Particle-reinforced aluminium-based composite intermediate alloy and preparation method therefor, and aluminium-based composite material and preparation

Abstract

The present invention relates to the technical field of aluminum-based alloys, and in particular to a particle-reinforced aluminum-based composite intermediate alloy and a preparation method therefor,

Description

[0002] The present disclosure belongs to the technical field of aluminum-based alloys, and specifically relates to a particle-reinforced aluminum-based composite medium alloy, an aluminum-based composite, and preparation methods thereof. BACKGROUND

[0003] 7000 series aluminum alloys (Al-Zn-Mg-Cu) are widely used in military defense and aviation fields. However, when the traditional 7000 series aluminum alloys are under a load at high temperature for a long time, grains will grow and a precipitated phase will be coarsened, such that an interfacial strength between the precipitated phase and an aluminum matrix is reduced, and thus the high-temperature creep resistance of the 7000 series aluminum alloys is significantly reduced, which further causes cracks.

[0004] Currently, the high-temperature creep resistance of 7000 series aluminum alloys is improved mainly by adding nanoparticles to 7000 series aluminum alloys; the nanoparticles are mainly alumina nanoparticles and zirconium diboride nanoparticles. However, the nanoparticles added will agglomerate to reduce a tightness of interfacial bonding, thereby adversely affecting the high-temperature creep resistance of an alloy. SUMMARY

[0005] In view of this, the present disclosure provides a particle-reinforced aluminum-based composite medium alloy, an aluminum-based composite, and preparation methods thereof. The introduction of the reinforcing phase according to the present disclosure into an aluminum-based alloy could significantly improve the high-temperature creep resistance of an aluminum-based composite.

[0006] In order to solve the above technical problem, the present disclosure provides a particle-reinforced aluminum-based composite medium alloy, including an alumina particle-reinforced aluminum-based composite medium alloy and a zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy, wherein the alumina particle-reinforced aluminum-based composite medium alloy includes an alumina nanoparticle-reinforced aluminum-based composite medium alloy and an alumina microparticle-reinforced aluminum-based composite medium alloy.

[0007] In some embodiments, a volume ratio of alumina nanoparticles, alumina microparticles, and zirconium diboride nanoparticles is in a range of (0.5-1) : (0.5-1) : 1.

[0008] In some embodiments, the alumina nanoparticle-reinforced aluminum-based composite medium alloy is prepared by a medium / high-temperature hot-pressing method including the following steps:

[0009] adding an aluminum hydroxide powder and an aluminum powder in a mass ratio of 2 : 5 to a ball-milling tank, conducting ball-milling in an argon atmosphere, and drying and pressing a ball-milled mixture to obtain a prefabricated block; and

[0010] sintering the prefabricated block under vacuum to obtain the alumina nanoparticle-reinforced aluminum-based composite medium alloy.

[0011] In some embodiments, the alumina microparticle-reinforced aluminum-based composite medium alloy is prepared by an in-situ reaction method including the following steps:

[0012] mixing a zirconia powder and an aluminum powder to obtain a mixed powder;

[0013] adding the mixed powder to an aluminum melt, and subjecting a resulting mixture to a reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field, to obtain a mixed melt;

[0014] cooling the mixed melt, adding a refining agent thereto, and refining, and conducting slag removal and degassing, to obtain a pure melt; and

[0015] casting the pure melt, to obtain the alumina microparticle-reinforced aluminum-based composite medium alloy.

[0016] In some embodiments, the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy is prepared by an in-situ reaction method including the following steps:

[0017] adding potassium fluoroborate and potassium fluorozirconate to an aluminum melt, and subjecting a resulting mixture to a reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field, to obtain a zirconium diboride nanoparticle-containing aluminum melt;

[0018] cooling the zirconium diboride nanoparticle-containing aluminum melt, adding a refining agent thereto, and refining, and conducting slag removal and degassing, to obtain a pure melt; and

[0019] casting the pure melt, to obtain the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy.

[0020] The present disclosure further provides an aluminum-based composite, including reinforcing phases and a 7000 series aluminum alloy, wherein the reinforcing phases are alumina nanoparticles, alumina microparticles, and zirconium diboride nanoparticles; a part of the alumina nanoparticles is derived from the alumina nanoparticle-reinforced aluminum-based composite medium alloy described in the above technical solution; and a remaining part of the alumina nanoparticles is produced during preparation of the aluminum-based composite, through an in-situ reaction of a part of aluminum hydroxide in the alumina nanoparticle-reinforced aluminum-based composite medium alloy that is not completely decomposed into alumina with an aluminum melt; the alumina microparticles and the zirconium diboride nanoparticles are derived from the particle-reinforced aluminum-based composite medium alloy described in the above technical solution; and

[0021] a mass ratio of the reinforcing phases to the 7000 series aluminum alloy is in a range of 1 : (20-500).

[0022] The present disclosure further provides a method for preparing the aluminum-based composite described in the above technical solutions, including the following steps:

[0023] mixing and smelting the particle-reinforced aluminum-based composite medium alloy and raw materials of the 7000 series aluminum alloy, and subjecting a resulting mixture to a reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field, to obtain a melt; and

[0024] subjecting the melt to heat preservation and casting the melt, to obtain the aluminum-based composite.

[0025] In some embodiments, the magnetic field has a frequency of 15 Hz to 20 Hz, the ultrasonic field has a power of 1.5 kW to 2 kW, and the pressure field has a pressure of 0.3 MPa to 0.8 MPa.

[0026] In some embodiments, the three field-coupled action is applied for 25 min to 35 min.

[0027] In some embodiments, the heat preservation is conducted at a temperature of 1,000 K to 1,100 K for 1 h to 2 h.

[0028] The present disclosure provides a particle-reinforced aluminum-based composite medium alloy, including an alumina particle-reinforced aluminum-based composite medium alloy and a zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy, wherein the alumina particle-reinforced aluminum-based composite medium alloy includes an alumina nanoparticle-reinforced aluminum-based composite medium alloy and an alumina microparticle-reinforced aluminum-based composite medium alloy. The particle-reinforced aluminum-based composite medium alloy according to the present disclosure includes both alumina and zirconium diboride particles, and the two types of particles, as high-temperature stable phases, could hinder a dislocation movement in a high-temperature environment for a long time, play an Orowan strengthening role, and pin grain boundaries to effectively hinder the migration and coarsening of grain boundaries, thereby inhibiting the grain coarsening. The particle-reinforced aluminum-based composite medium alloy according to the present disclosure includes nanoparticles and microparticles of different sizes, which could solve the problem that nanoparticles alone are prone to agglomeration. The introduction of two particles of different sizes into an aluminum-based alloy in the present disclosure could significantly improve the high-temperature creep resistance of an aluminum-based composite. In the present disclosure, reinforcing particles are introduced in a form of a medium alloy, which could avoid the problem that a large number of impurities occur or slag removal is incomplete during smelting for preparing the aluminum-based composite to cause unsatisfactory structure properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 shows a schematic diagram of a three field-coupled action in an embodiment, in which, the left panel shows a schematic diagram of a structure of a device, and the right panel shows a schematic diagram of a principle of the three field-coupled action.

[0030] FIG. 2 shows transmission electron microscopy (TEM) images of the aluminum-based composite prepared in Example 1.

[0031] FIG. 3 shows tensile curves of the aluminum-based materials prepared in Example 1 and Comparative Examples 1 and 2.

[0032] FIG. 4 shows high-temperature creep curves of the aluminum-based materials prepared in Example 1 and Comparative Examples 1 and 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The present disclosure provides a particle-reinforced aluminum-based composite medium alloy, including an alumina particle-reinforced aluminum-based composite medium alloy and a zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy, wherein the alumina particle-reinforced aluminum-based composite medium alloy includes an alumina nanoparticle-reinforced aluminum-based composite medium alloy and an alumina microparticle-reinforced aluminum-based composite medium alloy. In some embodiments of the present disclosure, a volume ratio of alumina nanoparticles, alumina microparticles, and zirconium diboride nanoparticles is in a range of (0.5-1) : (0.5-1) : 1 and preferably 0.5 : 0.5 : 1 or 1 : 1 : 1. In the present disclosure, there is no special restriction on the content of aluminum in the medium alloy. In some embodiments of the present disclosure, the alumina nanoparticle-reinforced aluminum-based composite medium alloy is prepared by a medium / high-temperature hot-pressing method preferably including the following steps:

[0034] an aluminum hydroxide powder and an aluminum powder are added in a mass ratio of 2 : 5 to a ball-milling tank and ball-milled in an argon atmosphere, and a ball-milled mixture is dried and pressed to obtain a prefabricated block; and

[0035] the prefabricated block is sintered under vacuum to obtain the alumina nanoparticle-reinforced aluminum-based composite medium alloy.

[0036] In some embodiments of the present disclosure, an aluminum hydroxide powder and an aluminum powder are added in a mass ratio of 2 : 5 to a ball-milling tank and ball-milled in an argon atmosphere, and a ball-milled mixture is dried and pressed to obtain a prefabricated block. In some embodiments of the present disclosure, the aluminum hydroxide powder has an average particle size of 2 pm to 5 pm and preferably 3 pm to 4 pm. In some embodiments of the present disclosure, the aluminum powder has an average particle size of 10 pm to 20 pm and preferably 13 pm to 15 pm.

[0037] In some embodiments of the present disclosure, the ball-milling is conducted at a rotational speed of 200 r / min to 500 r / min and preferably 300 r / min to 400 r / min. In some embodiments, the ball-milling is conducted for 5 h to 20 h and preferably 10 h to 15 h. In some embodiments of the present disclosure, the drying is performed by vacuum-drying. In some embodiments, the vacuum-drying is conducted at a temperature of 470 K to 480 K and preferably 473 K to 475 K. In some embodiments, the drying is conducted for 1.8 h to 2.2 h and preferably 2 h.

[0038] In some embodiments of the present disclosure, the pressing is conducted in a mold. In some embodiments, the pressing is performed to reach a density of not less than 75% and preferably 78% to 85%. In some embodiments of the present disclosure, the mold is in a shape of a cube preferably with a side length of 70 mm.

[0039] In some embodiments of the present disclosure, after the prefabricated block is obtained, the prefabricated block is sintered under vacuum to obtain the alumina nanoparticle-reinforced aluminum-based composite medium alloy. In some embodiments of the present disclosure, the vacuum represents a vacuum degree of 8 Pa to 12 Pa and preferably 10 Pa. In some embodiments of the present disclosure, the sintering includes low-temperature sintering and high-temperature sintering that are conducted sequentially. In some embodiments, the low-temperature sintering is conducted at a temperature of 720 K to 730 K and preferably 723 K to 728 K. In some embodiments, the low-temperature sintering is conducted for 1.8 h to 2.2 h and preferably 2 h. In some embodiments of the present disclosure, raising to the low-temperature sintering temperature is at a raising rate of 8 K / s to 12 K / s and preferably 10 K / s.

[0040] In some embodiments of the present disclosure, the high-temperature sintering is conducted at a temperature of 820 K to 830 K and preferably 823 K to 828 K. In some embodiments, the high-temperature sintering is conducted for 0.8 h to 1.2 h and preferably 1 h. In some embodiments of the present disclosure, the high-temperature sintering temperature is reached by raising from the low-temperature sintering temperature.

[0041] In some embodiments of the present disclosure, after the sintering, the medium / high-temperature hot-pressing method further includes: a system after the sintering is cooled to a temperature of 293 K to 308 K and preferably 298 K to 303 K. In some embodiments of the present disclosure, the cooling is performed by furnace-cooling. In some embodiments of the present disclosure, the cooling is conducted under a pressure of 250 MPa.

[0042] In the present disclosure, aluminum hydroxide is decomposed into alumina during the sintering, and a corresponding chemical reaction equation is shown in equation 1: inn^i ZAKOHY =Al,O. +3H.0 r ,

[0043] v / 3 2 2 equation 1.

[0044] In some embodiments of the present disclosure, the alumina microparticle-reinforced aluminum-based composite medium alloy is prepared by an in-situ reaction method preferably including the following steps:

[0045] a zirconia powder and an aluminum powder are mixed to obtain a mixed powder;

[0046] the mixed powder is added to an aluminum melt, and a reaction is performed under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field to obtain a mixed melt;

[0047] the mixed melt is cooled, and a refining agent is added thereto; a resulting mixture is refined, and subjected to slag removal and degassing, to obtain a pure melt; and

[0048] the pure melt is casted to obtain the alumina microparticle-reinforced aluminum-based composite medium alloy.

[0049] In some embodiments of the present disclosure, a zirconia powder and an aluminum powder are mixed to obtain a mixed powder. In some embodiments of the present disclosure, the zirconia powder has an average particle size of 300 nm to 400 nm and preferably 330 nm to 380 nm. In some embodiments of the present disclosure, the aluminum powder has an average particle size of 10 pm to 20 pm and preferably 13 pm to 18 pm. In some embodiments of the present disclosure, a mass ratio of the zirconia powder to the aluminum powder is in a range of (0.8-1.2) : 3 and preferably 1 : 3. In some embodiments of the present disclosure, the zirconia powder and the aluminum powder are mixed by ball-milling in a protective atmosphere. In some embodiments of the present disclosure, the protective atmosphere is nitrogen or argon and preferably argon. In some embodiments of the present disclosure, the ball-milling is conducted at a rotational speed of 200 r / min to 500 r / min and preferably 300 r / min to 400 r / min. In some embodiments, the ball-milling is conducted for 4 h to 16 h and preferably 6 h to 12 h. In some embodiments of the present disclosure, the in-situ reaction method further includes after mixing, the mixed powder is dried. In some embodiments of the present disclosure, the drying is performed by vacuum-drying. In some embodiments, the vacuum-drying is conducted at a temperature of 470 K to 480 K and preferably 473 K to 475 K. In some embodiments, the drying is conducted for 1.8 h to 2.2 h and preferably 2 h.

[0050] In some embodiments of the present disclosure, after the mixed powder is obtained, the mixed powder is added to an aluminum melt, and a reaction is performed under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field to obtain a mixed melt. In some embodiments of the present disclosure, aluminum is melted to obtain the aluminum melt. In some embodiments of the present disclosure, the aluminum melt has a temperature of 923 K to 933 K and preferably 925 K to 930 K. In some embodiments of the present disclosure, the mixed powder is added to the aluminum melt under stirring. In some embodiments, the stirring is performed by electromagnetic stirring. In some embodiments, the electromagnetic stirring is performed by clockwise electromagnetic stirring. In some embodiments of the present disclosure, the mixed powder is added in batches to the aluminum melt. In some embodiments, the mixed powder is added in 5 to 10 batches and preferably 6 to 8 batches to the aluminum melt.

[0051] In some embodiments of the present disclosure, the magnetic field is provided by electromagnetic stirring. In some embodiments, the electromagnetic stirring is performed by clockwise stirring and counterclockwise stirring that are conducted alternately. In some embodiments, the clockwise stirring and counterclockwise stirring each are conducted for 4 min to 6 min and preferably 5 min. In some embodiments of the present disclosure, the magnetic field has a frequency of 15 Hz to 20 Hz. In an embodiment of the present disclosure, when electromagnetic stirring is started, a magnetic field frequency of 15 Hz is maintained for 20 s and then the magnetic field frequency is increased to 20 Hz. In some embodiments of the present disclosure, the ultrasonic field has a power of 1.5 kW to 2 kW. In an embodiment of the present disclosure, when the ultrasonic field is started, a power of 1.5 kW is maintained for 20 s and then the power is increased to 2 kW. In some embodiments, the pressure field has a pressure of 0.3 MP to 0.8 MPa and preferably 0.5 MPa. In some embodiments of the present disclosure, the three field-coupled action is applied in a protective atmosphere. In some embodiments, the protective atmosphere is nitrogen or argon and preferably argon. In some embodiments of the present disclosure, the three field-coupled action is applied at a temperature of 1,073 K to 1,573 K and preferably 1,173 K to 1,473 K. In some embodiments of the present disclosure, the three field-coupled action is applied for 25 min to 35 min and preferably 30 min.

[0052] In the present disclosure, there is no special restriction on a device for conducting the three field-coupled action, as long as a magnetic field, an ultrasonic field, and a pressure field could be provided simultaneously. In an embodiment of the present disclosure, a schematic diagram of a structure of the device for conducting the three field-coupled action is shown in FIG. 1, in which the left panel shows a schematic diagram of the structure of the device, and the right panel shows a schematic diagram of a principle of the three field-coupled action. In examples of the present disclosure, the device for conducting the three field-coupled action includes a container, wherein an electromagnetic field is provided on a wall surface of the container, an ultrasonic amplitude transformer is provided in the container, and a feeding port and a vent pipe are provided at a top end of the container. In the present disclosure, a protective atmosphere could be introduced into the container through the vent pipe to provide the pressure field.

[0053] In some embodiments of the present disclosure, after the mixed melt is obtained, the mixed melt is cooled, and a refining agent is added thereto; a resulting mixture is refined, and subjected to slag removal and degassing to obtain a pure melt. In some embodiments of the present disclosure, the refining agent is C2CI6. In some embodiments of the present disclosure, a mass of the refining agent accounts for 3% to 6% and preferably 4% to 5% of the mixed melt. In some embodiments of the present disclosure, the mixed melt is cooled to a temperature of 970 K to 980 K and preferably 973 K to 976 K. In the present disclosure, there is no special requirement for the slag removal and degassing, and a conventional means for the slag removal and degassing in the art may be adopted.

[0054] In some embodiments of the present disclosure, after the pure melt is obtained, the pure melt is casted to obtain the alumina microparticle-reinforced aluminum-based composite medium alloy. In some embodiments of the present disclosure, the casting is conducted in a mold. In some embodiments of the present disclosure, the mold is a copper mold. In some embodiments of the present disclosure, the mold is preheated before the casting. In some embodiments, the preheating is conducted at a temperature of 520 K to 530 K and preferably 523 K to 526 K. In some embodiments, the preheating is conducted for 2 h to 4 h and preferably 3 h. In the present disclosure, there is no special restriction on the casting, and a conventional means for casting in the art may be adopted.

[0055] In some embodiments of the present disclosure, the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy is prepared by a process including the following steps.

[0056] potassium fluoroborate and potassium fluorozirconate are added to an aluminum melt, and a resulting mixture is subjected to reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field to obtain a mixed melt;

[0057] the mixed melt is cooled, and a refining agent is added thereto; a resulting mixture is refined, and subjected to slag removal and degassing to obtain a pure melt; and

[0058] the pure melt is casted to obtain the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy.

[0059] In some embodiments of the present disclosure, potassium fluoroborate and potassium fluorozirconate are added to the aluminum melt, and a resulting mixture is subjected to reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field to obtain a mixed melt. In some embodiments of the present disclosure, potassium fluoroborate (KBF4) and potassium fluorozirconate (K^ZrFe) are dried before being mixed. In some embodiments of the present disclosure, the drying is conducted at a temperature of 470 K to 480 K and preferably 473 K to 475 K. In some embodiments, the drying is conducted for 1.8 h to 2.2 h and preferably 2 h. In some embodiments of the present disclosure, the drying is conducted in an oven. In the present disclosure, the drying is conducted to remove water of crystallization in potassium fluoroborate and potassium fluorozirconate. In some embodiments of the present disclosure, aluminum is melted to obtain the aluminum melt. In some embodiments of the present disclosure, the aluminum melt has a temperature of 1,120 K to 1,130 K and preferably 1,123 K to 1,125 K.

[0060] In some embodiments of the present disclosure, the potassium fluoroborate and the potassium fluorozirconate are added to the aluminum melt under stirring. In some embodiments, the stirring is performed by electromagnetic stirring. In some embodiments, the electromagnetic stirring is performed by clockwise electromagnetic stirring. In some embodiments of the present disclosure, the potassium fluoroborate and the potassium fluorozirconate are added in batches to the aluminum melt. In some embodiments, the potassium fluoroborate and the potassium fluorozirconate are added in 5 to 10 batches and preferably 6 to 8 batches to the aluminum melt.

[0061] In some embodiments of the present disclosure, the magnetic field has a frequency of 15 Hz to 20 Hz and preferably 16 Hz to 18 Hz. In an embodiment of the present disclosure, when a magnetic field is started, a frequency of 15 Hz is maintained for 20 s and then the frequency is increased to 20 Hz. In some embodiments of the present disclosure, the magnetic field is provided by electromagnetic stirring. In some embodiments, the electromagnetic stirring is performed by clockwise stirring and counterclockwise stirring that are conducted alternately. In some embodiments, the clockwise stirring and counterclockwise stirring each are conducted for 4 min to 6 min and preferably 5 min. In some embodiments of the present disclosure, the ultrasonic field has a power of 1.5 kW to 2 kW. In an embodiment of the present disclosure, when the ultrasonic field is started, a power of 1.5 kW is maintained for 20 s and then the power is increased to 2 kW. In some embodiments of the present disclosure, the pressure field has a pressure of 0.3 MPa to 0.8 MPa and preferably 0.5 MPa. In some embodiments of the present disclosure, the three field-coupled action is applied in a protective atmosphere. In some embodiments, the protective atmosphere is nitrogen or argon and preferably argon. In some embodiments of the present disclosure, the three field-coupled action is applied at a temperature of 1,073 K to 1,573 K and preferably 1,173 K to 1,473 K. In some embodiments of the present disclosure, the three field-coupled action is applied for 25 min to 35 min and preferably 30 min.

[0062] In some embodiments of the present disclosure, after the mixed melt is obtained, the mixed melt is cooled, a refining agent is added thereto; a resulting mixture is refined, and subjected to slag removal and degassing to obtain a pure melt. In some embodiments of the present disclosure, the refining agent is C2O6. In some embodiments of the present disclosure, a mass of the refining agent accounts for 3% to 6% and preferably 4% to 5% of the mixed melt. In some embodiments of the present disclosure, the mixed melt is cooled to a temperature of 970 K to 980 K and preferably 973 K to 976 K. In the present disclosure, there is no special requirement for the slag removal and degassing, and a conventional means for the slag removal and degassing in the art may be adopted.

[0063] In some embodiments of the present disclosure, after the pure melt is obtained, the pure melt is casted to obtain the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy. In some embodiments of the present disclosure, the casting is conducted in a mold. In some embodiments of the present disclosure, the mold is a copper mold. In some embodiments of the present disclosure, the mold is preheated before the casting. In some embodiments, the preheating is conducted at a temperature of 520 K to 530 K and preferably 523 K to 526 K. In the present disclosure, there is no special restriction on the casting, and a conventional means for the casting in the art may be adopted.

[0064] The present disclosure further provides an aluminum-based composite, including reinforcing phases and a 7000 series aluminum alloy, wherein the reinforcing phases are alumina nanoparticles, alumina microparticles, and zirconium diboride nanoparticles; a part of the alumina nanoparticles is derived from the alumina nanoparticle-reinforced aluminum-based composite medium alloy described in the above technical solution; and a remaining part of the alumina nanoparticles is produced during preparation of the aluminum-based composite, through an in-situ reaction of a part of aluminum hydroxide in the alumina nanoparticle-reinforced aluminum-based composite medium alloy that is not completely decomposed into alumina with an aluminum melt; and the alumina microparticles and the zirconium diboride nanoparticles are derived from the alumina microparticle-reinforced aluminum-based composite medium alloy and the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy described in the above technical solutions, respectively. In some embodiments of the present disclosure, the 7000 series aluminum alloy includes a 7055 aluminum alloy.

[0065] In some embodiments of the present disclosure, a mass ratio of the reinforcing phases to the 7000 series aluminum alloy is in a range of 1 : (20-500) and preferably 1 : (50-400).

[0066] The aluminum-based composite according to the present disclosure has excellent mechanical performance and high-temperature creep resistance.

[0067] The present disclosure further provides a method for preparing the aluminum-based composite described in the above technical solutions, including the following steps:

[0068] the particle-reinforced aluminum-based composite medium alloy and the 7000 series aluminum alloy are mixed and smelted, and a resulting mixture is subjected to reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field to obtain a melt; and

[0069] the melt is subjected to heat preservation and casted to obtain the aluminum-based composite.

[0070] In the present disclosure, the particle-reinforced aluminum-based composite medium alloy and the 7000 series aluminum alloy are mixed and smelted, and a resulting mixture is subjected to reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field to obtain a melt. In the present disclosure, there is no special restriction on the 7000 series aluminum alloy, and a conventional commercially-available product may be adopted. In the present disclosure, there is no special requirement on the smelting, and a conventional means for the smelting in the art may be adopted.

[0071] In some embodiments of the present disclosure, the magnetic field has a frequency of 15 Hz to 20 Hz and preferably 16 Hz to 18 Hz. In an embodiment of the present disclosure, when a magnetic field is started, a frequency of 15 Hz is maintained for 20 s and then the frequency is increased to 20 Hz. In some embodiments of the present disclosure, the magnetic field is provided by electromagnetic stirring. In some embodiments, the electromagnetic stirring is performed by clockwise stirring and counterclockwise stirring that are conducted alternately. In some embodiments, the clockwise stirring and counterclockwise stirring each are conducted for 4 min to 6 min and preferably 5 min. In some embodiments of the present disclosure, the ultrasonic field has a power of 1.5 kW to 2 kW. In an embodiment of the present disclosure, when the ultrasonic field is started, a power of 1.5 kW is maintained for 20 s and then the power is increased to 2 kW. In some embodiments of the present disclosure, the pressure field has a pressure of 0.3 MPa to 0.8 MPa and preferably 0.5 MPa. In some embodiments of the present disclosure, the three field-coupled action is applied in a protective atmosphere. In some embodiments, the protective atmosphere is nitrogen or argon and preferably argon. In some embodiments of the present disclosure, the three field-coupled action is applied at a temperature of 1,073 K to 1,573 K and preferably 1,173 K to 1,473 K. In some embodiments of the present disclosure, the three field-coupled action is applied for 25 min to 35 min and preferably 30 min.

[0072] In the present disclosure, aluminum hydroxide in the particle-reinforced aluminum-based composite medium alloy that is not completely decomposed would further react with an aluminum matrix to produce alumina particles, and a corresponding reaction equation is shown in equation 2: inmu 2AKOHY +2Al =2AW. +3H.0 r o

[0073] \ 2 3 equation 2.

[0074] In the present disclosure, after the melt is obtained, the melt is subjected to heat preservation and casted to obtain the aluminum-based composite. In some embodiments of the present disclosure, the heat preservation is conducted at a temperature of 1,000 K to 1,100 K and preferably 1,053 K to 1,080 K. In some embodiments, the incubating is conducted for 0.8 h to 1.2 h and preferably 1 h.

[0075] In some embodiments of the present disclosure, the method further includes before the casting, a system obtained after the heat preservation is cooled. In some embodiments of the present disclosure, the system is cooled to a temperature of 990 K to 993 K.

[0076] In some embodiments of the present disclosure, the casting is conducted in a mold, and the mold is preferably a copper mold. In the present disclosure, there is no special restriction on the casting, and a conventional means for the casting in the art may be adopted. In some embodiments of the present disclosure, a solidification stage of the casting is conducted in a protective atmosphere. In some embodiments, the protective atmosphere is nitrogen or argon and more preferably argon; and a pressure of the protective atmosphere is preferably 0.6 MPa to 0.8 MPa and more preferably 0.7 MPa.

[0077] In order to further illustrate the present disclosure, the technical solutions provided by the present disclosure are described in detail below in connection with examples, but these examples should not be construed as limiting the claimed scope of the present disclosure.

[0078] Example 1

[0079] (1) An aluminum hydroxide powder with an average particle size of 3 pm and a pure aluminum powder with an average particle size of 13 pm were added in a mass ratio of 2 : 5 to a ball-milling tank and ball-milled for 15 h at a rotational speed of 300 r / min in an argon atmosphere to obtain a mixed powder. The mixed powder was vacuum-dried at 473 K for 2 h.

[0080] (2) A dried mixed powder was placed in a cube mold with a side length of 70 mm and pressed to a density of 85% to obtain a prefabricated block.

[0081] (3) Under a vacuum degree of 10 Pa, the prefabricated block was heated to 723 K at a raising rate of 10 K / s and subjected to low-temperature sintering at 723 K for 2 h, and then heated to 823 K at a raising rate of 10 K / s and subjected to high-temperature sintering at 823 K for 1 h. The sintered material was furnace-cooled to 293 K under a pressure of 250 MPa to obtain an alumina nanoparticle-reinforced aluminum-based composite medium alloy.

[0082] (4) A zirconia powder with an average particle size of 300 nm and an aluminum powder with an average particle size of 13 pm were added in a mass ratio of 1 : 3 to a ball-milling tank and ball-milled at a rotational speed of 400 r / min in an argon atmosphere for 15 h, to obtain a mixed powder. The mixed powder was dried at 473 K for 2 h.

[0083] (5) Pure aluminum was smelted to obtain an aluminum melt. The aluminum melt was cooled to 933 K, and clockwise stirred by turning on an electromagnetic stirrer. The dried mixed powder was added in 8 batches to the aluminum melt under clockwise electromagnetic stirring. An ultrasonic field was applied to the resulting mixture, and the ultrasonic had a power of 1.5 kW and was maintained for 20 s; and then its power was increased to 2 kW. Argon was introduced for pressurizing to 0.5 MP. A magnetic field was applied, and the magnetic field had a frequency of 15 Hz and was maintained for 20 s; and then its frequency was increased to 20 Hz. The electromagnetic stirring was performed by a cycle of clockwise stirring for 5 min and counterclockwise stirring for 5 min. The coupled action of a magnetic field, an ultrasonic field, and a pressure field was applied at 1,573 K for 30 min to obtain a mixed melt.

[0084] (6) The mixed melt was cooled to 973 k, and a refining agent C2CI6 was added to the cooled mixed melt, wherein a mass of the refining agent added accounted for 5% of the mixed melt. The resulting mixture was refined, and then subjected to slag removal and degassing to obtain a pure melt. The pure melt was casted into a copper mold which had been preheated at 523 k for 2 h to obtain an alumina microparticle-reinforced aluminum-based composite medium alloy.

[0085] (7) Pure aluminum was smelted in a smelting furnace to obtain an aluminum melt, and when a temperature of the aluminum melt reached 1,123 K, the aluminum melt was magnetic stirred by turning on a magnetic stirrer. KBF4 and K2ZrFe were preheated at 473 K for 2 h and then added in 8 batches to the aluminum melt under electromagnetic stirring. An ultrasonic field was applied to the resulting mixture, and the ultrasonic had a power of 1.5 kW and was maintained for 20 s; and then its power was increased to 2 kW. Argon was introduced for pressurizing to 0.5 MP. A magnetic field was applied, and the magnetic field had a frequency of 15 Hz and was maintained for 20 s; and then its frequency was increased to 20 Hz. The electromagnetic stirring was performed by a cycle of clockwise stirring for 5 min and counterclockwise stirring for 5 min. The coupled action of a magnetic field, an ultrasonic field, and a pressure field was applied at 1,573 K for 30 min to obtain a mixed melt.

[0086] (8) The mixed melt was cooled to 973 k, and a refining agent C2CI6 was added to the cooled mixed melt, wherein a mass of the refining agent added accounted for 5% of the mixed melt. The resulting mixture was refined, and then subjected to slag removal and degassing, to obtain a pure melt. The pure melt was casted into a copper mold which had been preheated at 523 k for 2 h to obtain a zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy.

[0087] (9) The alumina nanoparticle-reinforced aluminum-based composite medium alloy, the alumina microparticle-reinforced aluminum-based composite medium alloy, and the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy were placed in a smelting furnace. Alloy elements in a corresponding ratio required for 7055 aluminum alloy were added thereto. A three field-coupled action was applied: an ultrasonic field was applied to the resulting mixture, and the ultrasonic field had a power of 1.5 kW and was maintained for 20 s, and then its power was increased to 2 kW; argon was introduced for pressurizing to 0.5 MPa; and a magnetic field was applied and the magnetic field had a frequency of 15 Hz and was maintained for 20 s, and its frequency was increased to 20 Hz. The electromagnetic stirring was performed by a cycle of clockwise stirring for 5 min and counterclockwise stirring for 5 min. The coupled action of a magnetic field, an ultrasonic field, and a pressure field was applied at 1,053 K for 30 min. After coupled action of three fields, the resulting system was maintained at 1053 K for 1 h, and cooled to 993 K. The resulting mixture was casted in a copper mold in a pressure device to obtain an aluminum-based composite in which alumina nanoparticles accounted for 1 vol.%, alumina microparticles accounted for 1 vol.%, and zirconium diboride nanoparticles accounted for 1 vol.%.

[0088] Example!

[0089] A 0.5 vol.% alumina nanoparticle-reinforced aluminum-based composite medium alloy was prepared according to the method in Example 1.

[0090] A 0.5 vol.% alumina microparticle-reinforced aluminum-based composite medium alloy was prepared according to the method in Example 1.

[0091] A 1 vol.% zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy was prepared according to the method in Example 1.

[0092] The alumina nanoparticle-reinforced aluminum-based composite medium alloy, the alumina microparticle-reinforced aluminum-based composite medium alloy, and the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy were placed in a smelting furnace. Alloy elements in a corresponding ratio required for 7055 aluminum alloy were added thereto. A three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field was applied: the ultrasonic field was maintained at a power of 1.5 kW for 20 s, and then the power was increased to 2 kW; argon was introduced for pressurizing to 0.5 MPa; and the magnetic field was maintained at a frequency of 15 Hz for 20 s, and then the frequency was increased to 20 Hz. The electromagnetic stirring was performed by a cycle of clockwise stirring for 5 min and counterclockwise stirring for 5 min. The coupled action of the magnetic field, the ultrasonic field, and the pressure field was applied at 1,053 K for 30 min. After the coupled action of three fields, the resulting system was maintained at 1,053 K for 1 h, and cooled to 993 K. The resulting mixture was casted in a copper mold in a pressure device to obtain an aluminum-based composite in which alumina nanoparticles accounted for 0.5 vol.%, alumina microparticles accounted for 0.5 vol.%, and zirconium diboride nanoparticles accounted for 1 vol.%.

[0093] Comparative Example 1

[0094] The 7055 aluminum alloy in Example 1 was taken as a comparative example.

[0095] Comparative Example 2

[0096] Pure aluminum was smelted in a smelting furnace to obtain an aluminum melt, and when a temperature of the aluminum melt reached 1,123 K, the aluminum melt was magnetic stirred by turning on a magnetic stirrer. KBF4 and K2ZrF6 were preheated at 473 K for 2 h and then added in 8 batches to the aluminum melt under electromagnetic stirring. An ultrasonic field was applied to the resulting mixture, and the ultrasonic had a power of 1.5 kW and was maintained for 20 s, and then its power was increased to 2 kW. Argon was introduced for pressurizing to 0.5 MPa. A magnetic field was applied, and the magnetic field had a frequency of 15 Hz and was maintained for 20 s, and then its frequency was increased to 20 Hz. The electromagnetic stirring was performed by a cycle of clockwise stirring for 5 min and counterclockwise stirring for 5 min. The coupled action of the magnetic field, the ultrasonic field, and the pressure field was applied at 1,053 K for 30 min, to obtain a mixed melt.

[0097] The mixed melt was cooled to 973 k, and a refining agent C2CI6 was added to the cooled mixed melt, wherein a mass of the refining agent added accounted for 5% of the mixed melt. The resulting mixture was refined, and then subjected to slag removal and degassing, to obtain a pure melt. The pure melt was casted into a copper mold which had been preheated at 523 k for 2 h to obtain a ZrB2 / 7055 aluminum-based composite.

[0098] The aluminum-based composite prepared in Example 1 was subjected to TEM detection to obtain the TEM images shown in FIG. 2, in which (a) shows a TEM image of nano-alumina and nano-zirconium diboride and (b) shows a TEM image of micro-alumina. It can be seen from FIG. 2 that the aluminum-based composite includes zirconium diboride particles, alumina nanoparticles, and alumina microparticles, wherein the zirconium diboride particles and the alumina nanoparticles each have a particle size of 20 nm to 80 nm, and the alumina microparticles has a particle size of 4 pm to 6 pm.

[0099] An axial force was applied to the aluminum-based materials prepared in Example 1 and Comparative Examples 1 and 2 at room temperature (298 K) and 473 K, respectively, and tensile tests were performed to determine the mechanical performance of the aluminum-based materials. Test results are shown in Table 1.

[0100] Table 1 Mechanical performance of the aluminum-based materials prepared in Example 1 and Comparative Examples 1 and 2 Example Tensile strength Tensile strength Elongation (%) (MPa) at 473 K (MPa) at room temperature Example 1 396 703 17.9 Comparative Example 1 304 639 11.5 Comparative Example 2 347 680 15.2

[0101] Tensile curves were plotted according to Table 1, as shown in FIG. 3.

[0102] It can be seen from Table 1 and FIG. 3 that, a strength of the aluminum-based composite prepared in Example 1 is 10% higher than that of the aluminum alloy in Comparative Example 1, and is 3% higher than that of the aluminum-based composite in Comparative Example 2; and the aluminum-based composite prepared in Example 1 has higher room-temperature and high-temperature tensile strengths and elongations.

[0103] A constant axial tensile stress was applied to the aluminum-based materials in Example 1 and Comparative Examples 1 and 2 at 573 K and 70 MPa, to determine the high-temperature creep performance of the aluminum-based materials. The creep curves are shown in FIG. 4.

[0104] It can be seen from FIG. 4 that, the aluminum-based composite according to the present disclosure has a low steady-state creep rate, indicating that the aluminum-based composite according to the present disclosure has better creep resistance in a high-temperature environment.

[0105] Although the present disclosure has been described in detail through the above examples, the examples are merely some rather than all of the examples of the present disclosure. All other examples obtained by a person based on these examples without creative efforts shall fall within the scope of the present disclosure.

Claims

1. A particle-reinforced aluminum-based composite medium alloy, comprising an alumina particle-reinforced aluminum-based composite medium alloy and a zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy,wherein the alumina particle-reinforced aluminum-based composite medium alloy comprises an alumina nanoparticle-reinforced aluminum-based composite medium alloy and an alumina microparticle-reinforced aluminum-based composite medium alloy.

2. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 1, wherein a volume ratio of alumina nanoparticles, alumina microparticles, and zirconium diboride nanoparticles is in a range of (0.5-1): (0.5-1): 1.

3. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 1, wherein the alumina nanoparticle-reinforced aluminum-based composite medium alloy is prepared by a medium / high-temperature hot-pressing method comprising the steps ofadding an aluminum hydroxide powder and an aluminum powder in a mass ratio of 2 : 5 to a ball-milling tank, conducting ball-milling in an argon atmosphere, and drying and pressing a ball-milled mixture to obtain a prefabricated block; andsintering the prefabricated block under vacuum to obtain the alumina nanoparticle-reinforced aluminum-based composite medium alloy.

4. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 3, wherein the aluminum hydroxide powder has an average particle size of 2 pm to 5 pm, and the aluminum powder has an average particle size of 10 pm to 20 pm.

5. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 3, wherein the pressing is performed to reach a density of not less than 75%.

6. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 3, wherein the sintering comprises low-temperature sintering and high-temperature sintering that are conducted sequentially;the low-temperature sintering is conducted at a temperature of 720 K to 730 K for 1.8 h to 2.2 h, and raising to the temperature is at a raising rate of 8 K / s to 12 K / s; andthe high-temperature sintering is conducted at a temperature of 820 K to 830 K for 0.8 h to 1.2h.

7. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 1, wherein the alumina microparticle-reinforced aluminum-based composite medium alloy is prepared by an in-situ reaction method comprising the steps ofmixing a zirconia powder and an aluminum powder to obtain a mixed powder;adding the mixed powder to an aluminum melt, and subjecting a resulting mixture to reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field, to obtain a mixed melt;cooling the mixed melt, adding a refining agent thereto, and refining, and conducting slag removal and degassing, to obtain a pure melt; andcasting the pure melt, to obtain the alumina microparticle-reinforced aluminum-based composite medium alloy.

8. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 7, wherein the zirconia powder has an average particle size of 300 nm to 400 nm, and the aluminum powder has an average particle size of 10 pm to 20 pm; anda mass ratio of the zirconia powder to the aluminum powder is in a range of (0.8-1.2) : 3.

9. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 7, wherein the magnetic field has a frequency of 15 Hz to 20 Hz, the ultrasonic field has a power of 1.5 kW to 2 kW, and the pressure field has a pressure of 0.3 MPa to 0.8 MPa; andthe three field-coupled action is applied at a temperature of 1,073 K to 1,573 K for 25 min to 35 min.

10. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 1, wherein the zirconium diboride nanoparticle-reinforced aluminum-based composite medium alloy is prepared by an in-situ reaction method comprising the steps ofadding potassium fluoroborate and potassium fluorozirconate to an aluminum melt, and subjecting a resulting mixture to reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field, to obtain a zirconium diboride nanoparticle-containing aluminum melt;cooling the zirconium diboride nanoparticle-containing aluminum melt, adding a refining agent thereto and refining, and conducting slag removal and degassing, to obtain a pure melt; andcasting the pure melt, to obtain the zirconium diboride nanoparticle-reinforced aluminum-basedcomposite medium alloy.

11. The particle-reinforced aluminum-based composite medium alloy as claimed in claim 10, wherein the magnetic field has a frequency of 15 Hz to 20 Hz, the ultrasonic field has a power of 1.5 kW to 2 kW, and the pressure field has a pressure of 0.3 MPa to 0.8 MPa; andthe three field-coupled action is applied at a temperature of 1,073 K to 1,573 K for 25 min to 35 min.

12. An aluminum-based composite, comprising reinforcing phases and a 7000 series aluminum alloy, whereinthe reinforcing phases are alumina nanoparticles, alumina microparticles, and zirconium diboride nanoparticles;a part of alumina nanoparticles is derived from the alumina nanoparticle-reinforced aluminum-based composite medium alloy as defined in any one of claims 1 to 11; and a remaining part of the alumina nanoparticles is produced during preparation of the aluminum-based composite, through an in-situ reaction of a part of aluminum hydroxide in the alumina nanoparticle-reinforced aluminum-based composite medium alloy that is not completely decomposed into alumina with an aluminum melt;the alumina microparticles and the zirconium diboride nanoparticles are derived from the particle-reinforced aluminum-based composite medium alloy as claimed in any one of claims 1 to 11; anda mass ratio of the reinforcing phases to the 7000 series aluminum alloy is in a range of 1 : (20-500).

13. A method for preparing the aluminum-based composite as claimed in claim 12, comprising the steps ofmixing and smelting the particle-reinforced aluminum-based composite medium alloy and raw materials of the 7000 series aluminum alloy, and subjecting a resulting mixture to reaction under a three field-coupled action of a magnetic field, an ultrasonic field, and a pressure field, to obtain a melt; andsubjecting the melt to heat preservation and casting, to obtain the aluminum-based composite.

14. The method as claimed in claim 13, wherein the magnetic field has a frequency of 15 Hz to 20 Hz, the ultrasonic field has a power of 1.5 kW to 2 kW, and the pressure field has a pressure of 0.3 MPa to 0.8 MPa.

15. The method as claimed in claim 13 or 14, wherein the three field-coupled action is applied at a temperature of 1,073 K to 1,573 K for 25 min to 35 min.

16. The method as claimed in claim 13, wherein the heat preservation is conducted at a temperature of 1,000 K to 1,100 K for 1 h to 2 h.INTERNATIONAL SEARCH REPORT International application No. PCT / CN2023 / 097080A. CLASSIFICATION OF SUBJECT MATTER C22Cl / 10(2023.01)i; C22Cl / 059(2023.01)i; C22Cl / 03(2006.01)i; B22F3 / 00(2021.01)i; B82Y30 / 00(2011.01)i; B82Y40 / 00(2011.01)i According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) C22C B22F B82Y Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) CNABS. CNTXT, DWPI, CNKI: WS, W., al2o3, zrb2, micro-nano particle, reinforced, aluminum-based composite, aluminum alloy, master alloy, intermediate alloy, ceramic, in-situ reaction generation, C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. PX CN 116121581 A (JIANGSU UNIVERSITY) 16 May 2023 (2023-05-16) claims 1-10, and description, paragraphs 5-73 1-16 Y Y CN 111206166 A (JIANGSU UNIVERSITY) 29 May 2020 (2020-05-29) claim 1 CN 103866154 A (CHINA WEAPON SCIENCE ACADEMY NINGBO BRANCH) 18 June 2014 (2014-06-18) claims 1-2 1-16 1-16 Y CN 114990390 A (JIANGSU UNIVERSITY) 02 September 2022 (2022-09-02) claims 1-2 12-16 A A CN 110241321 A (NANJING HIGH TECHNOLOGY NANO MATERIAL CO., LTD.) 17 September 2019 (2019-09-17) entire document CN 115418520 A (JIANGSU UNIVERSITY) 02 December 2022 (2022-12-02) entire document 1-16 | | Further documents are listed in the continuation of Box C. | J | See patent family annex. * Special categories of cited documents: “T” later document published after the international filing date or priority “A” document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand the to be of particular- relevance principle or theory underlying the invention “D” document cited by the applicant in the international application -‘X” document of particular relevance; the claimed invention cannot be “E" earlier application or patent but published on or after the international considered novel or cannot be considered to involve an inventive step filing date when the document is taken alone “L" document which may throw doubts on priority claim(s) or which is “Y” document of particular relevance; the claimed invention cannot be cited to establish the publication date of another citation or other considered to involve an inventive step when the document is special reason (as specified) combined with one or more other such documents, such combination “O” document referring to an oral disclosure, use, exhibition or other being obvious to a person skilled in the ait means document member of the same patent family “P” document published prior to the international filing date but later than the priority date claimed Date of the actual completion of the international search 16 June 2023 Date of mailing of the international search report 20 June 2023 Name and mailing address of the ISA / CN China National Intellectual Property Administration (ISA / CN) China No. 6, Xitucheng Road, Jimenqiao, Haidian District, Beijing 100088 Authorized officer Telephone No.

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