Preparation method of high-hardness and high-wear-resistance magnesium-based composite material

Abstract

The invention discloses a preparation method of a high-hardness high-wear-resistance magnesium-based composite material, which comprises the following steps: material preparation, remelting, casting and extrusion: adding mass B4C at the semi-solid temperature of AZ91 alloy, stirring and cooling to form a casting rod for later use; additionally preparing an AZ91 alloy solution; a mold with the proper diameter is selected, the standby casting rod is placed in the center of the mold, the AZ91 alloy solution is poured into the mold, meanwhile, the mold is placed on a vibration platform to be continuously vibrated till the solution is completely solidified, and the magnesium-based composite material is formed; and the magnesium-based composite material which is completely solidified is subjected to texture heat treatment and cooling, and then is heated again for extrusion deformation. The problem that an existing composite material is difficult to extrude is effectively solved, meanwhile, the hardness of an alloy layer is greatly improved, internal defects are remarkably reduced, and the material density is improved; meanwhile, B4C particles are promoted to be uniformly dispersed in a matrix, local agglomeration is avoided, and the hardness and wear resistance of the composite material are improved; and the cracking risk in the extrusion process is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite material preparation, and in particular relates to a method for preparing a high-hardness and high-wear-resistant magnesium-based composite material. Background Art

[0002] With the country's emphasis on national defense security, the demand for magnesium alloys as lightweight structural materials in the military industry has increased. However, ordinary magnesium alloys have low hardness and poor wear resistance. Usually, a certain amount of particle reinforcement is added to the Mg matrix to improve the strength of the magnesium alloy. Common particle reinforcements include SiC, TiC, B4C, etc. At present, magnesium-based composite materials are usually cast using an external ultrasonic semi-solid method, which has high particle dispersion. However, late deformation is extremely difficult and defects such as blockage and cracking are easily generated during extrusion. Therefore, a new method for preparing and forming magnesium-based composite materials is urgently needed. Summary of the Invention

[0003] In order to at least partially solve the technical problems existing in the above-mentioned prior art, the present invention provides a method for preparing a high-hardness and high-wear-resistant magnesium-based composite material.

[0004] The method for preparing the high-hardness and high-wear-resistant magnesium-based composite material of the present invention comprises:

[0005] Preparation: AZ91 alloy is heated to a semi-solid temperature, and 20% by mass of B4C is added and stirred to uniformly disperse the particles to obtain a B4C reinforced AZ91 magnesium-based composite solution, which is then cooled to form a cast rod for use;

[0006] Remelting: placing the AZ91 alloy into a furnace and melting it to obtain an AZ91 alloy solution;

[0007] Casting: Select a mold with an appropriate diameter, heat the cooled cast rod to 500°C, place it in the center of the mold, pour the AZ91 alloy solution into the mold, and place the mold on a vibration platform for continuous vibration until the solution is completely solidified to form a magnesium-based composite material;

[0008] Extrusion, the completely solidified magnesium-based composite material is subjected to a heat treatment at a temperature of 420°C for 8 hours, and then heated to 380°C again after cooling for extrusion deformation.

[0009] Furthermore, in the above-mentioned method for preparing the high-hardness and high-wear-resistant magnesium-based composite material, in the material preparation step, after the cast rod is cooled and formed, the outer skin is turned by 3-5 mm.

[0010] Furthermore, in the above method for preparing the high-hardness and high-wear-resistant magnesium-based composite material, in the casting step, the vibration frequency of the vibration platform is controlled at 20-50 Hz.

[0011] Furthermore, in the above method for preparing the high-hardness and high-wear-resistant magnesium-based composite material, in the casting step, the outer skin is turned by 3-5 mm after solidification into the magnesium-based composite material.

[0012] Furthermore, in the above method for preparing the high-hardness and high-wear-resistant magnesium-based composite material, in the extrusion step, the extrusion ratio is 17.

[0013] The method for preparing the high-hardness and high-wear-resistant magnesium-based composite material of the present invention has the following advantages and beneficial effects:

[0014] This invention uses metallurgical bonding to produce a native, coated composite material, resolving the existing difficulties in extruding composite materials while significantly increasing the hardness of the alloy layer. Vibration during the casting process significantly reduces internal defects and improves material density. It also promotes the uniform dispersion of B4C particles within the matrix, preventing localized agglomeration and enhancing the composite's hardness and wear resistance. The AZ91 alloy-coated B4C reinforces the AZ91 magnesium-based composite, further strengthening the interface between the outer layer and the core and reducing the risk of cracking during subsequent extrusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only used to further understand the embodiments of the present invention and constitute part of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0016] Figure 1 The microstructure of the interface bonding of the high-hardness and high-wear-resistant magnesium-based composite material in the embodiment;

[0017] Figure 2 The hardness test position and microstructure of the high-hardness and high-wear-resistant magnesium-based composite material in the embodiment;

[0018] Figure 3 This is the hardness curve of the high-hardness and high-wear-resistant magnesium-based composite material in the embodiment;

[0019] Figure 4 The wear-resistant morphology of the high-hardness and high-wear-resistant magnesium-based composite material in the embodiment;

[0020] Figure 5 This is the three-dimensional morphology of the wear resistance test of the high-hardness and high-wear-resistant magnesium-based composite material in the embodiment. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] The method for preparing the high-hardness and high-wear-resistant magnesium-based composite material of the present invention comprises:

[0023] Preparation: AZ91 alloy is heated to a semi-solid temperature, and 20% by mass of B4C is added and stirred to uniformly disperse the particles to obtain a B4C reinforced AZ91 magnesium-based composite solution, which is then cooled to form a cast rod for use;

[0024] Remelting: placing the AZ91 alloy into a furnace and melting it to obtain an AZ91 alloy solution;

[0025] Casting: Select a mold with an appropriate diameter, heat the cooled cast rod to 500°C, place it in the center of the mold, pour the AZ91 alloy solution into the mold, and place the mold on a vibration platform for continuous vibration until the solution is completely solidified to form a magnesium-based composite material;

[0026] Extrusion, the completely solidified magnesium-based composite material is subjected to a heat treatment at a temperature of 420°C for 8 hours, and then heated to 380°C again after cooling for extrusion deformation.

[0027] Furthermore, in the method for preparing the high-hardness and high-wear-resistant magnesium-based composite material of the present invention, in the material preparation step, the outer skin of the cast rod is turned by 3-5 mm after the cast rod is cooled and formed.

[0028] Furthermore, in the method for preparing the high-hardness and high-wear-resistant magnesium-based composite material of the present invention, in the casting step, the vibration frequency of the vibration platform is controlled to be 20-50 Hz.

[0029] Furthermore, in the method for preparing the high-hardness and high-wear-resistant magnesium-based composite material of the present invention, in the casting step, the outer skin is turned by 3-5 mm after solidification into the magnesium-based composite material.

[0030] Furthermore, in the method for preparing the high-hardness and high-wear-resistant magnesium-based composite material of the present invention, in the extrusion step, the extrusion ratio is 17.

[0031] Example:

[0032] Preparation: AZ91 alloy was heated to a semi-solid temperature, and 20% by mass of B4C was added and stirred to uniformly disperse the particles to obtain a B4C-reinforced AZ91 magnesium-based composite solution. The solution was cooled to form a cast rod with a diameter of 70 mm. The outer skin of the cast rod was turned by 5 mm to obtain a 65 mm cast rod for later use;

[0033] Remelting: placing the AZ91 alloy into a furnace and melting it to obtain an AZ91 alloy solution;

[0034] For casting, a 95mm diameter mold was selected. A 65mm spare casting rod was heated to 500℃ and placed in the center of the mold. The AZ91 alloy solution was poured into the mold. The mold was placed on a vibration platform and continuously vibrated at a frequency of 40Hz until the solution was completely solidified to form a magnesium-based composite material.

[0035] Extrusion, the fully solidified magnesium-based composite material is subjected to a heat treatment at a temperature of 420°C for 8 hours, and then cooled and heated again to 380°C for extrusion deformation at an extrusion ratio of 17 to form a high-hardness and high-wear-resistant magnesium-based composite material;

[0036] Hardness and wear resistance test of high hardness and high wear resistance magnesium-based composite materials, such as Figures 1 to 5 shown.

[0037] In summary, compared with the prior art, the method for preparing a high-hardness, high-wear-resistant magnesium-based composite material of the present invention has the following advantages and beneficial effects: The present invention prepares a native coated composite material through metallurgical bonding, which solves the problem of difficult extrusion of existing composite materials and significantly improves the hardness of the alloy layer. Vibration during the casting process significantly reduces internal defects and improves material density; at the same time, it promotes the uniform dispersion of B4C particles in the matrix, avoiding local agglomeration and improving the hardness and wear resistance of the composite material. The AZ91 alloy coating of B4C reinforces the AZ91 magnesium-based composite material and combines it with vibration casting, further strengthening the interface bonding strength between the outer layer and the core, and reducing the risk of cracking during subsequent extrusion.

[0038] It should be noted that, in this document, unless otherwise expressly specified or limited, the term "connected" or its synonyms should be interpreted broadly. For example, "connected" can mean a fixed or removable connection; a mechanical or electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication between two elements or the interaction between two elements. A person of ordinary skill in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances. Furthermore, expressions such as "first" and "second" are used solely to distinguish one entity or operation from another and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Furthermore, the terms "front," "rear," "left," "right," "upper," and "lower" herein are used with reference to the positions shown in the accompanying drawings.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a high-hardness and high-wear-resistant magnesium-based composite material, characterized in that: The method for preparing the high-hardness and high-wear-resistant magnesium-based composite material comprises: Preparation: AZ91 alloy is heated to a semi-solid temperature, and 20% by mass of B4C is added and stirred to uniformly disperse the particles to obtain a B4C reinforced AZ91 magnesium-based composite solution, which is then cooled to form a cast rod for use; Remelting: placing the AZ91 alloy into a furnace and melting it to obtain an AZ91 alloy solution; Casting: Select a mold with an appropriate diameter, heat the cooled cast rod to 500°C, place it in the center of the mold, pour the AZ91 alloy solution into the mold, and place the mold on a vibration platform for continuous vibration until the solution is completely solidified to form a magnesium-based composite material; Extrusion, the completely solidified magnesium-based composite material is subjected to a heat treatment at a temperature of 420°C for 8 hours, and then heated to 380°C again after cooling for extrusion deformation.

2. The method for preparing a high-hardness and high-wear-resistant magnesium-based composite material according to claim 1, characterized in that: In the material preparation step, after the cast rod is cooled and formed, the outer skin is turned 3-5 mm.

3. The method for preparing a high-hardness and high-wear-resistant magnesium-based composite material according to claim 1, characterized in that: During the casting step, the vibration frequency of the vibration platform is controlled at 20-50 Hz.

4. The method for preparing a high-hardness and high-wear-resistant magnesium-based composite material according to claim 1, characterized in that: During the casting step, the outer skin is turned 3-5 mm after solidification into a magnesium-based composite material.

5. The method for preparing a high-hardness and high-wear-resistant magnesium-based composite material according to claim 1, characterized in that: In the extrusion step, the extrusion ratio was 17.

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