阅读说明：本技术 多元多维度增强相协同增强铝基复合材料力学性能的方法 (Method for enhancing mechanical property of aluminum matrix composite material by cooperation of multi-element multi-dimensional enhanced phase ) 是由 何春年 杨立壮 蒲博闻 张翔 师春生 赵乃勤 于 2019-09-27 设计创作，主要内容包括：本发明涉及一种多元多维度增强相协同增强铝基复合材料力学性能的制备方法,步骤如下：原位合成石墨烯负载碳纳米管和铜纳米颗粒复合增强相：以葡萄糖为碳源,三水合硝酸铜为铜源,氯化钠为模板,与羧基化碳纳米管共同溶于去离子水中并进行均匀分散,得到混合溶液；之后将混合溶液在液氮辅助下进行快速冷冻,采用冷冻干燥技术去除水分,得到复合粉末；将上述获得的复合粉末放置在方舟中,然后放入到高温管式炉的恒温区进行化学反应,合成条件为氢气下进行反应,合成温度为700～800℃,反应结束后将样品进行快速降温,得到混合粉末；将反应后获得的粉末用去离子水进行水洗和抽滤以除去氯化钠；最后将获得粉末进行真空干燥,得到石墨烯负载碳纳米管和铜纳米颗粒的复合增强相。(2)石墨烯负载碳纳米管和铜纳米颗粒协同增强铝基复合材料的成型制备。(The invention relates to a preparation method for the mechanical property of a multi-element multi-dimensional reinforced phase synergistic reinforced aluminum matrix composite, which comprises the following steps: in-situ synthesis of a graphene-loaded carbon nanotube and copper nanoparticle composite reinforcing phase: dissolving glucose as a carbon source, copper nitrate trihydrate as a copper source and sodium chloride as a template in deionized water together with the carboxylated carbon nanotubes, and uniformly dispersing to obtain a mixed solution; then, quickly freezing the mixed solution under the assistance of liquid nitrogen, and removing water by adopting a freeze drying technology to obtain composite powder; placing the obtained composite powder in a square boat, then placing the square boat in a constant-temperature area of a high-temperature tube furnace for chemical reaction, wherein the synthesis condition is that the reaction is carried out under hydrogen, the synthesis temperature is 700-800 ℃, and after the reaction is finished, rapidly cooling a sample to obtain mixed powder; washing the powder obtained after the reaction with deionized water and performing suction filtration to remove sodium chloride; and finally, carrying out vacuum drying on the obtained powder to obtain the composite reinforced phase of the graphene-loaded carbon nano tube and the copper nano particles. (2) And (3) molding and preparing the graphene-loaded carbon nanotube and copper nanoparticle synergistically enhanced aluminum matrix composite.)

1. a method for enhancing the mechanical property of an aluminum matrix composite material by the cooperation of a multi-element multi-dimensional enhancing phase comprises the following steps:

(1) In-situ synthesis of a graphene-loaded carbon nanotube and copper nanoparticle composite reinforcing phase: dissolving glucose as a carbon source, copper nitrate trihydrate as a copper source and sodium chloride as a template in deionized water together with the carboxylated carbon nanotubes, and uniformly dispersing to obtain a mixed solution; then, quickly freezing the mixed solution under the assistance of liquid nitrogen, and removing water by adopting a freeze drying technology to obtain composite powder; placing the obtained composite powder in a square boat, then placing the square boat in a constant-temperature area of a high-temperature tube furnace for chemical reaction, wherein the synthesis condition is that the reaction is carried out under hydrogen, the synthesis temperature is 700-800 ℃, the heating rate is 5-10 ℃/min, and after the reaction is finished, the sample is rapidly cooled to obtain mixed powder; washing the powder obtained after the reaction with deionized water and performing suction filtration to remove sodium chloride; and finally, carrying out vacuum drying on the obtained powder to obtain the composite reinforced phase of the graphene-loaded carbon nano tube and the copper nano particles.

(2) Molding and preparing the graphene-loaded carbon nanotube and copper nanoparticle synergistically enhanced aluminum matrix composite material: filling the obtained composite reinforcing phase and aluminum powder into a ball milling tank, wherein the ball-material ratio is 10:1, and filling argon gas into the ball milling tank to be used as protective gas; carrying out variable speed ball milling on the composite reinforcing phase and the aluminum powder to ensure that the reinforcing phase is uniformly dispersed in the aluminum powder and the structure is not seriously damaged; and finally, performing cold press molding on the ball-milled powder at 500-600MPa, sintering at the temperature of 600-630 ℃, selecting argon as a protective atmosphere, and performing hot extrusion on the sintered block material at the temperature of 500-600 ℃ to obtain the graphene-loaded carbon nanotube and copper nanoparticle synergistically enhanced aluminum-based composite material.

2. The method as claimed in claim 1, wherein the glucose, the copper nitrate and the sodium chloride are used according to a mass ratio of 1:1-3: 20-80.

Technical Field

The invention relates to a preparation method for improving the mechanical property of an aluminum-based composite material by utilizing a cold pressing-sintering forming mode, belonging to the field of powder metallurgy.

Background

Aluminum and aluminum alloys are widely used in aerospace, automotive and electronic applications due to their high thermal stability, low density, good ductility and toughness, excellent corrosion resistance, etc. However, the aluminum and aluminum alloy used by us at present generally have low strength and cannot meet many industrial requirements. Therefore, researchers have improved the mechanical properties of aluminum and aluminum alloys in a variety of ways. Among them, it is a very effective method to improve the mechanical strength by preparing the aluminum matrix composite.

Traditionally, aluminum-based composites have been prepared mainly by ceramic phase nanoparticles and fibers, such as alumina nanoparticles, boron nitride nanosheets, silicon carbide nanoparticles, titanium carbide whiskers, and the like. The preparation method mainly comprises powder metallurgy, stirring casting, pressure infiltration and the like. However, with the continuous improvement of the requirements of the scientific and technological development on the performance of the structural materials, the traditional reinforcing phases gradually expose the defects of low reinforcing efficiency, high density and poor ductility and toughness, so that the problem to be solved by searching a novel light reinforcing phase with high toughness and good comprehensive performance is urgently needed.

Carbon nanomaterials (mainly including carbon nanotubes and graphene) are novel nanomaterials that have received much attention in recent years. The carbon nano tube and the graphene have excellent performance, and the strength of the carbon nano tube and the graphene is more than 100 times that of steel; the Young modulus is 1100GPa, the thermal conductivity is about 6000J/(m.K.s), the carrier mobility can reach 2 x 105cm 2/(V.s), and the density is only 2.2g/cm 3. Therefore, under the condition of low mass fraction addition, the carbon nano tubes and the graphene can greatly improve the metal matrix, and meanwhile, the density of the carbon nano tubes and the graphene is smaller than that of the metal matrix, so that the density of the composite material is reduced while the mechanical property of the metal matrix is improved, and the requirements of light weight, high strength and the like of the existing composite material are met. The carbon nano tube and the graphene have super-strong mechanical properties far exceeding those of traditional ceramic phases, nano particles and other reinforcing phases, and can be produced in a large scale at present, so that the problems of low elongation and difficult plastic processing of the composite material are hopefully solved by using the carbon nano tube and the graphene to reinforce the metal matrix, and the production cost can be reduced while a good reinforcing effect is obtained. Therefore, the research on the carbon nano tube and graphene reinforced metal matrix composite material has very important significance. However, at present, the performance improvement obtained by adding carbon nanotubes or graphene as a single reinforcing phase to an aluminum matrix is very limited, so many researchers try to reinforce the aluminum matrix composite material by constructing a composite reinforcing phase of the carbon nanotubes and the graphene to achieve a better reinforcing effect. However, the carbon nano material is very easy to react with aluminum in the sintering or high-temperature smelting process to generate an aluminum carbide brittle phase, so that the plasticity of the composite material is reduced, and the problem brings difficulty for the carbon nano material to reinforce the aluminum-based composite material. Researchers find that the combination of graphene or carbon nanotubes and an aluminum matrix can be improved by coating or loading nano metal particles on the surface of graphene or carbon nanotubes, and the structural integrity of the carbon nanotubes and graphene can be ensured in the processing process. Therefore, the carbon nano tube and graphene composite reinforced phase is constructed and simultaneously the metal nano particles are loaded, so that the method has important significance for reinforcing the aluminum matrix composite and improving the aluminum matrix composite.

The graphene-loaded carbon nanotube and the copper nanoparticle are synthesized in situ by a salt template-assisted method. The carbon nano tube and the graphene form stable combination, and the copper nano particles enable the graphene to have high crystallinity through in-situ catalytic reaction and have higher combination strength between the graphene and the graphene, so that the composite reinforced phase with stable performance is prepared. And then, the composite reinforcing phase is uniformly distributed in the matrix in a speed-variable ball milling mode, and the structural integrity is protected. And then obtaining the rod-shaped composite material by cold-pressing sintering and hot extrusion molding. Experiments show that the mechanical property of the composite material is remarkably improved, and the composite material has better elongation.

Disclosure of Invention

The invention aims to provide a preparation method of a novel composite reinforcing phase for reinforcing an aluminum matrix composite, which mainly enables graphene to uniformly load carbon nanotubes and copper nanoparticles in an in-situ synthesis mode, and finally realizes the remarkable improvement of the mechanical property of the aluminum matrix composite. In order to achieve the above object, the present invention is achieved by the following technical solutions.

A method for enhancing the mechanical property of an aluminum matrix composite material by the cooperation of a multi-element multi-dimensional enhancing phase comprises the following steps:

(1) In-situ synthesis of a graphene-loaded carbon nanotube and copper nanoparticle composite reinforcing phase: dissolving glucose as a carbon source, copper nitrate trihydrate as a copper source and sodium chloride as a template in deionized water together with the carboxylated carbon nanotubes, and uniformly dispersing to obtain a mixed solution; then, quickly freezing the mixed solution under the assistance of liquid nitrogen, and removing water by adopting a freeze drying technology to obtain composite powder; placing the obtained composite powder in a square boat, then placing the square boat in a constant-temperature area of a high-temperature tube furnace for chemical reaction, wherein the synthesis condition is that the reaction is carried out under hydrogen, the synthesis temperature is 700-800 ℃, the heating rate is 5-10 ℃/min, and after the reaction is finished, the sample is rapidly cooled to obtain mixed powder; washing the powder obtained after the reaction with deionized water and performing suction filtration to remove sodium chloride; and finally, carrying out vacuum drying on the obtained powder to obtain the composite reinforced phase of the graphene-loaded carbon nano tube and the copper nano particles.

(2) Molding and preparing the graphene-loaded carbon nanotube and copper nanoparticle synergistically enhanced aluminum matrix composite material: filling the obtained composite reinforcing phase and aluminum powder into a ball milling tank, wherein the ball-material ratio is 10:1, and filling argon gas into the ball milling tank to be used as protective gas; carrying out variable speed ball milling on the composite reinforcing phase and the aluminum powder to ensure that the reinforcing phase is uniformly dispersed in the aluminum powder and the structure is not seriously damaged; and finally, performing cold press molding on the ball-milled powder at 500-600MPa, sintering at the temperature of 600-630 ℃, selecting argon as a protective atmosphere, and performing hot extrusion on the sintered block material at the temperature of 500-600 ℃ to obtain the graphene-loaded carbon nanotube and copper nanoparticle synergistically enhanced aluminum-based composite material.

Drawings

FIG. 1 is a scan, transmission, Raman and infrared test chart of carboxylated carbon nanotubes used in the preparation of the composite reinforcement phase of example 1. The figure shows that the diameter of the carbon nano tube is about 10-30nm, the carbon nano tube contains carboxyl functional groups and more defects, and the outer wall of the carbon nano tube contains a layer of amorphous carbon defects.

fig. 2 is a scanning and transmission diagram of the graphene-supported carbon nanotube and the copper nanoparticle prepared in example 1. From this figure, it can be clearly observed that the carbon nanotubes and the copper nanotubes are supported on the surface of the graphene and are tightly combined with the graphene.

FIG. 3(a) is a Raman spectrum of the composite reinforcing phase prepared in example 1 and a composite powder after ball milling with aluminum powder. It can be seen from the figure that the structure of the reinforcing phase can be effectively protected from being seriously damaged by the variable speed ball milling.

FIG. 3(b) is a scanned photograph of the powder after ball milling in example 1. From this figure it can be seen that the powder after the shift forms slightly cold-welded granules and no significant agglomeration is observed on the surface of the granules.

Fig. 4 is a stress-strain curve of the composite material prepared in example 1 of the present invention and the pure aluminum prepared in comparative example 1.

Detailed Description

The present invention is illustrated below with reference to specific examples, but the present invention is not limited thereto.