A high-elongation 6201 porcelain aluminum alloy based on TiB2 particle reinforcement, a preparation method and application thereof

Abstract

The application provides a TiB2 particle reinforced high-elongation 6201 porcelain aluminum alloy, a preparation method and application thereof, and the preparation method of the TiB2 particle reinforced high-elongation 6201 porcelain aluminum alloy comprises the following steps: smelting: TiB2 / Al precursors and Al-3% B intermediate alloy are proportioned according to a B / Ti stoichiometric ratio of 2.0-2.1, and are simultaneously put into a smelting furnace for heat preservation reaction, then alloying, degassing and ultrasonic melt treatment are carried out, and then the melt is poured into a steel mold; homogenization treatment; extrusion; solid solution treatment, room temperature water quenching; rolling; and artificial aging treatment, so that the TiB2 particle reinforced high-elongation 6201 porcelain aluminum alloy is prepared. The preparation process is simple, and the cost is low. The prepared conductive aluminum material has excellent mechanical properties, wherein the tensile strength is close to 370 MPa, and the elongation after fracture is more than 10%, and can be used for preparing high-elongation power transmission conductors.

Description

Technical Field

[0001] This invention relates to materials technology, and more particularly to a high elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement, its preparation method, and its applications. Background Technology

[0002] Aluminum and aluminum alloys are commonly used as conductors for overhead power transmission lines due to their high specific strength and good electrical conductivity. The round transmission wires are formed through rolling and drawing processes during manufacturing. However, aluminum and aluminum alloys undergo significant deformation, often resulting in severe fiber texture, which deteriorates the elongation of the aluminum conductor and can even lead to breakage during drawing. Therefore, finding a new approach to reduce the evolution and intensification of fiber texture, and thus improve the elongation of aluminum conductors without reducing strength, has become an urgent problem to be solved. Summary of the Invention

[0003] The purpose of this invention is to address the problem of low elongation and easy breakage of traditional aluminum alloys during drawing. It proposes a method for preparing a high-elongation 6201 ceramic-coated aluminum alloy based on TiB2 particle reinforcement. This method is simple, low-cost, and the resulting TiB2 particle-reinforced 6201 ceramic-coated aluminum alloy exhibits excellent strength and high elongation, making it suitable for preparing high-elongation power transmission conductors.

[0004] To achieve the above objectives, the technical solution adopted by this invention is: a method for preparing a high-elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement, comprising the following steps:

[0005] Step (1) Melting: a. Mix TiB2 / Al precursor (TiB2 exists in granular form, content is 5%, mass fraction, the same below) and Al-3%B master alloy (B mainly exists in AlB2 granules) according to a B / Ti stoichiometric ratio of 2.0 to 2.1, place them together in a graphite clay crucible, melt and heat to 750 to 780°C in a pit-type melting resistance furnace, stir to make it fully mixed and react, reaction time is 20 to 30 minutes, add Al-10%Mg master alloy and Al-12%Si master alloy for alloying; b. Pass high-purity argon gas to degas the melt for 3 to 10 minutes; c. Apply ultrasonic melt treatment for 3 to 5 minutes; d. Pour the melt into a steel mold, pouring temperature is 720 to 750°C;

[0006] Step (2) Homogenization treatment: Place the ingot in a heat treatment furnace and keep it at 540-570℃ for 12-24 hours. Then cool it with the furnace to 250-300℃ and air cool it.

[0007] Step (3) Extrusion: The ingot is preheated to 350-380℃ in a muffle furnace and then extruded at a speed of 0.2-0.5m / min and an extrusion ratio of 1:18-25.

[0008] Step (4) Solution treatment: Place the extrusion rod in a heat treatment furnace for solution treatment at a temperature of 550-570°C for 30-60 minutes, followed by quenching.

[0009] Step (5) Rolling: The solution-treated extrusion bar is rolled at room temperature using a twin-roll mill with a total reduction of 70-80% and a roll speed of 100-150 r / min;

[0010] Step (6) Aging: Artificial aging treatment is carried out in an aging furnace at a temperature of 150-190℃ for 0.5-5 hours.

[0011] Further, the TiB2 / Al precursor mentioned in step (1) is Al-TiB2 base material (aluminum material containing 5% titanium diboride, produced in industrial ton-scale); the master alloy includes high metallurgical quality Al-3%B master alloy, Al-10%Mg master alloy and Al-12%Si master alloy. The amount of Al-3%B master alloy added needs to ensure that the B / Ti stoichiometric ratio in the melt meets 2.0 to 2.1. The mass fractions of Al-10%Mg master alloy and Al-12%Si master alloy added are 7-9% and 5-6%, respectively. In step (1), the Al-3%B master alloy needs to be heated simultaneously with the TiB2 / Al precursor, while the Al-10%Mg master alloy and Al-12%Si master alloy need to be added after the heat preservation reaction of the former two are completed, to avoid the influence of alloying elements on the reaction process.

[0012] Furthermore, in step (1), the contents of Ti and B elements in the TiB2 / Al precursor are 3.5-3.6% and 1.4-1.5%, respectively.

[0013] Furthermore, the TiB2 / Al precursor and all intermediate alloys mentioned in step (1) are dried in a drying oven for 30 to 60 minutes before smelting at a temperature of 200 to 220°C.

[0014] Furthermore, the composition of the high elongation 6201 ceramic-aluminum alloy (containing 2% TiB2 ceramic particles) used in step (1) is 1.3-1.4% Ti, 0.6-0.7% B, 0.6-0.9% Mg, 0.5-0.9% Si, with Fe impurity content less than 0.2% and the content of each other impurity less than 0.1%.

[0015] Furthermore, in step (4), the quenching is room temperature water quenching.

[0016] Furthermore, step (4) requires strict control of the heat preservation temperature and heat preservation time of the solution treatment to prevent recrystallization and coarsening of the grains in the extruded structure.

[0017] Another objective of this invention is to disclose a high-elongation 6201 ceramic-aluminum alloy reinforced with TiB2 particles, prepared using the method described above. This TiB2 particle-reinforced high-elongation 6201 ceramic-aluminum alloy exhibits excellent mechanical properties, with a tensile strength approaching 370 MPa and an elongation after fracture exceeding 10%.

[0018] Furthermore, the high elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement comprises the following components by weight ratio:

[0019] TiB2 ceramic phase 1.8–2.2%;

[0020] Mg 0.6–0.9%;

[0021] Si 0.5-0.9%;

[0022] The Fe content of impurities is less than 0.2%;

[0023] The content of each other impurity is less than 0.1%;

[0024] The balance is Al.

[0025] Furthermore, the preferred high-elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement comprises the following components by weight proportions:

[0026] 2% TiB2 ceramic phase;

[0027] Mg 0.86%;

[0028] Si 0.6%;

[0029] The Fe content of impurities is less than 0.2%;

[0030] The content of each other impurity is less than 0.1%;

[0031] The balance is Al.

[0032] Another object of the present invention discloses the use of a high elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement in the field of power transmission conductors.

[0033] This invention relates to a high-elongation 6201 ceramic-coated aluminum alloy reinforced with TiB2 particles, its preparation method, and its applications. This invention generates TiB2 ceramic particles in situ within the aluminum alloy, which not only significantly refines the grain size but also enhances the strength of the aluminum conductor from the perspectives of second-phase strengthening and dispersion strengthening. Simultaneously, the addition of ceramic particles also improves the stiffness of the aluminum conductor. Furthermore, appropriate composition control ensures that the addition of TiB2 ceramic particles hardly impairs the conductor's conductivity. This material is called a ceramic-coated aluminum alloy. Specifically, this invention has the following advantages compared to existing technologies:

[0034] 1. This invention is based on the integration of TiB2 particle-reinforced high-elongation 6201 ceramic-coated aluminum alloy with the traditional aluminum wire preparation process, which is easy to promote and has low cost, and can be mass-produced on a large scale.

[0035] 2. The high elongation 6201 ceramic-coated aluminum alloy reinforced with TiB2 particles of this invention has a tensile strength of 355.2 MPa (national standard requires greater than 325 MPa) and an elongation of 13.7% (national standard requires greater than 3%) compared with the 6201 conductive aluminum alloy prepared by traditional process (GB / T 23308-2009), which is far superior to the mechanical properties of 6201 conductive aluminum alloy prepared by traditional process.

[0036] 3. The 2% TiB2 particle-reinforced high-elongation 6201 ceramic-aluminum alloy prepared by the method of the present invention has a 5.0 MPa increase in tensile strength (reaching 270.4 MPa) and a 2.6% increase in elongation (reaching 25.0%) compared with 6201 conductive aluminum alloy in the extrusion state. In the extrusion / rolling state, the tensile strength increases by 13.7 MPa (reaching 368.9 MPa), and the elongation does not decrease significantly.

[0037] 4. During the drawing process of aluminum alloy wires, the large deformation in multiple passes generates severe fibrous texture, which in turn deteriorates the elongation and formability of the aluminum wires. The reason for this is that coarse grains are prone to generating fibrous texture during deformation. This invention uses the method of adding TiB2 ceramic particles to greatly refine the grains and introduce a large number of grain boundaries. At the same time, the hard ceramic particles can hinder the evolution of texture to a certain extent. Furthermore, by using extrusion / rolling methods, the resulting ceramic-coated aluminum wires not only have superior tensile strength but also achieve an elongation of over 10%. Attached Figure Description

[0038] Figure 1The images show scanning electron microscope (SEM) images of the deformed microstructures of the 6201 aluminum alloy prepared in Comparative Example 1 and Example 1, and the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles. Figure (a) shows the deformed microstructure of the 6201 aluminum alloy in the extruded state, Figure (b) shows the deformed microstructure of the 6201 aluminum alloy in the extruded / rolled state, Figure (c) shows the deformed microstructure of the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles in the extruded state, and Figure (d) shows the deformed microstructure of the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles in the extruded / rolled state.

[0039] Figure 2 Engineering stress-engineering strain curves of 6201 aluminum alloy prepared for Comparative Example 1 and Example 1 and 6201 ceramic-coated aluminum alloy with high elongation reinforced with 2% TiB2 particles.

[0040] Figure 3 The tensile strength of the 6201 aluminum alloy prepared in Comparative Example 1 and Example 1 and the high elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles.

[0041] Figure 4 Elongation after fracture of 6201 aluminum alloy prepared for Comparative Example 1 and Example 1 and 6201 ceramic-coated aluminum alloy with high elongation reinforced with 2% TiB2 particles.

[0042] Figure 5 The images show scanning electron microscope (SEM) images of the fracture morphology of the 6201 aluminum alloy prepared in Comparative Example 1 and Example 1, and the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles. Figure (a) shows the fracture morphology of the 6201 aluminum alloy in the extruded state, Figure (b) shows the fracture morphology of the 6201 aluminum alloy in the extruded / rolled state, Figure (c) shows the fracture morphology of the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles in the extruded state, and Figure (d) shows the fracture morphology of the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles in the extruded / rolled state. Detailed Implementation

[0043] The present invention will be further described below with reference to the embodiments:

[0044] Comparative Example 1

[0045] This comparative example discloses a method for preparing a high elongation transmission conductor based on 6201 aluminum alloy, including the following steps:

[0046] Step (1) Raw material preparation: 1) Industrial pure aluminum (purity > 99.7%); 2) Al-10%Mg master alloy, mass fraction of 8.88%; 3) Al-12%Si master alloy, mass fraction of 5.03%; 4) The raw materials are dried in a drying oven for 30 minutes at 200℃ before smelting; 5) The composition of the high elongation transmission conductor used to prepare 6201 aluminum alloy is 0.86%Mg, 0.6%Si, Fe content less than 0.2%, and the content of each other impurity less than 0.1%.

[0047] Step (2) Melting: 1) Place industrial pure aluminum into a graphite clay crucible and heat it to 750°C in a pit-type melting resistance furnace; 2) Add Al-10%Mg and Al-12%Si master alloys for alloying; 3) Introduce high-purity argon gas to degas the melt for 5 minutes; 4) Apply ultrasonic melt treatment for 3 minutes; 5) Pour the melt into a steel mold at a pouring temperature of 720°C.

[0048] Step (3) Homogenization treatment: Place the ingot in a heat treatment furnace and keep it at 570℃ for 12 hours. Then cool it with the furnace to 250-300℃ and air cool it.

[0049] Step (4) Extrusion: The ingot is preheated to 380°C in a muffle furnace and then extruded at a speed of 0.2 m / min and an extrusion ratio of 1:20.

[0050] Step (5) Solution treatment: Place the extrusion rod into a heat treatment furnace for solution treatment at a temperature of 560°C for 30 minutes, followed by water quenching at room temperature.

[0051] Step (6) Rolling: The solution-treated extrusion bar is rolled at room temperature using a twin-roll mill with a total reduction of 75% and a roll speed of 150 r / min.

[0052] Step (7) Aging: Artificial aging treatment is carried out in an aging furnace at a temperature of 170℃ for 4 hours.

[0053] Example 1:

[0054] This embodiment discloses a method for preparing a high-elongation transmission conductor based on TiB2 particle-reinforced 6201 ceramic-aluminum alloy, comprising the following steps:

[0055] Step (1) Raw material preparation: 1) TiB2 / Al precursor (aluminum containing 5% titanium diboride) produced at the industrial ton level, with Ti and B content of 3.56% and 1.44% respectively; 2) High metallurgical quality Al-3%B master alloy, the amount added should make the B / Ti stoichiometric ratio in the melt meet 2.0~2.1; 3) Al-10%Mg master alloy, mass fraction of 8.88%; 4) Al-12%Si master alloy, mass fraction of 5.03%; 5) The raw materials are dried in a drying oven for 30 min at 200℃ before smelting; 6) The composition of the TiB2 particle-reinforced high elongation 6201 ceramic aluminum alloy is 1.37%Ti, 0.63%B, 0.86%Mg, 0.6%Si, Fe impurity content is less than 0.2%, and the content of each other impurity is less than 0.1%.

[0056] Step (2) Melting: 1) Place the TiB2 / Al precursor and Al-3B master alloy together into a graphite clay crucible and melt and heat to 750°C in a pit-type melting resistance furnace. Stir to ensure thorough mixing and reaction for 30 minutes; 2) To avoid the influence of alloying elements on the reaction process, after the first two have been kept at a constant temperature, add Al-10%Mg master alloy and Al-12%Si master alloy for alloying; 3) Introduce high-purity argon gas to degas the melt for 5 minutes; 4) Apply ultrasonic melt treatment for 3 minutes; 5) Pour the melt into a steel mold at a pouring temperature of 720°C.

[0057] Step (3) Homogenization treatment: Place the ingot in a heat treatment furnace and keep it at 570℃ for 12 hours. Then cool it with the furnace to 250-300℃ and air cool it.

[0058] Step (4) Extrusion: The ingot is preheated to 380°C in a muffle furnace and then extruded at a speed of 0.2 m / min and an extrusion ratio of 1:20.

[0059] Step (5) Solution treatment: Place the extrusion rod into a heat treatment furnace for solution treatment at a temperature of 560°C for 30 minutes, followed by water quenching at room temperature.

[0060] Step (6) Rolling: The solution-treated extrusion bar is rolled at room temperature using a twin-roll mill with a total reduction of 75% and a roll speed of 150 r / min.

[0061] Step (7) Aging: Artificial aging treatment is carried out in an aging furnace at a temperature of 170℃ for 4 hours.

[0062] Combining Comparative Example 1 and Example 1, the mechanical property test results and microstructure characterization are as follows: Figures 1-5 As shown:

[0063] Figure 1These are scanning electron microscope (SEM) images of the deformed microstructures of 6201 aluminum alloy and a high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles. Figure (a) shows the deformed microstructure of the 6201 aluminum alloy in the extruded state, Figure (b) shows the deformed microstructure of the 6201 aluminum alloy in the extruded / rolled state, Figure (c) shows the deformed microstructure of the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles in the extruded state, and Figure (d) shows the deformed microstructure of the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles in the extruded / rolled state. As can be seen from the images, after extrusion, the grains of the 6201 aluminum alloy are significantly elongated along the extrusion direction, forming discontinuous Al5FeSi phases along the grain boundaries. After rolling, the grains undergo a certain degree of tilting, resulting in the formation of discontinuous Al5FeSi phases along the grain boundaries, rather than being strictly parallel to the extrusion direction as in the extruded state. After extrusion, the grains of the TiB2 particle-reinforced high-elongation 6201 ceramic-coated aluminum alloy are also significantly elongated along the extrusion direction. The TiB2 ceramic particles gathered at the grain boundaries are strictly parallel to the extrusion direction, and no large-scale agglomeration or other structures detrimental to mechanical properties are observed. Moreover, compared with 6201 aluminum alloy, the content of Al5FeSi phase is significantly reduced. After rolling by the extrusion bar, the particles are still mainly parallel to the rolling direction, but their distribution is more dispersed, and the segregation state at the grain boundaries is somewhat improved.

[0064] Figure 2 The figures show the engineering stress-strain curves of the prepared 6201 aluminum alloy and the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles. The figures show that both materials have lower strength and higher elongation in the extruded state, while the strength increases significantly after rolling deformation, and the elongation decreases. Comparing the two materials, it can be found that the addition of TiB2 ceramic particles in the extruded state leads to a significant increase in elongation. This is because TiB2 ceramic particles can effectively refine the grains, resulting in grain refinement strengthening. Simultaneously, the tensile strength also increases to some extent. Besides grain refinement strengthening, this is also due to the fact that TiB2 ceramic particles can play a role in second-phase strengthening and dispersion strengthening. Especially after rolling deformation, TiB2 ceramic particles exhibit a better strengthening effect, and the elongation does not decrease significantly.

[0065] Figure 3 The figure shows the tensile strength of the prepared 6201 aluminum alloy and the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles. As can be seen from the figure, the addition of TiB2 ceramic particles in the extrusion state increases the tensile strength from 265.5 MPa to 270.4 MPa, and after rolling deformation, the tensile strength increases from 355.2 MPa to 368.9 MPa.

[0066] Figure 4The figure shows the elongation after fracture of the prepared 6201 aluminum alloy and the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles. As can be seen from the figure, the addition of TiB2 ceramic particles in the extrusion state increases the elongation from 22.4% to 25.0%. After rolling deformation, the elongation decreases to some extent, but is still as high as 11.2%.

[0067] Figure 5 These are scanning electron microscope (SEM) images of the fracture morphologies of the prepared 6201 aluminum alloy and the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles. Figure (a) shows the fracture morphology of the 6201 aluminum alloy in the extruded state, Figure (b) shows the fracture morphology of the 6201 aluminum alloy in the extruded / rolled state, Figure (c) shows the fracture morphology of the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles in the extruded state, and Figure (d) shows the fracture morphology of the high-elongation 6201 ceramic-coated aluminum alloy reinforced with 2% TiB2 particles in the extruded / rolled state. It is evident from the images that the obvious dimples in the tensile fracture surfaces of both materials indicate that the fracture mode is ductile fracture. In both the extruded and extruded / rolled states, the addition of TiB2 ceramic particles makes the dimples very fine, indicating that the addition of hard particles significantly refines the deformable microstructure of the matrix, thereby improving the strength of the material. Compared to the extrusion state, the dimples after rolling deformation are further refined and, unlike the equiaxed dimples in the extrusion state, they are elliptical in shape.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high-elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement, characterized in that, Includes the following steps: Step (1) Melting: a. Mix TiB2 / Al precursor and Al-3%B master alloy according to a B / Ti stoichiometric ratio of 2.0~2.1, place them together in a graphite clay crucible, melt and heat to 750~780℃ in a pit-type melting resistance furnace, stir to make them fully mixed and react, the reaction time is 20~30 min, add Al-10%Mg master alloy and Al-12%Si master alloy for alloying; b. Degas the melt by introducing high-purity argon gas for 3~10 min; c. Apply ultrasonic melt treatment for 3~5 min; d. Pour the melt into a steel mold at a pouring temperature of 720~750℃; Step (2) Homogenization treatment: Place the ingot in a heat treatment furnace and keep it at 540~570℃ for 12~24 h, then cool it with the furnace to 250~300℃ and air cool it. Step (3) Extrusion: The ingot is preheated to 350~380℃ in a muffle furnace and then extruded. The extrusion speed is 0.2~0.5 m / min and the extrusion ratio is 1:18~25. Step (4) Solution treatment: Place the extrusion rod in a heat treatment furnace for solution treatment at a temperature of 550~570℃ and a holding time of 30~60 min, followed by quenching. Step (5) Rolling: The solution-treated extrusion bar is rolled at room temperature using a twin-roll mill with a total reduction of 70-80% and a roll speed of 100-150 r / min; Step (6) Aging: Artificial aging treatment is carried out in an aging furnace at a temperature of 150~190℃ for 0.5~5 h.

2. The method for preparing high-elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement according to claim 1, characterized in that, In step (1), the mass fractions of Al-10%Mg master alloy and Al-12%Si master alloy added are 7-9% and 5-6%, respectively.

3. The method for preparing high-elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement according to claim 1, characterized in that, In step (1), the contents of Ti and B elements in the TiB2 / Al precursor are 3.5~3.6% and 1.4~1.5%, respectively.

4. The method for preparing high-elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement according to claim 1, characterized in that, The TiB2 / Al precursor and all intermediate alloys mentioned in step (1) are dried in a drying oven for 30-60 minutes before smelting at a temperature of 200-220℃.

5. A high-elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement, characterized in that, It is prepared by any one of the preparation methods described in claims 1-4.

6. The high elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement according to claim 5, characterized in that, The components include the following weight proportions: TiB2 ceramic phase 1.8~2.2%; Mg 0.6~0.9%; Si 0.5~0.9%; The Fe content of impurities is less than 0.2%; The content of each other impurity is less than 0.1%; The balance is Al.

7. The use of the high elongation 6201 ceramic-aluminum alloy based on TiB2 particle reinforcement as described in any one of claims 5-6 in the field of power transmission conductors.

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