阅读说明：本技术 一种碳纤维增强铝硅基复合材料及其制备方法 (Carbon fiber reinforced aluminum-silicon-based composite material and preparation method thereof ) 是由 蔡志勇 王日初 彭超群 钟剑锋 纪乐 于 2020-12-29 设计创作，主要内容包括：本发明涉及一种碳纤维增强铝硅基复合材料及其制备方法,所述碳纤维增强铝硅基复合材料包括以下原料组分：纯铝粉、碳纤维和Al-Si合金基体；其中,所述Al-Si合金基体中硅的质量分数为12％～70％。所述碳纤维增强铝硅基复合材料的制备方法,包括以下步骤：S1：制备含碳纤维的铝基预制块；S2：熔炼复合材料；S3：喷射沉积制坯；S4：致密化处理。本发明中碳纤维均匀分布在具有高硅含量(质量分数为12％～70％)的碳纤维增强铝硅基复合材料中,且碳纤维与Al-Si合金基体产生一定程度的界面反应,增强界面结合强度,使碳纤维增强铝硅基复合材料具有高强度和高韧性。(The invention relates to a carbon fiber reinforced aluminum-silicon-based composite material and a preparation method thereof, wherein the carbon fiber reinforced aluminum-silicon-based composite material comprises the following raw material components: pure aluminum powder, carbon fiber and Al-Si alloy matrix; wherein the mass fraction of silicon in the Al-Si alloy matrix is 12-70%. The preparation method of the carbon fiber reinforced aluminum-silicon-based composite material comprises the following steps: s1: preparing an aluminum-based precast block containing carbon fibers; s2: smelting the composite material; s3: spraying, depositing and blank making; s4: and (5) densification treatment. The carbon fibers are uniformly distributed in the carbon fiber reinforced aluminum-silicon-based composite material with high silicon content (the mass fraction is 12-70%), and the carbon fibers and the Al-Si alloy matrix generate a certain degree of interfacial reaction to enhance the bonding strength of the interface, so that the carbon fiber reinforced aluminum-silicon-based composite material has high strength and high toughness.)

1. A carbon fiber reinforced aluminum-silicon-based composite material is characterized in that: comprises the following raw material components: pure aluminum powder, carbon fiber and Al-Si alloy matrix; wherein the mass fraction of silicon in the Al-Si alloy matrix is 12-70%.

2. The carbon fiber reinforced aluminum silicon based composite material as recited in claim 1, wherein: the pure aluminum powder is gas atomized nearly spherical powder, the average particle size is 12-20 mu m, and the purity is higher than 99.5%.

3. The carbon fiber-reinforced aluminum-silicon-based composite material according to claim 2, characterized in that: the diameter of the carbon fiber is 5-10 mu m, and the length of the carbon fiber is 10-150 mu m.

4. The carbon fiber reinforced aluminum silicon based composite material as recited in claim 3, wherein: in the carbon fiber reinforced aluminum-silicon-based composite material, the volume fraction of the carbon fibers is 0.2-5%.

5. A method for preparing the carbon fiber reinforced aluminum-silicon-based composite material as claimed in any one of claims 1 to 4, which is characterized in that: the method comprises the following steps:

s1: preparing an aluminum-based precast block containing carbon fibers: fully mixing carbon fibers and pure aluminum powder, and then carrying out cold press molding to prepare an aluminum-based precast block containing carbon fibers;

s2: smelting the composite material: after an Al-Si alloy matrix is smelted, adding the aluminum-based precast block containing carbon fibers, and uniformly stirring to obtain a composite material melt;

s3: spray deposition blank making: spraying and depositing the composite material melt by adopting a spraying and depositing process to obtain a carbon fiber reinforced aluminum-silicon-based deposition blank;

s4: densification treatment: and densifying the carbon fiber reinforced aluminum-silicon-based deposition blank to obtain the carbon fiber reinforced aluminum-silicon-based composite material.

6. The method for preparing the carbon fiber reinforced aluminum-silicon-based composite material according to claim 5, wherein the method comprises the following steps: in step S3, the operating conditions of the spray deposition process are: the diameter of a nozzle is 3.2-4.5 mm, the pressure of atomizing gas is 0.9-1.3 MPa, the atomizing temperature is 850-1250 ℃, the receiving distance of a deposition disc is 380-520 mm, the scanning frequency of an atomizer is 21-24 Hz, the descending speed of the deposition disc is 19-25 mm/min, the atomizing gas is nitrogen, and the temperature of a tundish is 900-1000 ℃.

7. The method for producing a carbon fiber-reinforced aluminum-silicon-based composite material according to claim 6, characterized in that: in the step S1, a low-temperature ball milling process is adopted to ball mill the carbon fibers and the pure aluminum powder which are proportioned in proportion, and the carbon fibers and the pure aluminum powder are uniformly mixed; the process conditions of the low-temperature ball milling are as follows: the ball milling time is 6-24 h, the ball milling speed is 50-500 rpm, high-purity argon is adopted for protection, and the ball milling temperature is lower than 50 ℃; when the aluminum-based precast block containing the carbon fibers is prepared, a cold pressing forming process is adopted, the cold pressing pressure is 50-200 MPa, the pressure maintaining time is 10-180 s, and the length-to-height ratio of a pressing block is kept to be less than 2.

8. The method for preparing the carbon fiber reinforced aluminum-silicon-based composite material according to claim 7, wherein the method comprises the following steps: in the step S2, the melting temperature is 150-250 ℃ higher than the liquidus temperature of the Al-Si alloy matrix; under the protection of argon, coating an aluminum-based precast block containing carbon fibers with aluminum foil, placing the aluminum-based precast block into a graphite bell jar, pressing the aluminum-based precast block into the bottom of the Al-Si alloy matrix melt, and uniformly distributing the carbon fibers in the Al-Si alloy matrix melt through a stirring process; and the time for adding the aluminum-based precast block containing the carbon fiber and carrying out homogenization and heat preservation is less than 0.5-1 h.

9. The method for preparing the carbon fiber reinforced aluminum-silicon-based composite material according to claim 8, wherein the method comprises the following steps: in the step S4, the densification process includes hot isostatic pressing, hot press sintering, spark plasma sintering, or the like; the densification process is characterized in that the treatment temperature is 460-500 ℃, the heat preservation time is 1-4 h, the pressure is 120-150 MPa, the heating rate is 10-20 ℃/h, the cooling rate is 20-50 ℃/h, and the extrusion ratio is 10: 1; and before reaching the preset densification treatment temperature, preserving the heat of the carbon fiber reinforced aluminum-silicon-based deposition blank for 1h at the temperature of 400 ℃.

10. The method for preparing the carbon fiber reinforced aluminum-silicon-based composite material according to claim 8, wherein the method comprises the following steps: in step S4, for the carbon fiber reinforced aluminum-silicon-based composite material with the silicon mass fraction of less than 42% and the carbon fiber volume fraction of less than 2% in the Al-Si alloy matrix, a hot extrusion or hot forging process may be further adopted to densify and form the carbon fiber reinforced aluminum-silicon-based deposition blank; the heating temperature of the hot extrusion or hot forging processing technology is 380-400 ℃, and the heat preservation time is 2-4 h; and then carrying out stabilization annealing treatment to obtain the carbon fiber reinforced aluminum-silicon-based composite material.

Technical Field

The invention relates to the technical field of metal matrix composite materials and preparation thereof, in particular to a carbon fiber reinforced aluminum-silicon matrix composite material and a preparation method thereof.

Background

The high silicon content aluminum silicon alloy generally refers to an alloy with silicon content exceeding eutectic components (more than 12.6 percent, mass fraction), has the advantages of small density, high thermal conductivity, low thermal expansion coefficient, good process performance and the like, and has important application value in the high-tech fields of military affairs, aviation, aerospace, traffic and the like as electronic packaging materials, pistons and the like. In the conventional cast alloy, because the cooling rate is low (less than 100 ℃/s), the macrosegregation of the Si phase is serious, the distribution uniformity is poor, the primary Si phase is in various forms such as lath, star and polyhedron, the size is large (>100 mu m), the edge angle is sharp, and the continuity of the Al matrix is seriously cracked, so that the performances such as mechanics and processing are seriously reduced.

In the prior art, the aluminum-silicon alloys with different silicon contents are usually prepared by adopting a spray deposition technology, namely, a high-speed airflow is utilized to smash and cool a metal melt, and the metal melt is deposited into a deposition ingot blank with a certain shape and size when atomized liquid drops are not completely solidified. Because some holes are left in the deposited ingot blank, the relative density of the aluminum-silicon alloy material can only reach 80-96%, and the residual holes in the deposited ingot blank need to be removed through densification treatment. For example, Osprey metals, Inc. in England, which uses spray deposition technology in combination with hot isostatic pressing to produce aluminum-silicon alloys of varying silicon content, is an important route to large-gauge aluminum-silicon alloy ingots and has been used commercially (see for details patent publication No.: EP0839078B1, US6312535B 1). However, for the aluminum-silicon alloy with high silicon content, the plastic toughness and the machining performance are reduced while the thermal expansion coefficient of the alloy is reduced, so that the application of the aluminum-silicon alloy is greatly limited.

Under the trend of structure-function integrated development, carbon fibers with the advantages of high specific strength, high specific modulus, low expansion coefficient and the like are introduced into the aluminum-silicon alloy, so that the plasticity and toughness of the composite material can be improved, the service performance of the composite material is improved and the application field is widened under the condition of keeping good thermal conductivity and thermal expansion coefficient of the aluminum-silicon alloy. At present, the carbon fiber reinforced aluminum-silicon-based composite material and the jet deposition preparation method thereof are rarely reported. The carbon fiber reinforced metal matrix composite material has excellent comprehensive performance and is also widely concerned in the fields of aerospace, automobile manufacturing and the like. However, many existing methods for preparing carbon fiber reinforced metal matrix composites have great limitations, such as damage to carbon fibers or contamination of matrix alloys and carbon fiber surfaces, which are not favorable for enhancing mechanical properties and processability of aluminum-silicon matrix composites by carbon fibers.

Chinese patent 103628005A discloses a carbon fiber reinforced aluminum matrix composite material for brake discs and a preparation method thereof, wherein the mass fraction of silicon in aluminum matrix alloy is 10% -12%, and the cooling speed of the preparation process in the melt synthesis-die casting molding process is low, so that carbon fibers are easily pushed to the finally solidified crystal boundary by solid/liquid, which causes the segregation of the carbon fibers and is easily damaged. In addition, the existing preparation method of the metal matrix composite material can be divided into a liquid phase method and a solid phase method, and when the carbon fiber reinforced aluminum-silicon matrix composite material is prepared by the traditional liquid phase method, the carbon fibers are easy to gather, so that the strengthening and toughening effects of the carbon fibers cannot be effectively exerted; when the carbon fiber reinforced aluminum-silicon-based composite material is prepared by the traditional solid phase method, the interface bonding strength of the carbon fiber and the aluminum-silicon matrix is low, and the aluminum-silicon matrix powder and the carbon fiber are easy to oxidize and dirty by introducing impurities. Therefore, the existing preparation method of the metal-based composite material has certain limitation on the preparation of the carbon fiber reinforced aluminum-silicon-based composite material with high silicon content, and the popularization and application of the carbon fiber reinforced aluminum-silicon-based composite material are greatly influenced.

Disclosure of Invention

Based on the above, in order to overcome the defects and shortcomings of the prior art, the invention provides a carbon fiber reinforced aluminum-silicon-based composite material.

The carbon fiber reinforced aluminum-silicon-based composite material comprises the following raw material components: pure aluminum powder, carbon fiber and Al-Si alloy matrix; wherein the mass fraction of silicon in the Al-Si alloy matrix is 12-70%.

Compared with the prior art, the carbon fibers are uniformly distributed in the carbon fiber reinforced aluminum-silicon-based composite material with high silicon content (the mass fraction is 12-70%), and the carbon fibers and the Al-Si alloy matrix generate a certain degree of interface reaction to enhance the interface bonding strength, so that the carbon fiber reinforced aluminum-silicon-based composite material has high strength and high toughness. The method not only solves the problem that the strengthening and toughening effects of the carbon fiber are not effectively exerted because the carbon fiber is easy to gather when the carbon fiber reinforced aluminum-silicon-based composite material is prepared by the traditional liquid phase method; meanwhile, the defects that the interface bonding strength of the carbon fiber and the Al-Si alloy matrix is low, the carbon fiber is easy to oxidize, and impurities are introduced to dirty the carbon fiber by the traditional solid phase method are overcome. Therefore, the carbon fiber reinforced aluminum-silicon-based composite material with high silicon content is beneficial to batch and stable production in the field of electronic packaging shells or pistons and other members; and further has important application value in the high-tech fields of military affairs, aviation, aerospace, traffic and the like.

Further, the pure aluminum powder is gas atomized approximately spherical powder, the average particle size is 12-20 mu m, and the purity is higher than 99.5%. The pure aluminum powder keeps uniform and fine particle size, and can ensure that the pure aluminum powder and the carbon fiber are fully mixed to enhance the interface bonding strength.

Furthermore, the diameter of the carbon fiber is 5-10 μm, and the length of the carbon fiber is 10-150 μm. The carbon fiber has the characteristics of high temperature resistance, friction resistance, electric conduction, heat conduction, corrosion resistance and the like, and has high strength and modulus along the fiber axis direction due to the preferred orientation of the graphite microcrystal structure along the fiber axis. The diameter and the length of the carbon fiber are suitable, so that the carbon fiber and the Al-Si alloy matrix generate high interfacial reaction.

Further, in the carbon fiber reinforced aluminum-silicon-based composite material, the volume fraction of the carbon fibers is 0.2-5%. Generally, a higher silicon content corresponds to a lower carbon fiber content, and because of the high content of silicon phase, the optimal volume fraction of carbon fibers is suitably reduced.

The invention also provides a preparation method of the carbon fiber reinforced aluminum-silicon-based composite material, which comprises the following steps:

s1: preparing an aluminum-based precast block containing carbon fibers: fully mixing carbon fibers and pure aluminum powder, and then carrying out cold press molding to prepare an aluminum-based precast block containing carbon fibers;

s2: smelting the composite material: after an Al-Si alloy matrix is smelted, adding the aluminum-based precast block containing carbon fibers, and uniformly stirring to obtain a composite material melt;

s3: spray deposition blank making: spraying and depositing the composite material melt by adopting a spraying and depositing process to obtain a carbon fiber reinforced aluminum-silicon-based deposition blank;

s4: densification treatment: and densifying the carbon fiber reinforced aluminum-silicon-based deposition blank to obtain the carbon fiber reinforced aluminum-silicon-based composite material.

Compared with the prior art, the invention can effectively solve the problems of uniformity and interface of the carbon fiber reinforced aluminum-silicon-based composite material by utilizing a rapid solidification jet deposition method, completes the forming and cooling of the carbon fiber reinforced aluminum-silicon-based composite material in a short time, has high controllability of the preparation process and larger ingot blank size, thereby ensuring a proper amount of interface reaction and improving the bonding strength, and is suitable for industrial production. The carbon fibers are uniformly distributed in the carbon fiber reinforced aluminum-silicon-based composite material, and the carbon fibers and the Al-Si alloy matrix generate a certain degree of interfacial reaction to enhance the interfacial bonding strength, so that the carbon fiber reinforced aluminum-silicon-based composite material has high strength and high toughness. The method not only solves the problem that the strengthening and toughening effects of the carbon fiber are not effectively exerted because the carbon fiber is easy to gather when the carbon fiber reinforced aluminum-silicon-based composite material is prepared by the traditional liquid phase method; meanwhile, the defects that the interface bonding strength of the carbon fiber and the Al-Si alloy matrix is low, the carbon fiber is easy to oxidize, and impurities are introduced to dirty the carbon fiber by the traditional solid phase method are overcome. Therefore, the preparation method of the carbon fiber reinforced aluminum-silicon-based composite material is beneficial to batch and stable production in the field of electronic packaging shells or pistons and other members; and further has important application value in the high-tech fields of military affairs, aviation, aerospace, traffic and the like.

Further, in the step S3, the operating conditions of the spray deposition process are: the diameter of a nozzle is 3.2-4.5 mm, the pressure of atomizing gas is 0.9-1.3 MPa, the atomizing temperature is 850-1250 ℃, the receiving distance of a deposition disc is 380-520 mm, the scanning frequency of an atomizer is 21-24 Hz, the descending speed of the deposition disc is 19-25 mm/min, the atomizing gas is nitrogen, and the temperature of a tundish is 900-1000 ℃.

Further, in the step S1, a low-temperature ball milling process is adopted to ball mill the carbon fibers and the pure aluminum powder which are proportioned in proportion, and the carbon fibers and the pure aluminum powder are uniformly mixed; the process conditions of the low-temperature ball milling are as follows: the ball milling time is 6-24 h, the ball milling speed is 50-500 rpm, high-purity argon is adopted for protection, and the ball milling temperature is lower than 50 ℃. The ball milling temperature is kept low, so that the carbon fiber and the pure aluminum powder can be uniformly mixed; when the aluminum-based precast block containing the carbon fibers is prepared, a cold pressing forming process is adopted, the cold pressing pressure is 50-200 MPa, the pressure maintaining time is 10-180 s, and the length-to-height ratio of a pressing block is kept to be less than 2. The length-height ratio and the cold pressing pressure of the pressing block are controlled, so that damage to the carbon fibers can be avoided or reduced, and abrasion of the die is reduced. When the aluminum-based precast block containing the carbon fibers is prepared, the volume ratio of the carbon fibers to the pure aluminum powder is 1: 2-1: 10, the proportion of the carbon fibers is high, and compared with an aluminum-silicon alloy material, the weight is reduced by about 10-50%, and the light weight is realized; meanwhile, the carbon fiber reinforced aluminum-silicon-based composite material has improved plasticity and toughness and machining performance, and has wider application range.

Further, in the step S2, the melting temperature is 150-250 ℃ higher than the liquidus temperature of the Al-Si alloy matrix; under the protection of argon, coating an aluminum-based precast block containing carbon fibers with aluminum foil, placing the aluminum-based precast block into a graphite bell jar, pressing the aluminum-based precast block into the bottom of the Al-Si alloy matrix melt, and uniformly distributing the carbon fibers in the Al-Si alloy matrix melt through a stirring process; and the time for adding the aluminum-based precast block containing the carbon fiber and carrying out homogenization and heat preservation is less than 0.5-1 h. The stirring process comprises mechanical stirring, electromagnetic stirring, ultrasonic stirring and the like.

Further, in the step S4, the densification process includes hot isostatic pressing, hot press sintering, spark plasma sintering, or the like; the densification process is characterized in that the treatment temperature is 460-500 ℃, the heat preservation time is 1-4 h, the pressure is 120-150 MPa, the heating rate is 10-20 ℃/h, the cooling rate is 20-50 ℃/h, and the extrusion ratio is 10: 1; and before reaching the preset densification treatment temperature, preserving the heat of the carbon fiber reinforced aluminum-silicon-based deposition blank for 1h at the temperature of 400 ℃.

Further, the method for preparing a carbon fiber reinforced aluminum silicon based composite material according to claim 14, wherein: in step S4, for the carbon fiber reinforced aluminum-silicon-based composite material with the silicon mass fraction of less than 42% and the carbon fiber volume fraction of less than 2% in the Al-Si alloy matrix, a hot extrusion or hot forging process may be further adopted to densify and form the carbon fiber reinforced aluminum-silicon-based deposition blank; the heating temperature of the hot extrusion or hot forging processing technology is 380-400 ℃, and the heat preservation time is 2-4 h; and then carrying out stabilization annealing treatment to obtain the carbon fiber reinforced aluminum-silicon-based composite material.

Drawings

FIG. 1 is a flow chart of a preparation process of the carbon fiber reinforced aluminum-silicon-based composite material of the present invention.

FIG. 2 is a graph showing the spray deposition of Al-12% Si/5% C in example 1 of the present invention_FAnd (4) a real object diagram of the electronic packaging cover plate processed by the composite material.

FIG. 3 shows the spray deposition of Al-50% Si/0.5% C in example 2 of the present invention_FAnd (4) processing the composite material into a physical diagram of the electronic packaging shell.

FIG. 4 shows the spray deposition of Al-70% Si/0.2% C in example 3 of the present invention_FAnd (4) processing the composite material into a physical diagram of the electronic packaging shell.

Detailed Description

The inventor of the invention concentrates on the research of metal matrix composite materials for many years, and especially aims to research the high-silicon-content aluminum-silicon-based composite materials used as electronic packaging materials, pistons and the like in high technical fields such as military, aviation, aerospace, traffic and the like so as to make up the problems of uniformity and interface of the carbon fiber reinforced aluminum-silicon-based composite materials in the prior art.

The inventor tries various proportioning and combination preparation methods of carbon fibers and aluminum-silicon-based materials, finally finds that the uniformity and interface problems of the carbon fiber reinforced aluminum-silicon-based composite material can be effectively solved by utilizing a rapid solidification jet deposition method, the forming and cooling of the carbon fiber reinforced aluminum-silicon-based composite material are completed in a short time, the preparation process is high in controllability, and the ingot blank is large in size, so that a proper amount of interface reaction is guaranteed, the combination strength is improved, and the preparation method is suitable for industrial production.

The carbon fiber reinforced aluminum-silicon-based composite material is prepared firstly, and then the electronic packaging cover plate is processed, and the mechanical properties such as tensile strength, elongation, bending strength and the like, and the thermal mechanical properties such as thermal conductivity, thermal expansion coefficient and the like of the electronic packaging cover plate are compared and analyzed.

The invention provides a carbon fiber reinforced aluminum-silicon-based composite material which comprises the following raw material components: pure aluminum powder, carbon fiber and Al-Si alloy matrix; wherein the mass fraction of silicon in the Al-Si alloy matrix is 12-70%.

Preferably, the volume ratio of the carbon fibers to the pure aluminum powder is 1: 2-1: 10. The pure aluminum powder is gas atomized nearly spherical powder, the average particle size is 12-20 mu m, and the purity is higher than 99.5%. The diameter of the carbon fiber is 5-10 mu m, and the length of the carbon fiber is 10-150 mu m.

The invention also provides a preparation method of the carbon fiber reinforced aluminum-silicon-based composite material, and please refer to fig. 1, fig. 1 is a flow chart of a preparation process of the carbon fiber reinforced aluminum-silicon-based composite material of the invention. The method specifically comprises the following steps:

s1: preparing an aluminum-based precast block containing carbon fibers: and fully mixing the carbon fibers with the pure aluminum powder, and performing cold press molding to prepare the aluminum-based precast block containing the carbon fibers.

Preferably, the carbon fibers and the pure aluminum powder which are proportioned according to the proportion are subjected to ball milling treatment by adopting a low-temperature ball milling process and are uniformly mixed; the process conditions of the low-temperature ball milling are as follows: the ball milling time is 6-24 h, the ball milling speed is 50-500 rpm, high-purity argon is adopted for protection, and the ball milling temperature is lower than 50 ℃. When the aluminum-based precast block containing the carbon fibers is prepared, a cold pressing forming process is adopted, the cold pressing pressure is 50-200 MPa, the pressure maintaining time is 10-180 s, and the length-to-height ratio of a pressing block is kept to be less than 2. Further, when the aluminum-based precast block containing the carbon fiber is prepared, the volume fraction of the carbon fiber is 0.2-5%.

S2: smelting the composite material: and smelting an Al-Si alloy matrix, adding the aluminum-based precast block containing carbon fibers, and uniformly stirring to obtain a composite material melt.

Preferably, the melting temperature of the Al-Si alloy matrix is 150-250 ℃ higher than the liquidus temperature of the Al-Si alloy matrix. Under the protection of argon, coating an aluminum-based precast block containing carbon fibers with aluminum foil, placing the aluminum-based precast block into a graphite bell jar, pressing the aluminum-based precast block into the bottom of the Al-Si alloy matrix melt, and uniformly distributing the carbon fibers in the Al-Si alloy matrix melt through a stirring process; and the time for adding the aluminum-based precast block containing the carbon fiber and carrying out homogenization and heat preservation is less than 0.5-1 h. The stirring process comprises mechanical stirring, electromagnetic stirring, ultrasonic stirring and the like.

S3: spray deposition blank making: and (3) performing jet deposition on the composite material melt by adopting a jet deposition process to obtain the carbon fiber reinforced aluminum-silicon-based deposition blank.

Preferably, the working conditions of the spray deposition process are as follows: the diameter of a nozzle is 3.2-4.5 mm, the pressure of atomizing gas is 0.9-1.3 MPa, the atomizing temperature is 850-1250 ℃, the receiving distance of a deposition disc is 380-520 mm, the scanning frequency of an atomizer is 21-24 Hz, the descending speed of the deposition disc is 19-25 mm/min, the atomizing gas is nitrogen, and the temperature of a tundish is 900-1000 ℃.

S4: densification treatment: and densifying the carbon fiber reinforced aluminum-silicon-based deposition blank to obtain the carbon fiber reinforced aluminum-silicon-based composite material.

Preferably, the densification process comprises hot isostatic pressing, hot-pressing sintering, spark plasma sintering or the like; the densification process is characterized in that the treatment temperature is 460-500 ℃, the heat preservation time is 1-4 h, the pressure is 120-150 MPa, the heating rate is 10-20 ℃/h, the cooling rate is 20-50 ℃/h, and the extrusion ratio is 10: 1; and before reaching the preset densification treatment temperature, preserving the heat of the carbon fiber reinforced aluminum-silicon-based deposition blank for 1h at the temperature of 400 ℃.

Further, for the carbon fiber reinforced aluminum-silicon-based composite material with the silicon mass fraction of less than 42% and the carbon fiber volume fraction of less than 2% in the Al-Si alloy matrix, a hot extrusion or hot forging processing technology can be adopted to densify and form the carbon fiber reinforced aluminum-silicon-based deposition blank; the heating temperature of the hot extrusion or hot forging processing technology is 380-400 ℃, and the heat preservation time is 2-4 hours.

Step S5: annealing treatment: and stabilizing and annealing the carbon fiber reinforced aluminum-silicon-based composite material.

Step S6: and (3) machining treatment: and machining the carbon fiber reinforced aluminum-silicon-based composite material to obtain the carbon fiber reinforced aluminum-silicon-based component. And the annealed carbon fiber reinforced aluminum-silicon-based composite material is subjected to warp cutting, fine engraving and the like to obtain a required component, such as an electronic packaging shell and the like.

The technical solution of the present invention will be described in detail below with reference to specific examples.

Example 1

In this example, an Al-12% Si/5% C alloy was prepared_FThe composite material is processed into the electronic packaging cover plate, and the method comprises the following specific steps:

s1: preparing an aluminum-based precast block containing carbon fibers: pure aluminum powder selected as a raw material is gas atomized nearly spherical powder, the average particle size is 12-20 mu m, and the purity is higher than 99.5%; the carbon fiber has a diameter of 5 to 10 μm and a length of 10 to 150 μm. The method comprises the following steps of preparing materials according to designed components of the aluminum-based precast block containing carbon fibers, wherein the volume ratio of the carbon fibers to pure aluminum powder is 1: 2-1: 5, uniformly mixing the carbon fibers and the pure aluminum powder by adopting a low-temperature ball milling process, wherein the ball milling time is 6-12 hours, the rotating speed of a ball mill is 50-200 rpm, a ball milling tank is filled with high-purity argon for protection, and the ball milling temperature is lower than 50 ℃; when the pure aluminum matrix composite precast block is prepared, the pressure required by cold press molding is 50-120 MPa, the pressure maintaining time is 10-30 s, and the length-to-height ratio of a pressing block is kept to be less than 2.

S2: smelting the composite material: preparing an Al-Si alloy matrix by using the weight percentage of 12 percent of silicon and the balance of aluminum, and smelting the Al-Si alloy matrix, wherein the smelting temperature is 150-200 ℃ higher than the liquidus temperature of the Al-Si alloy matrix. Coating an aluminum-based precast block containing carbon fibers by using an aluminum foil, placing the aluminum-based precast block into a graphite bell jar, pressing the aluminum-based precast block into the bottom of an Al-Si alloy matrix melt, and uniformly distributing the carbon fibers in the Al-Si alloy matrix melt by adopting mechanical stirring, electromagnetic stirring and ultrasonic stirring; adding the precast block for less than 0.5-1 h, and carrying out smelting and carbon fiber-containing aluminum-based precast block under the protection of argon; wherein, the carbon fiber accounts for 5 percent of the volume fraction of the carbon fiber reinforced aluminum-silicon-based composite material.

S3: spray deposition blank making: the composite material melt is sprayed and deposited by adopting a spraying and depositing process, wherein the working conditions of the spraying and depositing process are as follows: the diameter of a nozzle is 3.5mm, the pressure of atomizing gas is 0.9-1.1 MPa, the atomizing temperature is 850-950 ℃, the receiving distance of a deposition disc is 380-420 mm, the scanning frequency of an atomizer is 21-24 Hz, the descending speed of the deposition disc is 19-25 mm/min, the atomizing gas is nitrogen, and the temperature of a tundish is 900-1000 ℃.

S4: densification treatment: performing densification treatment on the carbon fiber reinforced aluminum-silicon-based deposition blank by adopting hot isostatic pressing, wherein the heating temperature of the carbon fiber reinforced aluminum-silicon-based deposition blank is 460 ℃, the heat preservation time is 2 hours, the pressure is 120MPa, the heating rate is 10-20 ℃/h, and the cooling rate is 20-50 ℃/h; before reaching the preset temperature, the carbon fiber reinforced aluminum-silicon-based deposition blank is subjected to heat preservation for 1h at the temperature of 400 ℃; and (3) processing the carbon fiber reinforced aluminum-silicon-based deposition blank by adopting hot extrusion deformation to form the carbon fiber reinforced aluminum-silicon-based composite material, wherein the hot extrusion heating temperature is 380-400 ℃, the heat preservation time is 2-4 h, and the extrusion ratio is 10: 1.

S5: annealing treatment: spray deposition of Al-12% Si/5% C_FThe stabilizing annealing temperature of the composite material is 400 ℃, the heat preservation time is 6 hours, and the composite material is naturally cooled to room temperature after the heat preservation is finished, so that the carbon fiber reinforced aluminum-silicon-based composite material is obtained;

s6: and (3) machining treatment: spray deposition of Al-12% Si/5% C_FAnd sawing the composite material, and forming the surface of the film to obtain the electronic packaging cover plate with the thickness of 1.8 mm.

Referring to FIG. 2, FIG. 2 shows the spray deposition of Al-12% Si/5% C in example 1 of the present invention_FThe physical image of the electronic packaging cover plate processed by the composite material can be seen that the macroscopic surface quality and the machining performance are good.

Example 2

This example 2 is the same as the carbon fiber reinforced aluminum silicon based composite material of example 1 in the preparation steps, and the difference is the content of each component and the condition parameters in the preparation process.

In this example, an Al-50% Si/0.5% C alloy was prepared_FThe composite material is processed into the electronic packaging cover plate, and the method comprises the following specific steps:

s1: preparing an aluminum-based precast block containing carbon fibers: pure aluminum powder selected as a raw material is gas atomized nearly spherical powder, the average particle size is 12-20 mu m, and the purity is higher than 99.5%; the carbon fiber has a diameter of 5 to 10 μm and a length of 10 to 150 μm. The method comprises the following steps of preparing materials according to designed components of the aluminum-based precast block containing carbon fibers, wherein the volume ratio of the carbon fibers to pure aluminum powder is 1: 5-1: 8, uniformly mixing the carbon fibers and the pure aluminum powder by adopting a low-temperature ball milling process, wherein the ball milling time is 12-18 h, the rotating speed of a ball mill is 200-400 rpm, a ball milling tank is filled with high-purity argon for protection, and the ball milling temperature is lower than 50 ℃; when the pure aluminum matrix composite precast block is prepared, the pressure required by cold press molding is 120-150 MPa, the pressure maintaining time is 60-120 s, and the length-to-height ratio of a pressing block is kept to be less than 2.

S2: smelting the composite material: preparing an Al-Si alloy matrix by using the weight percentage of 50 percent of silicon and the balance of aluminum, and smelting the Al-Si alloy matrix, wherein the smelting temperature is 200-220 ℃ higher than the liquidus temperature of the Al-Si alloy matrix. Coating an aluminum-based precast block containing carbon fibers by using an aluminum foil, placing the aluminum-based precast block into a graphite bell jar, pressing the aluminum-based precast block into the bottom of an Al-Si alloy matrix melt, and uniformly distributing the carbon fibers in the Al-Si alloy matrix melt by adopting mechanical stirring, electromagnetic stirring and ultrasonic stirring; adding the precast block for less than 0.5-1 h, and carrying out smelting and carbon fiber-containing aluminum-based precast block under the protection of argon; wherein, the carbon fiber accounts for 0.5 percent of the volume fraction of the carbon fiber reinforced aluminum-silicon-based composite material.

S3: spray deposition blank making: the composite material melt is sprayed and deposited by adopting a spraying and depositing process, wherein the working conditions of the spraying and depositing process are as follows: the diameter of a nozzle is 4.0mm, the pressure of atomizing gas is 1.0-1.2 MPa, the atomizing temperature is 1000-1150 ℃, the receiving distance of a deposition disc is 450-500 mm, the scanning frequency of an atomizer is 21-24 Hz, the descending speed of the deposition disc is 19-25 mm/min, the atomizing gas is nitrogen, and the temperature of a tundish is 900-1000 ℃.

S4: densification treatment: performing densification treatment on the carbon fiber reinforced aluminum-silicon-based deposition blank by adopting hot isostatic pressing, wherein the heating temperature of the carbon fiber reinforced aluminum-silicon-based deposition blank is 500 ℃, the heat preservation time is 4h, the pressure is 120MPa, the heating rate is 10-20 ℃/h, and the cooling rate is 20-50 ℃/h; before reaching the preset temperature, the carbon fiber reinforced aluminum-silicon-based deposition blank is subjected to heat preservation for 1h at the temperature of 400 ℃; and (3) processing the carbon fiber reinforced aluminum-silicon-based deposition blank by adopting hot extrusion deformation to form the carbon fiber reinforced aluminum-silicon-based composite material, wherein the hot extrusion heating temperature is 380-400 ℃, the heat preservation time is 2-4 h, and the extrusion ratio is 10: 1.

S5: annealing treatment: spray deposition of Al-50% Si/0.5% C_FThe stabilizing annealing temperature of the composite material is 400 ℃, the heat preservation time is 6 hours, and the composite material is naturally cooled to room temperature after the heat preservation is finished, so that the carbon fiber reinforced aluminum-silicon-based composite material is obtained;

s6: and (3) machining treatment: spray deposition of Al-50% Si/0.5% C_FAnd sawing and engraving the composite material to obtain the electronic packaging cover plate.

Referring to FIG. 3, FIG. 3 shows the spray deposition of Al-50% Si/0.5% C in example 2 of the present invention_FAnd (4) processing the composite material into a physical diagram of the electronic packaging shell. The size of the shell meets the requirements of corresponding parameters, which shows that the Al-50% Si/0.5% C is deposited by spraying_FThe composite material can be applied to the field of electronic packaging shells.

Example 3

The preparation steps of this example 3 are the same as those of the carbon fiber reinforced aluminum-silicon-based composite materials of examples 1 and 2, and the differences are the content of each component and the condition parameters in the preparation process.

In this example, an Al-70% Si/0.2% C alloy was prepared_FThe composite material is processed into the electronic packaging cover plate, and the method comprises the following specific steps:

s1: preparing an aluminum-based precast block containing carbon fibers: pure aluminum powder selected as a raw material is gas atomized nearly spherical powder, the average particle size is 12-20 mu m, and the purity is higher than 99.5%; the carbon fiber has a diameter of 5 to 10 μm and a length of 10 to 150 μm. The method comprises the following steps of preparing materials according to designed components of the aluminum-based precast block containing carbon fibers, wherein the volume ratio of the carbon fibers to pure aluminum powder is 1: 8-1: 10, uniformly mixing the carbon fibers and the pure aluminum powder by adopting a low-temperature ball milling process, wherein the ball milling time is 18-24 hours, the rotating speed of a ball mill is 400-500 rpm, a ball milling tank is filled with high-purity argon for protection, and the ball milling temperature is lower than 50 ℃; when the pure aluminum matrix composite precast block is prepared, the pressure required by cold press molding is 150-200 MPa, the pressure maintaining time is 120-180 s, and the length-to-height ratio of a pressing block is kept to be less than 2.

S2: smelting the composite material: preparing an Al-Si alloy matrix by using the weight percentage of 70% of silicon and the balance of aluminum, and smelting the Al-Si alloy matrix, wherein the smelting temperature is 220-250 ℃ higher than the liquidus temperature of the Al-Si alloy matrix. Coating an aluminum-based precast block containing carbon fibers by using an aluminum foil, placing the aluminum-based precast block into a graphite bell jar, pressing the aluminum-based precast block into the bottom of an Al-Si alloy matrix melt, and uniformly distributing the carbon fibers in the Al-Si alloy matrix melt by adopting mechanical stirring, electromagnetic stirring and ultrasonic stirring; adding the precast block for less than 0.5-1 h, and carrying out smelting and carbon fiber-containing aluminum-based precast block under the protection of argon; wherein, the carbon fiber accounts for 0.2 percent of the volume fraction of the carbon fiber reinforced aluminum-silicon-based composite material.

S3: spray deposition blank making: the composite material melt is sprayed and deposited by adopting a spraying and depositing process, wherein the working conditions of the spraying and depositing process are as follows: the diameter of a nozzle is 4.5mm, the pressure of atomizing gas is 1.2-1.3 MPa, the atomizing temperature is 1150-1250 ℃, the receiving distance of a deposition disc is 500-520 mm, the scanning frequency of an atomizer is 21-24 Hz, the descending speed of the deposition disc is 19-25 mm/min, the atomizing gas is nitrogen, and the temperature of a tundish is 900-1000 ℃.

S4: densification treatment: performing densification treatment on the carbon fiber reinforced aluminum-silicon-based deposition blank by adopting hot isostatic pressing, wherein the heating temperature of the carbon fiber reinforced aluminum-silicon-based deposition blank is 500 ℃, the heat preservation time is 4h, the pressure is 150MPa, the heating rate is 10-20 ℃/h, and the cooling rate is 20-50 ℃/h; before reaching the preset temperature, the carbon fiber reinforced aluminum-silicon-based deposition blank is subjected to heat preservation for 1h at the temperature of 400 ℃; and (3) processing the carbon fiber reinforced aluminum-silicon-based deposition blank by adopting hot extrusion deformation to form the carbon fiber reinforced aluminum-silicon-based composite material, wherein the hot extrusion heating temperature is 380-400 ℃, the heat preservation time is 2-4 h, and the extrusion ratio is 10: 1.

S5: annealing treatment: spray deposition of Al-50% Si/0.5% C_FThe stabilizing annealing temperature of the composite material is 400 ℃, the heat preservation time is 6 hours, and the composite material is naturally cooled to room temperature after the heat preservation is finished, so that the carbon fiber reinforced aluminum-silicon-based composite material is obtained;

s6: and (3) machining treatment: spray deposition of Al-70% Si/0.2% C_FAnd sawing and engraving the composite material to obtain the electronic packaging cover plate.

Referring to FIG. 4, FIG. 4 shows the spray deposition of Al-70% Si/0.2% C in example 3 of the present invention_FAnd (4) processing the composite material into a physical diagram of the electronic packaging shell. The size of the shell meets the requirements of corresponding parameters, which shows that the Al-70% Si/0.2% C is deposited by spraying_FThe composite material can be applied to the field of electronic packaging shells.

Comparison of Performance

TABLE 1 comparison of the properties of the carbon fiber reinforced aluminum-silicon based composites prepared in examples 1-3

Performance of	Al-12Si	Example 1	Al-50Si	Example 2	Al-70Si	Example 3
							Tensile strength (MPa)	154.1	203.5	138	254.8	100	135.6
Elongation (%)	6.7	7.2	/	0.8	/	0.3
							Bending strength (MPa)	187.3	266.5	172	337.6	143	198.3
Thermal conductivity (W/m. K)	185.1	167.8	149	142.3	120	98.5
							Coefficient of thermal expansion (. times.10)-6/℃，20～200℃)	21.1	18.2	11.0	11.2	7.4	7.4

The properties of the carbon fiber reinforced aluminum-silicon based composite material prepared in examples 1 to 3 and the corresponding aluminum-silicon based composite material without the carbon fiber are shown in table 1. As can be seen from table 1, firstly, compared with the aluminum-silicon-based composite material without the carbon fiber, the carbon fiber reinforced aluminum-silicon-based composite material prepared in examples 1 to 3 has effectively improved tensile strength, elongation and bending strength, for example, the tensile strength is increased by 32.1% to 84.6%, the elongation is increased by about 7.5%, and the bending strength is increased by 38.7% to 96.3%; the thermal conductivity and the thermal expansion coefficient are effectively reduced, for example, the thermal conductivity is correspondingly reduced by 6.7 to 17.9 percent, and the thermal expansion coefficient is reduced by about 13.7 percent at most.

It is noteworthy that as the mass fraction of silicon in the aluminum-silicon-based composite material increases, e.g., from 12% to 50% and further to 70%, the corresponding tensile strength, elongation, thermal conductivity, and thermal expansion coefficient all gradually decrease; the bending strength tends to increase and then decrease. With the increase of the mass fraction of silicon in the Al-Si alloy matrix, the prepared carbon fiber reinforced aluminum-silicon-based composite material has better crystallinity, lower conductivity and better surface smoothness and thickness in the middle value of the preparation condition parameter range.

In summary, the carbon fiber reinforced aluminum-silicon-based composite material and the preparation method thereof have the following advantages:

(1) in the carbon fiber reinforced aluminum-silicon-based composite material, carbon fibers are uniformly distributed and generate a certain degree of interface reaction with an Al-Si alloy matrix, so that the interface bonding strength is enhanced;

(2) the carbon fiber reinforced aluminum-silicon-based composite material effectively improves the strength and toughness, and has higher reliability and better service performance when being used as an electronic packaging material;

(3) the carbon fiber reinforced aluminum-silicon-based composite material is prepared by adopting a spray deposition technology, so that the problem that the strengthening and toughening effects of carbon fibers cannot be effectively exerted because the carbon fibers are easy to gather when the carbon fiber reinforced composite material is prepared by the traditional liquid phase method is solved; meanwhile, the defects that the interface bonding strength of the carbon fiber and the Al-Si alloy matrix is low and the carbon fiber is easy to oxidize and dirty due to the introduction of impurities in the traditional solid phase method are overcome;

(4) the carbon fiber reinforced aluminum-silicon-based composite material is prepared by adopting a spray deposition technology, so that batch and stable production of the composite material and an electronic packaging shell or component is realized;

(5) the carbon fiber reinforced aluminum-silicon-based composite material can be processed into an electronic packaging shell and can also be processed into various wear-resistant components, such as automobile pistons and the like.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.