Method for preparing composite material through metal melt and ceramic liquid phase reaction

Abstract

The invention relates to a method for preparing a composite material by reaction of a metal melt and a ceramic liquid phase, which comprises the following steps: determining the proportion of ceramic raw materials according to an Al2O3-SiO2-MxO phase diagram, mixing the raw material powder, and forming to obtain a ceramic blank; preparing the ceramic green body and metal according to a mass ratio, heating until the metal is completely molten, performing pressurized seepage, and then cooling to obtain a prefabricated body; and carrying out high-temperature sintering on the preform, carrying out heat preservation until the liquid phase quantity generated by the ceramic is 38.9-85.5%, and carrying out furnace cooling to obtain the ceramic / metal matrix composite material. According to the ceramic / metal composite material prepared through the method, good wetting between a ceramic phase and a metal phase is achieved, the comprehensive mechanical property is improved, and the key problems that due to the fact that a metal ceramic composite material is poor in wettability and pores exist in an interface, residual stress is concentrated, and the interface cracks are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic / metal composite material preparation, and in particular relates to a method for preparing a composite material by reacting a metal melt with a ceramic liquid. Background Art

[0002] Ceramic / metal composites have high specific strength, fracture toughness, corrosion resistance, low thermal expansion coefficient, and good energy absorption performance. However, due to the poor wettability of molten metal and solid ceramic, the different thermal expansion coefficients between the ceramic and metal matrix, the low degree of bonding between the two, and the presence of interface defects, shear stress will form at the interface of the composite material. During the load transfer process, it will cause the ceramic phase to fall off and become unstable, and even lead to cracks, thereby reducing the overall mechanical properties of the material. Weak interfacial bonding also leads to a decrease in the machinability of the metal-ceramic, such as delamination and shedding between the metal and ceramic during processing. Therefore, it is necessary to improve the interfacial bonding strength of metal-ceramic composites to improve their overall mechanical properties and machinability.

[0003] The current conventional preparation method is to first prepare the ceramic and then composite it with the metal. Through ceramic surface treatment, such as chemical plating, ceramic interface corrosion, and changing the surface roughness, the wettability of the interface is adjusted to improve the interface bonding strength between the metal and the ceramic. Chinese patent CN1207436C discloses a method for preparing a Cu / Ti3SiC2 composite material by chemical copper plating, which provides a method of mixing titanium silicon carbide particles with copper powder by chemical copper plating and sintering to obtain a Cu / Ti3SiC2 composite material. Surface treatment methods such as chemical plating have certain limitations. Not only do they have certain requirements for the physical properties of the ceramic phase, but the entire process preparation process is complicated.

[0004] Chinese patent CN102700192A discloses a method for preparing a metal-ceramic composite material. This method achieves metallurgical bonding and an interface gradient effect between an aluminum alloy and an alumina ceramic core rod through post-cast sealing, insulation, and heat treatment. However, due to the poor wettability between alumina and aluminum metal, liquid-solid metallurgical bonding or liquid-solid interfacial reaction typically occurs, making it difficult to achieve a good interface bond using this method. This weakens the interface stability between the alumina and aluminum melt, leading to cracking and shedding at the metal-ceramic interface during load transfer or machining.

[0005] Chinese patent CN1145346 discloses a series of Al2O3-based composite materials and their preparation methods, which discloses the reaction formula 4Al+3SiO2=2Al2O3+3Si, that is, it proposes that the interface between the aluminum alloy and the ceramic is bonded by a chemical reaction. However, the temperature disclosed in its step (3) is 900℃~1200℃. If the ceramic is quartz glass, it is well known in the art that the melting point of quartz glass is 1700℃~1800℃. Without any treatment, the quartz glass does not reach the melting point at 900℃~1200℃ and remains in a solid state, indicating that it is still a liquid-solid reaction, that is, the molten aluminum alloy only reacts chemically with the surface of the quartz glass or ceramic. There are still problems such as small contact area between the two phases at the interface and the presence of pores. The wettability between the metal melt and the ceramic phase and the comprehensive mechanical properties still need to be improved. Summary of the Invention

[0006] Purpose of the invention: The present invention proposes a method for preparing a composite material by reacting a metal melt with a ceramic liquid phase, the purpose of which is to solve the problems of poor wettability and poor overall performance between the existing metal melt and ceramic phase.

[0007] Technical solution:

[0008] The present invention provides a method for preparing a composite material by reacting a metal melt with a ceramic liquid phase, comprising the following steps:

[0009] S1 ceramic raw materials are based on Al2O3-SiO2-M x The O phase diagram determines the ratio of each raw material, and the raw material powders are mixed and formed into a ceramic body;

[0010] S2: mixing the ceramic body and the metal in a mass ratio of 0.1 to 0.7:1, heating until the metal is completely melted, performing pressurized infiltration, and then cooling to obtain a preform;

[0011] S3 sintering the preform at high temperature and keeping the temperature until the amount of ceramic generated liquid phase is 38.9% to 85.5%, cooling the furnace to obtain a ceramic / metal matrix composite material. Preferably, the ceramic raw materials include Al2O3, SiO2 and a solvent M x O, or the ceramic raw materials are bulk industrial solid waste, the components are Al2O3, SiO2 and solvent M x The mass percentage of O content is 16% to 22% for Al2O3, 58% to 72% for SiO2, and the solvent M x Specifically, based on the ceramic raw material ratios obtained above, the amount of liquid phase generated at a certain temperature with different raw material ratios can be calculated using thermodynamic software Factsage 7.2.

[0012] Preferably, the cosolvent M xO is any one of CaO, MgO, Na2O and K2O.

[0013] Preferably, the bulk industrial solid waste is a variety of aluminum ash, coal gangue, blast furnace slag, ceramic industry waste, glass waste, diatomaceous earth, fly ash, red mud and feldspar tailings.

[0014] Preferably, the method for preparing the ceramic raw material powder in step S1 is to uniformly mix the ceramic raw materials through a ball mill to obtain a mixed powder, wherein the ball milling speed is 350 r / min to 450 r / min, and the ball milling time is 10 to 360 min.

[0015] Preferably, the forming process in step 1 is granulation or molding, and the shape of the obtained ceramic body is not limited.

[0016] Preferably, the pressurized seepage in step S2 is carried out in a positive pressure or negative pressure manner, wherein the positive pressure is 9.8 to 20.8 N and the negative pressure is 0.05 to 0.07 MPa; the pressurized seepage temperature is 670 to 700° C., the pressurized seepage time is 2 to 10 minutes, and the pressure is maintained for 1 to 10 minutes.

[0017] Preferably, the metal in step S2 is magnesium, aluminum, a magnesium alloy, or an aluminum alloy. The metal can be in bulk or powder form. Preferably, the sintering temperature in step S3 is 800-1400°C, and the holding time is 10-120 minutes.

[0018] Beneficial effects:

[0019] 1. The ceramic / metal matrix composite prepared by the present method achieves excellent wetting between the ceramic and metal phases, resolving the key issue of poor wettability and the presence of interfacial porosity in metal-ceramic composites, which leads to residual stress concentration and interfacial cracking. This effectively prevents cracking and shedding at the metal-ceramic interface during load transfer or machining.

[0020] 2. The present invention creatively discovered that when the amount of liquid phase generated by ceramics is 38.9% to 85.5%, the intermetallic compounds, elements and solid solutions precipitated by the interfacial reaction are distributed between the two phase interfaces and form an interfacial layer, thereby filling the pores left between the metal and ceramic due to mechanical bonding, greatly increasing the contact area between the two, and making the ceramic / metal composite material have a higher load-bearing capacity and the ability to resist deformation.

[0021] 3. Since metal and ceramic are in a continuous two-liquid phase coexistence state within a specific temperature range, matching metal and ceramic can be selected for compounding according to the actual service temperature conditions required. Therefore, the application range of this technology is wide.

[0022] 4. The ceramic / metal composite material prepared by the present invention has high specific strength, high compressive strength and high energy absorption capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a process flow chart of the present invention;

[0024] Figure 2 is the SEM image of the preform;

[0025] Figure 3 Figure 1 is an SEM image of ceramic / metal composites, where (a) is an SEM image of the composite interface, and (b) is an enlarged SEM image of a part in (a). 1 represents metallic aluminum, 2 is the interface reaction product, and 3 represents ceramic.

[0026] Figure 4 Figure 2 is the XRD pattern of the prepared samples, where Figure (a) is the XRD pattern of the preform, and Figure (b) is the XRD pattern of the prepared ceramic / metal composite material;

[0027] Figure 5 is the phase diagram of Al2O3-SiO2-MgO-K2O-Na2O in Example 1;

[0028] Figure 6 is a stress-strain curve diagram of the preform in Example 1;

[0029] Figure 7 is a stress-strain curve diagram of the ceramic / metal matrix composite material in Example 1;

[0030] Figure 8 is a stress-strain curve diagram of the preform in Example 2;

[0031] Figure 9 is a stress-strain curve diagram of the ceramic / metal matrix composite material in Example 2;

[0032] Figure 10 is a stress-strain curve diagram of the preform in Example 3;

[0033] Figure 11 is a stress-strain curve diagram of the ceramic / metal matrix composite material in Example 3;

[0034] Figure 12 is a stress-strain curve diagram of the preform in Example 4;

[0035] Figure 13 is a stress-strain curve diagram of the ceramic / metal matrix composite material in Example 4;

[0036] Figure 14 is the SEM image of the composite material at 750°C in Comparative Example 1;

[0037] Figure 15 for Figure 14 The local SEM enlarged image in;

[0038] Figure 16 is a stress-strain curve diagram of the composite material in Comparative Example 1;

[0039] Figure 17 is the SEM image of the composite material above 1400°C in Comparative Example 1;

[0040] Figure 18 is the SEM image of the composite material in Comparative Example 3;

[0041] Figure 19 for Figure 18 A local SEM enlarged image in . DETAILED DESCRIPTION

[0042] To further illustrate the technical means and effects of the present invention, the present invention is described below in conjunction with embodiments and drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention.

[0043] The present invention proposes a method for preparing a composite material by reacting a metal melt with a ceramic liquid phase. The method utilizes the reaction between the metal melt and the ceramic when generating a liquid phase to form a tightly bonded interface reaction transition layer between the ceramic phase and the metal phase, so as to solve the technical problems of poor wettability between the metal melt and the ceramic phase and low overall performance in the process of preparing ceramic / metal composite materials.

[0044] The present invention provides a method for preparing a composite material by reacting a metal melt with a ceramic liquid phase, such as Figure 1 As shown, the following steps are included:

[0045] S1 ceramic raw materials are based on Al2O3-SiO2-M x The O phase diagram determines the ratio of each raw material, and the raw material powders are mixed and formed into a ceramic body;

[0046] Specifically, the ceramic raw materials in this step are based on Al2O3-SiO2-M x The composition point corresponding to the low temperature liquid phase region in the O phase diagram is used as the ceramic raw material ratio by adding flux M x O, the flux M xO is any combination of two or more of CaO, MgO, Na2O and K2O. The ratio of each raw material of the ceramic body is limited, thereby reducing the temperature at which the ceramic body melts to produce a liquid phase, and then limiting the amount of the ceramic liquid phase, and further determining that the high-temperature sintering temperature in step S3 is 800℃~1400℃, preferably 1250℃~1400℃. High temperature is conducive to the melting of the ceramic body to produce a liquid phase, which can increase the contact area and wettability between the metal melt and the ceramic phase, but if the temperature is too high (>1400℃), the metal will be lost due to the high temperature, thereby reducing the toughness of the material; too high a temperature will also aggravate the interface reaction between the metal and the ceramic, forming an excessive amount of brittle phase, which is easy to cause interface separation; at the same time, excessive interface reaction will cause a large amount of ceramic component and metal content to be lost, resulting in loss inside the ceramic and loss of metal, thereby affecting the load transfer between the metal, the interface and the ceramic, and easily causing stress concentration and crack initiation, which reduces the overall mechanical properties of the composite material.

[0047] In this step, after determining the raw material ratios, the ceramic body is directly mixed and formed without any surface treatment. Unlike existing techniques for improving wettability through chemical plating, ceramic interface corrosion, or surface roughness modification, this step saves significant steps, time, and labor.

[0048] S2: The ceramic body and metal are mixed in a mass ratio of 0.1 to 0.7:1. The metal is magnesium, aluminum, a magnesium alloy, or an aluminum alloy, and can be in block or powder form. The metal is heated until it is completely melted, subjected to pressurized infiltration, and then cooled to obtain a preform. The pressurized infiltration reaction is carried out under positive or negative pressure, wherein the positive pressure is 9.8 to 20.8 N and the negative pressure is 0.05 to 0.07 MPa. The pressurized infiltration temperature is 670 to 700°C, the pressurized infiltration time is 2 to 10 minutes, and the pressure is maintained for 1 to 10 minutes.

[0049] The ceramic body is made of many small balls (or other three-dimensional structures) stacked together. The balls are in contact with each other and there are gaps between them. In this way, the contact between the balls will not be broken during the infiltration of molten aluminum, and the molten aluminum will fill the gaps between the balls. Figure 2 The figure shows the SEM image of the preform. It can be seen that the interface between the metallic aluminum and the ceramic phase is clear and there are gaps, indicating that the agglomerated powder particles in the ceramic body are combined with the aluminum liquid through mechanical bonding, and no obvious interface reaction occurs. This is because, on the one hand, the contact area between the two is small, on the other hand, the diffusion rate of the liquid-solid reaction is slow, and on the third hand, the reaction time is short. Therefore, an effective and obvious interface layer cannot be generated in the preform stage.

[0050] S3 preform sintering: Place the preform in a heating furnace and heat it to 800℃~1400℃, keep it warm for 10~120min, until the amount of ceramic liquid phase is 38.9%~85.5%. At this time, the metal aluminum is completely melted, and the ceramic liquid phase in the preform and the metal melt form a continuous double liquid phase coexistence state and an interfacial reaction occurs, thereby improving the interface bonding strength. The ceramic / metal composite material is obtained as the furnace cools.

[0051] Figure 3 is the SEM image of ceramic / metal composite material, where Figure 3 (a) is the SEM image of the interface of ceramic / metal composite material. Figure 3 (b) Figure 3 From the partial enlarged image of (a), it can be seen that the white interface transition reaction layer is well bonded with the metal aluminum and ceramics. There is no obvious crack in the interface area after solidification after being magnified 10,000 times, indicating that the formed interface layer matches the thermal expansion coefficients of the metal aluminum and the ceramics. There is no interface peeling from high temperature to low temperature. The interface stratification caused by stress concentration caused by thermal stress indicates that Si and aluminum-silicon solid solution formed by the redox reaction between molten aluminum and liquid ceramics can match the thermal expansion coefficients between metal, ceramic and the interface layer, thereby improving the bonding strength between metal and ceramic. During the process of generating liquid phase in ceramics, the ceramic liquid phase will expand outward and squeeze against the external metal liquid phase to promote the densification of the interface and the occurrence of interfacial reaction. After the liquid phase generated by the metal liquid phase and the ceramic diffuses and reacts with each other at the interface between the two phases, an interface zone will be formed in the interface zone with metal solid solutions or micron / submicron single particles in the form of strips, sheets or strips as the main phases. This interface zone has a thermal expansion coefficient that matches the metal and ceramic on both sides. During the cooling process, the difference in thermal expansion coefficient will not cause the concentration of thermal stress, resulting in separation and cracking of the interface layer. Instead, as the temperature decreases, the interface zone will maintain a relatively close bond with the metal and ceramic. The metal solid solution or single substance formed by the interfacial reaction has a similar crystal structure to the metal phase and the ceramic phase. Therefore, it is easier to form a semi-coherent or coherent interface structure with stronger interface bonding strength during the reaction, thereby achieving a close bond between the interface layer.

[0052] Figure 4 (a) is the phase composition of the preform, which is mainly composed of aluminum and oxides in ceramics. Figure 4 (b) is the XRD phase composition of the ceramic-metal composite material, in which silicon and aluminum-silicon compounds are new phases formed by the reaction between aluminum melt and ceramic liquid phase. In addition, forsterite, spinel and anorthite phases are also included. The chemical reactions involved are shown in the following table.

[0053]

[0054] In step S3, when the sintering temperature is 800°C to 1400°C and the amount of liquid phase generated by the ceramic is 38.9% to 85.5%, under this condition, the metal content in the composite material will not be lost due to excessive temperature, and the liquid phase generated by the ceramic and the metal liquid phase form a continuous double liquid phase coexistence state. The double liquid phase coexistence state increases the contact area and wettability of the ceramic phase and the metal phase, and the diffusion rate is fast, which is conducive to the occurrence of interfacial reaction (chemical reaction). The intermetallic compounds, elements and solid solutions precipitated by the interfacial reaction are distributed between the two phase interfaces and form an interface layer, which not only allows the interface layer to be fully combined with the ceramic and the metal, and makes up for the pores left between the metal and the ceramic due to mechanical bonding, and greatly increases the contact area between the two, but also the ceramic phase and the metal phase can diffuse with the interface layer to increase the interface bonding force, thereby effectively promoting load transfer, and can maximize the role of the interface layer so that the composite material has higher comprehensive properties such as bearing capacity and resistance to deformation. Furthermore, during the process of generating a liquid phase in the ceramic, the ceramic liquid phase expands outward and squeezes against the external metal liquid phase, promoting interface densification and interfacial reaction. After the metal liquid phase and the liquid phase generated by the ceramic diffuse and react at the interface between the two phases, an interfacial zone is formed, which is mainly composed of metal solid solutions or micron / submicron-sized elemental particles in the form of strips, flakes, or laths. This interfacial zone has a thermal expansion coefficient that matches that of the metal and ceramic on both sides. During the cooling process, the difference in thermal expansion coefficients does not cause thermal stress concentration, which leads to separation and cracking of the interface layer. Instead, as the temperature decreases, the interface zone maintains a relatively close bond with the metal and ceramic. Furthermore, the metal solid solution or elemental particles formed by the interfacial reaction have a similar crystal structure to the metal and ceramic phases, making it easier to form a semi-coherent or coherent interface structure with stronger interfacial bonding strength during the reaction process, thereby achieving a tight bond between the interface layer. This effectively avoids the occurrence of cracking and shedding at the metal-ceramic interface during load transfer or machining.

[0055] Example 1

[0056] The method for preparing the ceramic / metal matrix composite material of this embodiment comprises the following steps:

[0057] S1 Ceramic body preparation: Commercially available analytically pure chemical reagents Al2O3, SiO2, MgO, K2O and Na2O were selected as ceramic raw materials, and the Al2O3-SiO2-MgO-K2O-Na2O quinary phase diagram was calculated using thermodynamic software Factsage7.2, as shown in Figure 5As shown, under the premise of first meeting the melting temperature of the metal, any point in the low-temperature liquid phase region of the quinary phase diagram is selected as the basis for designing the ceramic raw material formula. In this embodiment, the composition near point 6 in the quinary phase diagram is selected as the basis for designing the ceramic raw material formula. The corresponding temperature is used as the sintering temperature in step S3, and the corresponding temperature range is 1280℃~1350℃, so the sintering temperature in step S3 is preferably 1350℃. The ratio of the raw materials for the ceramic green body is obtained. According to the percentage by mass, 20% Al2O3, 66% SiO2, 4% MgO, 4% K2O, and 6% Na2O are weighed respectively. The raw materials are evenly mixed by a ball mill to obtain ceramic raw material powder. The ceramic raw material powder is then placed in a round pot granulator for balling to obtain a spherical ceramic green body with a diameter of 4.5~5.5mm;

[0058] S2 preform preparation: 30g of spherical ceramic green bodies in step S1 are freely stacked in a graphite crucible, and then 300g of metal aluminum is placed in the graphite crucible, and placed in a heating furnace and heated to 700°C for pressurized infiltration. The infiltration pressure is 9.8N, the infiltration time is 2min, and the holding time is 1min, so that the ceramic green body and the molten aluminum are combined together. After cooling, a preform with a ceramic content of 10% is obtained.

[0059] The density of the preform in step S2 is 1.85 g / cm 3 ,like Figure 6 As shown, the compressive strength of the preform is 18MPa and the energy absorption capacity is 15.82MJ / m 2 .

[0060] S3 preform sintering: Place the preform in a heating furnace and heat it to 1350°C, then keep it warm for 10 minutes. At this point, the aluminum metal is completely melted, and the ceramic generates 82.6% of the liquid phase. The ceramic liquid phase and the metal liquid phase in the preform form a continuous double liquid phase coexistence state and an interfacial reaction occurs, thereby increasing the bonding strength of the interface. As the furnace cools, a ceramic / metal composite material is obtained.

[0061] The average density of the prepared ceramic / metal matrix composite material is 1.8 g / cm 3 ,like Figure 7 As shown in the stress-strain curve, the compressive strength is 110MPa and the energy absorption capacity is 61.06MJ / m 2 .

[0062] Example 2

[0063] The method for preparing the ceramic / metal matrix composite material prepared in this embodiment comprises the following steps:

[0064] S1 Ceramic body preparation: Select the temperature point with the lowest liquid phase in the corresponding phase diagram as the basis for designing the ceramic raw material formula. According to the mass percentage, weigh 20% aluminum ash, 10% red mud, 60% waste glass, and 10% feldspar tailings, (w(Al2O3):w(SiO2):w(M x O) = 18:70:12), and mixed uniformly in a ball mill to obtain a ceramic raw material powder. The ceramic raw material powder is then placed in a round pot granulator for pelletization to obtain spherical ceramic bodies with a ball diameter of 1.5 to 2.5 mm;

[0065] The smaller the particle size of the ceramic green body, the smaller the gaps between the spheres, the greater the resistance to seepage, and the higher the required seepage pressure. Therefore, increasing both the seepage temperature and pressure simultaneously can ensure that the aluminum liquid fully fills the gaps between the spheres. Furthermore, the smaller the particle size of the ceramic green body, the thinner the aluminum skeleton between the spheres, which reduces the load-bearing capacity of the aluminum skeleton. As the ceramic content increases, the overall strength of the material decreases. Therefore, spherical ceramic green bodies with a diameter of 1.5-2.5 mm are preferred.

[0066] S2 Preform Preparation: 150g of a ceramic green body and 300g of aluminum metal were placed in a graphite crucible and placed in a heating furnace. The crucible was heated to 690°C and subjected to pressurized infiltration at a pressure of 20.8N for 5 minutes and a holding time of 5 minutes to combine the ceramic green body and the molten aluminum. After cooling, a preform with a ceramic content of 50% was obtained.

[0067] The density of the preform in step S2 is 1.72 g / cm 3 ,like Figure 8 As shown, the compressive strength is 12MPa and the energy absorption capacity is 10.96MJ / m 2 .

[0068] S3 preform sintering: Place the preform in a heating furnace and heat it to 1150°C, then keep it warm for 90 minutes. At this point, the aluminum metal is completely melted, and the ceramic generates 68.9% of the liquid phase. The ceramic liquid phase and the metal liquid phase in the preform form a continuous double liquid phase coexistence state and undergo an interfacial reaction, thereby increasing the bonding strength of the interface. The ceramic / metal composite material is obtained as the furnace cools.

[0069] The average density of the prepared ceramic / metal matrix composite material is 1.67 g / cm 3 ,like Figure 9 As shown, the compressive strength is 76.3MPa and the energy absorption is 51.4MJ / m 2 As the ceramic content increases, the density of the material decreases, and the strength decreases as the ceramic content increases.

[0070] Example 3

[0071] The method for preparing the ceramic / metal matrix composite material prepared in this embodiment comprises the following steps:

[0072] Preparation of ceramic green body: weigh 30% aluminum ash, 60% fly ash, 10% blast furnace slag (w(Al2O3):w(SiO2):w(M x O) = 21:64:15), and mixed uniformly in a ball mill to obtain a ceramic raw material powder. The ceramic raw material powder was then placed in a round pot granulator for pelletization to obtain spherical ceramic bodies with a ball diameter of 3.5 to 4.5 mm;

[0073] (2) Preform preparation: 150 g of the prepared ceramic green body and 300 g of an Al-4Si alloy ingot were placed in a graphite crucible, and then placed in a heating furnace and heated to 700°C. Pressurized infiltration was performed at an infiltration pressure of 15.8 N, an infiltration time of 5 min, and a holding time of 5 min to combine the ceramic green body with the molten aluminum. After cooling, a preform with a ceramic content of 50% was obtained;

[0074] The density of the composite material (preform) in step S2 is 1.67 g / cm 3 ,like Figure 10 As shown, the compressive strength is 35MPa and the energy absorption capacity is 16.87MJ / m 2 .

[0075] (3) Preform sintering: The preform is placed in a heating furnace and heated to 1250°C and kept warm for 30 minutes. At this time, the metal aluminum is completely melted, and the ceramic generates 72.4% liquid phase. The ceramic liquid phase and the metal liquid phase in the preform form a continuous double liquid phase coexistence state and an interfacial reaction occurs, thereby improving the bonding strength of the interface. The ceramic / metal composite material is obtained as the furnace cools.

[0076] The average density of the ceramic / aluminum-silicon matrix composite material is 1.63 g / cm 3 ,like Figure 11 As shown, the compressive strength is 91.9MPa and the energy absorption is 53.3MJ / m 2 Compared to Example 2, replacing metallic aluminum with an aluminum-silicon alloy (Al-4Si) can significantly improve the compressive strength of the composite material. However, the eutectic silicon in the aluminum-silicon alloy improves the strength of the composite material at the expense of the metal's toughness, which shortens the platform region of the stress-strain curve and reduces its energy absorption capacity. The metals described in this application include elemental metals and metal alloys, and can be selected based on actual requirements for compressive strength and metal toughness.

[0077] Example 4

[0078] The method for preparing the ceramic / metal matrix composite material prepared in this embodiment comprises the following steps:

[0079] S1 Ceramic Body Preparation: 70% SiO2, 16% Al2O3, 4% MgO, 8% Na2O, and 2% K2O were weighed, by mass percentage, and mixed uniformly in a ball mill to obtain a ceramic raw material powder. The ceramic raw material powder was then pelletized in a round pot pelletizer to obtain spherical ceramic bodies with a diameter of 3.5-4.5 mm.

[0080] S2 Preform Preparation: 150g of a ceramic green body and 300g of aluminum metal were placed in a graphite crucible and placed in a heating furnace. The crucible was heated to 680°C and subjected to pressurized infiltration at a pressure of 20.8N for 2.5min and a holding time of 1min to combine the ceramic green body and the molten aluminum. After cooling, a preform with a ceramic content of 50% was obtained.

[0081] The density of the composite material (preform) in step S2 is 1.69 g / cm 3 ,like Figure 12 As shown, the compressive strength is 11.45MPa and the energy absorption capacity is 12.36MJ / m 2 .

[0082] S3 preform sintering: Place the preform in a heating furnace and heat it to 800°C, then keep it warm for 120 minutes. At this point, the aluminum metal is completely melted, and the ceramic generates a 42.7% liquid phase. The ceramic liquid phase and the metal liquid phase in the preform form a continuous double liquid phase coexistence state and undergo an interfacial reaction, thereby increasing the bonding strength of the interface. The ceramic / metal composite material is obtained as the furnace cools.

[0083] The average density of the prepared ceramic / metal matrix composite material is 1.65 g / cm 3 ,like Figure 13 As shown, the compressive strength is 76.32Mpa and the energy absorption capacity is 56.23MJ / m 2 .

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 1 is that the sintering temperature of the preform in step S3 is 750°C.

[0086] like Figure 14 and Figure 15The figure shows the interface microstructure of a sample sintered at 750°C. Numerous needle-like whisker structures and agglomerated particles can be observed in the ceramic. Due to the relatively low sintering temperature, the ceramic had not yet formed a liquid phase. Furthermore, the boundary of the aluminum metal is uneven, indicating that at high temperatures, the aluminum liquid diffused into the ceramic, possibly accompanied by a liquid-solid interface reaction. The interface between the aluminum metal and the ceramic is clearly defined, with a significant gradient and porosity. This indicates that the liquid-solid interface reaction occurring at the lower sintering temperature cannot produce a good interface reaction layer and is insufficient to improve the interfacial bonding strength between the aluminum metal and the ceramic.

[0087] The average density of the prepared ceramic / metal matrix composite material is 1.69 g / cm 3 ,like Figure 16 As shown, the compressive strength is 37MPa and the energy absorption is 24.14MJ / m 2 .

[0088] However, when the sintering temperature is too high, higher than 1400℃, the liquid phase ratio of the ceramic is higher than 85.5%. Figure 17 The figure shows the microscopic interface morphology of aluminum / ceramic at a temperature exceeding 1400°C. Too high a sintering temperature will produce too much liquid phase, far exceeding 85.5%. Too high a temperature will accelerate the rate of the interface reaction and form an overly thick interface reaction layer. An overly thick interface reaction layer will easily lead to the separation of metal and ceramic, which is not conducive to the bonding of the interface. Figure 17 It can be seen that the thickness of the interface layer reaches 100μm, and the interface surface is rough. There are obvious gaps at the interfaces with metal aluminum and ceramics. During the compression process, these gaps can easily cause stress concentration, causing cracks to initiate and expand here, and eventually lead to premature failure and collapse of the material.

[0089] Comparative Example 2

[0090] The difference between Comparative Example 2 and Example 1 is that the ceramic raw material contains Al2O3 and SiO2, and does not contain flux.

[0091] In the absence of flux, the ceramic raw materials Al2O3 and SiO2 do not produce a liquid phase at the temperature of Example 1. The interface reaction is the reaction between molten aluminum and solid SiO2. The average density of the obtained ceramic / metal matrix composite material is 1.82g / cm 3 , compressive strength is 29MPa, energy absorption is 30.47MJ / m 3 ,Since no ceramic liquid phase is produced, the bonding strength between the metal and the ceramic is very weak, and under the action of shear stress, the stress-strain curve exhibits subtle jagged fluctuations.

[0092] Comparative Example 3

[0093] The difference between Comparative Example 3 and Example 1 is that the preform sintering temperature in step S3 is 1000°C, and the calculated liquid phase content of the ceramic is 18.6%. Figure 18 and 19 As shown, at this time, the degree of interface reaction between the ceramic liquid phase and the molten aluminum decreases, resulting in insufficient interface reaction, which makes it impossible to obtain an interface layer with strong bonding strength. Therefore, the material is prone to interface debonding or even cracking during the cooling process.

[0094] The average density of the prepared ceramic / metal matrix composite material is 1.78 g / cm 3 , compressive strength is 51MPa, energy absorption capacity is 21.8MJ / m 2 .

[0095] The present invention allows the ceramic body in the preform to produce a liquid phase, which forms a continuous two-liquid phase coexistence state with the metal liquid phase, and an interfacial reaction occurs to form intermetallic compounds, simple substances and solid solutions, thereby obtaining a ceramic / metal composite material with an interfacial reaction transition layer. The prepared ceramic / metal composite material has high specific strength, high compressive strength and high energy absorption capacity. The preparation method has a short process flow and is easy to implement. Moreover, since metal and ceramic will be in a continuous two-liquid phase coexistence state within a specific temperature range, matching metals and ceramics can be selected for compounding according to the actual service temperature conditions required. Therefore, the application range of this technology is wide. The method is simple in process, and the interface obtained by the reaction can effectively improve the comprehensive mechanical properties of the composite material.

[0096] The above description is only a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiment. For those skilled in the art, any modification, equivalent replacement, improvement, etc. made without departing from the technical concept of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a composite material by reacting a metal melt with a ceramic liquid phase, characterized in that: The following steps are involved: S1 ceramic raw materials are based on Al2O3-SiO2-M x The O phase diagram determines the ratio of each raw material, and the raw material powders are mixed and formed into a ceramic body; S2: mixing the ceramic body and the metal in a mass ratio of 0.1 to 0.7:1, heating until the metal is completely melted, performing pressurized infiltration, and then cooling to obtain a preform; S3 sintering the preform at a high temperature and keeping the temperature until the ceramic liquid phase volume is 38.9% to 85.5%, and cooling the preform along with the furnace to obtain a ceramic / metal matrix composite material.

2. The method for preparing a composite material by reacting a metal melt with a ceramic liquid phase according to claim 1, characterized in that: The ceramic raw materials include Al2O3, SiO2 and solvent M x O, or the ceramic raw materials are bulk industrial solid waste, the components are Al2O3, SiO2 and solvent M x The mass percentage of O content is 16% to 22% for Al2O3, 58% to 72% for SiO2, and the solvent M x O is 12% to 20%.

3. The method for preparing a composite material by reacting a metal melt with a ceramic liquid phase according to claim 2, characterized in that: The cosolvent M x O is any one of CaO, MgO, Na2O and K2O.

4. The method for preparing a composite material by reacting a metal melt with a ceramic liquid phase according to claim 2, characterized in that: The bulk industrial solid wastes include various types of aluminum ash, coal gangue, blast furnace slag, ceramic industry waste, glass waste, diatomaceous earth, fly ash, red mud and feldspar tailings.

5. The method for preparing a composite material by reacting a metal melt with a ceramic liquid phase according to claim 1, characterized in that: The method for preparing the ceramic raw material powder in step S1 is to uniformly mix the ceramic raw materials through a ball mill to obtain a mixed powder, wherein the ball milling speed is 350r / min to 450r / min and the ball milling time is 10 to 360min.

6. The method for preparing a composite material by reacting a metal melt with a ceramic liquid phase according to claim 1, characterized in that: The forming process in step 1 is granulation or molding, and the shape of the obtained ceramic body is not limited.

7. The method for preparing a composite material by reacting a metal melt with a ceramic liquid phase according to claim 1, characterized in that: In step S2, the pressurized seepage is carried out in a positive pressure or negative pressure manner, wherein the positive pressure is 9.8-20.8N and the negative pressure is 0.05-0.07Mpa; the pressurized seepage temperature is 670-700°C, the pressurized seepage time is 2-10min, and the pressure is maintained for 1-10min.

8. The method for preparing a composite material by reacting a metal melt with a ceramic liquid phase according to claim 1, characterized in that: The metal in step S2 is magnesium, aluminum, a magnesium alloy or an aluminum alloy.

9. The method for preparing a composite material by reacting a metal melt with a ceramic liquid phase according to claim 1, characterized in that: In step S3, the sintering temperature is 800-1400° C., and the holding time is 10-120 minutes.

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