Method for preparing high-hardness high-wear-resistance magnesium-based composite material

Abstract

The application discloses a preparation method of high-hardness and high-wear-resistance magnesium-based composite material, which comprises the following steps: preparing materials, remelting, casting, and extruding; AZ91 alloy semi-solid-state temperature is added with B4C for stirring and cooling to form a casting rod for standby; an AZ91 alloy solution is prepared; a mold with a proper diameter is selected, the standby casting rod is placed at a center position of the mold, the AZ91 alloy solution is poured into the mold, meanwhile, the mold is placed on a vibration platform to continuously vibrate until the solution completely solidifies, so that the magnesium-based composite material is formed; and the magnesium-based composite material after complete solidification is subjected to heat treatment and cooling, and then is heated again to be extruded and deformed. The application effectively solves the extrusion difficulty of the existing composite material, greatly improves the hardness of the alloy layer, significantly reduces internal defects, improves the material density, uniformly disperses B4C particles in the matrix, avoids local agglomeration, improves the hardness and wear resistance of the composite material, and effectively reduces the cracking risk in the extrusion process.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, and particularly relates to a method for preparing a high-hardness, high-wear-resistant magnesium-based composite material. Background Technology

[0002] With the increasing emphasis on national defense and security, the demand for magnesium alloys as lightweight structural materials in the military industry is growing. However, ordinary magnesium alloys suffer from low hardness and poor wear resistance. Typically, a certain amount of particulate reinforcement is added to the Mg matrix to improve the strength of magnesium alloys. Common particulate reinforcements include SiC, TiC, and B4C. Currently, magnesium-based composite materials are usually cast using an external ultrasonic semi-solid casting method, which achieves high particle dispersion. However, subsequent deformation is extremely difficult, easily leading to defects such as stalling and cracking during extrusion. Therefore, a novel method for preparing and forming magnesium-based composite materials is urgently needed. Summary of the Invention

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

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

[0005] Prepare materials by heating AZ91 alloy to a semi-solid temperature and adding 20% ​​by mass of B4C while stirring to disperse the particles evenly, thus obtaining a B4C-reinforced AZ91 magnesium-based composite solution and cooling it to form a cast rod for later use.

[0006] Remelting involves placing the AZ91 alloy into a furnace for melting to obtain an AZ91 alloy solution.

[0007] Casting: Select a mold of appropriate diameter, heat the cooled cast rod to 500°C and place it in the center of the mold, and pour the AZ91 alloy solution into the mold. At the same time, place the mold on a vibration platform and vibrate continuously until the melt is completely solidified to form a magnesium-based composite material.

[0008] Extrusion involves heat treatment of the fully solidified magnesium-based composite material at a temperature of 420°C for 8 hours, followed by cooling and reheating to 380°C for extrusion deformation.

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

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

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

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

[0013] The preparation method of 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 prepares a native coated composite material through a metallurgical bonding method, solving the problem of extrusion difficulties in existing composite materials and significantly improving the hardness of the alloy layer. Vibration during the casting process significantly reduces internal defects and increases material density; simultaneously, it promotes 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 the vibration casting further strengthens the interfacial bonding strength between the outer layer and the core, reducing the risk of cracking during subsequent extrusion. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for further understanding of the embodiments of the present invention and constitute a part of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0016] Figure 1 The microstructure of the interface bonding of the high-hardness, high-wear-resistant magnesium-based composite material in the embodiment is shown.

[0017] Figure 2 The hardness test locations and microstructure of the high-hardness, high-wear-resistant magnesium-based composite material in the examples are shown.

[0018] Figure 3 The figure shows the hardness curve of the high-hardness, high-wear-resistant magnesium-based composite material in the embodiment.

[0019] Figure 4 The wear-resistant morphology of the high-hardness, high-wear-resistant magnesium-based composite material in the embodiments is shown.

[0020] Figure 5 The image shows the three-dimensional morphology of the high-hardness, high-wear-resistant magnesium-based composite material in the wear resistance test of the embodiment. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

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

[0023] Prepare materials by heating AZ91 alloy to a semi-solid temperature and adding 20% ​​by mass of B4C while stirring to disperse the particles evenly, thus obtaining a B4C-reinforced AZ91 magnesium-based composite solution and cooling it to form a cast rod for later use.

[0024] Remelting involves placing the AZ91 alloy into a furnace for melting to obtain an AZ91 alloy solution.

[0025] Casting: Select a mold of appropriate diameter, heat the cooled cast rod to 500°C and place it in the center of the mold, and pour the AZ91 alloy solution into the mold. At the same time, place the mold on a vibration platform and vibrate continuously until the melt is completely solidified to form a magnesium-based composite material.

[0026] Extrusion involves heat treatment of the fully solidified magnesium-based composite material at a temperature of 420°C for 8 hours, followed by cooling and reheating to 380°C for extrusion deformation.

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

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

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

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

[0031] Example:

[0032] In the preparation of materials, the AZ91 alloy is heated to a semi-solid temperature, and 20% by mass of B4C is added and stirred to disperse the particles evenly, so as to obtain a B4C-reinforced AZ91 magnesium-based composite solution and cool it to form a casting rod with a diameter of 70mm. After machining the outer skin of the casting rod by 5mm, a 65mm casting rod is obtained for later use.

[0033] Remelting involves placing the AZ91 alloy into a furnace for melting to obtain an AZ91 alloy solution.

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

[0035] Extrusion involves heat treatment of the fully solidified magnesium-based composite material at a temperature of 420℃ for 8 hours. After cooling, the material is reheated to 380℃ for extrusion deformation at an extrusion ratio of 17, resulting in a high-hardness, high-wear-resistant magnesium-based composite material.

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

[0037] In summary, compared with existing technologies, the preparation method of the 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, solving the problem of extrusion difficulties in existing composite materials, while significantly improving 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 combination of AZ91 alloy coating of B4C to enhance the AZ91 magnesium-based composite material and vibration casting further strengthens the interfacial bonding strength between the outer layer and the core, reducing the risk of cracking during subsequent extrusion.

[0038] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Meanwhile, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, the terms "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states 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, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing a high hardness and high wear resistance magnesium-based composite material, characterized by, The preparation method of the high-hardness high-wear-resistance magnesium-based composite material comprises the following steps: Preparation, AZ91 alloy is heated to semi-solid temperature, and 20% of B4C by mass percentage is added for stirring to uniformly disperse the particles, so that a B4C reinforced AZ91 magnesium-based composite solution is obtained, and a casting rod is formed after cooling and is reserved; After the casting rod is cooled and formed, the outer skin is turned for 3-5 mm; Remelting, the AZ91 alloy is placed in a furnace for smelting, so that an AZ91 alloy solution is obtained; Casting, an appropriate diameter mold is selected, the casting rod formed after cooling is placed in the center position of the mold after being heated to 500 DEG C, the AZ91 alloy solution is poured into the mold, and the mold is placed on a vibration platform for continuous vibration until the solution is completely solidified, the vibration frequency of the vibration platform is controlled to be 20-50 Hz, the internal defects are reduced, the material density is improved, the B4C particles are uniformly dispersed in the matrix, local agglomeration is avoided, the hardness and wear resistance of the composite material are improved, the magnesium-based composite material is formed, and the outer skin is turned for 3-5 mm after the magnesium-based composite material is solidified; Through the combination of the B4C reinforced AZ91 magnesium-based composite material coated by the AZ91 alloy and the vibration casting, the interface bonding strength of the outer layer and the core part is further strengthened, and the cracking risk in the subsequent extrusion process is reduced; Extrusion, the magnesium-based composite material completely solidified is subjected to normalization heat treatment, the normalization heat treatment temperature is 420 DEG C, the normalization heat treatment time is 8 h, the magnesium-based composite material is cooled, heated to 380 DEG C again, and then subjected to extrusion deformation, and the extrusion ratio is 17.

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