CN110578066A - in situ generation of AlN and AlB2preparation method of dual-phase particle reinforced aluminum matrix composite material - Google Patents

Abstract

The invention relates to a preparation method of a boron nitride nanosheet reinforced aluminum-based composite material, which comprises the following steps: the method comprises the following steps of (1) putting aluminum powder and boron nitride nanosheets into a ball milling tank according to the mass ratio (96-99) to (1-4) of the aluminum powder to the boron nitride nanosheets, and uniformly mixing the aluminum powder and the boron nitride nanosheets through ball milling in an inert gas atmosphere; putting the ball-milled powder into a grinding tool, and performing cold press molding; semi-solid sintering is carried out on the cold-pressed block body, the sintering temperature is 600-750 ℃, and the sintering time is 1-3 hours; and (3) placing the semi-solid sintered block body in an extrusion device for extrusion to obtain the aluminum-based composite material of the uniform and continuous infiltration layer generated in situ.

Description

In situ generation of AlN and AlB2Preparation method of dual-phase particle reinforced aluminum matrix composite material

Technical Field

The invention belongs to the technical field of composite materials, and particularly relates to a preparation method of an aluminum-based composite material.

Background

With energy conservation and environmental protection becoming the subject of the world, the demand for light-weight and high-specific-modulus-strength structural materials in the fields of automobiles, aerospace and the like is increasing day by day. Aluminum and aluminum alloys are lightweight metallic structural materials that are currently in widespread use. The particle-reinforced aluminum-based composite material is widely researched by virtue of the advantages of high specific strength, high hardness, high elastic modulus, good wear resistance, simple preparation process, low cost and the like. When the content of the reinforcing particles is constant, the more uniform the particle distribution, the better the reinforcing effect. Therefore, the research on the preparation and performance of the aluminum-based composite material reinforced by the nano-particles has become one of the research targets of many scholars.

AlN and AlB₂The particles have the advantages of high hardness, high elastic modulus, low expansion coefficient, lower density and the like, and are widely applied to the reinforcing phase of the metal matrix composite material. Traditional aluminum-based composite material of particle reinforcement is mostly single-phase particle reinforcement, easily causes the granule to distribute unevenly, and the reinforcing effect is relatively poor and the cost is higher. Therefore, the performance of the single-phase particle-reinforced aluminum matrix composite is greatly affected.

Disclosure of Invention

The invention aims to provide an AlN and AlB synthesized by simple process aiming at the defects of the existing preparation method of the particle reinforced aluminum matrix composite material₂The preparation method of the biphase particle reinforced aluminum matrix composite material has the advantages of uniform particle distribution, tight combination with a matrix interface and controllable generation amount. The method is mainly characterized in that the BN nanosheet and the aluminum matrix are completely reacted in the sintering process after the high-energy ball milling to generate AlN and AlB in situ₂And extruding the aluminum-based composite material cooperatively enhanced by the particles to obtain a composite material block.

the technical scheme is as follows:

a preparation method of an in-situ generated AlN and AlB2 dual-phase particle reinforced aluminum matrix composite material comprises the following steps:

(1) the reactant raw materials are aluminum powder and boron nitride nanosheets;

(2) according to the mass ratio of the aluminum powder to the boron nitride nanosheets of 96:4, filling the aluminum powder and the BN nanosheets into a ball milling tank, introducing high-purity argon, and uniformly mixing the aluminum powder and the BN nanosheets by ball milling for 6 hours at the ball milling speed of 500 r;

(3) putting the ball-milled powder into a grinding tool, and performing cold press molding;

(4) Sintering the cold-pressed block at high temperature of 800-900 ℃ for 3-5 hours to generate AlN and AlB in situ₂Particles;

(5) Placing the block body after high-temperature sintering in an extrusion device, and extruding at 550 ℃ to obtain AlN and AlB generated in situ₂Particulate synergistically enhanced aluminum matrix composites.

compared with the prior art, the invention has the following advantages:

1. High-energy ball milling and high-temperature sintering in-situ preparation of AlN and AlB₂The aluminum-based composite material with synergistically enhanced particles has the advantages that the synthesized two-phase enhanced particles are uniformly distributed and well combined with a matrix interface, and finally AlN and AlB with excellent performance can be obtained₂Particulate synergistically enhanced aluminum matrix composites.

2. The preparation process is simple and has wide industrial application prospect.

Drawings

FIG. 1 is a high resolution view of the interface between the AlN nanoparticles and the aluminum matrix prepared in example 2;

FIG. 2 AlB prepared in example 2₂the interface of the nano particles and the aluminum matrix is high resolution.

Detailed Description

Example 1:

Weighing 9.6g of aluminum powder (with the purity of 99.5 wt%) and 0.4gBN nanosheet (with the purity of 99.5 wt%) together, filling the mixture into a ball milling tank with the volume of 250ml, and filling the ball milling tank into a ball mill, wherein the ball milling time is 6 hours, and the rotating speed of the ball mill is 400 r;

After the ball milling is finished, taking the powder out of the glove box, putting the powder into a cold-pressing grinding tool, and cold-pressing the powder into a block blank at room temperature under 500 MPa; loading the blank into a tube furnace for high-temperature sintering at 700 ℃ for 1 hour to generate AlN and AlB through in-situ reaction₂Particles;

putting the sintered block into an extrusion device, and carrying out thermal extrusion at 550 ℃ for 50 minutes to obtain AlN and AlB₂particulate synergistically enhanced aluminum matrix composites.

Example 2

Weighing 9.6g of aluminum powder (with the purity of 99.5 wt%) and 0.4gBN nanosheet (with the purity of 99.5 wt%) together, filling the mixture into a ball milling tank with the volume of 250ml, and filling the ball milling tank into a ball mill, wherein the ball milling time is 6 hours, and the rotating speed of the ball mill is 400 r;

after the ball milling is finished, taking the powder out of the glove box, putting the powder into a cold-pressing grinding tool, and cold-pressing the powder into a block blank at room temperature under 500 MPa; loading the blank into a tube furnace for high-temperature sintering at 800 ℃ for 3 hours to generate AlN and AlB through in-situ reaction₂Particles;

Putting the sintered block into an extrusion device, and carrying out thermal extrusion at 550 ℃ for 50 minutes to obtain AlN and AlB₂particulate synergistically enhanced aluminum matrix composites.

As shown in FIG. 1 and FIG. 2, the produced nano AlN and AlB₂the interface between the particles and the aluminum matrix is clean and has close bonding at the atomic level.

Example 3

Weighing 9.6g of aluminum powder (with the purity of 99.5 wt%) and 0.4gBN nanosheet (with the purity of 99.5 wt%) together, filling the mixture into a ball milling tank with the volume of 250ml, and filling the ball milling tank into a ball mill, wherein the ball milling time is 6 hours, and the rotating speed of the ball mill is 400 r;

After the ball milling is finished, taking the powder out of the glove box, putting the powder into a cold-pressing grinding tool, and cold-pressing the powder into a block blank at room temperature under 500 MPa; loading the blank into a tube furnace for high-temperature sintering at 900 ℃ for 3 hours to generate AlN and AlB through in-situ reaction₂Particles;

putting the sintered block into an extrusion device, and carrying out thermal extrusion at 550 ℃ for 50 minutes to obtain AlN and AlB₂particulate synergistically enhanced aluminum matrix composites.

it can be seen that AlN and AlB are generated in situ by high-temperature sintering₂The particles are well combined with the interface of the matrix.

Claims (1)

1. A preparation method of an in-situ generated AlN and AlB2 dual-phase particle reinforced aluminum matrix composite material comprises the following steps:

(1) The reactant raw materials are aluminum powder and boron nitride nanosheets;

(2) According to the mass ratio of 96:4 of the aluminum powder to the boron nitride nanosheets, filling the aluminum powder and the BN nanosheets into a ball milling tank, and uniformly mixing the aluminum powder and the boron nitride nanosheets by ball milling in an inert atmosphere for 6 hours at the rotating speed of 500 r;

(3) Putting the ball-milled powder into a grinding tool, and performing cold press molding;

(4) sintering the cold-pressed block at high temperature of 800-900 ℃ for 3-5 hours to generate AlN and AlB in situ₂Particles;

(5) Placing the block body after high-temperature sintering in an extrusion device, and extruding at 550 ℃ to obtain AlN and AlB generated in situ₂Particulate synergistically enhanced aluminum matrix composites.