smaller than 10 microns is manufactured through alternate inverted extrusion; and equipment is simple, cost is low, efficiency is high, operation is easy, and industrialization is achieved.

Description

technical field [0001] The invention belongs to the technical field of magnesium alloy processing, and in particular relates to a method for preparing fine-grained magnesium alloy by alternate reverse extrusion. Background technique [0002] As an advanced lightweight metal structure material, magnesium alloy has high specific strength and good impact resistance, which can meet the lightweight requirements of aerospace, automobiles and electronic products, and reduce energy consumption and environmental pollution. One of the fastest growing materials for industrial applications. However, the close-packed hexagonal lattice structure determines the poor plastic deformation ability of magnesium alloy at room temperature, which greatly limits its application range. Grain refinement can not only effectively improve the room temperature plasticity of magnesium alloy, but also significantly improve its corrosion resistance and fatigue. performance. The use of solid-state deformat...

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Problems solved by technology

[0003] In view of the above-mentioned shortcomings that the existing fine-grained magnesium alloy blocks are difficult to prepare, the present invention provides a method for preparing fine-grained magnesium alloys by alternate back extrusion, which is a special forming method for preparing fine-grained magnesium alloys by alternate back extrusion: Using ordinary extrusion punches and dies, the magnesium alloy undergoes multiple severe plastic deformations through alternate back-extrusion processes to refine the grains of the magnesium alloy. Back pressure keeps the deformed body in a strong three-dimensional compressive stress state, preventing cracks; improving the plastic deformation capacity of magnesium alloys

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