Method for preparing aluminum-based composite material by pressureless infiltration process capable of easily separating residual aluminum material

Abstract

A method for preparing an aluminum-based composite material by a pressureless infiltration process capable of easily separating a residual aluminum material, comprising the steps: using aluminum alloy as a base material and ceramic particles as a reinforcement body material, laying a stripping layer powder between the reinforcement body material and the base material, and performing the pressureless infiltration process to prepare a composite blank ingot; and putting the composite blank ingot into normal-temperature water for cooling, and stripping off residual aluminum from cracks at the four sides, so as to obtain the aluminum-based composite material. In the method, laying the stripping layer powder simplifies the separation of the aluminum-based composite material from the residual aluminum material, the separated residual aluminum material is complete and clean, and the extensive residual aluminum material on the upper surface of the aluminum-based composite material blank ingot prepared by the pressureless infiltration process can be completely and efficiently separated, thereby avoiding the adverse situation that only mechanical processing on large milling machines or machining centers can completely remove residual aluminum materials.

Description

A method for preparing aluminum-based composite materials by a pressureless infiltration process with easy separation of residual aluminum material Technical Field

[0001] The present invention belongs to the technical field of metal-based composite materials, and more particularly relates to a method for preparing aluminum-based composite materials through a pressureless infiltration process in which residual aluminum material is easily separated. Background Art

[0002] Properties such as low expansion, high specific modulus, high thermal conductivity, and high resonant frequency enable high-volume-fraction ceramic particle-reinforced aluminum-based composites to simultaneously possess excellent structural load-bearing capabilities, superior thermal control capabilities, and unique anti-resonance capabilities. For example, a high-volume-fraction (55%) silicon carbide particle-reinforced aluminum-based composite material has a specific modulus three times that of aluminum alloys and titanium alloys, a thermal expansion coefficient less than 40% of aluminum alloys and lower than titanium alloys, an average resonant frequency over 60% higher than that of three commonly used metal structural materials: aluminum, titanium, and steel, and a thermal conductivity far higher than that of aluminum alloys. This new material, with its comprehensive performance advantages of structural / functional integration, has been widely used in precision aerospace instruments and military electronic components in my country, achieving remarkable results.

[0003] The pressureless infiltration process is an effective method for preparing aluminum-based composites reinforced with high-volume-fraction ceramic particles. It features a short process flow, high production efficiency, uniform distribution of ceramic particles within the aluminum alloy matrix, and good dimensional stability of the billet, and is relatively easy to manufacture on a large scale. For billets with a projected area of ​​1 square meter, large-scale pressureless infiltration preparation technology for aluminum-based composites reinforced with high-volume-fraction ceramic particles has achieved stable production. Key pressureless infiltration preparation technologies for billets with a projected area of ​​2 square meters have also been achieved, and research is underway on highly uniform and stable pressureless infiltration preparation technologies for billets with a projected area of ​​3 square meters.

[0004] However, the large-scale production of high-volume-fraction ceramic particle-reinforced aluminum-matrix composites through pressureless infiltration presents a technical challenge: After infiltration, some aluminum inevitably remains on the surface of the aluminum-matrix composite ingot. This is done to ensure sufficient aluminum for complete infiltration and a safety margin, and also because the surface aluminum is nitrided during the process (nitrogen is an essential atmosphere for this process), which consumes some of the remaining aluminum. Efficient, convenient, and cost-effective removal of the residual aluminum after infiltration and solidification of the matrix aluminum alloy—that is, cleanly separating it from the aluminum-matrix composite ingot—has become a crucial technical challenge. Currently, there are two approaches to this problem. For smaller projected areas, manual steel wedges can be used to separate the aluminum from the sides of the ingot. However, for larger ingots (e.g., exceeding 0.3 square meters), manual wedge removal becomes ineffective, and the remaining aluminum must be removed by milling. However, this method has the following disadvantages: long working hours (often taking up dozens of machine hours on a large milling machine or machining center); severe tool consumption (the upper surface of the residual aluminum material is often severely nitrided, forming a hard ceramic phase, which greatly consumes the milling cutter); and high overall costs (equipment machine hours, labor, consumables, etc.).

[0005] Therefore, how to find a new way and a low-cost and high-efficiency method to separate the residual aluminum material from the aluminum-based composite material ingot conveniently and cleanly has become one of the key points in the engineering and even industrialization of the large-scale preparation and manufacturing technology of pressureless infiltration of high volume fraction ceramic particle reinforced aluminum-based composite materials. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing aluminum-based composite materials by a pressureless infiltration process in which residual aluminum material is easily separated, so as to solve the problems existing in the above-mentioned prior art and realize the easy separation of residual aluminum in the preparation of aluminum-based composite materials by the pressureless infiltration process.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] One of the technical solutions of the present invention is to provide a method for preparing an aluminum-based composite material by a pressureless infiltration process in which residual aluminum material is easily separated, the steps comprising:

[0009] Aluminum alloy is used as a matrix material, ceramic particles are used as a reinforcement material, peeling layer powder is laid between the reinforcement material and the matrix material, and a composite ingot is prepared by a pressureless infiltration process;

[0010] After the composite ingot is placed in water at room temperature and cooled, the residual aluminum is peeled off through the cracks around the ingot to obtain the aluminum-based composite material.

[0011] Furthermore, the peeling layer powder includes silicon powder or quartz powder, with a particle size of 20 to 300 μm and a spreading thickness of 0.5 to 2 mm.

[0012] Furthermore, the ceramic particles include one of silicon carbide particles, aluminum oxide particles, aluminum nitride particles, titanium carbide particles and boron carbide particles, and the particle size d50 is 1 μm to 120 μm.

[0013] Furthermore, the aluminum alloy includes one of an aluminum-silicon-magnesium cast aluminum alloy, a 2000 series deformed aluminum alloy, and a 7000 series deformed aluminum alloy.

[0014] Furthermore, the steps of the pressureless infiltration process include:

[0015] The ceramic particles are stacked into a stack with a stacking density of 40-70%, a peeling layer powder is laid on the upper surface of the stack, and the aluminum alloy is placed on the upper surface of the peeling layer powder. The stack is heated to 800-950°C under nitrogen atmosphere and kept at this temperature for 2-15 hours, and then cooled to 150-250°C to obtain the composite ingot.

[0016] The purpose of cooling to 150-250°C is to obtain a solid composite ingot. If the temperature is too high, the composite ingot is still in a molten state or a relatively soft state, which will affect the subsequent stripping of residual aluminum.

[0017] Furthermore, the temperature of the composite ingot before being placed in water at room temperature is not less than 100° C.; and the cooling is to cool the composite ingot to the same temperature as the water.

[0018] The composite billet includes residual aluminum and aluminum-based composite materials, wherein the thermal expansion coefficient of the residual aluminum is about twice that of the aluminum-based composite material. The peeling layer powder is added in the middle to form a weakly bonded interface layer. When placed in room temperature water for rapid cooling, due to the difference in thermal expansion coefficients between the residual aluminum and the aluminum-based composite material, thermal mismatch stress will be formed, which will lead to cracking of the weakly bonded interface layer, making it easier to separate the residual aluminum and the aluminum-based composite material. However, if the temperature of the composite billet is too low, the thermal mismatch stress generated is small, and it cannot generate sufficient thermal mismatch stress to cause the weakly bonded interface layer to crack, resulting in the residual aluminum and the aluminum-based composite material being difficult to separate.

[0019] Furthermore, the stripping is performed by lightly driving a steel wedge into the cracked area around the edges to complete the stripping of the residual aluminum.

[0020] Furthermore, the specific steps of the method include:

[0021] S1. Pile the ceramic particles into a pile with a bulk density of 40% to 70%, and flatten the upper surface of the pile;

[0022] S2. Evenly spread the peeling layer powder on the upper surface of the flattened ceramic particle pile;

[0023] S3, placing an aluminum alloy ingot on the upper surface of the peeling layer powder, heating it to 800-950° C. under nitrogen atmosphere protection, keeping it warm for 2-15 hours, and then cooling it to 150-250° C. to obtain a composite ingot;

[0024] S4. Place the composite billet while it is hot (not less than 100°C) into a water pool at room temperature for cooling. When the temperature of the composite billet is consistent with the water temperature, take it out and use a steel wedge to gently drive into the cracked areas around it (at this time, a large number of cracks have appeared between the residual aluminum material and the aluminum-based composite material billet). The residual aluminum material in a large area (at least more than 2 square meters) will be completely (the entire aluminum plate) and the aluminum-based composite material billet will be cleanly separated, thus obtaining the aluminum-based composite material.

[0025] The present invention discloses the following technical effects:

[0026] This invention uses a simple, easy, efficient, and low-cost method to cleanly and efficiently separate large areas (at least over 2 square meters) of residual aluminum from the surface of aluminum-based composite ingots produced by pressureless infiltration. This method eliminates the need for dozens of hours of machining on large milling machines or machining centers to completely remove residual aluminum. This method is crucial for the production of large-scale (large-projected-area) billets of aluminum-based composites reinforced with high volume fraction ceramic particles by pressureless infiltration. It can significantly save machining time, tooling (typically expensive diamond milling cutters), and labor costs, significantly improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0028] FIG1 shows the surface state of the aluminum-based composite material after separation from the residual aluminum material in Example 1;

[0029] FIG2 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material when the composite ingot of Example 1 is cooled to 200±10° C.;

[0030] FIG3 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material after the composite ingot of Example 1 is cooled using room temperature water;

[0031] FIG4 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material after the composite ingot of Comparative Example 1 is cooled using room temperature water;

[0032] FIG5 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material in the material cooled to room temperature in Comparative Example 2;

[0033] FIG6 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material after the composite ingot of Comparative Example 3 is cooled using room temperature water at 50° C. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0039] Unless otherwise specified, the room temperature in the examples of the present invention and the comparative examples is 25°C.

[0040] Example 1

[0041] In this embodiment, the ceramic particles selected as the reinforcement are silicon carbide (SiC) particles with a particle size (d50) of 63 μm. The silicon carbide particles are loaded into a graphite crucible to form a pile with a bulk density of 55%. The upper surface of the pile is flattened with a glass plate. Silicon powder with a particle size of 20 μm is then evenly spread to a thickness of approximately 0.5 mm. On top of the pile, an aluminum-silicon-magnesium cast aluminum alloy ingot is placed. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and its porosity (45%), and the amount is 10% to 20% more than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere and heated to 800°C, held at this temperature for 8 hours, and then cooled to 200±10°C. The composite material ingot is buckled out of the graphite crucible to obtain a composite ingot; while the composite ingot is hot (not less than 100°C), it is placed in a room temperature water pool for cooling, and when the temperature of the composite ingot is basically consistent with the water temperature, it is taken out of the water, and finally a steel wedge is used to drive into the cracks between the residual aluminum material on the surrounding area and the aluminum-based composite material ingot, so that the residual aluminum material is completely separated from the aluminum-based composite material ingot.

[0042] Example 2

[0043] In this embodiment, the ceramic particles selected as the reinforcement are alumina (Al2O3) particles with a particle size (d50) of 12.8 μm. The alumina particles are loaded into a graphite crucible to form a pile with a bulk density of 40%. The upper surface of the pile is flattened with a glass plate. Silicon powder with a particle size of 45 μm is then evenly spread to a thickness of approximately 1 mm. A 2000 series wrought aluminum alloy (2024 wrought aluminum alloy) ingot is placed on top. The amount of the aluminum alloy ingot is calculated based on the volume and porosity of the pile (60%) and is 10% to 20% greater than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere and heated to 920°C, held at this temperature for 4 hours, and then cooled to 150±10°C. The composite material ingot is buckled out of the graphite crucible to obtain a composite ingot; while the composite ingot is hot (not less than 100°C), it is placed in a room temperature water pool for cooling, and when the temperature of the composite ingot is basically consistent with the water temperature, it is taken out of the water, and finally a steel wedge is used to drive into the cracks between the residual aluminum material on the surrounding area and the aluminum-based composite material ingot, so that the residual aluminum material is completely separated from the aluminum-based composite material ingot.

[0044] Example 3

[0045] In this embodiment, the ceramic particles selected as the reinforcement are silicon carbide (SiC) particles. The SiC particles are composed of two particle sizes (d50) of 75 μm and 17.3 μm mixed in a ratio of 8:2. The silicon carbide particles are loaded into a graphite crucible to form a pile with a bulk density of 70%. The upper surface of the pile is flattened with a glass plate. Silicon powder with a particle size of 88 μm is then evenly spread to a thickness of approximately 1.5 mm. On top of the pile, an aluminum-silicon-magnesium cast aluminum alloy ingot is placed. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and its porosity (30%), and the amount is 10% to 20% more than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere, heated to 950°C, held at this temperature for 15 hours, and then cooled to 245±5°C. The composite material ingot is buckled out of the graphite crucible to obtain a composite ingot; while the composite ingot is hot (not less than 100°C), it is placed in a room temperature water pool for cooling, and when the temperature of the composite ingot is basically consistent with the water temperature, it is taken out of the water, and finally a steel wedge is used to drive into the cracks between the residual aluminum material on the surrounding area and the aluminum-based composite material ingot, so that the residual aluminum material is completely separated from the aluminum-based composite material ingot.

[0046] Example 4

[0047] In this embodiment, the ceramic particles selected as the reinforcement are titanium carbide (TiC) particles with a particle size (d50) of 1 μm. The titanium carbide particles are loaded into a graphite crucible to form a pile with a bulk density of 45%. The upper surface of the pile is flattened with a glass plate. Silicon powder with a particle size of 220 μm is then evenly spread to a thickness of approximately 2 mm. A 7000 series wrought aluminum alloy (7075 wrought aluminum alloy) ingot is placed on top. The amount of the aluminum alloy ingot is calculated based on the volume and porosity of the pile (55%) and is 10% to 20% greater than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere and heated to 900°C, held at this temperature for 12 hours, and then cooled to approximately 245±5°C. The composite material ingot is buckled out of the graphite crucible to obtain a composite ingot; while the composite ingot is hot (not less than 100°C), it is placed in a room temperature water pool for cooling, and when the temperature of the composite ingot is basically consistent with the water temperature, it is taken out of the water, and finally a steel wedge is used to drive into the cracks between the residual aluminum material on the surrounding area and the aluminum-based composite material ingot, so that the residual aluminum material is completely separated from the aluminum-based composite material ingot.

[0048] Example 5

[0049] In this embodiment, the ceramic particles selected as the reinforcement are silicon carbide (SiC) particles with a particle size (d50) of 120 μm. The silicon carbide particles are loaded into a graphite crucible to form a pile with a bulk density of 63%. The upper surface of the pile is flattened with a glass plate. Quartz powder with a particle size of 300 μm is then evenly spread to a thickness of approximately 1.5 mm. On top of the pile, an aluminum-silicon-magnesium cast aluminum alloy ingot is placed. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and its porosity (37%), and the amount is 10% to 20% more than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere and heated to 880°C, held at this temperature for 6 hours, and then cooled to 200±10°C. The composite material ingot is buckled out of the graphite crucible to obtain a composite ingot; while the composite ingot is hot (not less than 100°C), it is placed in a room temperature water pool for cooling, and when the temperature of the composite ingot is basically consistent with the water temperature, it is taken out of the water, and finally a steel wedge is used to drive into the cracks between the residual aluminum material on the surrounding area and the aluminum-based composite material ingot, so that the residual aluminum material is completely separated from the aluminum-based composite material ingot.

[0050] Example 6

[0051] In this embodiment, the ceramic particles selected as the reinforcement are aluminum nitride (AlN) particles with a particle size (d50) of 75 μm. The aluminum nitride particles are loaded into a graphite crucible to form a pile with a bulk density of 58%. The upper surface of the pile is flattened with a glass plate. Then, quartz powder with a particle size of 110 μm is evenly spread to a thickness of approximately 1 mm. On top of the pile, an aluminum-silicon-magnesium cast aluminum alloy ingot is placed. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and its porosity (42%), and the amount is 10% to 20% more than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere and heated to 830°C, kept at this temperature for 9 hours, and then cooled to 200±10°C. The composite material ingot is buckled out of the graphite crucible to obtain a composite ingot; while the composite ingot is hot (not less than 100°C), it is placed in a room temperature water pool for cooling, and when the temperature of the composite ingot is basically consistent with the water temperature, it is taken out of the water, and finally a steel wedge is used to drive into the cracks between the residual aluminum material on the surrounding area and the aluminum-based composite material ingot, so that the residual aluminum material is completely separated from the aluminum-based composite material ingot.

[0052] Example 7

[0053] In this embodiment, the ceramic particles selected as the reinforcement are boron carbide (B4C) particles with a particle size (d50) of 29.2 μm. The boron carbide particles are loaded into a graphite crucible to form a pile with a bulk density of 50%. The upper surface of the pile is flattened with a glass plate. Then, quartz powder with a particle size of 20 μm is evenly spread to a thickness of approximately 0.5 mm. A 2000 series wrought aluminum alloy (2024 wrought aluminum alloy) ingot is placed on the pile. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and the porosity of the pile (50%), and the amount is 10% to 20% more than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere, heated to 940°C, held at this temperature for 13 hours, and then cooled to 150±10°C. The composite material ingot is buckled out of the graphite crucible to obtain a composite ingot; while the composite ingot is hot (not less than 100°C), it is placed in a room temperature water pool for cooling, and when the temperature of the composite ingot is basically consistent with the water temperature, it is taken out of the water, and finally a steel wedge is used to drive into the cracks between the residual aluminum material on the surrounding area and the aluminum-based composite material ingot, so that the residual aluminum material is completely separated from the aluminum-based composite material ingot.

[0054] Example 8

[0055] In this embodiment, the ceramic particles selected as the reinforcement are alumina (Al2O3) particles with a particle size (d50) of 103 μm. The alumina particles are loaded into a graphite crucible to form a pile with a bulk density of 53%. The upper surface of the pile is flattened with a glass plate. Quartz powder with a particle size of 200 μm is then evenly spread to a thickness of approximately 2 mm. On top of the pile, an aluminum-silicon-magnesium cast aluminum alloy ingot is placed. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and its porosity (47%), and the theoretical amount is increased by 10% to 20%. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere and heated to 860°C, held at this temperature for 2 hours, and then cooled to 150±10°C. The composite material ingot is buckled out of the graphite crucible to obtain a composite ingot; while the composite ingot is hot (not less than 100°C), it is placed in a room temperature water pool for cooling, and when the temperature of the composite ingot is basically consistent with the water temperature, it is taken out of the water, and finally a steel wedge is used to drive into the cracks between the residual aluminum material on the surrounding area and the aluminum-based composite material ingot, so that the residual aluminum material is completely separated from the aluminum-based composite material ingot.

[0056] Comparative Example 1

[0057] Compared with Example 1, the only difference is that the peeling layer powder is not laid. The specific steps are as follows:

[0058] The ceramic particles selected as the reinforcement in this comparative example are silicon carbide (SiC) particles with a particle size (d50) of 63 μm. The silicon carbide particles are loaded into a graphite crucible to form a pile with a packing density of 55%. The upper surface of the pile is flattened with a glass plate, and an aluminum-silicon-magnesium cast aluminum alloy ingot is placed thereon. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and the porosity of the pile (45%) and is 10% to 20% more than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere and heated to 800°C, kept warm for 8 hours, and then cooled to 200±10°C. The composite material ingot is deducted from the graphite crucible to obtain a composite ingot. The composite ingot is placed in a room temperature water pool while hot (not less than 100°C) to cool, and is taken out of the water when the temperature of the composite ingot is basically the same as the water temperature.

[0059] Comparative Example 2

[0060] Compared with Example 1, the only difference is that the method is not cooled by constant temperature water, but is directly cooled to room temperature after the insulation is completed. The specific steps are as follows:

[0061] The ceramic particles selected as reinforcement in this comparative example are silicon carbide (SiC) particles with a particle size (d50) of 63 μm. The silicon carbide particles are loaded into a graphite crucible to form a pile with a packing density of 55%, and the upper surface of the pile is flattened with a glass plate; then, silicon powder with a particle size of 20 μm is evenly spread with a thickness of about 0.5 mm, and an aluminum-silicon-magnesium cast aluminum alloy ingot is placed thereon. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and the porosity of the pile (45%) and is 10% to 20% more than the theoretical amount; the graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere, heated to 800°C, kept warm for 8 hours, and then cooled to room temperature.

[0062] Comparative Example 3

[0063] Compared with Example 1, the only difference is that the temperature of the composite ingot is 50° C. before being cooled with room temperature water. The specific steps are:

[0064] In this comparative example, the ceramic particles selected as the reinforcement are silicon carbide (SiC) particles with a particle size (d50) of 63 μm. The silicon carbide particles are loaded into a graphite crucible to form a pile with a bulk density of 55%. The upper surface of the pile is flattened with a glass plate. Silicon powder with a particle size of 20 μm is then evenly spread to a thickness of approximately 0.5 mm. An aluminum-silicon-magnesium cast aluminum alloy ingot is placed on top. The amount of the aluminum alloy ingot is calculated based on the volume of the pile and the porosity of the pile (45%), and the amount is 10% to 20% more than the theoretical amount. The graphite crucible and its contents are placed in a heating device with a nitrogen atmosphere and heated to 800°C, kept at this temperature for 8 hours, and then cooled to 200±10°C. The composite ingot is removed from the graphite crucible to obtain a composite ingot. While still hot (the composite ingot temperature is 50°C), it is placed in a room-temperature water pool to cool. When the composite ingot temperature is roughly the same as the water temperature, it is removed from the water. Finally, a steel wedge is driven into the crack between the residual aluminum material on the periphery and the aluminum-based composite ingot to completely separate the residual aluminum material from the aluminum-based composite ingot.

[0065] FIG1 shows the surface state of the aluminum-based composite material after separation from the residual aluminum material in Example 1. As can be seen from FIG1 , the aluminum-based composite material and the residual aluminum material can be completely and cleanly separated by the method of Example 1.

[0066] The positions indicated by arrows in Figures 2 to 6 are the junctions of the residual aluminum material and the aluminum-based composite material.

[0067] FIG2 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material when the composite ingot of Example 1 is cooled to 200±10° C., and only slight traces can be seen at the position indicated by the arrow in FIG2 , and no crack traces can be seen.

[0068] FIG3 is a diagram showing the state of the junction between the aluminum-based composite material and the residual aluminum material after the composite ingot of Example 1 is cooled with room temperature water. As can be seen from FIG3 , when room temperature water cooling is performed at a temperature not lower than 100° C., the cracks between the residual aluminum material and the aluminum-based composite material are very obvious after water cooling.

[0069] Figure 4 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material after the composite ingot of Comparative Example 1 is cooled with room temperature water. It can be seen from Figure 4 that since no separation layer is laid in Comparative Example 1, the cracks between the residual aluminum material and the aluminum-based composite material after rapid cooling with room temperature water are not very continuous and the crack width is small.

[0070] FIG5 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material in the material cooled to room temperature in Comparative Example 2. As can be seen from FIG5 , for the material that was not quenched with room temperature water, there are slight cracks at the junction between the aluminum-based composite material and the residual aluminum material, but no obvious cracks.

[0071] Figure 6 is a state diagram of the junction between the aluminum-based composite material and the residual aluminum material after the composite ingot of Comparative Example 3 is cooled with room temperature water at 50°C. It can be seen from Figure 6 that when the composite ingot is water-cooled at a lower temperature, although there will be a crack at the junction between the aluminum-based composite material and the residual aluminum material, the size of the crack is significantly smaller than that of Example 1, which leads to the inability to completely peel off the residual aluminum material when a steel wedge is used to peel off the residual aluminum material. It can be seen that when the temperature of the composite ingot is too low and it is rapidly cooled, the thermal mismatch stress generated is not enough to cause a large crack between the residual aluminum material and the aluminum-based composite material.

[0072] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0073] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an aluminum-based composite material by a pressureless infiltration process with easy separation of residual aluminum material, characterized in that the steps include: Aluminum alloy is used as a matrix material, ceramic particles are used as a reinforcement material, a peeling layer powder is laid between the reinforcement material and the matrix material, and a composite ingot is prepared by a pressureless infiltration process; After the composite ingot is placed in water at room temperature for cooling, the residual aluminum is peeled off through the cracks around the edges to obtain the aluminum-based composite material; The peeling layer powder includes silicon powder or quartz powder.

2. The method according to claim 1, characterized in that The aluminum alloy includes one of aluminum-silicon-magnesium cast aluminum alloy, 2000 series deformed aluminum alloy and 7000 series deformed aluminum alloy; the ceramic particles include one of silicon carbide particles, aluminum oxide particles, aluminum nitride particles, titanium carbide particles and boron carbide particles.

3. The method according to claim 1, characterized in that The particle size of the peeling layer powder is 20 to 300 μm, and the spreading thickness is 0.5 to 2 mm.

4. The method according to claim 2, characterized in that: The particle size d50 of the ceramic particles is 1 μm to 120 μm.

5. The method according to claim 1, characterized in that: The steps of the pressureless infiltration process include: The ceramic particles are stacked into a stack with a stacking density of 40-70%, a peeling layer powder is laid on the upper surface of the stack, the aluminum alloy is placed on the upper surface of the peeling layer powder, and heated to 800-950° C. for 2-15 hours under nitrogen atmosphere protection, and then cooled to 150-250° C. to obtain the composite ingot.

6. The method according to claim 1, characterized in that The temperature of the composite billet before being placed in normal temperature water is not less than 100° C.; the cooling is to cool the composite billet to the same temperature as the water.

7. The method according to claim 1, characterized in that The stripping is accomplished by lightly driving a steel wedge into the cracked area around the edges to remove the residual aluminum.

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