阅读说明：本技术 一种轻质高模量铝基复合材料及其制备方法 (Light high-modulus aluminum-based composite material and preparation method thereof ) 是由 高通 刘相法 卞一涵 刘玲玉 于 2021-07-29 设计创作，主要内容包括：本发明属金属基复合材料领域,涉及一种轻质高模量铝基复合材料及其制备方法。该铝基复合材料特征是：铝基体晶粒为亚微米级,尺寸为0.2～1μm；原位生成的AlB-(2)颗粒为亚微米级,尺寸为0.2～1μm,质量百分比为1.4～14,弥散分布在基体晶粒间；原位生成的γ-Al-(2)O-(3)颗粒尺寸为纳米级,尺寸为5～100nm,质量百分比为2.9～29,沿基体晶粒的晶界分布。其制备方法是：将原材料与催化剂高速球磨处理,在冷等静压机中压制成预制体,将预制体加热、挤压,即可得到由γ-Al-(2)O-(3)和AlB-(2)增强的轻质高模量铝基复合材料。本发明工艺简单,制备的材料表面洁净无污染,增强相与基体结合强度高,材料弹性模量可达90～120GPa。(The invention belongs to the field of metal matrix composite materials, and relates to a light high-modulus aluminum matrix composite material and a preparation method thereof. The aluminum matrix composite material is characterized in that: the aluminum matrix crystal grain is submicron grade, and the size is 0.2-1 μm; in situ generated AlB 2 The particles are submicron-sized, have the size of 0.2-1 mu m and the mass percentage of 1.4-14, and are dispersed among the crystal particles of the matrix; in situ generated gamma-Al 2 O 3 The particle size is nano-scale, the size is 5-100 nm, and the mass is hundredThe ratio of the grain size is 2.9-29, and the grain size is distributed along the grain boundary of the matrix grains. The preparation method comprises the following steps: ball-milling the raw materials and the catalyst at a high speed, pressing the raw materials and the catalyst into a prefabricated body in a cold isostatic press, heating and extruding the prefabricated body to obtain the gamma-Al alloy 2 O 3 And AlB 2 A reinforced aluminum matrix composite with light weight and high modulus. The method has the advantages of simple process, clean and pollution-free surface of the prepared material, high bonding strength of the reinforcing phase and the matrix, and elastic modulus of the material up to 90-120 GPa.)

1. A light high-modulus aluminum matrix composite is characterized in that: the aluminum matrix crystal grain is submicron grade, and the size is 0.2-1 μm; in situ generated AlB₂The particles are submicron-sized, have the size of 0.2-1 mu m and the mass percentage of 1.4-14, and are dispersed among the crystal particles of the matrix; in situ generated gamma-Al₂O₃The particle size is nano-scale, the size is 5-100 nm, the mass percentage is 2.9-29, and the particles are distributed along the crystal boundary of the matrix crystal grains.

2. The method for preparing the light high modulus aluminum matrix composite material as claimed in claim 1, which is characterized by comprising the following steps:

(1) preparing the required raw materials according to the following mass percentages: 79.5-97.9 parts of industrial pure aluminum powder with the size less than or equal to 50 microns, 2.0-20.0 parts of boron oxide powder with the size less than or equal to 100 microns and 0.1-0.5 part of magnesium nitride;

(2) weighing the industrial pure aluminum powder, the boron oxide powder and the magnesium nitride in the step (1) according to the proportion, and carrying out high-speed ball milling on the materials for 2-12 h in an argon atmosphere, wherein the rotating speed of a ball mill is more than or equal to 300r/min, and the ball-to-material ratio is set to be 4: 1-8: 1;

(3) degassing and covering the ball-milled material in the step (2), and pressing the ball-milled material into a prefabricated body in a cold isostatic press;

(4) putting the prefabricated body into a heating furnace, preserving heat for 1-6 h at 550-650 ℃, and extruding by using a hot extruder at an extrusion ratio of 5: 1-20: 1 to obtain the gamma-Al alloy₂O₃And AlB₂Particulate reinforced aluminum matrix composites.

Technical Field

The invention belongs to the field of metal matrix composite materials, and relates to a light high-modulus aluminum matrix composite material and a preparation method thereof.

Background

Energy conservation and emission reduction become important ideas for development of high-end manufacturing fields such as aerospace, transportation, national defense and military industry, the rapid development of light weight forces aluminum materials to be accelerated to realize upgrading, and high requirements are provided for the performances such as heat resistance, modulus and the like of traditional aluminum alloys. However, the elastic modulus of aluminum alloy is only about 70GPa, and the elastic modulus of the third generation aluminum-lithium alloy which is a high modulus material does not exceed 90GPa either, and the smelting condition is harsh, the cost is high and the processing formability is poor.

To increase the modulus of aluminum alloys, particle reinforced aluminum matrix composites are receiving increasing attention. The ceramic particles generally have a high melting point and a high modulus of elasticity, and the strengthening effect on the matrix is more significant than that of the alloying elements. At present, most of common particle reinforced aluminum matrix composite preparation methods are external addition methods, but the problem of poor wettability of particle and matrix interface exists. Compared with an external method, the interface bonding strength of the reinforced particles and the aluminum matrix in the aluminum matrix composite material prepared by the endogenous method is high, and the performance advantages of the particles can be better exerted. Among the numerous endogenous systems in situ, AlB₂、Al₃BC. AlN and Al₂O₃The particle density is similar to that of an aluminum matrix, and the high-temperature stability is good, so that the particle reinforcing phase is commonly adopted. However, due to the low solubility of B, C, N and O in aluminum melts, the in situ synthesis of such particles is difficult and often difficult to avoid with other problems. For example, Chinese patent publication No. CN101948978A provides an Al alloy₂O₃Preparation method of nano-particle reinforced aluminum-based composite material by using borax and K₂ZrF₆For reacting mixed salts, the mixed salts are synthesized by a melt direct reaction method, but the involved chemical reaction is complex and can generate K₂NaAlF₆、ZrB₂、AlF₃And ZrO₂Residues and harmful gases of fluoride can be emitted in the preparation process, thereby causing damage to human bodies and equipment.

In addition, different theoretical models are proposed by researchers about the relationship between the microstructure and the elastic modulus of the aluminum-based composite material. It is predicted from the literature (J.Summercales, et al., Composites Part B,2019,160: 167-. In addition, the distribution of the reinforcing phase also has a significant effect on the elastic modulus of the composite, as calculated by theory of the H-S equation (Z. Hashin, et al, Journal of the Mechanics and Physics of Solids,1963,11: 127-. Based on the theory, researchers develop various aluminum-based composite materials, but the improvement range of the elastic modulus is limited and does not exceed 90 GPa.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a light high-modulus aluminum-based composite material and a preparation method thereof.

The invention is realized by the following modes:

a light high-modulus aluminum matrix composite is characterized in that: the aluminum matrix crystal grain is submicron grade, and the size is 0.2-1 μm; in situ generated AlB₂The particles are submicron-sized, have the size of 0.2-1 mu m and the mass percentage of 1.4-14, and are dispersed among the crystal particles of the matrix; in situ generated gamma-Al₂O₃The particle size is nano-scale, the size is 5-100 nm, the mass percentage is 2.9-29, and the particles are distributed along the crystal boundary of the matrix crystal grains.

The preparation method of the composite material is characterized by comprising the following steps:

(1) preparing the required raw materials according to the following mass percentages: 79.5-97.9 percent of industrial pure aluminum powder (the size is less than or equal to 50 mu m), 2.0-20.0 percent of boron oxide powder (the size is less than or equal to 100 mu m) and 0.1-0.5 percent of catalyst (magnesium nitride);

(2) weighing the industrial pure aluminum powder, the boron oxide powder and the catalyst in the step (1) according to the proportion, and carrying out high-speed ball milling on the materials in an argon atmosphere (the rotating speed of a ball mill is more than or equal to 300r/min) for 2-12 h, wherein the ball-material ratio is set to be 4: 1-8: 1;

(3) degassing and covering the ball-milled material in the step (2), and pressing the ball-milled material into a prefabricated body in a cold isostatic press;

(4) putting the prefabricated body into a heating furnace, preserving heat for 1-6 h at 550-650 ℃, extruding by using a hot extruder with the extrusion ratio of 5: 1-20: 1 to obtain the gamma-Al alloy₂O₃And AlB₂Particulate reinforced aluminum matrix composites.

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

Gamma-Al in composite material₂O₃And AlB₂The particles are self-generated in situ, the surface is clean and pollution-free, the wettability with the matrix is good, and the interface bonding strength is high. gamma-Al₂O₃The particles are distributed along the grain boundary of the matrix grains, and can fully play a role of configuration strengthening according to the H-S equation. AlB₂The particles are dispersed and distributed among the crystal grains, and because the size of the particles is similar to that of the crystal grains of the matrix, the effect of improving the elastic modulus of the matrix can be exerted to the maximum extent according to the mixing law. Based on the synergy of the two strengthening effects, the elastic modulus of the composite material can reach 90-120 GPa. The catalyst can reduce the reaction temperature and avoid AlB₂The particles grow into unfavorable morphologies such as needles, rods, etc., and tend to form spheres. Due to gamma-Al₂O₃And AlB₂The density of the particles is lower, and the density of the composite material prepared by the method is less than or equal to 2.7g/cm³. In addition, the method has simple process and low raw material price. The mass percentage of the reinforcing particles can be regulated and controlled by changing the proportion of the industrial pure aluminum powder and the boron oxide powder, and the scale of the reinforcing particles can be controlled by changing the reaction temperature and the heat preservation time, so that the strength and the elastic modulus of the composite material are customized according to the application requirements.

Drawings

FIG. 1 is a schematic view of the microstructure of the composite material of the present invention; in the figure, 1 is aluminum matrix grain, 2 is gamma-Al₂O₃Particles, 3 is AlB₂And (3) granules.

FIG. 2 is an Al-7 AlB prepared according to example 3 of the present invention₂–14.5Al₂O₃Transmission electron microscope photographs of the composite; in the figure, 1 is aluminum matrix grain, 2 is gamma-Al₂O₃Particles, 3 is AlB₂And (3) granules.

Detailed Description

Three preferred embodiments of the present invention are given below.

Example 1

(1) Preparing the required raw materials according to the following mass percentages: commercial purity aluminum powder 97.9 (size about 50 μm), boron oxide powder 2.0 (size about 100 μm), catalyst (magnesium nitride) 0.1;

(2) weighing the industrial pure aluminum powder, the boron oxide powder and the catalyst in the step (1) according to the proportion, and carrying out high-speed ball milling (the rotating speed of a ball mill is 400r/min) on the materials for 2h in an argon atmosphere, wherein the ball-material ratio is set to be 8: 1;

(3) degassing and covering the ball-milled material in the step (2), and pressing the ball-milled material into a prefabricated body in a cold isostatic press;

(4) and (3) putting the prefabricated body into a heating furnace, preserving heat for 6 hours at 550 ℃, and extruding by using a hot extruder at an extrusion ratio of 20: 1.

The gamma-Al can be obtained according to the proportion and the process₂O₃And AlB₂The reinforced light high-modulus aluminum matrix composite material comprises the following components in percentage by mass: al-1.4 AlB₂–2.9Al₂O₃. Matrix grains and AlB₂Particle size of 0.2 to 0.5 μm, Al₂O₃The particle size is 5-30 nm. AlB₂The particles are dispersed and distributed among the matrix grains, and the gamma-Al₂O₃The particles are distributed along the grain boundaries of the matrix grains. The test result shows that: the modulus of elasticity of the composite material is about 91 GPa.

Example 2

(1) Preparing the required raw materials according to the following mass percentages: commercial pure aluminum powder 79.5 (size about 20 μm), boron oxide powder 20 (size about 10 μm), catalyst (magnesium nitride) 0.5;

(2) weighing the pure aluminum powder, the boron oxide powder and the catalyst in the step (1) in proportion, and carrying out high-speed ball milling (the rotating speed of a ball mill is 360r/min) on the materials for 4 hours in an argon atmosphere, wherein the ball-material ratio is set to be 7: 1;

(3) degassing and covering the ball-milled material in the step (2), and pressing the ball-milled material into a prefabricated body in a cold isostatic press;

(4) and (3) putting the prefabricated body into a heating furnace, preserving heat for 4 hours at 580 ℃, and extruding by using a hot extruder at an extrusion ratio of 10: 1.

The gamma-Al can be obtained according to the proportion and the process₂O₃And AlB₂The reinforced light high-modulus aluminum matrix composite material comprises the following components in percentage by mass: al-14 AlB₂–29Al₂O₃. Matrix grains and AlB₂Particle size of 0.4 to 0.8 μm, Al₂O₃The particle size is 10-60 nm. AlB₂The particles are dispersed and distributed among the matrix grains, and the gamma-Al₂O₃The particles are distributed along the grain boundaries of the matrix grains. The test result shows that: the modulus of elasticity of the composite material is about 119 GPa.

Example 3

(1) Preparing the required raw materials according to the following mass percentages: 89.8 parts of industrial pure aluminum powder (size about 10 microns), 10 parts of boron oxide powder (size about 30 microns) and 0.2 part of catalyst (magnesium nitride);

(2) weighing the pure aluminum powder, the boron oxide powder and the catalyst in the step (1) according to the proportion, and carrying out high-speed ball milling (the rotating speed of a ball mill is 500r/min) on the materials for 12h in an argon atmosphere, wherein the ball-material ratio is set to be 4: 1;

(3) degassing and covering the ball-milled material in the step (2), and pressing the ball-milled material into a prefabricated body in a cold isostatic press;

(4) and (3) putting the prefabricated body into a heating furnace, preserving heat for 1h at 650 ℃, and extruding by using a hot extruder at an extrusion ratio of 5: 1.

The gamma-Al can be obtained according to the proportion and the process₂O₃And AlB₂The reinforced light high-modulus aluminum matrix composite material comprises the following components in percentage by mass: al-7 AlB₂–14.5Al₂O₃. Matrix grains and AlB₂Particle size of 0.5 to 1 μm, Al₂O₃The particle size is 20-100 nm. AlB₂The particles are dispersed and distributed among the matrix grains, and the gamma-Al₂O₃Grains of particles along the matrix grainsAnd (4) boundary distribution. The test result shows that: the modulus of elasticity of the composite material is about 105 GPa.

As can be seen from fig. 2: al-7 AlB₂–14.5Al₂O₃The grain size of the composite material is submicron, and submicron AlB is dispersed among the grains₂Particles, grain boundary being nano-grade gamma-Al₂O₃Covered by a particle network.