CN116024463A - A kind of high hardness and low friction coefficient aluminum alloy material and preparation method thereof - Google Patents

Abstract

The invention relates to a high-hardness low-friction coefficient aluminum alloy material and a preparation method thereof, which greatly improve the performance of aluminum alloy, in particular to high-hardness low-friction coefficient, and in addition, high strength and elongation are obtained by introducing a small amount of glassy carbon and mixed rare earth elements into an aluminum alloy high-temperature melt, so that the aluminum alloy material can be used for casting without heat treatment.

Description

A kind of high hardness and low friction coefficient aluminum alloy material and preparation method thereof

technical field

technical field

The invention belongs to the technical field of new materials, and in particular relates to an aluminum alloy material and a preparation method thereof.

Background technique

Aluminum alloy has low density. Specific stiffness, high specific strength, good thermal and electrical conductivity, good plasticity, and small expansion coefficient are widely used in many fields. However, aluminum alloys have disadvantages such as low hardness, poor wear resistance, and high friction coefficient. Aluminum alloy is a relatively soft material, which is easy to wear and produce defects. It is difficult to use under high hardness requirements, such as bolts, nuts, screws and other parts with severe friction and wear. The hardness range of aluminum alloy is between Vickers 110-135, which is far lower than that of steel parts. Improving the hardness of aluminum alloy to replace steel with aluminum can greatly expand the application range of aluminum alloy. There are many factors that determine the performance of materials, and the performance of metal materials is mainly affected by the organizational structure. Aluminum alloy is widely used because of its light weight, easy processing and forming, and superior economy. Aluminum itself has the characteristics of high elongation. Because it needs to meet the die-casting process, it must have mold release, fluidity, and various mechanical properties. must meet the standard, the current mainstream die-casting aluminum alloys need heat treatment to increase the elongation to more than 10%. The purpose of heat treatment is to improve the strength, hardness and corrosion resistance of aluminum alloy.

Aluminum alloy heat treatment technology is to select a certain heat treatment specification, control the heating rate to rise to a certain corresponding temperature when heat treating aluminum alloy products, keep it for a certain period of time, and cool it at a certain speed to change the structure of the alloy. The specific process and mechanism include annealing, quenching and aging treatment, among which annealing is to remove the internal stress of the casting and promote the spheroidization of part of the silicon crystal of the Al-Si alloy, thereby effectively improving the plasticity of the alloy. Quenching is solid solution treatment and rapid cooling treatment, the purpose is to fix the strengthening phase. Solution treatment can fully dissolve various phases in the alloy, strengthen the solid solution, and improve the toughness and corrosion resistance of the alloy. Aging treatment is divided into natural aging and artificial aging, which refers to the process of storing materials at room temperature or at a higher temperature for a longer period of time. Generally speaking, after aging treatment, the hardness and strength of aluminum alloys have increased, but the plasticity, Toughness and internal stress are reduced.

Aluminum alloy die castings are not suitable for heat treatment. During the heat treatment process, due to stress release, self-weight and quenching, it is easy to cause quality risks such as deformation and foaming of the castings, and it is not economical and the purpose of the country to promote energy conservation and emission reduction.

In addition, the large-scale integrated die-casting technology that emerged with Tesla has become one of the most popular development trends in the industry, and the promotion and application of integrated die-casting technology requires equipment, molds, processes, materials, etc. to match it. Due to the large projected area of integrated die castings, heat treatment can easily cause dimensional deformation and surface defects of parts. For large integrated parts, it is necessary to bear huge cost risks. Therefore, integrated die castings tend to use heat-free aluminum alloy materials.

Contents of the invention

The object of the present invention is to disclose a high-hardness low-friction aluminum alloy material and a preparation method thereof for the problems in the above-mentioned background technology. A high hardness and low friction coefficient aluminum alloy material is characterized in that it includes silicon, iron, copper, manganese, magnesium and strontium, and also contains a small amount of glassy carbon. The mass percentages of each group are: zirconium 7-12%, glassy carbon 0.1- 1.4%, titanium 0.3-0.7%, rhenium 0.0001-0.2%, cerium 0.0001-0.2%, strontium 0.0001-0.2%, and the rest are aluminum and unavoidable impurities; wherein, the mass percentage of the impurity content is less than 0.15%. Another object of the present invention is to provide a method for preparing the above-mentioned high hardness and low friction coefficient aluminum alloy material. It includes the following preparation steps: use 99.7% or more primary aluminum A00 to heat up and melt, the melting temperature is 650°C-720°C, add zirconium at a percentage of 7-12% after A00 is melted, and heat up to melt, the melting temperature is 730°C-800°C, after the zirconium melts, introduce 0.1-1.4% glassy carbon fine powder into the melt, the particle size of glassy carbon fine powder is 5-1000 nm, stir evenly and then add at a percentage of 0.4-0.7% titanium. After it is melted, aluminum, zirconium, titanium and carbon melts are obtained, the aluminum alloy solution is adjusted to 690°C-720°C, and the rare earth aluminum master alloy is added at a percentage of 0.0001-0.2% of rhenium, cerium, and strontium, and the mold is heated to obtain Aluminum alloy ingots or castings. Due to the introduction of nitrogen element, the aluminum alloy material disclosed by the present invention has high hardness, reaching 150HBW, elongation ≥ 10%, friction coefficient lower than 0.25, and can be used for casting without heat treatment.

Specific implementation method

Example 1

In this embodiment, an aluminum alloy A ₁ is provided, the chemical composition of which is: 7.0% zirconium, 0.1% glassy carbon, 0.4% titanium, 0.02% rhenium, cerium, and strontium, and the rest is aluminum and unavoidable impurities; among them, The mass percentage of the impurity content is less than 0.15%, and the balance is Al. The preparation method of aluminum alloy: use 99.7% and above primary aluminum A00 to heat up and melt, the melting temperature is 650°C, add zirconium at a percentage of 7% after A00 is melted, and heat up to melt, the melting temperature is 730°C, and the zirconium melts Then introduce 0.1% glassy carbon with a particle size of 5 nanometers into the melt, and add titanium at a percentage of 0.4%. After it is melted, a molten product of aluminum, zirconium, titanium and carbon is obtained, the aluminum alloy solution is adjusted to 690°C, and a rare earth aluminum master alloy is added at a percentage of 0.0001% of rhenium, cerium, and strontium, and the obtained aluminum alloy A ₁ The aluminum alloy ingots are sent to the side furnace of the die-casting machine for melting and die-casting production. The die-casting process parameters are: casting temperature 700°C, mold preheating temperature 260°C, casting boost pressure 300MPa, injection speed 4m/s. The die-casting sample obtained in this example is a thin-walled casting (thickness 3mm), with a measured hardness of 82HBW, an elongation of 11%, and a coefficient of friction of 0.25.

Example 2

In this embodiment, an aluminum alloy A ₂ is provided, the chemical composition of which is: 9.6% zirconium, 0.8% glassy carbon, 0.5% titanium, 0.1% rhenium, cerium, and strontium, and the rest is aluminum and unavoidable impurities; among them, The mass percentage of the impurity content is less than 0.15%, and the balance is Al. The preparation method of aluminum alloy: use 99.7% and above primary aluminum A00 to heat up and melt, the melting temperature is 650°C, add zirconium at a percentage of 9.6% after A00 is melted, and heat up to melt, the melting temperature is 730°C, and the zirconium melts Introduce 0.8% glassy carbon fine powder into the melt afterward, the particle size of glassy carbon fine powder is 100 nanometers, then add titanium by the percentage of 0.5%. After it is melted, aluminum, zirconium, titanium and carbon melts are obtained, and the aluminum alloy solution is adjusted to 700°C, and a rare earth aluminum master alloy is added at a percentage of 0.1% of rhenium, cerium, and strontium, and the obtained aluminum alloy _A2 is The aluminum alloy ingots are sent to the side furnace of the die-casting machine for melting and die-casting production. The die-casting process parameters are: casting temperature 700°C, mold preheating temperature 260°C, casting boost pressure 300MPa, injection speed 4m/s. The die-casting sample obtained in this example is a thin-walled casting (thickness 3mm), the measured hardness is 102HBW, the elongation is 11%, and the friction coefficient is 0.22.

Example 3

In this example, an aluminum alloy _A3 is provided, the chemical composition of which is: 12.0% zirconium, 1.4% glassy carbon, 0.7% titanium, 0.02% rhenium, cerium, and strontium, and the rest is aluminum and unavoidable impurities; among them, The mass percentage of the impurity content is less than 0.15%, and the balance is Al. The preparation method of aluminum alloy: use 99.7% and above primary aluminum A00 to heat up and melt, the melting temperature is 650°C, add zirconium at a percentage of 12% after A00 is melted, and heat up to melt, the melting temperature is 730°C, zirconium melts Then introduce 1.4% glassy carbon into the melt, the particle size of glassy carbon is 1000 nm, and then add titanium at a percentage of 0.7%. After it is melted, aluminum, zirconium, titanium and carbon melts are obtained, and the aluminum alloy solution is adjusted to 690°C, and a rare earth aluminum master alloy is added at a percentage of 0.2% of rhenium, cerium, and strontium, and the obtained aluminum alloy A ₃ The aluminum alloy ingots are sent to the side furnace of the die-casting machine for melting and die-casting production. The die-casting process parameters are: casting temperature 700°C, mold preheating temperature 260°C, casting boost pressure 300MPa, injection speed 4m/s. The die-casting sample obtained in this example is a thin-walled casting (thickness 3mm), the measured hardness is 150HBW, the elongation is 13%, and the friction coefficient is 0.18.

Claims (5)

1. The high-hardness low-friction-coefficient aluminum alloy material is characterized by comprising the following components in percentage by mass: 7-12% of zirconium, 0.1-1.4% of glassy carbon, 0.3-0.7% of titanium, 0.0001-0.2% of rhenium, 0.0001-0.2% of cerium, 0.0001-0.2% of strontium and the balance of aluminum and unavoidable impurities, wherein the mass percentage of the impurity content is less than 0.15%.

2. A process for preparing high-hardness low-friction-coefficient aluminium alloy material includes such steps as heating to smelting raw Al (A00) at temp (650-720 deg.C) to 7-12% of Zr, heating to 730-800 deg.C, smelting Si, adding fine glass-carbon powder and 0.4-0.7% of Ti. And after the aluminum, zirconium, titanium and carbon are melted, obtaining aluminum, zirconium, titanium and carbon melts, adjusting the temperature of the aluminum alloy solution to 690-720 ℃, adding an aluminum rare earth intermediate alloy into the aluminum alloy solution according to the percentage of 0.0001-0.2% of rhenium, cerium and strontium, and heating a die to obtain an aluminum alloy cast ingot or casting.

3. According to the preparation method of the high-hardness low-friction coefficient aluminum alloy material, the mass fraction of the glassy carbon fine powder is 0.1-1.4%, and the particle size is 5-1000 nanometers.

4. According to the preparation method of the high-hardness low-friction-coefficient aluminum alloy material, the hardness of the prepared aluminum alloy material can reach 120HBW, the friction coefficient is lower than 0.25, and the elongation is more than or equal to 10%.

5. According to the method for preparing the high-hardness low-friction-coefficient aluminum alloy material in claim 2, the prepared aluminum alloy material can be used for casting without heat treatment.