An electromagnetic stirring-assisted method for preparing TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profiles and the preparation method thereof

Abstract

The present invention discloses an electromagnetic stirring-assisted preparation method for TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profiles and the profiles prepared thereby. The aluminum alloy profiles comprise the following chemical components by weight percentage: 9.0% - 12.0% of Zn, 2.0% - 3.5% of Mg, 0.6% - 2.6% of Cu, 0.06% - 2.0% of Zr, 0.05% - 0.2% of Sc, 1.0% - 3.0% of TiB2, Fe ≤ 0.1%, Si ≤ 0.1%, other impurities ≤ 0.05% individually and ≤ 0.15% in total, with the balance being Al. The yield strength of the bars can reach 790 Mpa and the elongation rate reaches 10%. The prepared profiles can be used in the fields of aviation, aerospace, transportation, consumer electronics, etc., and have broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and particularly relates to a method for preparing TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profiles assisted by electromagnetic stirring and a preparation method thereof. Background Art

[0002] With the increasing urgent demand for lightweight and high-strength structural materials in the future electronic consumer market, high-performance aluminum alloys have become a research hotspot. Currently, the methods for preparing ultra-high-strength aluminum alloys include traditional melting and casting method, rapid solidification / powder metallurgy, and spray forming method. The latter two preparation processes are relatively complex and the preparation cost is also high. At the same time, the semi-finished product specifications are limited by the billets, which to a certain extent affects their development. The traditional melting and casting method has a short process flow, low preparation cost, a complete variety of semi-finished products, and large specifications, and is still the aluminum alloy preparation method with the highest degree of engineering promotion at present.

[0003] Ultra-high aluminum alloys prepared by traditional melting methods mainly adopt the methods of adding master alloying elements or introducing high-modulus particles. However, increasing the content of alloying elements will inevitably exacerbate the element segregation in the prepared materials, easily generate hot cracks or macroscopic segregation in large ingots, thereby reducing the qualified rate and plasticity of products. In recent years, studies have found that some ceramic particles such as ZrB2, TiN, B4C, Al3Ti, SiC, TiB2, TiC, etc. play a crucial role in the solidification behavior, microstructure and properties of aluminum alloys. In particular, TiB2 has received extensive attention due to its stable interface bonding with the Al matrix, good high-temperature stability, and simple preparation method. At present, the methods for introducing TiB2 particles include direct addition and in-situ synthesis in the matrix by the melt self-propagating direct synthesis method.

[0004] Currently, there is already a related patent CN106367644A that introduces TiB2 into Al-Zn-Mg-Cu by the melt self-propagating direct synthesis method. However, when introducing particles by the melt self-propagating direct synthesis method, in addition to the difficulty in controlling the particle size uniformity and dispersibility, the most important thing is that it will introduce by-products such as Al2O3, which affects the further improvement of the alloy strength. The direct addition can ensure the particle uniformity and cleanliness of TiB2 particles, which is crucial for further improving the alloy strength. Therefore, directly adding high-modulus particles has become a relatively simple method, but the micron-sized high-modulus particles directly added are prone to agglomeration in the alloy, which has become a difficulty of this method.

[0005] Therefore, it is necessary to propose a preparation process to solve the above problems, achieve high strength and high ductility of Al-Zn-Mg-Cu alloys, and make them have broad application prospects in the fields of aviation, aerospace, electronic consumption, transportation, etc. Summary of the Invention

[0006] The object of the present invention is to provide, in view of the deficiencies of the prior art, a method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profile assisted by electromagnetic stirring, so as to solve the problem of low elongation of existing ultra-high strength aluminum alloys.

[0007] In the first aspect, the present invention provides a method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profile assisted by electromagnetic stirring, comprising chemical components in the following weight percentages:

[0008] Zn 9.0% - 12.0%, Mg 2.0% - 3.5%, Cu 0.6% - 2.6%, Zr 0.06% - 2.0%, Sc 0.05% - 0.2%, TiB2 1.0% - 3.0%, Fe ≤ 0.1%, Si ≤ 0.1%, other impurities ≤ 0.05% individually, total amount ≤ 0.15%, and the balance is Al.

[0009] In the second aspect, the present invention provides a method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profile assisted by electromagnetic stirring, comprising the following steps:

[0010] Step 1: Weigh materials according to the following weight percentages of chemical components: Zn 9.0% - 12.0%, Mg 2.0% - 3.5%, Cu 0.6% - 2.6%, Zr 0.06% - 2.0%, Sc 0.05% - 0.2%, TiB2 1.0% - 3.0%, Fe ≤ 0.1%, Si ≤ 0.1%, other impurities ≤ 0.05% individually, total amount ≤ 0.15%, and the balance is Al; add the materials except TiB2 particles into an intermediate frequency furnace with electromagnetic stirring. When all the alloy materials are completely melted, add CCl6 and introduce argon for degassing treatment. After repeating the degassing treatment twice, press the aluminum foil package containing TiB2 particles into the melt.

[0011] Step 2: Turn on the magnetic field of the intermediate frequency furnace for stirring, and the stirring lasts for at least 10 min; after the stirring is completed, pour to obtain a cylindrical ingot, and the size of the ingot is

[0012] Step 3: Perform a homogenization process on the ingot cast by electromagnetic-assisted casting. After peeling the homogenized ingot, perform hot extrusion, and control the extrusion ratio at 25 or more.

[0013] Step 4: Subject the extruded profile to solution and aging heat treatments.

[0014] Further, in the above Step 1, melting is carried out in a melting furnace, and the melting temperature is 690°C - 750°C;

[0015] Refine the completely melted metal, and maintain the metal temperature in the range of 710°C - 740°C during refining;

[0016] After refining and purging with argon, it is allowed to stand still, and the standing time is not less than 10 minutes. After standing, the slag is skimmed off.

[0017] After two times of refining, purging with argon and skimming off the slag, the aluminum foil package containing TiB2 particles is pressed into the melt.

[0018] Further, the intermediate frequency furnace used in the second step is equipped with a high and low frequency control module. The high frequency module is used for heating. Only the low frequency is turned on for stirring during stirring. The low frequency power is set to 40 - 60 Kw, the frequency is set to 80 - 130 Hz, and the phase shift angle is set to 70 - 100 degrees. After stirring, casting is carried out. The casting temperature is 690°C - 700°C, and the casting speed is 20 mm / min - 50 mm / min.

[0019] Further, in the third step, after homogenization is completed, it is cooled with the furnace and cooled to below 300°C, and then taken out of the furnace and air-cooled.

[0020] Further, in the third step, the parameters during the hot extrusion process are: the billet temperature is 390°C - 430°C, and the extrusion speed is 2 m / min - 10 m / min.

[0021] Further, in the fourth step, the solution treatment adopts a two-stage solution treatment system. The first-stage solution treatment temperature is 450°C - 470°C, and the second-stage solution treatment temperature is 470°C - 480°C; the aging adopts peak aging, and its process is: keep warm at 110°C - 130°C for 12 h - 24 h.

[0022] The present invention has the following beneficial effects: A method for preparing TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profiles assisted by electromagnetic stirring provided by the present invention. The prepared aluminum alloy has a relatively uniform microstructure and stable performance. The tensile strength and yield strength of the bar can reach up to 790 Mpa at most, the yield ratio is close to 1, and the elongation is higher than 10%. The profiles produced by this type of alloy can replace the low-ductility ultra-high-strength aluminum alloys prepared by the traditional casting method. The prepared profiles can be used in fields such as aviation, aerospace, transportation, and consumer electronics, and have broad application prospects. Brief Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a flow schematic diagram of preparing TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profiles assisted by electromagnetic stirring;

[0025] Figure 2 For the homogenization diagram of the matrix alloy of Example 1 with and without magnetic field assistance, where (a) is without magnetic field assistance and (b) is with magnetic field assistance;

[0026] Figure 3 Schematic diagram of the room temperature tensile properties of the bar obtained in Example 1;

[0027] Figure 4 Schematic diagram of the room temperature tensile properties of the bar obtained in Example 2. Detailed implementation manners

[0028] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments. It should be pointed out that the following detailed descriptions are all illustrative and are intended to provide further descriptions of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0029] The present invention provides a method for preparing TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profiles assisted by electromagnetic stirring, including the following chemical components by weight percentage:

[0030] Zn 9.0% - 12.0%, Mg 2.0% - 3.5%, Cu 0.6% - 2.6%, Zr 0.06% - 2.0%, Sc 0.05% - 0.2%, TiB2 1.0% - 3.0%, Fe ≤ 0.1%, Si ≤ 0.1%, other impurities single ≤ 0.05%, total amount ≤ 0.15%, and the balance is Al.

[0031] Please refer to Figure 1 , the preparation method of the TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profiles assisted by electromagnetic stirring of the present invention includes the following steps:

[0032] Step 1: Weigh the raw materials according to the following chemical components by weight percentage: Zn 9.0% - 12.0%, Mg 2.0% - 3.5%, Cu 0.6% - 2.6%, Zr 0.06% - 2.0%, Sc 0.05% - 0.2%, TiB2 1.0% - 3.0%, Fe ≤ 0.1%, Si ≤ 0.1%, other impurities single ≤ 0.05%, total amount ≤ 0.15%, and the balance is Al; Add the raw materials except for the TiB2 particles into an intermediate frequency furnace with electromagnetic stirring. When all the alloy raw materials are melted, add CCl6 and introduce argon for degassing treatment. After repeating the degassing treatment twice, press the aluminum foil package containing the TiB2 particles into the melt.

[0033] Specifically, the casting process includes: melting in a melting furnace at a melting temperature of 690°C to 750°C; refining the completely melted metal, with the metal temperature maintained within the range of 710°C to 740°C during refining; after refining and purging with argon, standing still for no less than 10 minutes, and skimming the slag after standing still.

[0034] Step 2: Turn on the magnetic field of the intermediate frequency furnace for stirring, with the stirring lasting for no less than 10 minutes; after the stirring ends, pour to obtain a cylindrical ingot, and the dimensions of the ingot are

[0035] Among them, turn on the magnetic field of the intermediate frequency furnace for stirring, with the stirring lasting for no less than 10 minutes. Briefly stand still, and when the melt temperature drops to 700°C to 710°C, pour.

[0036] Specifically, the used intermediate frequency furnace is equipped with a high and low frequency control module. The high frequency module is used for heating. Only the low frequency is turned on for stirring during stirring. The low frequency power is set to 40 - 60 Kw, the frequency is set to 80 - 130 Hz, the phase shift angle is set to 70 - 100 degrees. After the stirring ends, pour, with the pouring temperature of 690°C to 700°C and the pouring speed of 20 mm / min to 50 mm / min.

[0037] Step 3: Perform a homogenization process on the electromagnetic assisted casting ingot. After peeling the homogenized ingot, perform hot extrusion, with the extrusion ratio controlled at 25 or more.

[0038] Specifically, the parameters during the hot extrusion process are: 390°C to 430°C, and the extrusion speed is 2 m / min to 10 m / min.

[0039] Step 4: Subject the extruded profile to solution and aging heat treatment.

[0040] Specifically, the solution in Step 4 is a two-stage solution treatment system. The first-stage solution temperature is 450°C to 470°C, and the second-stage solution temperature is: 470°C to 480°C; aging adopts peak aging, and its process is: heat preservation at 110°C to 130°C for 12 h to 24 h.

[0041] The present invention adopts the electromagnetic stirring assistance method, and fully stirs the melt with the help of an electromagnetic field during the casting stage. It can not only disperse TiB2 particles, but also evenly disperse the solute atoms of the matrix alloy elements, weakening the element segregation of high alloyed aluminum alloys. Therefore, introducing electromagnetic stirring can solve the above problems, achieve high strength and high ductility of Al-Zn-Mg-Cu alloys, and make them have broad application prospects in the fields of aviation, aerospace, consumer electronics, transportation, etc.

[0042] The electromagnetic stirring assisted preparation of TiB2 particle reinforced Al-Zn-Mg-Cu aluminum alloy profiles and the preparation method thereof of the present invention are described in detail below in combination with several specific embodiments.

[0043] Embodiment 1:

[0044] The preparation process steps of the alloy are as follows:

[0045] (1) The alloy composition is as follows: Zn: 11.5%, Mg: 2.6%, Cu: 1% by weight; according to the above weight percentage, 99.99% refined Al ingot, pure Zn ingot, pure Mg ingot, Al-Cu master alloy and micron-sized TiB2 particles are used.

[0046] (2) Melting in a smelting furnace at a melting temperature of 690°C to 730°C.

[0047] (3) Refining agent is added to the completely melted metal for refining, and argon gas is passed after refining. During refining, the metal temperature is maintained in the range of 710°C to 730°C.

[0048] (4) After refining, allow the product to stand for 20 to 40 minutes with argon gas, and then remove the slag.

[0049] (5) Press the aluminum foil package containing TiB2 particles into the melt, and then turn on the low-frequency module of the medium-frequency furnace for electromagnetic stirring, and the stirring lasts for 10 minutes.

[0050] (6) After electromagnetic stirring, when the melt temperature drops to 700°C to 710°C, pouring is performed at a pouring speed of 20 mm / min to 40 mm / min.

[0051] (7) Casting to obtain a cylindrical ingot with a size of

[0052] (8) After homogenization, cool down with the furnace until the temperature drops below 300°C and then air cool down after being taken out of the furnace.

[0053] (9) peeling the homogenized ingot, the ingot diameter after peeling is 60 mm;

[0054] (10) Select a rod extrusion die to hot extrude the ingot with an extrusion ratio of 25.

[0055] (11) During the extrusion process, the initial heating temperature of the ingot is 400°C, the ingot temperature is controlled at 400°C to 420°C, and the extrusion speed is controlled at 5m / min to 10m / min.

[0056] (12) The extruded rods were subjected to a two-stage solution treatment, wherein the first stage solution treatment temperature was 465°C and the holding time was 2 h; the second stage solution treatment temperature was 475°C and the holding time was 1 h.

[0057] (13) The extruded profiles are subjected to peak aging heat treatment at a holding temperature of 120°C for 24 h and then air-cooled in the furnace.

[0058] The room temperature tensile properties of the rod obtained in Example 1 are shown in Table 1 below, where σ b is the tensile strength, σ 0.2 is the yield strength and δ is the elongation.

[0059] Table 1 Room temperature tensile properties of the rod obtained in Example 1

[0060]

[0061] Figure 2 The homogenization diagram of the alloy composition of Example 1 with and without magnetic field assistance, where (a) is without magnetic field assistance and (b) is with magnetic field assistance. Figure 2 The effect of the magnetic field on the highly alloyed base alloy can be seen in FIG. Figure 3 Schematic diagram of the room temperature tensile properties of the rod obtained in Example 1.

[0062] Embodiment 2:

[0063] (1) The alloy composition is as follows: Zn: 11.0%, Mg: 2.4%, Cu: 1% by weight; according to the above weight percentage, 99.99% refined Al ingot, pure Zn ingot, pure Mg ingot, Al-Cu master alloy and micron-sized TiB2 particles are used.

[0064] (2) Melting in a smelting furnace at a melting temperature of 720°C to 750°C.

[0065] (3) Refining agent is added to the completely melted metal and the mixture is continuously stirred for refining. Argon gas is passed through the mixture after refining, and the metal temperature is maintained within the range of 720°C to 740°C during refining.

[0066] (4) After refining, allow the product to stand for 10 to 20 minutes with argon gas, then remove the slag.

[0067] (5) Press the aluminum foil package containing TiB2 particles into the melt, and then turn on the low-frequency module of the medium-frequency furnace for electromagnetic stirring, and the stirring lasts for 20 minutes.

[0068] (6) After electromagnetic stirring, when the melt temperature drops to 700°C to 710°C, pouring is performed at a pouring speed of 30 mm / min to 50 mm / min.

[0069] (7) Casting to obtain a cylindrical ingot with a size of

[0070] After homogenization is completed, it is cooled in the furnace and cooled to below 300 °C, and then taken out of the furnace and air-cooled.

[0071] (9) The skin of the homogenized ingot is peeled off, and the diameter of the ingot after peeling is 176 mm.

[0072] (10) Select a bar extrusion die to perform hot extrusion on the ingot, and the extrusion ratio is 36.

[0073] (11) During the extrusion process, the initial heating temperature of the ingot is 410 °C, the temperature of the ingot during extrusion is controlled at 410 °C - 430 °C, and the extrusion speed is controlled at 2 m / min - 6 m / min.

[0074] (12) The extruded bar is subjected to two-stage solution treatment, and the solution treatment system is: the first-stage solution temperature is 460 °C, the holding time is 3 h, and the second-stage solution temperature is: 475 °C, and the holding time is 0.5 h.

[0075] (13) The extruded profile is subjected to peak aging heat treatment, the holding temperature: 120 °C, the holding time is 18 h, and it is air-cooled in the furnace.

[0076] The room-temperature tensile properties of the bar obtained in Example 2 are shown in Table 1 below, where σ b is the tensile strength, σ 0.2 is the yield strength, and δ is the elongation.

[0077] Table 2 Room-temperature tensile property table of the bar obtained in Example 2

[0078]

[0079] Figure 4 is the schematic diagram of the room-temperature tensile properties of the profile obtained in Example 2.

[0080] It can be seen from the above performance analysis that the performance of the TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profile prepared by electromagnetic stirring assistance in the present invention is stable, the tensile strength is higher than 780 MPa, and at the same time the elongation is higher than 8.6%. When the tensile strength is higher than 788 MPa, the elongation of the sheet is higher than 10.3%. It has broad application prospects in the fields of aviation, aerospace, transportation, and consumer electronics.

[0081] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0082] It should be noted that the terms "first", "second", etc. in the description, claims and the above-mentioned drawings of the present application are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example.

[0083] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method for preparing TiB2 particle-reinforced Al-Zn-Mg-Cu aluminum alloy profiles assisted by electromagnetic stirring, characterized in that, It includes the following steps: Step 1: Weigh the chemical components according to the following weight percentages: Zn 9.0% - 12.0%, Mg 2.0% - 3.5%, Cu 0.6% - 2.6%, Zr 0.06% - 2.0%, Sc 0.05% - 0.2%, TiB₂ 1.0% - 3.0%, Fe ≤ 0.1%, Si ≤ 0.1%, other impurities ≤ 0.05% individually, total impurities ≤ 0.15%, and the balance is Al. Add the ingredients except TiB₂ particles into an intermediate frequency furnace with electromagnetic stirring. When all the alloy ingredients are completely melted, add CCl₆ and introduce argon for degassing treatment. After repeating the degassing treatment twice, press the aluminum foil package containing TiB₂ particles into the melt. Step 2: Turn on the magnetic field of the medium-frequency furnace for stirring, and the stirring lasts for no less than 10 minutes. After the stirring is completed, casting is carried out to obtain a cylindrical ingot, and the size of the ingot is Step 3: Perform homogenization treatment on the electromagnetic-assisted casting ingot. After peeling the homogenized ingot, conduct hot extrusion, and control the extrusion ratio at 25 or above. Step 4: Subject the extruded profile to solution and aging heat treatment. In Step 1, melting is carried out in a melting furnace, and the melting temperature is 690°C - 750°C. Refine the completely melted metal, and maintain the metal temperature within the range of 710°C - 740°C during refining. After refining and introducing argon, let it stand for no less than 10 minutes, and then skim the slag after standing. After two times of refining, introducing argon and skimming the slag, press the aluminum foil package containing TiB₂ particles into the melt. The intermediate frequency furnace used in Step 2 is equipped with a high and low frequency control module. The high frequency module is used for heating. Only turn on the low frequency for stirring during stirring. The low frequency power is set at 40 - 60 Kw, the frequency is set at 80 - 130 Hz, and the phase shift angle is set at 70 - 100 degrees. After stirring, pour the molten metal, and the pouring temperature is 690°C - 700°C, and the pouring speed is 20 mm / min - 50 mm / min. In Step 3, after homogenization, cool it in the furnace, cool it below 300°C, and then take it out and air-cool it. In Step 3, the parameters during the hot extrusion process are: the billet temperature is 390°C - 430°C, and the extrusion speed is 2 m / min - 10 m / min. In Step 4, the solution is a two-stage solution treatment system. The first-stage solution temperature is 450°C - 470°C, and the second-stage solution temperature is 470°C - 480°C. Aging adopts peak aging, and its process is: keep it at 110°C - 130°C for 12 h - 24 h. The tensile strength and yield strength of the profile prepared by the said method can reach up to 790 Mpa at most, the yield ratio is close to 1, and the elongation is higher than 10%.

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