CN110444320B - A kind of high-strength and high-conductivity carbon fiber reinforced aluminum matrix composite wire and preparation method thereof - Google Patents

Abstract

The invention provides a high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire and a preparation method thereof, and belongs to the technical field of aluminum-based composite wires. The high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire provided by the invention comprises carbon fiber bundles and an aluminum-based matrix, wherein the carbon fiber bundles are wrapped by the aluminum-based matrix and are soaked among carbon fiber filaments of the carbon fiber bundles. The aluminum-based matrix is filled among the carbon fiber yarns of the carbon fiber bundles in the high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire, the carbon fibers and the aluminum-based matrix are tightly combined, the high-conductivity carbon fiber reinforced aluminum-based composite wire has high conductivity and excellent mechanical property, the tensile strength can reach 114MPa, the high-conductivity carbon fiber reinforced aluminum-based composite wire has certain bending capacity, and wires and cables with different section sizes can be manufactured through subsequent stranding.

Description

A kind of high-strength and high-conductivity carbon fiber reinforced aluminum matrix composite wire and preparation method thereof

technical field

The invention relates to the technical field of aluminum-based composite wires, in particular to a high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wire and a preparation method thereof.

Background technique

High-strength and high-conductivity aluminum alloy wire is an important high-voltage transmission line material, which has been widely used around the world since 1950. However, aluminum alloys have the contradiction that high strength and high conductivity cannot be achieved simultaneously. Table 1 shows several common aluminum alloy wire materials. Among them, the conductivity of 1350 pure aluminum wire can reach 61% IACS, but the tensile strength is only 124MPa; With the increase of the content of alloying elements Mg and Si, the strength of the aluminum alloy increases continuously, but the electrical conductivity decreases significantly. Taking 6061 alloy as an example, by increasing the elements of Mg and Si, combined with a suitable heat treatment process (T6), the tensile strength is improved. The strength can reach 310MPa, but the presence of too many reinforcing particles in the matrix leads to the reduction of the electrical conductivity to 40%, and the excessive power transmission loss seriously restricts the large-scale application of high-strength aluminum alloy wires.

Table 1 Commonly used aluminum alloy wire grades, main strengthening element content and properties

Improving strength while maintaining high electrical conductivity and achieving a good match between electrical conductivity and mechanical properties has always been a hot issue in the field of power materials. Aluminum matrix composites provide new ideas for the research and development of high-strength and high-conductivity aluminum alloy wires. The metal-based cladding material composed of the continuous carbon fiber bundle reinforcement phase as the core layer and the high-conductivity aluminum alloy as the outer layer retains the advantages of low density, high electrical conductivity, good corrosion resistance and processability of the aluminum-based material. with the addition of high strength. The carbon fiber bundles are concentrated in the aluminum alloy core and have little effect on the electrical conductivity of the material, so the composite material can have both high strength and high electrical conductivity. Since the 1990s, Japan, the United States, and China have successively developed carbon fiber composite core aluminum conductors. The core layer is a single mandrel rod made of carbon fiber as the center and covered with glass fiber. to make. Composite wire has strong impact resistance, tensile strength and bending stress. However, the composite mandrel needs to have a certain size and volume ratio, which leads to high stiffness of the composite wire, large cross-section and difficult bending, which affects the process requirements of coiling, stranding and construction.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire and a preparation method thereof. Subsequent stranding produces wires and cables of different cross-sectional dimensions.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The present invention provides a high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wire, comprising carbon fiber bundles and an aluminum-based matrix, wherein the aluminum-based matrix wraps the carbon fiber bundles and is infiltrated between the carbon fiber filaments of the carbon fiber bundles.

Preferably, the diameter of the high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire is 5-15 mm.

Preferably, the volume percentage of the carbon fiber bundles is 1-5%.

Preferably, the aluminum base is aluminum alloy or metal aluminum

The present invention also provides the preparation method of the high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire according to the above technical solution, which includes the following steps:

The carbon fiber bundles are pulled and dipped into the aluminum-based melt, followed by ultrasonic treatment, pulsed magnetic field treatment, indirect cooling, extrusion and direct cooling to obtain high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wires.

Preferably, the ultrasonic direction of the ultrasonic treatment is perpendicular to the carbon fiber bundle, the power of the ultrasonic treatment is ≥300W, and the time is 1-2 min.

Preferably, the direction of the magnetic field lines of the pulsed magnetic field treatment is perpendicular to the carbon fiber bundle, the frequency of the pulsed magnetic field treatment is 1-30 Hz, the pulsed magnetic field intensity is 10-40 mT, and the time is 2-4 min.

Preferably, the deformation amount of the extrusion is 6-10%.

Preferably, the temperature of the circulating water used in the indirect cooling is 10-20°C, and the time of the indirect cooling is 1-2min; the temperature of the cooling water used in the direct cooling is 10-20°C, and the time of the direct cooling is 1-2min .

Preferably, the temperature of the aluminum-based melt is 710-730°C.

The present invention provides a high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wire, comprising carbon fiber bundles and an aluminum-based matrix, wherein the aluminum-based matrix wraps the carbon fiber bundles and is infiltrated between the carbon fiber filaments of the carbon fiber bundles. In the high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire provided by the present invention, an aluminum-based matrix is filled between the carbon fiber filaments of the carbon fiber bundle, and the carbon fiber and the aluminum-based matrix are closely combined, which can improve the electrical conductivity, and has excellent mechanical properties and a tensile strength greater than 114MPa, and has higher flexural strength than pure aluminum wire and similar bendability to pure aluminum wire, so it can be made into wires and cables of different cross-sectional sizes through subsequent stranding.

The present invention also provides a preparation method of the high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire according to the above technical solution, which includes the following steps: pulling the carbon fiber bundle into the aluminum-based melt, and sequentially performing ultrasonic treatment, pulse magnetic field treatment, Through indirect cooling, extrusion and direct cooling, high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wires are obtained. The preparation method is simple, easy to operate, can realize continuous preparation, and is suitable for industrial application.

Description of drawings

Fig. 1 device used for preparing high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire according to an embodiment of the present invention,

1 is the carbon fiber bundle, 2- is the aluminum-based melt, 3 is the positioning roller, 4 is the ultrasonic tool head, 5 is the pulsed magnetic field generator, 6 is the crystallizer, 7 is the extrusion nozzle, 8 is the direct cooling part, 9 It is a traction roller, and 10 is a high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire;

2 is the SEM image of the cross section of the high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wire obtained in Example 1;

Figure 3 Three-point bending samples and three-point bending curves of Example 2 and Comparative Example 1.

Detailed ways

The present invention provides a high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wire, comprising carbon fiber bundles and an aluminum-based matrix, wherein the aluminum-based matrix wraps the carbon fiber bundles and is infiltrated between the carbon fiber filaments of the carbon fiber bundles.

In the present invention, the diameter of the high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire is 5-15 mm, more preferably 10 mm. In the present invention, the high-strength and high-conductivity carbon fiber reinforced aluminum wire composite wire retains a certain deformability, and the above diameter is conducive to making wires and cables of different cross-sectional sizes through subsequent twisting.

In the present invention, the volume percentage of the carbon fiber bundles is preferably 1-5%; the diameter of the carbon fiber filaments is preferably 6-8 μm.

In the present invention, the aluminum-based matrix is an aluminum alloy or metal aluminum; the aluminum alloy is preferably an aluminum alloy containing Mg and/or Si, the content of Mg is preferably <0.3wt%, and the content of Si is preferably <0.2 wt%.

The present invention also provides a preparation method of the high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire according to the above technical solution, comprising the following steps:

The carbon fiber bundles are pulled and dipped into the aluminum-based melt, followed by ultrasonic treatment, pulsed magnetic field treatment, indirect cooling, extrusion and direct cooling to obtain high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wires.

In the present invention, in the ultrasonic treatment process, when the ultrasonic wave propagates in the aluminum-based melt, the tiny bubbles (cavitation nuclei) in the liquid rapidly expand and close under the action of ultrasonic waves, and can release huge energy when they collapse sharply. A micro jet with a speed of 110m/s is generated, and high temperature and high pressure are generated in the local micro area. The strong cavitation is beneficial to improve the wettability of the Al/C system and promote the infiltration of aluminum liquid into the carbon fiber. During the pulsed magnetic field treatment, the pulsed magnetic field generates electromagnetic force, which makes the aluminum-based melt generate periodicity on the carbon fiber bundle. The repeated extrusion of the aluminum-based melt promotes the infiltration process on the one hand, and on the other hand forms an electromagnetic pressure gradient in the melt, which causes forced convection inside the aluminum-based melt, so that the temperature and solute (ie, alloying elements) inside the melt are uniformly distributed. The infiltration effect is improved; during indirect cooling, the outer layer in contact with the cooling equipment is first condensed, and the interior is semi-solidified, and then extruded. The extrusion process promotes the combination of aluminum-based melt and carbon fiber on the one hand, and on the other hand On the one hand, a certain deformation treatment can effectively eliminate casting defects such as pores at the interface, improve the density of the material, and then completely solidify after direct cooling, thereby obtaining high-strength and high-conductivity carbon fiber reinforced aluminum matrix composite wires. In addition, the preparation method provided by the present invention can realize the continuous preparation of high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wires, which is suitable for industrial production.

In the present invention, the ultrasonic direction of the ultrasonic treatment is preferably perpendicular to the carbon fiber bundle, the power of the ultrasonic treatment is preferably ≥300W, and the time (that is, the time for the carbon fiber bundle to pass through the ultrasonic treatment area) is preferably 1-2 min; The frequency of the ultrasonic treatment is preferably 20 kHz; the vertical distance between the ultrasonic tool head of the ultrasonic equipment used for the ultrasonic treatment and the carbon fiber bundle is preferably 10-20 mm. Under the combination of the above ultrasonic power and time, the infiltration effect of the aluminum-based melt is optimal.

In the present invention, the direction of the magnetic field lines of the pulsed magnetic field treatment is preferably perpendicular to the carbon fiber bundle, the frequency of the pulsed magnetic field treatment is preferably 1-30 Hz, the intensity of the pulsed magnetic field treatment is preferably 10-40 mT, and the time (that is, the time for the carbon fiber bundle to pass through the pulsed magnetic field treatment area) is preferably 2 to 4 minutes. In the embodiment of the present invention, in order to obtain the frequency and intensity of the magnetic field treatment, the discharge voltage of the capacitor used in the pulse magnetic field treatment is preferably 700V, the number of turns of the pulse magnetic field generator coil is preferably 80, and the pulse width of a single pulse is preferably 0.5-5ms , the single-pulse power is preferably 0.5 to 5kW. In one cycle of the pulsed magnetic field treatment, the aluminum-based melt is first subjected to a magneto-induced pressure directed towards the carbon fiber bundle, so that the aluminum-based melt is squeezed from around the carbon fiber bundle. When the tensile force occurs, the aluminum-based melt stretches under the action of the tensile force, so that the aluminum-based melt periodically and repeatedly extrudes the carbon fiber bundle, which promotes the infiltration process.

In the present invention, the indirect cooling is preferably performed in a cooling crystallizer, the indirect cooling is preferably cooled by circulating water, and the time of the indirect cooling (ie the time for the carbon fiber bundles to pass through the cooling area) is preferably 1-2 minutes, so The water flow rate of the indirect cooling is preferably 30-50L/h; the temperature of the circulating water is preferably 10-20°C; in the present invention, the indirect cooling can condense the aluminum-based melt in the crystallizer to form a certain The strong shell ensures continuous traction, and at the same time, since the internal aluminum-based melt is still in liquid state, it is conducive to further infiltration of the aluminum-based melt in the subsequent extrusion process.

In the present invention, the deformation amount in the extrusion process is preferably 6-10%. In the present invention, the above-mentioned deformation amount can ensure that the carbon fiber bundle remains intact and does not break, and the unimpregnated area is well filled; at the same time, there is no obvious interface between the carbon fiber filament and the aluminum matrix, and there is no obvious hole ( delamination) defects remain.

In the present invention, the direct cooling method is preferably water spray cooling, the temperature of the cooling water used in the direct cooling is preferably 10-20° C., and the direct cooling time is preferably 1-2 min. In the present invention, direct cooling enables the composite material to be rapidly cooled and completely solidified.

In the present invention, the pulling speed is preferably 30-60 mm/min. In the present invention, the above-mentioned pulling rate can result in a higher yield.

In the present invention, the temperature of the aluminum-based melt is preferably 50 to 80° C. above the melting point of the aluminum-based substrate. In the embodiment of the present invention, when the aluminum-based substrate is metal aluminum, the aluminum-based melt The temperature is preferably 710 ~ 730 ℃. In the present invention, maintaining the high temperature state of the aluminum-based melt is conducive to fully exerting the effects of ultrasonic and pulsed magnetic fields, and promoting the infiltration of carbon fiber bundles by the aluminum-based melt.

The present invention has no special limitation on the device used to realize the above preparation method, and the above process can be implemented. In the embodiment of the present invention, the device shown in FIG. 1 is preferably used to prepare the high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire, as shown in the figure 1 , the device includes a positioning roller 3 , an ultrasonic tool head 4 , a pulsed magnetic field generator 5 , a mold 6 , an extrusion nozzle 7 , a direct cooling member 8 , and a pulling roller 9 . During the use of the device, the carbon fiber bundle is pulled by the traction roller to step, and the carbon fiber bundle 1 enters the aluminum-based melt 2 under the traction of the traction roller. The ultrasonic tool head is set parallel to the carbon fiber bundle, so that the direction of the ultrasonic wave is perpendicular to the carbon fiber bundle. , ultrasonically treat the carbon fiber bundles to infiltrate the carbon fiber bundles with the aluminum-based melt, and then convert them to a direction perpendicular to the ultrasonic tool head after passing through the positioning roller, and step into the pulsed magnetic field treatment area under the action of traction (that is, the pulsed magnetic field generator corresponds to After the pulsed magnetic field treatment, the aluminum-based melt is further infiltrated into the carbon fiber bundle, and then enters the mold for indirect cooling. The outside has been solidified into a shell, but the inside remains semi-solid, and then the material undergoes small-scale deformation under the action of the extrusion nozzle. On the one hand, the extrusion process promotes the combination of the aluminum matrix and the carbon fiber, and on the other hand, certain deformation treatment is effective. Eliminate casting defects such as pores at the interface, improve the density of the material, extrude the material, and perform direct cooling (in the embodiment of the present invention, water spray cooling) to obtain a high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire.

A high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire and a preparation method thereof provided by the present invention are described in detail below with reference to the examples, but they should not be construed as limiting the protection scope of the present invention.

Example 1

Using the device shown in Figure 1 to prepare high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wires, a carbon fiber bundle consisting of 3,000 single carbon fiber filaments with a diameter of 7 μm was immersed in an aluminum solution at 720 °C under the pulling action (the pulling rate was 36 mm/min). During the ultrasonic treatment, the distance between the ultrasonic tool head and the carbon fiber bundle is 10mm, the power of ultrasonic treatment is 300W, the frequency is 20kHz, the length of the ultrasonic region is 60mm, and the time for the carbon fiber bundle to pass through the ultrasonic region is 1.67min; Under the action, it reaches the positioning roller, turns to the direction perpendicular to the ultrasonic tool head, and then enters the pulse magnetic field treatment area for pulse magnetic field treatment. The magnetic field strength is 40mT, and the time to pass through the pulse magnetic field treatment area is 4 minutes; after the pulse magnetic field treatment is completed, the carbon fiber bundles enter the mold under the action of traction for cooling. The temperature of the cooling water is 15 °C, and the water flow in the mold is 40L/ h, the time passed through the crystallizer is 2min. At this time, the outer part of the composite material has formed a condensate shell, and the inner part is not completely cooled. The carbon fiber bundle enters the extrusion nozzle under the action of the traction force and is extruded, and the extrusion deformation amount is 8%. ; Directly cool the formed composite wire from the extrusion nozzle with water at 15°C, and the cooling time is 2 min; after cooling, a high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire with a diameter of 10 mm is obtained.

The SEM image of the cross-section of the high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wire obtained in this example was tested. The result is shown in Figure 2. It can be seen from Figure 2 that the aluminum matrix in the wire obtained in this embodiment is fully filled between the fiber filaments of the carbon fiber bundle, There are no voids in the wire.

Example 2

The high-strength and high-conductivity carbon fiber reinforced aluminum-based composite wire was prepared by the method of Example 1, except that the carbon fiber bundle used was a carbon fiber bundle composed of 20,000 carbon fiber filaments with a diameter of 7 μm.

The tensile strength of the high-strength and high-conductivity carbon fiber-reinforced aluminum-based composite wire obtained in this example was tested according to the method disclosed in the standard number GB/T228.1-2010, and the result was 114 MPa.

Comparative Example 1

A pure aluminum wire with a diameter of 10 mm was prepared under the same conditions.

The tensile strength of the pure aluminum wire obtained in this comparative example was tested according to the method disclosed in the standard number GB/T228.1-2010, and the result was 65MPa.

According to the method disclosed in the standard number GB/T232-2010, a three-point bending test was performed on the wires obtained in Example 2 and Comparative Example 1. The three-point bending samples and three-point bending curves obtained are shown in Figure 3, wherein (a) is the obtained three-point bending test. Point bending the sample, (b) is the resulting bending curve. It can be seen from (a) that the composite wire obtained in this example has similar flexibility to the pure aluminum wire, and can be coiled, twisted and other operations; from (b), it can be seen that the composite wire obtained in Example 2 is the same as the one obtained in Comparative Example 1. The pure aluminum wire has higher bending strength, and a certain bending strength can avoid the wire damage caused by bending during the use of the wire to a certain extent.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. The high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire is characterized by comprising carbon fiber bundles and an aluminum-based matrix, wherein the carbon fiber bundles are wrapped by the aluminum-based matrix and are infiltrated among carbon fiber filaments of the carbon fiber bundles;

the preparation method of the high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire comprises the following steps:

the carbon fiber bundle is drawn and immersed into the aluminum-based melt, and ultrasonic treatment, pulsed magnetic field treatment, indirect cooling, extrusion and direct cooling are sequentially carried out, so that the high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire is obtained;

the indirect cooling is carried out by using circulating water for cooling, the time of the indirect cooling is 1-2 min, and the water flow of the indirect cooling is 30-50L/h; the temperature of the circulating water is 10-20 ℃.

2. The high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire according to claim 1, wherein the diameter of the high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire is 5-15 mm.

3. The high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire as claimed in claim 1 or 2, wherein the volume percentage of the carbon fiber bundles is 1-5%.

4. The high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire according to claim 1 or 2, wherein the aluminum-based substrate is an aluminum alloy or metal aluminum.

5. The preparation method of the high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire according to any one of claims 1 to 4, characterized by comprising the following steps:

the carbon fiber bundle is drawn and immersed into the aluminum-based melt, and ultrasonic treatment, pulsed magnetic field treatment, indirect cooling, extrusion and direct cooling are sequentially carried out, so that the high-strength high-conductivity carbon fiber reinforced aluminum-based composite wire is obtained; the indirect cooling is carried out by using circulating water for cooling, the time of the indirect cooling is 1-2 min, and the water flow of the indirect cooling is 30-50L/h; the temperature of the circulating water is 10-20 ℃.

6. The preparation method according to claim 5, wherein the ultrasonic wave direction of the ultrasonic treatment is perpendicular to the carbon fiber bundle, the power of the ultrasonic treatment is not less than 300W, and the time is 1-2 min.

7. The method according to claim 5, wherein the pulsed magnetic field treatment has a magnetic induction line perpendicular to the carbon fiber bundle, a frequency of 1 to 30Hz, a magnetic field strength of 10 to 40mT, and a time of 2 to 4 min.

8. The method according to claim 5, wherein the extrusion deformation amount is 6 to 10%.

9. The preparation method according to claim 5, wherein the temperature of the circulating water for indirect cooling is 10-20 ℃, and the time for indirect cooling is 1-2 min; the temperature of cooling water for direct cooling is 10-20 ℃, and the time for direct cooling is 1-2 min.

10. The method according to claim 5, wherein the temperature of the aluminum-based melt is 50 to 80 ℃ above the melting point of the aluminum-based substrate.

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