Process for the production of a metal / aluminide composite

Abstract

This invention relates to a preparation process for a metal / aluminide composite material, comprising the following steps: S1. Preparing a matrix with a layered cavity structure using selective laser melting technology; S2. Cleaning the aluminum block and the matrix prepared in S1 to remove impurities and surface oxide films from the matrix and the aluminum block; S3. Placing the cavity opening of the matrix treated in S2 upwards at the bottom of a crucible, then pressing the aluminum block on top of the cavity, and finally placing the crucible in a vacuum melting furnace for vacuum infiltration to form a sample block; S4. The matrix and the molten aluminum infiltrating into the cavity of the matrix are referred to as a preform. The sample block prepared in S3 is used to cut out the preform using wire cutting, and then the preform is subjected to a vacuum hot pressing diffusion reaction in a vacuum hot pressing furnace to obtain a metal / aluminide composite material. This yields a metal / aluminide laminated composite material with controllable layer thickness, diverse layered structures, high growth kinetics index, and excellent mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of metal / aluminide composite material preparation, and more specifically to a preparation process for metal / aluminide composite materials. Background Technology

[0002] Metal / aluminide composites are designed based on the biomimetic structure of seashells in nature. They utilize a tough metal layer to epitaxially toughen a brittle intermetallic compound. Furthermore, due to the material's unique layered structure and special failure modes, it possesses excellent properties such as low density, high specific strength, high toughness, and high impact filtering performance. Therefore, metal / aluminide laminated composites can not only be used as high-temperature structural materials, but also in aerospace, weaponry, and armor protection systems.

[0003] Currently, extensive research has been conducted both domestically and internationally on metal / aluminide composite materials in Ti / Al, Ni / Al, and Fe / Al systems. Common preparation processes for metal / aluminide composite materials include hot-press diffusion, rolling composite, explosive composite, and spark plasma sintering. Hot-press diffusion is simple, highly controllable, has low environmental pollution, and few limitations on sample size. Rolling composite is fast and can be continuously produced, but the process is complex, has poor control over product uniformity, and has strict requirements on material size. Explosive composite has a short sample preparation time and can achieve high-strength composites, but the preparation process generates significant noise and air pollution. Spark plasma composite can achieve high densification of composite materials at relatively low temperatures, producing samples with fine grains. However, due to the high local heating temperature and rapid cooling rate, residual thermal stress at the material interface easily leads to cracking, reducing the overall toughness of the material, and making it difficult to prepare large-size laminated materials.

[0004] In addition, current preparation processes all suffer from the problem of rapid growth of pre-fabricated aluminum foil oxide film. This makes it difficult for excited-state atoms to break through the oxide film and carry out rapid diffusion reaction during the diffusion reaction at the dissimilar metal interface. Moreover, after breaking through the oxide film, oxide film inclusions will continue to restrict the diffusion reaction at the front end, and eventually form oxide inclusion defects at the center of the aluminide, reducing the mechanical properties of the material.

[0005] To address this issue, researchers have attempted to reduce the impact of oxide films on diffusion rates and material properties by improving surface treatment processes and reducing operation intervals, but with limited success. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a preparation process for metal / aluminide composite materials with controllable layer thickness, diversified layered structure, high growth kinetic index and excellent mechanical properties, which is in contrast to the above-mentioned prior art.

[0007] The technical solution adopted by this invention to solve the above-mentioned technical problems is: a preparation process of a metal / aluminide composite material, characterized by comprising the following steps:

[0008] S1. A matrix with a layered cavity structure is prepared using selective laser melting technology;

[0009] S2. Clean the aluminum block and the substrate prepared in S1 to remove impurities and surface oxide film from the substrate and the aluminum block;

[0010] S3. Place the cavity of the substrate treated in S2 with the opening facing upwards at the bottom of the crucible, then press the aluminum block on top of the cavity, and finally place the crucible in a vacuum melting furnace for vacuum infiltration to produce a sample block.

[0011] S4. The matrix and the molten aluminum that seeps into the cavity of the matrix are called preforms. The sample block prepared in S3 is cut out of the preforms using wire cutting. Then, the preforms are subjected to vacuum hot pressing diffusion reaction in a vacuum hot press furnace to obtain metal / aluminide composite materials.

[0012] Preferably, in step S1, the selective laser melting technology process is as follows:

[0013] (1.1) Select metal powder that meets the forming requirements of selective laser melting technology and dry the metal powder;

[0014] (1.2) Place the metal powder and substrate in a selective laser melting and forming device;

[0015] (1.3) Based on the geometric characteristics of the substrate forming, establish a three-dimensional model and set the process parameters for selective laser melting;

[0016] The geometric characteristics of the substrate forming are as follows: the substrate length is 20-80mm, the height is 10-40mm, the layer thickness is 0.1-1mm, the cavity layer thickness is 0.2-1mm, and the substrate is placed on the substrate through a substrate support base. Due to the limitation of vacuum infiltration, it is difficult to fill the layered cavities that are too deep or too narrow, and unfilled parts are likely to appear. Therefore, the substrate forming parameters need to be selected according to the wettability between the substrate metal and the aluminum liquid.

[0017] The process parameters for selective laser melting are as follows: substrate temperature 90–120℃, powder layer thickness 0.02–0.06 mm, scanning power 150–190 W, scanning speed 400–600 mm / s, scanning spacing 0.05–0.09 mm, and scanning deflection angle per layer 80°–90°. This process ensures that problems such as overall collapse and single-layer bending deformation will not occur during the additive manufacturing of layered substrates.

[0018] (1.4) After the substrate is prepared, the substrate is cut off from the substrate along the lower edge of the substrate support base using wire cutting technology.

[0019] Preferably, in step S2, the cleaning process is as follows: the substrate and the aluminum block are cleaned together. Under the assistance of ultrasonic vibration, the substrate and the polished aluminum block are washed with an alkaline solution, dried, and then acid-washed with an acid solution. After acid washing, they are cleaned with anhydrous ethanol in an ultrasonic cleaner and then placed in a vacuum drying oven for vacuum drying to ensure that there is no anhydrous ethanol residue in the cavity of the substrate.

[0020] Preferably, before cleaning the substrate and aluminum block together, the substrate is first ultrasonically cleaned separately to ensure that there is no residual metal powder in the cavity layer and on the layer wall of the substrate.

[0021] Preferably, in step S3, the melting parameters in the vacuum melting furnace are: vacuum degree ≤ 1×10⁻⁶. -3 Pa is heated to between 750°C and 850°C at a set heating rate, and then cooled to room temperature in a vacuum furnace to form a sample block.

[0022] In the above scheme, the melting parameters in the vacuum melting furnace are as follows: heating to 750℃ at 30℃ / min and holding for 10 min; heating to 800℃ at 40℃ / min and holding for 6 min; heating to 850℃ at 50℃ / min and holding for 1 min.

[0023] Preferably, in step S4, the hot pressing parameters of the vacuum hot press furnace are: the vacuum hot press furnace is evacuated to ≤1×10⁻⁶. -1 Pa, set the pressure column pressure to 1~21MPa and hold the pressure for a set time, use direct heating or staged heating to control the preform to be within the set temperature range of 500℃~655℃, hold the temperature for 1h~24h, and then the vacuum furnace cools to room temperature and reduces the pressure to 0MPa.

[0024] Preferably, in step S4, the hot pressing parameters of the vacuum hot press furnace are: the pressure is increased directly to the set pressure or increased in stages to the set pressure in the vacuum hot press equipment, and the pressure is decreased directly or decreased in stages to 0MPa.

[0025] Compared with the prior art, the advantages of the present invention are as follows: The preparation process of the metal / aluminide composite material of the present invention adopts additive manufacturing + vacuum infiltration + vacuum hot pressing steps in sequence. The method first uses selective laser melting technology to prepare a layered cavity structure matrix with controllable layer thickness and diverse layered structure. The layered cavity structure matrix prepared by selective laser melting additive manufacturing technology can precisely control the thickness of the metal layer and the cavity layer according to actual needs, and can also increase the diversity of the layered structure to prepare laminated composite materials with different amplitude wave-shaped layered structures.

[0026] Then, the aluminum block and the substrate are placed in a vacuum melting furnace in sequence for vacuum infiltration. The high negative pressure vacuum state of vacuum infiltration allows the aluminum liquid to fully fill the layered cavity of the substrate, obtaining an atomic diffusion interface state without the restriction of the aluminum block oxide film. This solves the problem of the influence of aluminum foil oxide film on the diffusion reaction rate and material properties in the conventional laminated composite material preparation process.

[0027] Finally, the preforms were placed in a vacuum hot press furnace for vacuum hot press diffusion reaction. The growth kinetics index of the preforms prepared by additive manufacturing and vacuum infiltration was significantly improved in the vacuum hot press diffusion reaction, and the bending strength, fracture toughness and impact filtering performance of the metal / aluminide composite materials prepared by them were significantly improved.

[0028] In other words, by using a vacuum infiltration process to combine liquid aluminum with the matrix in a solid-liquid composite, the influence of aluminum foil oxide film on laminated composite materials can be solved, and the Kirkendal pores caused by the long reaction time in the vacuum hot-pressing diffusion reaction can be reduced. This can yield metal / aluminide laminated composite materials with controllable layer thickness, diverse layered structures, high growth kinetic index, and excellent mechanical properties.

[0029] In addition, the preparation method of the present invention has low material cost, simple process, low noise and air pollution, and good product performance. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of vacuum seepage according to the present invention;

[0031] Figure 2 This is a schematic diagram of the vacuum thermo-pressure diffusion reaction of the present invention;

[0032] Figure 3 This is a diagram of the additively manufactured layered cavity structure substrate prepared in Example 1 of the present invention;

[0033] Figure 4 This is a growth kinetics index diagram of the aluminide layer of the material prepared in Example 1 of the present invention;

[0034] Figure 5 An interface diagram of the material prepared in Example 1 of this invention;

[0035] Figure 6 This is a growth kinetics index diagram of the aluminide layer of the material prepared in Example 2 of the present invention;

[0036] Figure 7 An interface diagram of the material prepared in Example 2 of this invention;

[0037] Figure 8 This is a growth kinetics index diagram of the aluminide layer of the material prepared in Example 3 of the present invention;

[0038] Figure 9 This is an interface diagram of the material prepared in Example 3 of the present invention. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0040] A preparation process for a metal / aluminide composite material includes the following steps:

[0041] S1. A matrix with a layered cavity structure is prepared using selective laser melting technology;

[0042] S2. Clean the aluminum block and the substrate prepared in S1 to remove impurities and surface oxide film from the substrate and the aluminum block;

[0043] S3. Place the cavity of the substrate treated in S2 with the opening facing upwards at the bottom of the crucible, then press the aluminum block on top of the cavity, and finally place the crucible in a vacuum melting furnace for vacuum infiltration to produce a sample block.

[0044] S4. The matrix and the molten aluminum that seeps into the cavity of the matrix are called preforms. The sample block prepared in S3 is cut out of the preforms using wire cutting (the molten aluminum that overflows into the cavity of the matrix is ​​cut off, i.e., the preforms are removed). Then the preforms are subjected to vacuum hot pressing diffusion reaction in a vacuum hot press furnace to obtain metal / aluminide composite material.

[0045] The four steps described above will be explained in detail below:

[0046] S1:

[0047] In step S1, the process of selective laser melting technology is as follows:

[0048] (1.1) Select metal powder that meets the forming requirements of selective laser melting technology. Dry the metal powder in a vacuum drying oven at 90-110℃ for 2-5 hours, and then pass it through a 150-mesh sieve to ensure that there are no impurities or coarse particles.

[0049] (1.2) After the substrate surface is sanded, the surface is cleaned with special paper sprayed with a small amount of anhydrous ethanol, and the metal powder and substrate are placed in a selective laser melting and forming equipment.

[0050] (1.3) Based on the geometric characteristics of the substrate forming, establish a three-dimensional model and set the process parameters for selective laser melting;

[0051] The geometric characteristics of the substrate forming are as follows: the substrate length is 20-80mm, the height is 10-40mm, the layer thickness is 0.1-1mm, the cavity layer thickness is 0.2-1mm, and the substrate is placed on the substrate through a substrate support base, which is a cuboid with a height of 3mm. Due to the limitation of vacuum infiltration, it is difficult to completely fill excessively deep or narrow layered cavities, and unfilled areas are likely to appear. Therefore, the substrate forming parameters need to be selected according to the wettability of the metal powder and the aluminum liquid.

[0052] The process parameters for selective laser melting are as follows: substrate temperature 90–120℃, powder layer thickness 0.02–0.06 mm, scanning power 150–190 W, scanning speed 400–600 mm / s, scanning spacing 0.05–0.09 mm, and scanning deflection angle per layer 80°–90°. This process ensures that problems such as overall collapse and single-layer bending deformation will not occur during the additive manufacturing of layered substrates.

[0053] (1.4) After the substrate is prepared, the substrate is cut off from the substrate along the lower edge of the substrate support base using a wire cutting process. The wire cutting process is existing technology and will not be described in detail here.

[0054] S2:

[0055] First, the substrate is ultrasonically cleaned separately: The substrate prepared by S1 is repeatedly cleaned in clean water three times using an ultrasonic cleaner, with the amplitude set to 15μm each time, to ensure that there is no residual metal powder in the cavity layer and on the layer wall of the substrate.

[0056] Then, the substrate and aluminum block are cleaned together: First, the aluminum block is machined into a cylinder with a diameter of 20-80 mm and a height of 10-100 mm to ensure that the aluminum block can completely cover the cavity of the substrate during vacuum permeation, and that the molten aluminum can immerse the substrate; then, with the assistance of ultrasonic vibration with an amplitude of 10-20 μm, the substrate and the aluminum block, whose surface has been polished with 100-grit sandpaper, are alkaline washed with 2-10 mol / L NaOH solution. After alkaline washing, they are quickly rinsed and dried with anhydrous ethanol, and then acid washed with 5-20% HCl solution. After acid washing, they are cleaned with anhydrous ethanol in an ultrasonic cleaner and then quickly placed in a vacuum drying oven for vacuum drying to ensure that there is no anhydrous ethanol residue in the cavity layer.

[0057] S3:

[0058] Place the cavity of the S2-treated substrate with the opening facing upwards at the bottom of the crucible, then press the aluminum block on top of the opening, and finally place the crucible in a vacuum melting furnace and quickly evacuate it. Figure 1 This is a schematic diagram of vacuum percolation, where component 1 is a crucible, component 2 is an aluminum block, and component 3 is a substrate.

[0059] The melting parameters in the vacuum melting furnace are: vacuum degree ≤ 1×10-3 Pa is heated to between 750°C and 850°C at a set heating rate, and then cooled to room temperature in a vacuum furnace to form a sample block.

[0060] For example, during the vacuum infiltration process, the temperature is raised to between 750℃ and 850℃ at a certain heating rate, and the infiltration time is ≥1min. Specifically, the vacuum infiltration process is set according to the type of aluminum block and the type of matrix material. It can be, but is not limited to, heating to 750℃ at 30℃ / min and holding for 10min; heating to 800℃ at 40℃ / min and holding for 6min; heating to 850℃ at 50℃ / min and holding for 1min, etc.

[0061] S4: The matrix and the molten aluminum that seeps into the cavity of the matrix are called preforms. The sample block prepared in S3 is used to cut out the preforms using wire cutting. Then, the preforms are subjected to vacuum hot pressing diffusion reaction in a vacuum hot press furnace to obtain metal / aluminide composite materials. The vacuum hot press furnace is an existing graphite hot pressing mold, and the wire cutting process is existing technology, which will not be described in detail here.

[0062] like Figure 2 As shown, the preform is placed between graphite hot press molds, and the upper and lower surfaces of the preform are separated from the graphite molds by 1mm thick graphite paper to prevent the sample from undergoing a diffusion reaction and bonding with the graphite molds, which could damage the graphite molds. Figure 2 Component 4 is a prefabricated part, component 5 is graphite paper, component 6 is a graphite mold, and component 7 is a graphite pressure column.

[0063] The vacuum hot pressing process is as follows: the vacuum hot pressing equipment is evacuated to a vacuum level of ≤1×10. -1 Pa, the pressure column pressure is set to 1-21 MPa, the temperature of the preform is controlled, and then the vacuum furnace cools to room temperature. Specifically, the pressure column pressure can be, for example, but not limited to, any one or any two of 1 MPa, 5 MPa, 9 MPa, 13 MPa, 17 MPa, and 21 MPa.

[0064] The precast components can be controlled using either a direct heating and holding process or a staged heating and holding process. Specifically, the heating rate, holding temperature, and holding time can be set according to the specific type of aluminum foil. The direct heating process involves directly heating to a certain temperature and holding it for a period of time, such as, but not limited to, directly heating to 550℃ and holding for 15 hours; directly heating to 600℃ and holding for 10 hours; or directly heating to 655℃ and holding for 5 hours. Staged heating process: The temperature is raised to a first temperature at a first heating rate, then raised to a second temperature at a second heating rate, and so on, until the temperature is raised to the Nth temperature at the Nth heating rate and held for a certain period of time. For example, it can be, but is not limited to, raising the temperature to 500℃ at 20℃ / min, then raising it to 600℃ at 10℃ / min, then raising it to 650℃ at 5℃ / min and holding it for 4 hours, and then cooling it to room temperature with the furnace; raising the temperature to 550℃ at 15℃ / min, then raising it to 600℃ at 8℃ / min, and finally raising it to 655℃ at 5℃ / min and holding it for 6 hours, and finally cooling it to room temperature with the furnace; raising the temperature to 580℃ at 10℃ / min, then raising it to 620℃ at 5℃ / min, and finally raising it to 650℃ at 1℃ / min and holding it for 20 hours, and finally cooling it to room temperature with the furnace.

[0065] The pressure column can be pressurized using a direct pressurization and holding process or a staged pressurization and holding process. Specifically, the pressurization rate and holding time can be set according to the specific layer thickness or precast component thickness. The direct pressurization process involves directly pressurizing to a certain pressure and holding it, for example, but not limited to, directly pressurizing to 10MPa and holding for 15 hours; directly pressurizing to 15MPa and holding for 10 hours; directly pressurizing to 20MPa and holding for 5 hours, etc. Staged pressure increase and holding process: The pressure is increased to the first pressure at the first pressure increase rate, then increased to the second pressure at the second pressure increase rate, and so on, until the pressure is increased to the Nth pressure at the Nth pressure increase rate and held for a certain period of time. For example, it can be, but is not limited to, increasing the pressure to 5MPa at 3MPa / h and holding for 1h, then increasing the pressure to 8MPa at 2MPa / h and holding for 2h, then increasing the pressure to 10MPa at 1MPa / h and holding for 3h; increasing the pressure to 5MPa at 4MPa / h and holding for 2h, then increasing the pressure to 10MPa at 2MPa / h and holding for 4h, then increasing the pressure to 15MPa at 1MPa / h and holding for 6h; increasing the pressure to 10MPa at 5MPa / h and holding for 2h, then increasing the pressure to 15MPa at 2MPa / h and holding for 4h, then increasing the pressure to 20MPa at 1MPa / h and holding for 10h.

[0066] Pressure column depressurization can be achieved using a direct depressurization and holding process or a staged depressurization and holding process. Specifically, the depressurization rate and holding time of the pressure column can be set according to the vacuum hot pressing temperature. The direct depressurization process involves directly depressurizing to a certain pressure and holding it until the temperature drops to room temperature, at which point the pressure drops to 0. For example, it can be, but is not limited to, directly depressurizing to 3 MPa and holding until the temperature drops to room temperature; directly depressurizing to 2 MPa and holding until the temperature drops to room temperature; directly depressurizing to 1 MPa and holding until the temperature drops to room temperature, etc. Staged pressure reduction and holding process: Pressure is reduced to a first pressure at a first pressure reduction rate, then reduced to a second pressure at a second pressure reduction rate, and so on, until the pressure reaches zero when the temperature drops to room temperature. For example, but not limited to, reducing pressure to 10 MPa at 1 MPa / h and holding for 2 hours, then reducing pressure to 5 MPa at 2 MPa / h and holding for 1 hour, then reducing pressure to 2 MPa at 1 MPa / h, and finally reducing pressure to zero when the temperature drops to room temperature. The pressure was reduced to 15 MPa at 1.5 MPa / h and held for 2 hours, then reduced to 10 MPa at 2 MPa / h and held for 2 hours, then reduced to 1 MPa at 3 MPa / h, and finally reduced to 0 MPa when the temperature dropped to room temperature; the pressure was reduced to 18 MPa at 1 MPa / h and held for 2 hours, then reduced to 12 MPa at 1.5 MPa / h and held for 1 hour, then reduced to 1 MPa at 2 MPa / h, and finally reduced to 0 MPa when the temperature dropped to room temperature.

[0067] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0068] Example 1

[0069] The preparation process of the metal / aluminide composite material in this embodiment includes the following steps:

[0070] S1. A matrix with a layered cavity structure is prepared using selective laser melting technology;

[0071] This step specifically includes the following steps:

[0072] (1.1) Prepare CoCrFeMnNi high-entropy alloy powder and dry it in a vacuum drying oven at 90℃ for 3 hours, then pass it through a 150-mesh sieve.

[0073] (1.2) After the substrate surface is polished with 1000-grit sandpaper, the surface is cleaned with special paper sprayed with a small amount of anhydrous ethanol. The metal powder and the substrate are then placed in a selective laser melting and forming equipment.

[0074] (1.3) Based on the geometric characteristics of the substrate forming, establish a three-dimensional model and set the process parameters for selective laser melting;

[0075] Import the 3D model of the substrate into the system. The substrate is 80mm long, 10mm high, and 1mm thick. The cavity layer is 0.4mm thick. The substrate support base is a cuboid with a height of 3mm. Figure 3 As shown.

[0076] The selective laser melting process parameters were set as follows: substrate temperature 120℃, powder layer thickness 0.02mm, scanning power 150W, scanning speed 400mm / s, scanning spacing 0.05mm, and scanning deflection angle of each layer 85°.

[0077] (1.4) After the substrate is prepared, the substrate is cut off from the substrate along the lower edge of the substrate support base using wire cutting technology.

[0078] S2. Clean the aluminum block and the substrate prepared in S1 to remove impurities and surface oxide film from the substrate and the aluminum block;

[0079] Specifically as follows:

[0080] First, the substrate was cleaned separately: the substrate prepared in S1 was repeatedly cleaned three times in clean water using an ultrasonic cleaner, with the amplitude set to 15 μm each time.

[0081] Then, the substrate and the aluminum block were cleaned together: the aluminum block was turned into a cylinder with a diameter of 80 mm and a height of 30 mm. Under the assistance of ultrasonic vibration with an amplitude of 10 μm, the substrate and the pure aluminum block, whose surface had been polished with 100-grit sandpaper, were alkaline washed with 2 mol / L NaOH solution for 10 min. After alkaline washing, they were quickly rinsed and dried with anhydrous ethanol, and then acid-washed with 10% HCl solution for 5 min. After acid washing, they were cleaned with anhydrous ethanol in an ultrasonic cleaner and then quickly vacuum dried.

[0082] S3. Place the cavity of the substrate treated in S2 with the opening facing upwards at the bottom of the crucible, then press the aluminum block on top of the cavity. Finally, place the crucible in a vacuum melting furnace and quickly evacuate the furnace. Vacuum infiltration is then performed within the furnace. The process parameters for the vacuum melting furnace are: vacuum degree ≤ 1×10⁻⁶. -3 Pa, heat to 850℃ at 50℃ / min, hold for 1 min for infiltration, and cool to room temperature in a vacuum furnace to prepare a sample block;

[0083] S4. The matrix and the molten aluminum that seeps into the cavity of the matrix are called preforms. The sample block prepared in S3 is cut out of the preforms using wire cutting. Then, the preforms are subjected to vacuum hot pressing diffusion reaction in a vacuum hot press furnace to obtain metal / aluminide laminated composite material.

[0084] The vacuum hot press furnace is evacuated to ≤1×10 -1Pa, the temperature is increased to 655℃ at 10℃ / min and held for 1h, the pressure column is directly increased to 15MPa at a rate of 2MPa / h, then the vacuum furnace is cooled to room temperature, the pressure is directly reduced to 1MPa at a rate of 2MPa / h, and finally the pressure is reduced to 0 when the temperature drops to room temperature.

[0085] The growth kinetics index diagram and microstructure interface of the aluminide layer in the high-entropy alloy / aluminide laminate composite are shown in the figure. Figure 4 and 5 As shown, Figure 5 In the diagram, a represents a high-entropy alloy, b represents an aluminide, c represents aluminum, d represents an aluminide, and e represents a high-entropy alloy.

[0086] from Figure 4 The growth kinetics indices *n* of different aluminide layers indicate that the first and third aluminide layers tend towards grain boundary diffusion growth, while the second aluminide layer tends towards bulk diffusion growth. Overall, the aluminide layers exhibit a mixed diffusion growth pattern controlled by both grain boundary and bulk diffusion. Although the hysteresis diffusion effect of high-entropy alloys significantly limits the diffusion rate, the absence of an initial oxide film interface layer greatly improves the overall growth rate of the aluminide layers, transforming it from a grain boundary diffusion pattern to a near-bulk diffusion mixed diffusion pattern. This significantly reduces the vacuum hot-pressing diffusion process time and improves the efficiency of laminated composite material preparation. Figure 5 As can be seen from the front end of the aluminide layer, the front end of the diffusion reaction is relatively flat, without any abnormal protrusion growth caused by the influence of the initial oxide film interface. Furthermore, there are no oxide inclusions at the front end of the diffusion reaction, which greatly reduces the stress concentration at the reaction interface and improves the overall mechanical properties of the laminated composite material.

[0087] Example 2

[0088] The preparation process of the metal / aluminide composite material in this embodiment includes the following steps:

[0089] S1. A matrix with a layered cavity structure is prepared using selective laser melting technology;

[0090] This step specifically includes the following steps:

[0091] (1.1) Prepare 316 stainless steel powder and dry it in a vacuum drying oven at 90℃ for 2 hours, then pass it through a 150-mesh sieve.

[0092] (1.2) After the substrate surface is polished with 1000-grit sandpaper, the surface is cleaned with special paper sprayed with a small amount of anhydrous ethanol. The metal powder and the substrate are then placed in a selective laser melting and forming equipment.

[0093] (1.3) Based on the geometric characteristics of the substrate forming, establish a three-dimensional model and set the process parameters for selective laser melting;

[0094] The geometric features of the substrate molding are as follows: the three-dimensional model of the substrate is imported into the system. The substrate is 20mm long, 40mm high, 0.5mm thick, and the cavity layer is 0.2mm thick. The substrate support base is a cuboid with a height of 3mm.

[0095] The selective laser melting process parameters were set as follows: substrate temperature 90℃, powder layer thickness 0.04mm, scanning power 190W, scanning speed 600mm / s, scanning spacing 0.07mm, and scanning deflection angle of each layer 90°.

[0096] (1.4) After the substrate is prepared, the substrate is cut off from the substrate along the lower edge of the substrate support base using wire cutting technology.

[0097] S2. Clean the aluminum block and the substrate prepared in S1 to remove impurities and surface oxide film from the substrate and the aluminum block;

[0098] Specifically as follows:

[0099] First, the substrate was cleaned separately: the substrate prepared by S1 was repeatedly cleaned in clean water three times using an ultrasonic cleaner, with the amplitude set to 15μm each time.

[0100] Then, the substrate and the aluminum block were cleaned together: the aluminum block was turned into a cylinder with a diameter of 50 mm and a height of 40 mm. Under the assistance of ultrasonic vibration with an amplitude of 15 μm, the substrate and the aluminum alloy block, whose surfaces had been polished with 100-grit sandpaper, were alkaline washed with 7 mol / L NaOH solution for 5 min. After alkaline washing, they were quickly rinsed and dried with anhydrous ethanol, and then acid-washed with 20% HCl solution for 6 min. After acid washing, they were cleaned with anhydrous ethanol in an ultrasonic cleaner and then quickly vacuum dried.

[0101] S3. Place the cavity of the substrate treated in S2 with the opening facing upwards at the bottom of the crucible, then press the 6061 aluminum alloy block on top of the cavity. Finally, place the crucible in a vacuum melting furnace, quickly evacuate the furnace, and perform vacuum infiltration inside the furnace to produce a sample block. The process parameters for the vacuum melting furnace are: vacuum degree ≤ 1×10⁻⁶. -3 Pa, heat up to 750℃ at 30℃ / min, hold for 10 min for percolation, and then cool to room temperature in a vacuum with the furnace.

[0102] S4. The matrix and the molten aluminum that seeps into the cavity of the matrix are called preforms. The sample block prepared in S3 is cut out of the preforms using wire cutting. Then, the preforms are subjected to vacuum hot pressing diffusion reaction in a vacuum hot press furnace to obtain metal / aluminide laminated composite material.

[0103] The vacuum hot press furnace is evacuated to ≤1×10 -1Pa, the temperature was increased to 500℃ at 8℃ / min and held for 24h. The pressure column was directly increased to 12MPa at a rate of 2MPa / h. Then the vacuum furnace was cooled to room temperature, and the pressure was directly reduced to 1MPa at a rate of 1.5MPa / h. Finally, the pressure dropped to 0 when the temperature dropped to room temperature.

[0104] The growth kinetics index diagram and microstructure interface of the aluminide layer in the stainless steel / aluminide laminate composite are shown in the figure. Figure 6 and 7 As shown, Figure 7 In the diagram, f represents a 316 stainless steel layer, g represents an aluminide layer, h represents an aluminum layer, and i represents a 316 stainless steel layer.

[0105] from Figure 6 The growth kinetics index *n* of different aluminide layers indicates that the first and second aluminide layers tend to exhibit a mixed diffusion growth pattern controlled by both bulk and interfacial diffusion. Due to the absence of an initial oxide interfacial layer, the overall growth rate of the aluminide layers is significantly improved, transitioning from a bulk diffusion pattern to a mixed diffusion pattern. This drastically reduces the vacuum hot-pressing diffusion process time and improves the efficiency of laminated composite material fabrication. Figure 7 As can be seen from the front end of the aluminide layer, the front end of the diffusion reaction is relatively flat, and there is no abnormal protrusion growth caused by the influence of the initial oxide film interface. Furthermore, there are no large-sized oxide inclusions retained at the front end of the diffusion reaction interface, which greatly reduces the stress concentration at the reaction interface and improves the overall mechanical properties of the laminated composite material.

[0106] Example 3

[0107] The preparation process of the metal / aluminide composite material in this embodiment includes the following steps:

[0108] S1. A matrix with a layered cavity structure is prepared using selective laser melting technology;

[0109] This step specifically includes the following steps:

[0110] (1.1) Prepare titanium alloy powder and dry it in a vacuum drying oven at 90°C for 1 hour, then pass it through a 150-mesh sieve.

[0111] (1.2) After the substrate surface is polished with 1000-grit sandpaper, the surface is cleaned with special paper sprayed with a small amount of anhydrous ethanol. The metal powder and the substrate are then placed in a selective laser melting and forming equipment.

[0112] (1.3) Based on the geometric characteristics of the substrate forming, establish a three-dimensional model and set the process parameters for selective laser melting;

[0113] The geometric features of the substrate forming are as follows: the three-dimensional model of the substrate is imported into the system. The substrate is 50mm long, 25mm high, 0.5mm thick, and the cavity layer is 1mm thick. The substrate support base is a cuboid with a height of 3mm.

[0114] The selective laser melting process parameters were set as follows: substrate temperature 100℃, powder layer thickness 0.06mm, scanning power 170W, scanning speed 500mm / s, scanning spacing 0.09mm, and scanning deflection angle of each layer 80°.

[0115] (1.4) After the substrate is prepared, the substrate is cut off from the substrate along the lower edge of the substrate support base using wire cutting technology.

[0116] S2. Clean the aluminum block and the substrate prepared in S1 to remove impurities and surface oxide film from the substrate and the aluminum block;

[0117] Specifically as follows:

[0118] First, the substrate was cleaned separately: the substrate prepared by S1 was repeatedly cleaned in clean water three times using an ultrasonic cleaner, with the amplitude set to 15μm each time.

[0119] Then, the substrate and the aluminum block were cleaned together: the aluminum block was turned into a cylinder with a diameter of 60 mm and a height of 45 mm. Under the assistance of ultrasonic vibration with an amplitude of 20 μm, the substrate and the pure aluminum block, whose surface had been polished with 100-grit sandpaper, were alkaline washed with 10 mol / L NaOH solution for 5 min. After alkaline washing, they were quickly rinsed and dried with anhydrous ethanol, and then acid-washed with 5% HCl solution for 10 min. After acid washing, they were cleaned with anhydrous ethanol in an ultrasonic cleaner and then quickly vacuum dried.

[0120] S3. Place the cavity of the substrate treated in S2 with the opening facing upwards at the bottom of the crucible, then press the 6061 aluminum alloy block on top of the cavity. Finally, place the crucible in a vacuum melting furnace, quickly evacuate the furnace, and perform vacuum infiltration inside the furnace to produce a sample block. The process parameters for the vacuum melting furnace are: vacuum degree ≤ 1×10⁻⁶. -3 Pa, heat to 800℃ at 30℃ / min, hold for 6 minutes for percolation, then cool to room temperature in a vacuum with the furnace.

[0121] S4. The matrix and the molten aluminum that seeps into the cavity of the matrix are called preforms. The sample block prepared in S3 is cut out of the preforms using wire cutting. Then, the preforms are subjected to vacuum hot pressing diffusion reaction in a vacuum hot press furnace to obtain metal / aluminide laminated composite material.

[0122] The vacuum hot press furnace is evacuated to ≤1×10 -1Pa, the temperature was increased to 620℃ at 6℃ / min and held for 12h. The pressure column was directly increased to 8MPa at a rate of 1MPa / h. Then the vacuum furnace was cooled to room temperature, and the pressure was directly reduced to 1MPa at a rate of 1MPa / h. Finally, when the temperature dropped to room temperature, the pressure dropped to 0.

[0123] The growth kinetics index diagram and microstructure interface of the aluminide layer in the titanium alloy / aluminide laminate composite are shown in the figure. Figure 8 and 9 As shown, Figure 9 In the diagram, j represents the titanium alloy layer, k represents the aluminide layer, and l represents the titanium alloy layer.

[0124] from Figure 8 Different growth kinetic indices (n) for the aluminide layer indicate that the aluminide layer growth model approaches a bulk diffusion type. Due to the absence of an initial oxide film interface layer, the aluminide layer growth rate is significantly improved, transitioning from an interface diffusion type to a bulk diffusion type. This greatly reduces the vacuum hot-pressing diffusion process time and improves the efficiency of laminated composite material preparation. Figure 9 As can be seen from the front end of the aluminide layer, the center of the aluminide layer is relatively uniform and straight, and there is no situation of oxide inclusion retention and diffusion reaction front end interface caused by the influence of the initial oxide film interface. This greatly reduces the stress concentration at the reaction interface and improves the overall mechanical properties of the laminated composite material.

[0125] The aluminum blocks in the above embodiments are made of pure aluminum or aluminum alloy.

Claims

1. A preparation process for a metal / aluminide composite material, characterized in that, Includes the following steps: S1. A substrate with a layered cavity structure is prepared using selective laser melting technology; S2. The aluminum block and the substrate prepared in S1 are cleaned to remove impurities and surface oxide films from the substrate and the aluminum block. S3. Place the cavity of the substrate treated in S2 with the opening facing upwards at the bottom of the crucible, then press the aluminum block on top of the cavity. Finally, place the crucible in a vacuum melting furnace and perform vacuum infiltration to produce a sample block. The melting parameters in the vacuum melting furnace are: vacuum degree ≤ 1×10⁻⁶. -3 Pa is heated to between 750°C and 850°C at a set heating rate, and then cooled to room temperature in a vacuum furnace to prepare a sample block; S4. The matrix and the molten aluminum that seeps into the cavity of the matrix are called preforms. The sample block prepared in S3 is cut out of the preforms using wire cutting. Then, the preforms are subjected to vacuum hot pressing diffusion reaction in a vacuum hot pressing furnace to obtain metal / aluminide composite material. The hot pressing parameters of the vacuum hot press are: the vacuum hot press is evacuated to ≤1×10 -1 Pa, set the pressure column pressure to 1~21MPa and hold the pressure for a set time, use direct heating or staged heating to control the preform to be within the set temperature range of 500℃~655℃, hold for 1h~24h, and then the vacuum furnace cools to room temperature and reduces the pressure to 0MPa.

2. The preparation process according to claim 1, characterized in that: In step S1, the process of selective laser melting technology is as follows: (1.1) Select metal powder that meets the forming requirements of selective laser melting technology and dry the metal powder; (1.2) Place the metal powder and substrate in a selective laser melting and forming device; (1.3) Based on the geometric characteristics of the substrate forming, establish a three-dimensional model and set the process parameters for selective laser melting; The geometric features of the substrate molding are as follows: the substrate length is 20~80mm, the height is 10~40mm, the layer thickness is 0.1~1mm, the cavity layer thickness is 0.2~1mm, and the substrate is placed on the substrate through the substrate support base; The process parameters for selective laser melting are as follows: substrate temperature 90~120℃, powder layer thickness 0.02~0.06mm, scanning power 150~190W, scanning speed 400~600mm / s, scanning spacing 0.05~0.09mm, and scanning deflection angle of each layer 80°~90°. (1.4) After the substrate is prepared, the substrate is cut off from the substrate along the lower edge of the substrate support base using wire cutting technology.

3. The preparation process according to claim 1, characterized in that: In step S2, the cleaning process is as follows: the substrate and the aluminum block are cleaned together. Under the assistance of ultrasonic vibration, the substrate and the polished aluminum block are cleaned with an alkaline solution, dried, and then acid-washed with an acid solution. After acid washing, they are cleaned with anhydrous ethanol in an ultrasonic cleaner and then placed in a vacuum drying oven for vacuum drying to ensure that there is no anhydrous ethanol residue in the cavity of the substrate.

4. The preparation process according to claim 3, characterized in that: Before cleaning the substrate and aluminum block together, the substrate is first ultrasonically cleaned separately.

5. The preparation process according to claim 1, characterized in that: The melting parameters in the vacuum melting furnace are: heating to 750℃ at 30℃ / min and holding for 10min. Heat to 800℃ at 40℃ / min and hold for 6 minutes for seepage; heat to 850℃ at 50℃ / min and hold for 1 minute for seepage.

6. The preparation process according to claim 1, characterized in that: In step S4, the hot pressing parameters of the vacuum hot press furnace are as follows: the pressure is increased directly to the set pressure or increased in stages to the set pressure in the vacuum hot press equipment, and the pressure is also decreased directly or in stages to 0MPa.

Images