CN114774728A - Wear-resistant aluminum alloy and preparation method thereof - Google Patents

Abstract

The invention relates to a wear-resistant aluminum alloy and a preparation method thereof, belonging to the technical field of nonferrous metals. The aluminum alloy comprises the following chemical components in percentage by mass: 10.4 to 11.8% of Si, 1.5 to 2.5% of Zr, 1.2 to 2.2% of Ti, 0.05 to 0.1% of Cu, 1.2 to 1.7% of Sn, 0.5 to 0.7% of Mn, 1.4 to 2.4% of Nb, 0.07 to 0.2% of Fe, 0.03 to 0.15% of Ni, 0.05 to 0.15% of Cr, 0.14 to 0.22% of V, 0.2 to 0.25% of Mo, and the balance of Al. The preparation method comprises the steps of firstly carrying out mechanical alloying by high-energy ball milling, and then carrying out microwave sintering, low-temperature rolling, vacuum annealing treatment and magnetic field cryogenic treatment. The invention optimizes the contents of elements such as silicon, zirconium, copper, nickel, manganese and the like, adds chromium, vanadium, molybdenum and tin elements, realizes the forced solid solution among atoms of different elements by means of mechanical alloying, and applies a microwave sintering technology, a low-temperature rolling technology and a magnetic field deep cooling technology to refine crystal grains, improve compactness, form deformation stress reinforcement and improve the hardness and wear resistance of the aluminum alloy.

Description

A kind of wear-resistant aluminum alloy and preparation method thereof

technical field

The invention belongs to the field of aluminum alloy materials, and particularly relates to a novel high wear-resistant aluminum alloy and a preparation method thereof.

Background technique

Aluminum alloy has low density, but relatively high strength, close to or surpassing high-quality steel, good plasticity, can be processed into various profiles, has excellent electrical conductivity, thermal conductivity and corrosion resistance, widely used in industry, second only to steel However, the wear resistance and hardness of aluminum alloys are generally lower than those of other alloys, which leads to a limited range of applications.

With the increasing demand for energy in various countries in the world, materials with low density, high specific strength and specific stiffness have been paid more and more attention by designers and material scientists. , magnesium alloys, lithium alloys and titanium alloys, etc.; due to the rich resources of aluminum, and the characteristics of aluminum alloys with low density, large strength-to-weight ratio, strong corrosion resistance, good processing performance and welding performance, aluminum alloys have been widely used. Used in aviation, aerospace, automobile, machinery and other fields; replacing steel with aluminum can greatly reduce the weight of parts, save energy, reduce costs and reduce environmental pollution.

For aviation and aerospace products, an important part of improving the performance of aircraft and missiles is to reduce the weight of their structural components; aluminum alloy, as one of the main structural materials of aviation products, is suitable for casting production with complex shapes, high specific strength requirements, Parts with uniform overall performance are required; in the modern automobile industry, due to energy, environmental and safety reasons, the requirements for lightweight automobiles are becoming more and more urgent; as the preferred material for lightweight automobiles, aluminum alloys have been widely used in automobiles. Chassis, body, engine, steering system, brakes and various accessories.

However, the aluminum alloy itself as a material for mechanical parts has defects such as low hardness, poor wear resistance, high friction coefficient, and not easy lubrication, which greatly limit the application range of aluminum alloys; because the surface wear resistance of aluminum alloys is poor. , resulting in a shortened service life of the workpiece; and due to the high friction coefficient of the aluminum alloy surface, it not only accelerates its own wear, increases the energy loss, but also leads to the wear of the dual material; therefore, improving the tribological properties of the aluminum alloy surface is conducive to Save energy, reduce costs, increase productivity and economic efficiency.

In recent years, in order to improve the tribological properties of aluminum alloy surfaces, many scholars have carried out some surface treatments on aluminum alloys. These surface treatment methods mainly include: surface spraying, magnetron sputtering, laser cladding, bonded solid lubricants, anodes Oxidation and micro-arc oxidation, etc.; although the surface spraying process is relatively simple, the hardness, compactness and bonding force of the obtained film are usually difficult to achieve the desired effect; magnetron sputtering and laser cladding often require higher processing temperatures , it is easy to cause the degradation of the substrate, and the cost of these two processes is too high; the solid lubricant film layer bonded on the aluminum alloy substrate does not have a certain hardness, which is not suitable for heavy-duty working conditions; anodized film The thickness and hardness of the layer are not enough, and the pretreatment process is complicated, and the treatment process has strict requirements on temperature; because of the special film-forming principle and film-forming process of micro-arc oxidation, the prepared film inevitably has micropores and microcracks , rough surface, poor acid corrosion resistance of the main phase, etc., which limit the improvement of the performance of the micro-arc oxidation film.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a novel high wear-resistant aluminum alloy and a preparation method thereof, so as to solve the problems of poor wear resistance and low hardness of the existing aluminum alloys.

The purpose of this invention is to realize through the following technical solutions:

A preparation method of wear-resistant aluminum alloy, characterized in that, comprising the following steps:

Step (1) Weighing the aluminum alloy powder: the powders of Si, Zr, Ti, Cu, Sn, Mn, Nb, Fe, Ni, Cr, V, Mo are weighed and mixed according to the following mass percentages, 10.4-11.8% Si, 1.5-2.5% Zr, 1.2-2.2% Ti, 0.05-0.1% Cu, 1.2-1.7% Sn, 0.5-0.7% Mn, 1.4-2.4% Nb, 0.07-0.2% Fe, 0.03-0.15% Ni, 0.05-0.15% Cr, 0.14-0.22% V, 0.2-0.25% Mo, the balance is Al; the particle size of the powder is 100-200 mesh;

Step (2) high-energy ball milling alloying: the mixed metal powder is loaded into a zirconia ball mill jar, the ball mill jar is evacuated, and the alloyed aluminum alloy powder is obtained after ball milling and drying with a planetary ball mill;

Step (3) cold isostatic pressing: put the aluminum alloy powder prepared in step (2) into a rubber mold for cold isostatic pressing, with a static pressure of 400 MPa and a holding time of 30 minutes to obtain a green body;

Step (4) microwave sintering: put the green body obtained in step (3) into a microwave sintering muffle furnace for microwave sintering;

Step (5) low-temperature rolling: put the microwave sintered sample obtained in step (4) into liquid nitrogen for immersion, and then perform low-temperature rolling;

Step (6) vacuum annealing: vacuum annealing the sample after the low temperature rolling in step (5);

Step (7) Magnetic field cryogenic treatment: put the sample obtained in step (6) into a magnetic field for cryogenic treatment.

Further, in the step (2), when grinding the balls, the ball grinding balls are proportioned according to the mass ratio of 1:2:4 according to the number of 15mm large balls, 10mm medium balls and 5mm small balls, and the ball-to-material ratio is 5:1 , the ball milling medium is anhydrous ethanol, and the ratio of anhydrous ethanol to powder is 3:5.

Further, the ball milling speed is 320-400 r/min, and the ball-milling time is 8-12 hours; when the ball-milling is finished, the prepared alloy powder is dried in a vacuum drying oven at a drying temperature of 70-80 °C and a drying time of 36 hours.

Further, the parameters used in the microwave sintering in step (4) are: the heating rate is 35-50° C./min, the sintering temperature is 570-700° C., and the sintering time is 60-80 min.

Further, in step (5), before rolling, the sample is immersed in liquid nitrogen for 10-20 minutes, so that the temperature of the sample is lowered to the temperature of liquid nitrogen; during the rolling process, liquid nitrogen is sprayed on the roll; The amount of deformation is 10% to 70%.

Further, the vacuum annealing described in step (6) is: adopting step-by-step annealing under vacuum conditions, the first step is at 400～500°C, the holding time is 1～3h, then air-cooled to room temperature, and the second step is at 220～500°C 300℃, keep warm for 20-40min, and then air-cool to room temperature.

Further, the magnetic field used in the magnetic field cryogenic treatment described in step (7) is a pulsed magnetic field, the magnetic induction intensity is 2.5-3T, and the number of pulses is 30 times.

Further, the temperature of the magnetic field cryogenic treatment in step (7) is -110°C to -196°C, and the cryogenic time is 24 to 48 hours.

The wear-resistant aluminum alloy prepared by the preparation method.

The beneficial effects of the present invention are:

1) The present invention improves the hardness and wear resistance of the alloy through multi-element microalloying, and adds elements of silicon, zirconium, titanium, copper, tin, manganese, niobium, iron, nickel, chromium, vanadium and molybdenum to the alloy, which can improve the hardness and wear resistance of the alloy. Significantly improve the wear resistance of aluminum alloys. Compared with the existing aluminum-silicon cast wear-resistant aluminum alloys and aluminum-zinc-magnesium-copper series and aluminum-copper series high-strength wear-resistant aluminum alloys, it does not use rare earths such as yttrium, strontium and other rare earths with less resources and high prices. Alkali metal modifiers reduce environmental pollution and cost; the present invention optimizes the content of elements such as silicon, zirconium, copper, nickel, and manganese, and adds chromium, vanadium, molybdenum, and tin elements, which are combined with aluminum, silicon, zirconium, Copper, nickel and manganese are easy to form high-strength, tough and wear-resistant alloys by mechanical alloying; the tensile strength of the material is increased to more than 800MPa, which is about 30% higher than the existing high-strength aluminum alloys. The alloy has high hardness and fine dispersion strengthening phase. , The wear resistance is significantly higher than that of the seven series wear-resistant aluminum alloy, about 18.09%.

2) Compared with the traditional melting preparation method, the mechanical alloying used in the present invention is a kind of forced solid solution between atoms of different elements through non-equilibrium means, and finally, fine grains, composition and structure can be obtained. The compound technology of uniformly distributed alloy powder; the advantage of mechanical alloying is that it can effectively solve the problem of combining them without considering the melting point of the raw materials, whether the melting temperature is too high or the melting point difference is too large, and the obtained The alloy composition is uniform and there is no segregation phenomenon. The alloy prepared by this method does not have the problem of shrinkage porosity, and the grain size of the alloy is relatively small, which can effectively improve the hardness and wear resistance of the aluminum alloy.

3) In the present invention, the microwave sintering technology is used, which has the advantages of low temperature and fast sintering, and can form a uniform fine-grained structure and high density inside the material, thereby improving the material properties; There is no temperature difference, the particles are uniformly distributed in the powder, there are almost no defects such as segregation, and the aluminum alloy properties are greatly improved.

4) In the present invention, liquid nitrogen low-temperature rolling is used. With the increase of rolling deformation, the strength and plasticity of the material are improved at the same time. The improvement of strength is due to the increase of dislocation density caused by plastic deformation, and the improvement of plasticity is Because of the high density of pre-existing dislocations under stress, nanocrystals and subcrystals are formed.

5) In the present invention, it is used to promote the formation of twin crystals and sub-crystal structures, promote phase transformation, and improve the density of the material, thereby improving the wear resistance of the material.

Detailed ways

In order to make those skilled in the art better understand the technical solutions of the present invention, these embodiments are only for illustrating the present invention, rather than limiting the scope of the present invention in any way; The procedures and methods are conventional methods well known in the art.

The microhardness test of aluminum alloy was carried out on a digital microhardness tester; the wear test of aluminum alloy was carried out on a MMU-5GA microcomputer-controlled high-temperature friction and wear tester; sample size: 4.8mm×12.7mm pin sample, for The abrasive material is GCr15 steel processed into a D54mm×8mm disk sample; dry sliding friction and wear are used, the experimental temperature is 25°C, the load is 150N, the rotation speed is 50r/min, and the wear time is 20min; the wear resistance is based on wear loss. Express.

Example 1:

The composition of the wear-resistant aluminum alloy in this embodiment is: 10.4% Si, 1.5% Zr, 1.2% Ti, 0.05% Cu, 1.2% Sn, 0.5% Mn, 1.4% Nb, 0.07% Fe, 0.03% Ni, 0.05% Cr, 0.14% V, 0.2% Mo, and the balance is Al.

The preparation method of the wear-resistant aluminum alloy of the present invention adopts the following steps:

Step (1), prepare aluminum alloy powder:

The powders of Si, Zr, Ti, Cu, Sn, Mn, Nb, Fe, Ni, Cr, V, and Mo are prepared according to the mass percentage composition of claim 1, and the particle size of all these powders is 100-200 mesh, The purity is 99.9% grade.

Step (2), high-energy ball milling alloying:

The metal powder prepared according to step (1) is put into a zirconia ball mill jar, then the ball mill jar is evacuated, and a planetary ball mill is used for ball milling. Small ball: 5mm, the ratio of ball mill balls is 1:2:4 by mass, the ratio of ball to material is 5:1, the ball milling medium is anhydrous ethanol, the ratio of anhydrous ethanol to powder is 3:5, and the ball milling speed is 400r /min, the ball milling time is 10 hours; when the ball milling is finished, the prepared alloy powder is dried in a vacuum drying oven, the drying temperature is 75 °C, and the drying time is 36 h to obtain alloyed powder.

Step (3), cold isostatic pressing:

The alloyed powder prepared in step (2) is put into a rubber mold for cold isostatic pressing with a static pressure of 400 MPa and a pressure holding time of 30 minutes to obtain a green body.

Step (4), microwave sintering:

The green body obtained in step (3) is put into a microwave sintering muffle furnace for microwave sintering, the sintering temperature is 570°C, the sintering time is 80min, and the heating rate is 35°C/min.

Step (5), low temperature rolling:

The microwave sintered sample obtained in step (4) was soaked in liquid nitrogen for 10 minutes, and then low-temperature rolling was performed, and the rolling deformation amount was 20%.

Step (6), vacuum annealing:

The sample after low-temperature rolling in step (5) is subjected to vacuum annealing treatment, and step-by-step annealing is adopted under vacuum conditions. 30min, then air-cooled to room temperature.

Step (7), magnetic field cryogenic treatment:

Put the sample obtained in step (6) into a magnetic field for cryogenic treatment, the magnetic field is a pulsed magnetic field, the magnetic induction intensity is 2.5T, and the number of pulses is 30 times; the cryogenic treatment temperature is -110°C, and the cryogenic time is 24h.

A friction and wear test and a microhardness test were performed on the aluminum alloy prepared in Example 1, and the experimental results are shown in Table 1.

Example 2:

The composition of the wear-resistant aluminum alloy of this embodiment is: 10.9% Si, 2% Zr, 1.7% Ti, 0.07% Cu, 1.5% Sn, 0.6% Mn, 1..7% Nb, 0.15% Fe, 0.12% Ni, 0.1% Cr, 0.19% V, 0.21% Mo, and the balance is Al.

The preparation method of the wear-resistant aluminum alloy of the present invention adopts the following steps:

Step (1), prepare aluminum alloy powder:

The powders of Si, Zr, Ti, Cu, Sn, Mn, Nb, Fe, Ni, Cr, V, and Mo are prepared according to the mass percentage composition of claim 1, and the particle size of all these powders is 100-200 mesh, The purity is 99.9% grade.

Step (2), high-energy ball milling alloying:

The metal powder prepared according to step (1) is put into a zirconia ball mill jar, then the ball mill jar is evacuated, and a planetary ball mill is used for ball milling. Small ball: 5mm, the ratio of ball mill balls is 1:2:4 by mass, the ratio of ball to material is 5:1, the ball milling medium is anhydrous ethanol, the ratio of anhydrous ethanol to powder is 3:5, and the ball milling speed is 400r /min, the ball milling time is 10 hours; when the ball milling is finished, the prepared alloy powder is dried in a vacuum drying oven, the drying temperature is 75 °C, and the drying time is 36 h to obtain alloyed powder.

Step (3), cold isostatic pressing:

The alloyed powder prepared in step (2) is put into a rubber mold for cold isostatic pressing with a static pressure of 400 MPa and a pressure holding time of 30 minutes to obtain a green body.

Step (4), microwave sintering:

The green body obtained in step (3) is put into a microwave sintering muffle furnace for microwave sintering, the sintering temperature is 620°C, the sintering time is 70min, and the heating rate is 40°C/min.

Step (5), low temperature rolling:

The microwave sintered sample obtained in step (4) was soaked in liquid nitrogen for 15 minutes, and then low-temperature rolling was performed, and the rolling deformation amount was 45%.

Step (6), vacuum annealing:

The sample after low-temperature rolling in step (5) is subjected to vacuum annealing treatment, and step-by-step annealing is adopted under vacuum conditions. 20min, then air-cooled to room temperature.

Step (7), magnetic field cryogenic treatment:

The sample obtained in step (6) is placed in a magnetic field for cryogenic treatment, the magnetic field is a pulsed magnetic field, the magnetic induction intensity is 3T, and the number of pulses is 30 times; the cryogenic treatment temperature is -196°C, and the cryogenic time is 36h.

A friction and wear test and a microhardness test were performed on the aluminum alloy prepared in Example 2, and the experimental results are shown in Table 1.

Comparative Example 1:

In order to illustrate the technical effect of the present invention, commercialized 7075 aluminum alloy is selected to carry out a performance comparison experiment. Comparative example 1 adopts a commercially available 7075 deformed aluminum alloy, and carries out a friction and wear test and a microhardness test. The method is detailed in the specific embodiments. The experimental results are shown in Table 1.

Comparative Example 2:

Using the exact same aluminum alloy composition as in Example 1, the aluminum alloy casting billet was prepared by the traditional method of producing wear-resistant aluminum alloy by smelting alloying-air refining-semi-continuous casting-T6 heat treatment. The same performance test experiment as in Example 1 was carried out, and the experimental comparison data of Comparative Example 2 were obtained, which were summarized in Table 1. From the comparison results, it can be seen that the wear resistance and hardness of the material were significantly improved by using the preparation method of the present invention.

Comparative Example 3:

The same 7075 aluminum alloy composition as in Comparative Example 1 was used, and only the preparation method of the present invention was used. The preparation process was exactly the same as that in Example 2, and a 7075 aluminum alloy block was obtained. 2. The same performance test experiment was carried out, and the experimental comparison data of Comparative Example 3 was obtained, which was summarized in Table 1. It can be seen from the comparison results that the wear resistance and hardness of the material were significantly improved by the preparation method of the present invention.

Table 1 Friction and wear properties and microhardness of different aluminum alloys

It can be seen from the comparison of the performance test results of the examples in Table 1 and the comparative examples that the wear-resistant aluminum alloy of the present invention and the preparation method are relatively comparable to the current commercial wear-resistant aluminum alloys in terms of composition and preparation method. The advantages reflect the progress of the present invention, that is, according to the present invention, an aluminum alloy with high wear resistance can be prepared.

The embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or All modifications belong to the protection scope of the present invention.

Claims (10)

1. The method for preparing the wear-resistant aluminum alloy of claim 1, comprising the steps of:

weighing aluminum alloy powder: weighing and mixing powders of Si, Zr, Ti, Cu, Sn, Mn, Nb, Fe, Ni, Cr, V and Mo according to the following mass percent, wherein the powders comprise 10.4-11.8% of Si, 1.5-2.5% of Zr, 1.2-2.2% of Ti, 0.05-0.1% of Cu, 1.2-1.7% of Sn, 0.5-0.7% of Mn, 1.4-2.4% of Nb, 0.07-0.2% of Fe, 0.03-0.15% of Ni, 0.05-0.15% of Cr, 0.14-0.22% of V, 0.2-0.25% of Mo and the balance of Al;

step (2) high-energy ball milling alloying: putting the mixed metal powder into a zirconia ball milling tank, vacuumizing the ball milling tank, and carrying out ball milling and drying by adopting a planetary ball mill to obtain alloyed aluminum alloy powder;

and (3) cold isostatic pressing: putting the aluminum alloy powder prepared in the step (2) into a rubber mold for cold isostatic pressing to prepare a green body;

and (4) microwave sintering: placing the green body obtained in the step (3) into a microwave sintering muffle furnace for microwave sintering;

step (5) low-temperature rolling: soaking the microwave sintering sample obtained in the step (4) in liquid nitrogen, and then rolling at low temperature;

step (6) vacuum annealing: carrying out vacuum annealing treatment on the sample rolled at the low temperature in the step (5);

step (7) magnetic field cryogenic treatment: and (4) placing the sample obtained in the step (6) into a magnetic field for cryogenic treatment.

2. The method of producing a wear-resistant aluminum alloy according to claim 1, wherein: the particle size of the powder in the step (1) is 100-200 meshes.

3. The method of making a wear resistant aluminum alloy of claim 1, wherein: in the step (2), during ball milling, the ball milling balls are prepared according to the mass ratio of 15mm large balls, 10mm medium balls and 5mm small balls of 1:2:4, the ball-material ratio is 5:1, the ball milling medium is absolute ethyl alcohol, and the ratio of the absolute ethyl alcohol to the powder-material ratio is 3: 5.

4. The method of making a wear resistant aluminum alloy of claim 1, wherein: in the step (2), the ball milling speed is 320-400 r/min, and the ball milling time is 8-12 hours; and after the ball milling is finished, drying the prepared alloy powder by using a vacuum drying oven at the drying temperature of 70-80 ℃ for 36 hours.

5. The method of producing a wear-resistant aluminum alloy according to claim 1, wherein: the parameters adopted by the microwave sintering in the step (4) are as follows: the heating rate is 35-50 ℃/min, the sintering temperature is 570-700 ℃, and the sintering time is 60-80 min.

6. The method of making a wear resistant aluminum alloy of claim 1, wherein: soaking the sample in liquid nitrogen for 10-20 min before rolling in the step (5) to reduce the temperature of the sample to the temperature of the liquid nitrogen; spraying liquid nitrogen on the roller in the rolling process; the rolling deformation is 10-70%.

7. The method of producing a wear-resistant aluminum alloy according to claim 1, wherein: the vacuum annealing in the step (6) comprises the following steps: and (2) annealing step by step under a vacuum condition, wherein the first step is at 400-500 ℃ for 1-3 h, then air cooling is carried out to room temperature, the second step is at 220-300 ℃, heat preservation is carried out for 20-40 min, and then air cooling is carried out to room temperature.

8. The method of producing a wear-resistant aluminum alloy according to claim 1, wherein: the magnetic field used in the magnetic field cryogenic treatment in the step (7) is a pulse magnetic field, the magnetic induction intensity is 2.5-3T, and the pulse number is 30 times.

9. The method of making a wear resistant aluminum alloy of claim 1, wherein: the temperature of the magnetic field cryogenic treatment in the step (7) is-110 ℃ to-196 ℃, and the cryogenic time is 24-48 hours.

10. The wear-resistant aluminum alloy prepared by the preparation method of any one of claims 1 to 9.