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Preparation method of nanocrystalline magnesium alloy by continuous and severe plastic deformation

A technology of severe plastic deformation and magnesium alloys, applied in the field of plastic forming of magnesium alloys, can solve problems such as difficulty in obtaining nano-grain magnesium alloys and nano-crystalline magnesium alloys, achieve excellent mechanical properties and physical chemistry, simple methods, and good mutual coordination The effect of deformability

Inactive Publication Date: 2013-07-24
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007]Technical problem: the purpose of this invention is to provide a continuous nanocrystalline magnesium alloy that can solve the problem that the existing plastic deformation method is difficult to obtain nanoscale grain magnesium alloy below 100nm. Severe plastic deformation preparation method

Method used

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  • Preparation method of nanocrystalline magnesium alloy by continuous and severe plastic deformation
  • Preparation method of nanocrystalline magnesium alloy by continuous and severe plastic deformation
  • Preparation method of nanocrystalline magnesium alloy by continuous and severe plastic deformation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Prepare AZ31 magnesium alloy, its composition is Al 3.0wt%, Zn 1.0wt%, Mn 0.5wt%, the rest is Mg and unavoidable impurities. Specific steps are as follows:

[0027] (a) Place the prepared raw materials in the crucible of the melting furnace in SF 6 +CO 2 Melting is carried out under the protection of mixed gas. After the raw materials are completely melted, they are cast at 720°C into round rod ingots with a diameter of Φ72mm. The casting mold is a pure copper water-cooled mold;

[0028] (b) Put the cast Φ72mm round rod ingot into the extrusion barrel of the same diameter on the extruder, and hot-extrude it into a Φ9mm round rod at 340°C at an extrusion speed of 30mm / s, and the extrusion ratio is 64 ;

[0029] (c) After cutting the extruded round rod into sections, put it into a circular equal-channel corner extrusion die with a cavity cross-sectional diameter of Φ9mm, a channel corner of 90° and no arc, and carry out 8 passes continuously at 200°C Angle extrusion, ...

Embodiment 2

[0034] Prepare Mg-Al alloy, its composition is Al 1.5wt%, Mn 0.2wt%, rare earth Ce 2.0wt%, the rest is Mg and unavoidable impurities.

[0035] The difference between the method of this example and Example 1 is that in step (a), the casting temperature is 700°C, and the diameter of the round rod ingot is 60mm; 25. The hot extrusion temperature is 400°C, and the extrusion speed is 10mm / s; in step (c), put it into a circular equal-channel corner extrusion mold with a cavity cross-sectional diameter of Φ12mm, a channel corner of 100°, and no arc. The equal-channel extrusion temperature is 225°C, the number of extrusion passes is 4, and the extrusion speed is 1mm / s; in step (d), the thickness of the wafer sample is 1mm, the pressure is 4Gpa, the rotation speed is 0.5 circles / min, and the high-pressure twist The number of laps is 4 laps. Other processing parameters are identical with embodiment 1 with operation process.

[0036] Through the method of this embodiment, the average g...

Embodiment 3

[0038] Prepare Mg-Al alloy, its composition is Al 6.5wt%, Zn 6.5wt%, Mn 1.0wt%, La, Ce mixed rare earth 4.5wt%, the rest is Mg and unavoidable impurities.

[0039] The difference between the method of this example and Example 1 is that in step (a), the casting temperature is 680°C, and the diameter of the round rod ingot is 40mm; 16. The hot extrusion temperature is 460°C, and the extrusion speed is 20mm / s; in step (c), put it into a circular equal-channel corner extrusion mold with a cavity cross-sectional diameter of Φ10mm, a channel corner of 120° and no arc, The equal-channel extrusion temperature is 325°C, the number of extrusion passes is 6, and the extrusion speed is 3mm / s; The number of twisting circles is 10 circles. Other processing parameters are identical with embodiment 1 with operation process.

[0040] Through the method of this embodiment, the average grain size of the Mg-Al alloy can be finally refined to 82-87 nm, and the average micro-Vickers hardness is 1...

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Abstract

The invention discloses a preparation method of a nanocrystalline magnesium alloy by continuous and severe plastic deformation. The method comprises the following steps of: firstly, smelting a prepared magnesium alloy raw material and casting into a round cast ingot; then, thermally extruding at 340-460 DEG C to a bar with diameter of 9-12mm; cutting the extruded round bar and performing equal channel corner extrusion with 4-8 channels at 200-350 DEG C; and then, cutting the bar into wafer samples which are 0.8-1mm in thickness for twisting at room temperature and high pressure, wherein the pressure is 4-6Gpa and twisting for 2-10 rings. According to the method provided by the invention, conventional thermal extrusion is combined with equal channel corner extrusion and high pressure twisting belonging to a severe plastic deformation process, and the magnesium alloy with the average grain size below 100nm and uniform tissue can be easily prepared, so that the mechanical property of the magnesium alloy is greatly improved, and meanwhile, the method has the characteristics of large size of nanocrystalline magnesium alloy material, simple process, high processing efficiency, less impurities and defects and the like.

Description

technical field [0001] The invention belongs to the field of plastic forming of magnesium alloys, and relates to a method for preparing nanocrystalline magnesium alloys through continuous severe plastic deformation. Background technique [0002] As the lightest metal structural material, magnesium alloy has the advantages of high specific strength and specific stiffness, good machinability and damping performance, abundant resources and easy recycling, and has broad application prospects. However, due to the low strength and poor plasticity of magnesium alloys due to their own structural characteristics, their application scope is greatly limited. How to improve the comprehensive mechanical properties of magnesium alloys has become the research and development focus of the industry. [0003] Grain refinement can not only improve the strength of the material, but also effectively improve the coordinated deformation ability of the grain boundary during the plastic deformation ...

Claims

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Application Information

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IPC IPC(8): C22F1/06B21C23/00
Inventor 白晶刘欢彭婷婷薛烽周健孙扬善
Owner SOUTHEAST UNIV
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