阅读说明：本技术 原位生成氧化铝协同碳纳米管增强铝基复合材料的制备方法 (Preparation method of in-situ generated aluminum oxide and carbon nanotube reinforced aluminum matrix composite ) 是由 赵乃勤 单永超 何春年 师春生 李群英 蒲博闻 于 2019-09-03 设计创作，主要内容包括：本发明涉及一种原位生成氧化铝协同碳纳米管增强铝基复合材料的制备方法,包括以下几步过程：配制混合粉末:将碳纳米管分散在酒精中,制得碳纳米管溶液,取硼酸在酒精中溶解后加入碳纳米管溶液,混合溶液热干后加入球形铝粉制成混合粉末,碳纳米管：硼酸：铝粉质量比为(0.004-0.006):(0.10-0.14):1；对混合粉末进行球磨处理；冷压烧结成型。(The invention relates to a preparation method of an aluminum-based composite material reinforced by aluminum oxide generated in situ and carbon nano tubes, which comprises the following steps: preparing mixed powder, namely dispersing carbon nano tubes in alcohol to prepare a carbon nano tube solution, dissolving boric acid in the alcohol, adding the carbon nano tube solution, heating and drying the mixed solution, and adding spherical aluminum powder to prepare the mixed powder, wherein the carbon nano tubes: boric acid: the mass ratio of the aluminum powder is (0.004-0.006): 0.10-0.14): 1; performing ball milling treatment on the mixed powder; and (5) cold pressing, sintering and forming.)

1. A preparation method of an in-situ generated aluminum oxide and carbon nanotube reinforced aluminum matrix composite material comprises the following steps:

(1) Preparing mixed powder

Dispersing carbon nanotubes in alcohol to prepare a carbon nanotube solution, dissolving boric acid in the alcohol, adding the carbon nanotube solution, drying the mixed solution by heating, and adding spherical aluminum powder to prepare mixed powder, wherein the carbon nanotube: boric acid: the mass ratio of the aluminum powder is (0.004-0.006): 0.10-0.14): 1.

(2) Ball milling the mixed powder

Ball milling the mixed powder under the protection of argon;

(3) Cold pressing and sintering for shaping

Putting the powder subjected to ball milling into a die, performing cold press molding at room temperature, sintering the block material obtained by cold pressing in a tubular furnace under the protection of argon, wherein the sintering temperature is as follows: 550-650 ℃.

2. The method of claim 1, wherein in step (2), the ball milling parameters are: the ball-material ratio is 15:1 to 20:1, the rotating speed is 300 to 500 turns, and the ball milling time is 2 to 3 hours.

3. The method of claim 1, wherein in step (3), cold press forming parameters: the pressure is 500-600 MPa.

Technical Field

The invention relates to a method for preparing an aluminum-based composite material reinforced by in-situ generated aluminum oxide and carbon nano tubes by using a powder metallurgy process, belonging to the technical field of preparation of metal-based composite materials.

Background

aluminum element is the metal element with the largest content, which is arranged in the total reserves of crust elements, and is easy to obtain and enrich in aluminum resources compared with non-renewable resources such as gold, silver, rare earth and the like on the earth of our life. Aluminum is an important light metal, has excellent properties of low density, easy processing, corrosion resistance, heat and electricity conduction, strong recyclability and the like, is widely used in the industrial fields of aerospace, transportation, mechanical manufacturing, building, packaging and the like, and is a key supporting material for the development of modern high-tech industries. For metallic materials, strength and plasticity have been traded off against the property that aluminum has excellent ductility but lower hardness and strength compared to steel, which property constraint is one of the reasons limiting its widespread use. To solve this problem, it is an effective method to add reinforcement to prepare aluminum matrix composite material to improve the mechanical properties of aluminum matrix. The aluminum matrix composite has many excellent properties, such as low density, high specific strength and rigidity, high elastic modulus, high fatigue resistance and creep resistance, high wear resistance, high damping and vibration damping capacity, low thermal expansion rate, low cost and the like.

Carbon nanotubes have received extensive and continuous attention and research since their first report in 1991. Single-layer carbon nanotube with sp²The carbon atoms hybridized by the method form a hexagonal network space topological structure, have extremely high elastic modulus as high as 1TPa and tensile strength of 800GPa, and are an ideal reinforcement for metal-based composite materials. In addition, the ceramic particles are also a reinforcing phase which can be used for reinforcing the aluminum matrix composite, and the aluminum matrix composite reinforced by the ceramic particles has the advantages of low cost, high modulus, good wear resistance, small thermal expansion coefficient and the like. Alumina in the ceramic phase, formula Al₂O₃The ionic crystal is a high-hardness compound, has a melting point of 2054 ℃ and a boiling point of 2980 ℃, and can be ionized at high temperature.

The carbon nano tube and the alumina are directly added into the aluminum matrix to be used as the reinforcing body, so that the reinforcing body agglomeration, poor interface bonding and the like are brought to cause limited reinforcing effect. A method for enhancing an aluminum matrix composite by in-situ generation of alumina and carbon nano tubes is provided by utilizing powder metallurgy, an alumina reinforcement is generated in situ by using boric acid, and the mechanical property of an aluminum matrix is improved by cooperating with the added carbon nano tubes. The invention provides a process for in-situ generation of an aluminum-based composite material reinforced by aluminum oxide and carbon nano tubes by using a powder metallurgy process.

Disclosure of Invention

The invention aims to provide a method for compounding and reinforcing an aluminum-based composite material by in-situ generation of alumina and carbon nanotubes. The method can overcome the defects of external reinforcement agglomeration and low bonding strength of the reinforcement and the aluminum matrix interface to a certain extent. The technical scheme is as follows:

A preparation method of an in-situ generated aluminum oxide and carbon nanotube reinforced aluminum matrix composite material comprises the following steps:

(1) Preparing mixed powder

Dispersing carbon nanotubes in alcohol to prepare a carbon nanotube solution, dissolving boric acid in the alcohol, adding the carbon nanotube solution, drying the mixed solution by heating, and adding spherical aluminum powder to prepare mixed powder, wherein the carbon nanotube: boric acid: the mass ratio of the aluminum powder is (0.004-0.006): 0.10-0.14): 1.

(2) Ball milling the mixed powder

Ball milling the mixed powder under the protection of argon;

(3) Cold pressing and sintering for shaping

Putting the powder subjected to ball milling into a die, performing cold press molding at room temperature, sintering the block material obtained by cold pressing in a tubular furnace under the protection of argon, wherein the sintering temperature is as follows: 550-650 ℃.

In the step (2), ball milling parameters are as follows: the ball-material ratio is 15:1 to 20:1, the rotating speed is 300 to 500 turns, and the ball milling time is 2 to 3 hours.

In the step (3), cold press molding parameters are as follows: the pressure is 500-600 MPa.

The reaction mechanism is as follows: under high temperature conditions, aluminum atoms in the aluminum matrix diffuse and react with boric acid to form particulate and whisker-like alumina. The morphology of the alumina is related to the ball milling energy and the amount of boric acid added, which allows the alumina to grow in a specific direction when the ball milling energy is low and the boric acid is sufficient.

The reaction equation is as follows: 2H₃BO₃+3Al→Al₂O₃+AlB₂+3H₂O

Drawings

FIG. 1 is an XRD pattern of the composite material prepared in example 1 of the present invention.

FIG. 2 is an SEM photograph of a composite material prepared in example 1 of the present invention.

Detailed Description

The present invention is further illustrated by the following examples, which are intended to be illustrative only and not limiting.