CN1417362A

CN1417362A - Prepn of alumina-titanium carbide particle reinforced aluminium-base composite material

Info

Publication number: CN1417362A
Application number: CN 02135971
Authority: CN
Inventors: 于化顺; 闵光辉; 王执福; 冯刚; 宋文启; 张书民; 颜君衡
Original assignee: China Qingqi Group Qufu Pistons Factory; Shandong University
Current assignee: QUFU JINHUANG PISTON CO Ltd; Shandong University
Priority date: 2002-12-11
Filing date: 2002-12-11
Publication date: 2003-05-14
Anticipated expiration: 2022-12-11
Also published as: CN100376705C

Abstract

The present invention relates to the preparation of an alumina-titanium carbide particle reinforced aluminium-base composite material. Powder of at least two of active carbon, graphite, titanium powder, potassium fluorotitanate and aluminium powder is blown by gas mixture of CO2, CH4, Ar or O2 into aluminum alloy melt and reinforcing particle is produced through reation. The present invention solves the problems of bad moistening property and interface reaction between the added particle and matrix alloy and poor performance stability in high temperature use. The material of the present invention is especially suitable for use in cylinder, piston and other high temperature working parts and antiwear parts.

Description

Preparation method of aluminum oxide-titanium carbide particle reinforced aluminum-based composite material

The technical field is as follows: the invention belongs to the field of metal materials, and particularly relates to a preparation method of an aluminum oxide-titanium carbide particle reinforced aluminum matrix composite material.

Background art: the metal matrix composite can simultaneously exert the advantages of a metal matrix and a reinforcing phase, remarkably improve the strength, the elastic modulus, the hardness and the wear resistance, and has wide application prospect in the fields of aerospace, weapons, automobiles and the like. The aluminum-based composite material has low density, high specific strength and high specific rigidity, and is the material with the best application prospect, the most common research and the most rapid development in the metal-based composite material. Various composite material preparation techniques have been developed such as powder metallurgy, preform infiltration (including vacuum infiltration, pressure infiltration, pressureless infiltration), stir casting, composite casting (or semi-solid stir casting), spray co-deposition, in-situ composite, and the like; various reinforcing phases have been studied, including long fibers (e.g., carbon fibers, nylon, etc.), short fibers (e.g., Al)₂O₃SiC, aluminum silicate, etc.), particles (e.g. SiC, B)₄C，AlN，Al₂O₃，TiC，TiB₂Graphite, etc.), as well as various base alloy compositions. Liquid metal infiltration and stir casting are the most studied and used methods at present. However, the pressure or vacuum infiltration method requires a large investment in equipment, causes uneven infiltration due to poor wettability, causes a material to be brittle due to reaction of a liquid with a binder or a reinforcing phase, and makes it difficult to manufacture a part having a complicated structure. Although the stirring casting method has low cost and is suitable for large-scale continuous production, due to the characteristics of particles, surface pollution, gas adsorption and the like, the wetting property of the stirring casting method and the alloy melt is poor, so that the adding and dispersing are difficult, the interface combination is poor, the performance is low, and the process stability is poor. The in-situ compounding method is a composite material preparation method developed in recent years. Because of the in situ formation of the enhancement phase, surface cleaning without contamination, high chemical stability, and large volume fraction and size selectivity are favored. Patent number6290748 discloses in situ generation of TiB using a reduced fluoride flux of alloying elements (Mg, Ca) in Al or aluminum alloys₂The preparation method of the particle reinforced aluminum matrix composite material needs to be completed under the vacuum condition, has high equipment investment and is inconvenient to operate. The chinese patent No. 99116247 discloses a method of making Al by combining a stirring casting method and an in-situ reaction method₂(SO₄)₃Decomposition to Al₂O₃Method for dispersion strengthening aluminum-based composites, but reaction by-products such as SO₂And the like easily cause pollution to the environment.

The invention content is as follows: the invention aims to overcome the defects of the prior art and provide a preparation method of an alumina-titanium carbide particle reinforced aluminum matrix composite material, which has stable process, low production cost and no pollution and can be produced under conventional conditions. The invention is realized by the following modes:

the preparation method of alumina-titanium carbide particle reinforced aluminum-base composite material is characterized by that it utilizes the CO-containing material₂、CH₄、Ar、O₂The mixed gas is characterized in that mixed powder containing at least two combinations of activated carbon, graphite, titanium powder, potassium fluotitanate and aluminum powder is blown into an aluminum alloy melt, reinforced particles are generated through reaction, and then the particle reinforced aluminum matrix composite is obtained through mechanical stirring, modification, refining and casting. The activated carbon and graphite are used for providing carbon element, the titanium powder and the potassium fluotitanate are used for providing titanium element, and the aluminum powder is used as a buffering agent and is used for controlling the reaction speed and the distribution of particles.

The preparation method is also characterized in that the volume content of each component in the mixed gas is CH₄5～50％、Ar5～40％，O₂5～40％CO₂10-80%; the pressure of the mixed gas is 0.02-0.2 Mpa, the gas flow is 0.01-0.1 m³/min。CO₂For supplying element C, CO₂，O₂Used for providing O element, Ar is diluent and used for adjusting the reaction speed and the particle growth speed.

The preparation method of the aluminum oxide-titanium carbide particle reinforced aluminum matrix composite is characterized in that the aluminum alloy melt contains 0.2-2% by mass of titanium, and the temperature of the aluminum alloy melt is 780-900 ℃. The time for generating the reinforced particles through the reaction is 5-20 minutes, and mainly depends on the required particle content.

(1) TiC and Al synthesized by liquid reaction of reinforced phase₂O₃Particles, i.e. mainly the following reaction occurs:

and the reaction of the two products is accelerated by each other, thereby increasing the reaction rate. The reinforcing particle size is 0.1 to 1 μm. By adjusting the reaction temperature, reaction time, composition of the mixed gas, composition of the reaction mixture, etc., the composition of the reaction product to form the reinforcing particles (TiC and Al) can be controlled₂O₃Proportion of (d), particle size, quantity and distribution to meet different use requirements.

The base alloy of the present invention may be selected from any commercial aluminum alloy depending on the application requirements. The aluminum alloy is melted in a resistance heating crucible furnace, and can be carried out under atmospheric conditions.

The invention fundamentally solves the problems of poor wettability of the added particles and the matrix alloy, easy interface reaction, poor performance stability in use under high temperature and the like because the enhanced particles are generated by reaction in the aluminum alloy melt. The generated particles have small size, the floating/sinking speed caused by the difference of specific gravity is small, the segregation is not easy to occur, the production process has high stability, and the mechanical property difference of the casting sample at intervals of 2 hours is less than 5 percent, so that the stable production of large-scale, medium and small parts is facilitated. The reinforced particles have the advantages of fine size, uniform distribution, high thermal stability, no surface pollution and good combination with an aluminum alloy matrix. The room temperature mechanical property, the high temperature mechanical property (300 ℃) and the wear resistance of the material are obviously improved, and the material is particularly suitable for parts working under high temperature conditions such as motorcycle cylinders, automobile cylinders, high-power internal combustion engine pistons and the like, and parts with higher requirements on the wear resistance.

The preparation process of the composite material does not need special equipment (such as stirring, pressurizing, vacuum furnace and the like), can organize production under the conventional aluminum alloy production condition, and has low investment and low production cost.

The specific implementation mode is as follows:

two preferred embodiments of the invention are given below: the first embodiment is as follows: the ZL109 alloy is smelted in a resistance smelting furnace, and the alloy comprises the components of Si12.52, Mg0.85, Cu1.52, Ni1.39, Mn0.18, Zn0.12 and the balance of Al. When the mixture is melted and overheated to 750 ℃, slagging off, modifying, refining and pouring test bars; superheating the alloy melt to 880 deg.C with a mixed gas (CO)₂70% + 30% Ar) A mixed powder (flux 50% + titanium powder 30% + 20% activated carbon) was blown into the alloy melt at a gas pressure of 0.02MPa and a gas flow of 0.01m³And/min for 5 minutes, wherein the adding amount of the mixed powder is 2 percent of the weight of the alloy melt, then modification treatment and refining treatment are carried out, test bars are cast, heat preservation is carried out, and the test bars are cast respectively for 30 minutes, 60 minutes and 120 minutes. Then, T6 treatment was carried out, and a performance test was carried out. The experimental result shows that the room temperature strength of the composite material is 295Mpa, the high temperature strength at 300 ℃ is 136Mpa, the hardness of the composite material is HBS133, and the performances of the matrix alloy are 242Mpa, 82Mpa and HBS98 respectively. The performance is reduced with the prolonged heat preservation time, but even if the heat preservation time is 2 hours, the performance difference is less than 5 percent. For example, the strength at room temperature after 2 hours of heat preservation is 288MPa, the strength at high temperature at 300 ℃ is 130MPa, and the hardness is HBS 127. Therefore, the room temperature strength, particularly the hardness and the high temperature strength of the material after the composite treatment are obviously improved, and the production process has good stability and is convenient for batch production. Example two: smelting titanium-containing Al-Cu alloy in a resistance smelting furnace, wherein the alloy comprises the following components: cu4.65, Mn0.68, Ti0.92, Mg0.03, Si0.12 and the balance of Al. When the alloy is melted and overheated to 750 ℃, slagging off, refining and pouring a test bar; will be provided withThe alloy melt is superheated to 850 ℃ with a gas mixture (CO)₂50% + 50% Ar) was melt processed. Gas pressure 0.03MPa, gas flow 0.015m³Min for 5 min, then refining with argon, casting a test bar, then carrying out T5 treatment, and carrying out performance test. The room temperature strength of the composite material is 482Mpa, the high temperature strength at 300 ℃ is 198Mpa, and the hardness is HBS125, namely the room temperature strength, particularly the hardness and the high temperature strength of the composite material are obviously improved.

Claims

1. The preparation method of alumina-titanium carbide particle reinforced aluminum-base composite material is characterized by that it utilizes the CO-containing material₂、CH₄、Ar、O₂The mixed gas is characterized in that mixed powder containing at least two combinations of activated carbon, graphite, titanium powder, potassium fluotitanate and aluminum powder is blown into an aluminum alloy melt, reinforced particles are generated through reaction, and then the particle reinforced aluminum matrix composite is obtained through mechanical stirring, modification, refining and casting.

2. The method of claim 1, wherein the volume content of each component in the mixed gas is CH₄5～50％、Ar5～40％，O₂5～40％CO₂10-80%; the pressure of the mixed gas is 0.02-0.2 Mpa, the gas flow is 0.01-0.1 m³/min。

3. The method for preparing an alumina-titanium carbide particle-reinforced aluminum matrix composite material as claimed in claim 1, wherein the aluminum alloy melt contains 0.2 to 2 mass% of titanium, and the temperature of the aluminum alloy melt is 780 to 900 ℃.

4. The method for preparing an alumina-titanium carbide particle-reinforced aluminum-based composite material as claimed in claim 1, wherein the time for generating the reinforcing particles by the reaction is 5 to 20 minutes.