CN1094987C

CN1094987C - Process for preparing al-base composite material

Info

Publication number: CN1094987C
Application number: CN99116247A
Authority: CN
Inventors: 欧阳柳章; 隋贤栋; 罗承萍
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 1999-06-21
Filing date: 1999-06-21
Publication date: 2002-11-27
Anticipated expiration: 2019-06-21
Also published as: CN1238391A

Abstract

The present invention relates to a process for preparing aluminum-base composite materials, which is characterized in that the existing general smelting equipment for aluminum alloy is adopted to enable Al2 (SO4)3 to generate Al2O3 dispersion reinforced aluminum-base composite materials through decomposition reaction by combining a stirring casting method and an in-situ reaction method. The process enables interfaces between an additional reinforced body and a basal body to have good compatibility, and enables particles of the reinforced body to be distributed uniformly; the prepared composite material has the advantages of immediate use after conventional heat treatment, low porosity and stable performance, simultaneously has the advantages of low preparation cost and simple process, and can realize mass industrial production.

Description

Preparation method of aluminum-based composite material

The invention relates to a preparation method of an aluminum-based composite material, belonging to the technical field of synthesis of metal-based composite materials by a reaction casting method.

The aluminum matrix composite is prepared by adopting a method of adding a reinforcement, and the reinforcement effect is seriously influenced due to the physical and chemical incompatibility between the reinforcement and a matrix; meanwhile, the metal liquid is difficult to wet the external particles, the performance of the composite material is also influenced by the interface reaction between the external particles and the matrix, and the preparation cost of the method is high. These problems greatly restrict the research, popularization and application of aluminum matrix composite materials. The in-situ reaction method is another method for preparing metal matrix composite materials appearing in recent years, and is referred to in the text of "the progress of preparing metal matrix composite materials by in-situ reaction composite method" of Lichunyu et al (Material engineering, 1995, 11 th edition), because the method directly reacts to generate the reinforcement from the matrix, the combination between the reinforcement and the matrix is better, and the particles are fine and uniform. However, the method is limited to preparation of a few of particle-reinforced composite materials such as TiC, TiB, AlN and the like, and has high requirements on equipment and complex process, so that the production cost is high, and the composite materials can be used by secondary processing.

The invention aims to overcome and solve the problems of physical and chemical incompatibility between an external reinforcement and a matrix, difficult wetting of external particles by metal liquid, interfacial reaction between the external particles and the matrix and the like in the prior art for preparing the aluminum-based composite material, and provides a preparation method of the aluminum-based composite material with good interface compatibility between the reinforcement and the matrix by combining a stirring casting method and an in-situ reaction method.

The method of the invention is realized by the following technical scheme: the method utilizes the conventional aluminum alloy smelting equipment, firstly heats and melts the aluminum alloy, and raises the temperature to be more than 950 ℃; adding Al into the melt according to the mass percent of 5-40%₂(SO₄)₃Stirring the powder until no bubbles emerge; cooling the melt to 650-750 deg.c, and extruding to cast. In order to remove oil and water of crystallization, to reduce hydrogen absorption and to avoid casting defects as much as possible, Al may be first used₂(SO₄)₃The powder is heated for 1 to 3 hours at the temperature of 400 to 600 ℃. In order to reduce the requirements on equipment, the temperature of the aluminum alloy melt can be raised to 950-1100 ℃. The principle of the method of the invention is as follows: combining stirring casting method and in-situ reaction method to make Al₂(SO₄)₃The powder is rapidly and spontaneously decomposed into Al at the temperature of more than 950 DEG C₂O₃And SO₃I.e. by

Because the size of the ceramic particles generated by the decomposition reaction reaches submicron level and the interface compatibility with the matrix is good,therefore, compared with the existing externally added particle reinforced composite material, the composite material has higher strength and modulus and good high-temperature performance. At the same time, SO is decomposed₃Continuously react with the molten aluminum, namely

Al₂O₃In-situ synthesis of dispersion-strengthened aluminum-based composite material, and SO generated by reaction₂The melt can be refined and degassed, and the defects of uneven particle distribution, high porosity, unstable performance and the like in the particle reinforcement body are further improved.

Compared with the prior art, the method of the invention has the following advantages and beneficial effects:

1. the method is based on the existing aluminum alloy smelting process, combines a stirring casting method and an in-situ reaction method, adopts the existing conventional aluminum alloy smelting equipment, and adopts the raw material Al₂(SO₄)₃The composite material can be used after conventional heat treatment, and the defects of high equipment requirement, complex process, high production cost, secondary processing requirement of the composite material, availability and the like of a common in-situ reaction method are greatly overcome, so that the preparation cost is low, the stirring casting process is simple, secondary processing is not required, and large-scale industrial production can be realized.

2. By the method of the present invention, Al₂O₃Can be in a wide range by Al₂(SO₄)₃The addition amount is adjusted, the particle size of the reinforcement can reach submicron level, the compatibility with the matrix interface is good, and simultaneously, the SO is used₂The reinforcing body has the advantages of uniform particle distribution, low porosity and stable performance of the composite material.

3. The aluminum-based composite material prepared by the method has the advantages of high wear resistance, high toughness and wide application prospect.

The embodiment of the method of the invention is as follows:

example one

First 235 g of Al₂(SO₄)₃Heating the powder at 600 deg.C for 2 hr; simultaneously heating 2500 g of aluminum alloy ZL109 to melt, and heating to 950 ℃; adding Al to the melt₂(SO₄)₃Stirring the powder until no bubbles emerge; cooling the melt to 700 ℃, and performing extrusion casting molding.

Example two

470 g of Al are added₂(SO₄)₃Heating the powder at 500 deg.C for 1 hr; simultaneously heating 2500 g of aluminum alloy Al-9Si to melt, and heating to 980 ℃; adding Al to the melt₂(SO₄)₃Stirring the powder until no bubbles emerge; cooling the melt to 650 ℃, and performing extrusion casting molding.

EXAMPLE III

First 1000 g of Al₂(SO₄)₃Heating the powder at 400 deg.C for 3 hr; simultaneously heating 2500 g of aluminum alloy Al-6Cu to melt, and heating to 1100 ℃; adding Al to the melt₂(SO₄)₃The powder is prepared by mixing the components of the powder,stirring until no bubbles emerge; and cooling the melt to 750 ℃, and performing extrusion casting molding.

The porosity of the aluminum matrix composite prepared by the three embodiments is 0.8 percent at most, and the aluminum matrix composite has the load of 150N, the rotating speed of 400r/min and the rotating speed of 20^#Under the condition of engine oil lubrication, the abrasion time is 30min, and the abrasion performance of the material is shown in table 1. Under the conditions of 50N load, 400r/min rotating speed and dry grinding, the abrasion timeis 30min, and the abrasion performance of the material is shown in Table 2. TABLE 1

Sample number	ZL109	ZL109+5％Al₂O₃	Al-9Si+10％Al₂O₃	Al-6Cu+20％Al₂O₃
Sample number	ZL109	ZL109+5％Al₂O₃	Al-9Si+10％Al₂O₃	Al-6Cu+20％Al₂O₃	Wear volume (mm)³)	0.613	0.175	0.191	0.192
Coefficient of friction	0.025	0.014	0.017	0.016	Wear volume (mm)³)	0.613	0.175	0.191	0.192

TABLE 2

Sample number	ZL109	ZL109+5％Al₂O₃	Al-9Si+10％Al₂O₃	Al-6Cu+20％Al₂O₃
Sample number	ZL109	ZL109+5％Al₂O₃	Al-9Si+10％Al₂O₃	Al-6Cu+20％Al₂O₃	Wear volume (mm)³)	26.27	3.76	4.25	3.98
Coefficient of friction	0.23	0.13	0.17	0.17	Wear volume (mm)³)	26.27	3.76	4.25	3.98

As can be seen from tables 1 and 2, compared with the base material, the friction coefficient of the composite material is reduced, and the wear resistance is improved and is 4-7 times that of the base material.

Claims

1. A preparation method of an aluminum-based composite material is characterized in that the conventional aluminum alloy smelting equipment is utilized, firstly, the aluminum alloy is heated and melted, and the temperature is raised to more than 950 ℃; adding Al into the melt according to the mass percent of 5-40%₂(SO₄)₃Stirring the powder until no bubbles emerge; cooling the melt to 650-750 deg.c, and extruding to cast.

2. The method of claim 1, wherein Al is first added₂(SO₄)₃The powder is heated for 1 to 3 hours at the temperature of 400 to 600 ℃.

3. The method for preparing an aluminum matrix composite according to claim 1 or 2, wherein the aluminum alloy is heated and melted, and the temperature is raised to 950 ℃ to 1100 ℃.