Directional solidification aluminum alloy, preparation method thereof, aluminum alloy component and terminal product

Abstract

The invention relates to the technical field of aluminum alloys, and discloses a preparation method of a directionally solidified aluminum alloy, which comprises the following steps: placing a crucible containing an aluminum alloy cast ingot in an inert atmosphere and a smelting chamber with a certain vacuum degree, heating, melting and preserving heat to obtain an aluminum alloy melt; the crucible containing the molten aluminum alloy is controlled to be subjected to pull-down operation at the preset pull-down speed, after pull-down is finished, the crucible is taken out after cooling is conducted in the smelting chamber, and an initial aluminum alloy is obtained; and the initial aluminum alloy is subjected to homogenization treatment, quenching and aging treatment, and the directionally solidified aluminum alloy is obtained. The preparation method is a novel composite preparation process combining directional solidification and a heat treatment process, the process is simple, the production effect is improved, the production cost is low, collaborative optimization of an aluminum matrix and a precipitated phase is achieved by means of the coupling effect between solidification and heat treatment, and the strength, toughness and other comprehensive mechanical properties of the alloy are comprehensively improved. The invention further discloses the directionally solidified aluminum alloy, an aluminum alloy component and a terminal product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum alloy, for example, relates to a directional solidification aluminum alloy and a preparation method thereof, and an aluminum alloy component and a terminal product. BACKGROUND

[0002] Currently widely used light alloys mainly include aluminum alloys and magnesium alloys, wherein the aluminum alloy plays a key role in the fields of automobile industry, aerospace and construction engineering due to excellent plasticity, high specific strength and good forming ability. The research and application degree of the aluminum alloy has become one of important indexes for evaluating the high-end manufacturing capacity and technological strength of a country.

[0003] In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art: The preparation process of the existing aluminum alloy needs to go through multiple complex procedures such as casting, homogenization, rolling, solid solution and aging, and has long production process and high cost.

[0004] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] To have a basic understanding of some aspects of the disclosed embodiments, a brief overview is given below. The summary is not a general review, nor is it intended to determine key / important components or delineate the scope of protection of these embodiments, but as a prelude to the detailed description below.

[0006] The embodiments of the present disclosure provide a directional solidification aluminum alloy and a preparation method thereof, and an aluminum alloy component and a terminal product, to solve the technical problem that the preparation process of the existing aluminum alloy needs to go through multiple complex procedures such as casting, homogenization, rolling, solid solution and aging, and has long production process and high cost.

[0007] In some embodiments, the preparation method of the directional solidification aluminum alloy comprises: placing a crucible containing an aluminum alloy ingot in a smelting chamber with inert atmosphere and a certain vacuum degree, heating and melting, and obtaining an aluminum alloy melt; controlling the crucible containing the aluminum alloy melt to perform a downward drawing operation at a preset downward drawing speed, after the downward drawing is completed, taking out the crucible after cooling in the smelting chamber, and obtaining an initial aluminum alloy; after homogenization treatment and quenching of the initial aluminum alloy, performing aging treatment, and obtaining the directional solidification aluminum alloy.

[0008] In some embodiments, the directional solidification aluminum alloy is prepared by the preparation method of the directional solidification aluminum alloy described above.

[0009] In some embodiments, the aluminum alloy member comprises the directionally solidified aluminum alloy prepared by the aforementioned method for preparing a directionally solidified aluminum alloy, or comprises the aforementioned directionally solidified aluminum alloy.

[0010] In some embodiments, the terminal product comprises the aforementioned aluminum alloy member.

[0011] The directionally solidified aluminum alloy, the method for preparing the directionally solidified aluminum alloy, and the aluminum alloy member and the terminal product provided by the embodiments of the present disclosure can achieve the following technical effects. The method for preparing the directionally solidified aluminum alloy provided by the embodiments of the present disclosure is a novel composite preparation process combining directional solidification and heat treatment processes. High-performance aluminum alloys can be obtained through directional solidification, homogenization treatment, and aging treatment. The process is simple, the production effect is improved, the production cost is low, and the entire preparation process is green. Not only is the production process greatly shortened and the cost reduced, but also the coupling effect between solidification and heat treatment can be utilized to realize the synergistic optimization of the aluminum matrix and precipitated phases, thereby opening up a new technical path for developing aluminum alloy materials with better comprehensive performance.

[0012] The directionally solidified aluminum alloy provided by the embodiments of the present disclosure has good performance, with a tensile strength of 480 MPa or higher and an elongation after fracture of 7% or higher, and has good strength and plasticity, and is widely applicable.

[0013] The foregoing general description and the following description are merely exemplary and explanatory, and are not intended to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0014] One or more embodiments are exemplarily illustrated by corresponding drawings, which do not constitute a limitation on the embodiments, and elements with the same reference numerals in the drawings are shown as similar elements, the drawings do not constitute a proportional limitation, and wherein: Figure 1 is a flowchart of a method for preparing a directionally solidified aluminum alloy provided by the embodiments of the present disclosure; Figure 2 is a flowchart of a method for preparing an aluminum alloy ingot provided by the embodiments of the present disclosure; Figure 3 is a flowchart of a method for preparing an aluminum alloy ingot provided by the embodiments of the present disclosure; Figure 4 is a tensile curve diagram of an initial aluminum alloy, an aluminum alloy after homogenization treatment, a directionally solidified aluminum alloy A, a directionally solidified aluminum alloy B, and a directionally solidified aluminum alloy C according to Embodiment 2 of the present disclosure; Figure 5a is a metallographic structure diagram of an initial aluminum alloy according to Embodiment 2 of the present disclosure; Figure 5bis a metallographic structure diagram of the aluminum alloy after homogenization treatment of the embodiment 2 of the present disclosure; Figure 5c is a metallographic structure diagram of the directional solidification aluminum alloy A of the embodiment 2 of the present disclosure; Figure 5d is a metallographic structure diagram of the directional solidification aluminum alloy B of the embodiment 2 of the present disclosure. DETAILED DESCRIPTION

[0015] In order to enable a more detailed understanding of the features and technical content of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings, which are only used for reference and do not limit the embodiments of the present disclosure. In the following technical description, in order to facilitate explanation, through multiple details, a sufficient understanding of the disclosed embodiments is provided. However, one or more embodiments can still be implemented without these details. In other cases, in order to simplify the drawings, well-known structures, steps and devices can be simplified.

[0016] The terms "first", "second", and the like in the specification and claims of the embodiments of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, so as to implement the embodiments of the present disclosure described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The term "multiple" means two or more. In the embodiments of the present disclosure, the character " / " represents an "or" relationship between the front and rear objects. For example, A / B means: A or B. The term "and / or" is a description of the relationship between the objects, which means that there can be three relationships. For example, A and / or B means: A or B, or, A and B, the three relationships.

[0018] It should be noted that the embodiments in the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0019] Those skilled in the art can understand that the order of the steps in the methods described in the specification and other parts of the present application, for example, in the methods of the embodiments, embodiments or claims, does not mean a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. If not specifically stated, all steps of the present application can be performed in sequence or randomly, preferably in sequence. For example, the method comprises steps A and B, which means that the method can comprise steps A and B in sequence, or steps B and A in sequence. For example, the method also comprises step C, which means that step C can be added to the method in any order, for example, the method can comprise steps A, B and C, or steps A, C and B, or steps C, A and B, etc.

[0020] In the present application, the open technical features or technical solutions described by the words "containing", "including", "comprising" and the like do not exclude additional members other than the listed members, which can be regarded as providing both a closed feature or solution composed of the listed members and an open feature or solution including additional members in addition to the listed members. For example, A includes a1, a2 and a3, and if there is no other statement, it can also include other members or can not include additional members, which can be regarded as providing both the feature or solution that "A is composed of a1, a2 and a3" and the feature or solution that "A not only includes a1, a2 and a3, but also includes other members".

[0021] "RANGES" disclosed herein can be defined with both a lower and an upper limit. Ranges built-up from a lower limit and an upper limit are defined to include the boundary number of the lower and upper limit, unless otherwise specifically stated. Ranges built-up from a lower limit and an upper limit can be either inclusive or exclusive of the boundary numbers, either or both of which can be combined in any manner, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges from 500 to 900 and 750 to 800 are listed, it is understood that ranges from 500 to 800 and 750 to 900 are also contemplated. Further, if a minimum range value of 1 and 2 are listed, and if a maximum range value of 3, 4, and 5 are also listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, numerical ranges "a-b" are intended to indicate any and all subcombinations of the same, wherein a and b are both real numbers. For example, the numerical range "1-9" is intended to indicate that all real numbers between 1 and 9, inclusive of the endpoints, have been listed herein. In addition, when a parameter is stated to be an integer ≥ 2, it is equivalent to listing the parameter as, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is stated to be an integer selected from "2-10", it is equivalent to listing the parameter as integer 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0022] In this application, A (such as B) means B is one non-limiting example of A, and A is not limited to B, unless otherwise specified.

[0023] In combination Figure 1 As shown in the drawings, the embodiments of the present disclosure provide a preparation method of a directionally solidified aluminum alloy, comprising the following steps: S1, placing a crucible containing an aluminum alloy ingot in a smelting chamber with inert atmosphere and a certain vacuum degree, heating and melting, and keeping warm to obtain an aluminum alloy melt; S2, controlling the crucible containing the aluminum alloy melt to move downward at a first downward speed, after the downward pulling is completed, taking out the crucible after cooling in the smelting chamber, and obtaining an initial aluminum alloy; S3, uniformly treating and quenching the initial aluminum alloy, and then performing aging treatment to obtain a directionally solidified aluminum alloy.

[0024] The preparation method of the embodiment of the present disclosure successfully prepares the initial aluminum alloy with columnar crystal characteristics through the directional solidification technology, and then performs homogenization treatment on the initial aluminum alloy, so that the coarse second phase on the grain boundary is successfully dissolved into the grain, and the coarse second phase in the grain is reduced; the directional solidification aluminum alloy is directly subjected to aging treatment after the homogenization treatment, and the hot rolling and solid solution stages of the normal aluminum alloy are skipped, the grain of the aluminum alloy in the aging process is columnar crystal grain, the constraint condition at the grain boundary is reduced to increase the plasticity, and the dispersed phase formed by the aging material in the grain improves the strength of the alloy, and therefore a high-performance directional solidification aluminum alloy is successfully prepared.

[0025] The preparation method of the directional solidification aluminum alloy provided by the embodiment of the present disclosure is a new composite preparation process combining directional solidification and heat treatment process, and high-performance aluminum alloy can be obtained through directional solidification, homogenization treatment and aging treatment, the process is simple, the production effect is improved, the production cost is low, and the whole preparation process is green and environmentally friendly. Not only the production process is greatly shortened and the cost is reduced, but also the coupling effect between solidification and heat treatment is used to realize the synergistic optimization of the aluminum matrix and the precipitated phase, thereby opening up a new technical path for developing aluminum alloy materials with better comprehensive performance.

[0026] The "directional solidification-homogenization-aging" integrated short process technical path of the embodiment of the present disclosure directly saves the rolling and solid solution key processes with high energy consumption and complex equipment requirements, significantly reduces the equipment investment, energy consumption and comprehensive operating cost while significantly improving the production efficiency. Moreover, it realizes the deep coupling of the material solidification process and the heat treatment system. By actively regulating the grain orientation and structure of the aluminum matrix in the directional solidification stage, and by means of the columnar crystal structure formed, the deformation ability and grain boundary synergistic response ability of the aluminum alloy in the room temperature stretching process are effectively coordinated, thereby laying a foundation for the morphology, size and distribution optimization of the precipitated phase in the subsequent homogenization and aging process. This strategy of implementing accurate microstructure regulation from the source of material solidification realizes the synergistic optimization between the aluminum matrix and the strengthening phase, significantly shortens the process flow and reduces the manufacturing cost, and comprehensively improves the comprehensive mechanical properties such as strength and toughness of the alloy, thereby providing a new technical route for developing a new generation of high-performance aluminum alloy materials, and having a wide engineering application prospect.

[0027] In step S1, the initial material of the aluminum alloy ingot for directional solidification can obtain a composition-uniform aluminum alloy melt, thereby effectively improving the directional solidification crystallization in the directional solidification process and improving the performance of the coarse-grained aluminum alloy. The composition of the aluminum alloy ingot is not limited and is determined according to actual needs. The shape and size of the aluminum alloy ingot are not limited, for example, the shape of the aluminum alloy ingot includes cylindrical, prismatic, cubic, etc., and is determined according to actual conditions.

[0028] It can be understood that in step S1, the crucible can be a crucible made of a material that does not introduce impurities or cause other effects to the aluminum alloy melt, for example, the crucible includes a corundum crucible.

[0029] Optionally, the aluminum alloy ingot includes an Al-Zn series alloy, an Al-Cu series alloy, an Al-Mg series alloy, or an Al-Si series alloy. The applicable alloy system is wide and easy to promote.

[0030] Optionally, the aluminum alloy ingot includes a 7-series aluminum alloy ingot. In this embodiment, the 7-series aluminum alloy belongs to the Al-Zn series alloy, specifically the Al-Zn-Mg-Cu series alloy, and a 7-series directional solidification aluminum alloy is obtained by using a 7-series aluminum alloy ingot. The 7-series aluminum alloy (7xxx series aluminum alloy, usually with zinc as the main alloying element, supplemented by magnesium, copper and other elements) belongs to a heat-treatable strengthening type high-strength aluminum alloy, which has excellent mechanical properties and significant lightweight effect, and has broad application prospects in fields such as aerospace and national defense industry that have strict requirements on material performance. The performance of the 7-series directional solidification aluminum alloy obtained by using the process flow simplified preparation method of the embodiment of the present disclosure can reach the performance of the 7-series aluminum alloy prepared by the existing complex process, thereby reducing the cost.

[0031] In some embodiments, the total mass percentage content of impurity elements in the aluminum alloy ingot is less than or equal to 0.2%. Controlling the impurity content is more conducive to controlling the grain orientation and microstructure of the aluminum matrix, preventing grain boundary segregation, avoiding damage to the continuity of the columnar crystal structure, and forming a better columnar crystal structure.

[0032] Optionally, the mass percentage content of impurity elements Fe and / or Si in the aluminum alloy ingot is less than or equal to 0.02%. Further optimizing the content of impurities Fe and Si further optimizes the columnar crystal structure.

[0033] Optionally, the aluminum alloy ingot in step S1 is prepared by using an aluminum raw material with a purity greater than or equal to 99.9%. By using high-purity aluminum raw materials, the impurity content in the aluminum alloy ingot can be effectively controlled. Optionally, the aluminum raw material is high-purity aluminum prepared from electrolytic aluminum after magnetic control directional solidification treatment.

[0034] Optionally, an aluminum alloy ingot is combined with Figure 2As shown, the following steps are taken: S11, according to the components of the aluminum alloy ingot and the preset amount of each component, prepare each raw material; wherein the raw materials at least include aluminum with a purity greater than or equal to 99.9%. S12, after melting the aluminum, add other raw materials to obtain molten aluminum. S13, pour the molten aluminum into a mold, cool, demold, and obtain an aluminum alloy ingot. In step S13, after demolding, cutting can be performed to obtain an aluminum alloy ingot with a specific shape and size suitable for a crucible. In this embodiment, in addition to aluminum, other raw materials can be prepared according to the composition of the directional solidification aluminum alloy required.

[0035] Optionally, step S12 can be completed in a medium-frequency induction furnace.

[0036] Optionally, when the directional solidification aluminum alloy is a 7-series aluminum alloy, the raw materials further include zinc, magnesium, copper, etc.

[0037] Optionally, when the directional solidification aluminum alloy is a 6-series aluminum alloy, the raw materials further include magnesium, silicon, etc.

[0038] Optionally, when the directional solidification aluminum alloy is a 5-series aluminum alloy, the raw materials further include magnesium, etc.

[0039] Optionally, when the raw materials further include Mg, step S12 includes: after melting the aluminum, adding other raw materials except magnesium, and finally adding magnesium to obtain molten aluminum. This reduces the ablation loss of magnesium. Before adding magnesium, the oxide skin on the surface of the magnesium block needs to be removed.

[0040] Optionally, a 7-series aluminum alloy ingot, the mass percentage of Zn is 5% to 6.5%, the mass percentage of Mg is 2% to 3%, and the mass percentage of Cu is 1% to 2.5%, based on the total mass of the aluminum alloy ingot; wherein the total mass percentage of impurities is less than or equal to 0.2%. In this embodiment, the content of Al is determined according to the actual situation, and the sum of the mass percentages of each component is ensured to be 100%.

[0041] Optionally, the mass percentage of Zn is 5.5% to 6.3%. Optionally, the mass percentage of Zn is 5.9% to 6.2%.

[0042] Optionally, the mass percentage of Mg is 2% to 2.5%. Optionally, the mass percentage of Mg is 2.0% to 2.2%.

[0043] Optionally, the mass percentage of Cu is 1.5% to 2.3%. Optionally, the mass percentage of Cu is 1.8% to 2.1%.

[0044] Optionally, in step S1, a heat insulation gasket is arranged between the aluminum alloy ingot and the bottom wall of the crucible to prevent the bottom temperature from being too low.

[0045] In some embodiments, in step S1, the inert atmosphere includes argon.

[0046] In some embodiments, in step S1, the vacuum degree includes 500-900 Pa. Alternatively, the vacuum degree includes 600-850 Pa. Alternatively, the vacuum degree includes 700-850 Pa. Alternatively, the vacuum degree includes 750-800 Pa.

[0047] Alternatively, the smelting chamber with the inert atmosphere and the vacuum degree is obtained by: keeping the gas inlet valve of the smelting chamber closed, then vacuumizing the smelting chamber to (1-9) x 10 -3 Pa, stopping vacuumizing; then opening the gas inlet valve, introducing inert gas into the smelting chamber, and closing the gas inlet valve when the vacuum degree in the smelting chamber reaches 500-900 Pa; thus obtaining the smelting chamber with the inert atmosphere and the vacuum degree. In the operation of vacuumizing the smelting chamber to (1-5) x 10 -3 Pa, the operation can be completed at one time or in two stages according to the specific conditions of the equipment. For example, in two stages, the first stage is to vacuumize the smelting chamber to not higher than 20 Pa by using a mechanical pump, and then to continue vacuumizing by using a molecular pump until the vacuum degree in the smelting chamber is vacuumized to (1-9) x 10 -3 Pa.

[0048] Alternatively, the smelting chamber is vacuumized to (2-8) x 10 -3 Pa, and vacuumizing is stopped. Alternatively, the smelting chamber is vacuumized to (3-7) x 10 -3 Pa, and vacuumizing is stopped. Alternatively, the smelting chamber is vacuumized to (4-6) x 10 -3 Pa, and vacuumizing is stopped. Alternatively, the smelting chamber is vacuumized to 5 x 10 -3 Pa, and vacuumizing is stopped.

[0049] In some embodiments, in step S1, the smelting chamber with the inert atmosphere and the vacuum degree is obtained by: placing the ingot of the aluminum alloy into the corundum crucible, and placing the bottom of the ingot of the aluminum alloy into the corundum gasket. Then, the sample table with the corundum crucible containing the ingot of the aluminum alloy is fixed on the machine cooling table of the directional solidification device, and the machine cooling table is adjusted to the corresponding position in the directional solidification device.

[0050] In some embodiments, in step S1, the heating and melting include stepwise heating to the melting temperature of the ingot of the aluminum alloy. The melting temperature is determined according to the specific ingot of the aluminum alloy used. For example, when the aforementioned ingot of the 7-series aluminum alloy is used, the melting temperature is 850-950℃.

[0051] In some embodiments, in step S1, the holding includes holding for 40-100 minutes. Optionally, the holding includes holding for 50-80 minutes. Optionally, the holding includes holding for 60 minutes.

[0052] In some embodiments, in step S2, the preset pulling-down speed is 30-150 μm / s. The speed should not be too fast, otherwise a large number of columnar crystals cannot be formed. Optionally, during the pulling-down process, the temperature gradient is kept at 30-70 k / cm.

[0053] Optionally, the preset pulling-down speed is 30-70 μm / s. Optionally, the preset pulling-down speed is 30-60 μm / s. Optionally, the preset pulling-down speed is 30-50 μm / s. Further optimization of the pulling-down speed increases the number of columnar crystals in the obtained initial aluminum alloy and improves the continuity of the columnar crystal structure.

[0054] Optionally, in step S2, during the pulling-down process, the preset pulling-down speed is kept unchanged. That is, the pulling-down is performed by using a fixed pulling-down speed.

[0055] Optionally, during the pulling-down process, the temperature gradient is kept at 40-65 k / cm. Optionally, the temperature gradient is kept at 50-65 k / cm. Optimization of the temperature gradient increases the number of columnar crystals in the obtained initial aluminum alloy and improves the continuity of the columnar crystal structure.

[0056] In the embodiments of the present disclosure, the crystal grains in the initial aluminum alloy obtained in step S1 are columnar crystal grains, and coarse second phases exist on the grain boundaries. Therefore, in step S2, homogenization treatment is first performed to successfully dissolve the coarse second phases on the grain boundaries into the crystal grains, and the coarse second phases in the crystal grains are reduced.

[0057] In some embodiments, the homogenization treatment is holding at a preset temperature for a preset length of time. The preset temperature is 460-480 ℃, and the preset length of time is 20-40 hours.

[0058] Optionally, the homogenization treatment includes: holding at a first temperature for a first length of time, and then holding at a second temperature for a second length of time; wherein the first temperature is less than the second temperature, and both the first temperature and the second temperature are in the temperature range of 460-480 ℃. By using two-stage homogenization treatment, more coarse second phases can be successfully dissolved into the crystal grains, and the coarse second phases in the crystal grains are further reduced.

[0059] Optionally, the first temperature is 460-470 ℃, and the second temperature is 470-480 ℃.

[0060] Optionally, the first length of time is 6-12 hours. Optionally, the first length of time is 6-10 hours.

[0061] Optionally, the second time length is 12-36 h. Optionally, the second time length is 20-30 h.

[0062] Optionally, the homogenization treatment comprises: holding at 460-470 DEG C for 6-12 h, and then holding at 470-480 DEG C for 12-36 h.

[0063] Optionally, the homogenization treatment comprises: holding at 460-465 DEG C for 6-10 h, and then holding at 470-475 DEG C for 20-30 h.

[0064] In step S2, after the homogenization treatment, quenching is performed, which can prevent the solute after homogenization from precipitating during cooling, and prepares for the next step of aging. The quenching mode is not limited, for example, water cooling is used for quenching.

[0065] In step S2, after the aging treatment, there are fine and dispersed second phases in the intracrystalline distribution, which greatly improves the strength of the alloy. In some embodiments, the aging treatment comprises: aging treatment at 100-150 DEG C for 20-30 h.

[0066] Optionally, the aging treatment comprises: aging treatment at 100-130 DEG C for 20-30 h.

[0067] Optionally, the aging treatment comprises: aging treatment at 110-130 DEG C for 22-28 h.

[0068] In some embodiments, in step S3, after the aging treatment, it further comprises: removing the top region of the aluminum alloy after the aging treatment, and the remaining part is used as the directionally solidified aluminum alloy. In the directionally solidified process, the heat flow of the middle and lower regions is stable, and the temperature gradient is large, which can form more and more regular columnar crystals.

[0069] In the preparation method of the embodiments of the present disclosure, the directionally solidified process of step S1 and step S2 is carried out in a directionally solidified equipment such as a vacuum melting and directionally solidified furnace.

[0070] The embodiments of the present disclosure provide a directionally solidified aluminum alloy, which is prepared by using the preparation method of the directionally solidified aluminum alloy of any of the preceding embodiments.

[0071] The directionally solidified aluminum alloy of the embodiments of the present disclosure has good performance, the tensile strength reaches more than 480 MPa, and the elongation after fracture reaches more than 7%, which has good strength and plasticity, and is widely used in various application scenarios.

[0072] The directionally solidified aluminum alloy of the embodiments of the present disclosure has a large proportion of columnar crystals, and the area proportion of the columnar crystals in the observation field of view is at least greater than or equal to 70%. Here, the observation field of view refers to the observation field of view of an instrument for observing the microstructure morphology of the alloy, for example, the observation field of view of a metallographic microscope.

[0073] The aluminum alloy member according to any one of the preceding embodiments is prepared by the method for preparing the directionally solidified aluminum alloy according to any one of the preceding embodiments.

[0074] The aluminum alloy member according to any one of the preceding embodiments is prepared by the method for preparing the directionally solidified aluminum alloy according to any one of the preceding embodiments.

[0075] In the embodiments of the present disclosure, the directionally solidified aluminum alloy can be processed to form an aluminum alloy member to adapt to different application scenarios.

[0076] Optionally, the aluminum alloy member can be applied in the fields of building, machinery, industrial manufacturing, transportation, electronics and electrical appliances, or aerospace, etc.

[0077] Optionally, the field of transportation includes the field of automobiles and the field of rail transportation, etc. Optionally, the field of industrial manufacturing includes the field of national defense manufacturing, etc. Optionally, the field of industrial manufacturing includes the field of home appliances manufacturing and the field of medical equipment manufacturing, etc.

[0078] Optionally, when the aluminum alloy member is applied in the field of electronics and electrical appliances, the aluminum alloy member is a conductive piece, a wire harness, a winding, an electronic component, or a connecting wire, etc.

[0079] Optionally, when the aluminum alloy member is applied in the field of machinery or the field of industrial manufacturing, the aluminum alloy member is a fastener, a mechanical part, a heat dissipation piece, etc. For example, an aluminum alloy rivet, a screw, a bolt, a connecting pin, a connecting shaft, a support rib, a home appliance device strip, a home appliance accessory, etc.

[0080] Optionally, when the aluminum alloy member is applied in the field of building, the aluminum alloy member is a building component or a decorative component. For example, a building pull rod, a cable, a handrail skeleton, a protective net, a fence, a door and window frame, etc.

[0081] Optionally, when the aluminum alloy member is applied in the field of transportation, the aluminum alloy member is a structural piece for automobiles or a structural piece for rail transportation. For example, a door skeleton, a seat skeleton, a chassis suspension connecting piece, a brake piece, etc.

[0082] Optionally, when the aluminum alloy member is applied in the field of aerospace, the aluminum alloy member is a standard fastener, an aviation rivet, an electronic cable, a structural piece support component, a precision instrument part, or a welding filler material, etc.

[0083] Optionally, the embodiments of the present disclosure further provide a terminal product comprising the aluminum alloy member according to the preceding embodiments. The terminal product is a final product prepared by using the aluminum alloy member or using the aluminum alloy member.

[0084] Optionally, the terminal product includes a vehicle, a household appliance, an electronic product, an aviation device, a general mechanical device, a medical device, a sports equipment, etc. For example, a car, a train, a mobile phone, a computer, a washing machine, a refrigerator, an airplane, a ship, a spacecraft, a robot, a machine tool, a hand tool, an oven, a furnace, a door and window curtain wall, a railing, a bicycle, fishing gear, surgical equipment, a wheelchair, etc.

[0085] It can be understood that the terminal product refers to a tangible product or functional system in the final delivery link in the industry chain, directly facing specific users, and being able to independently meet the core needs of the users.

[0086] The terminal product of the embodiment of the present disclosure includes the aluminum alloy component of any one of the foregoing embodiments, and therefore, the terminal product has all the beneficial effects of the foregoing aluminum alloy component, which will not be described here again.

[0087] Optionally, the terminal product includes a vehicle. For example, a new energy vehicle.

[0088] The following specific embodiments are given to specifically illustrate the directional solidification aluminum alloy and the preparation method thereof, the aluminum alloy component and the terminal product of the embodiment of the present disclosure, so as to more clearly illustrate the technical problems, technical solutions and beneficial effects solved by the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application.

[0089] Unless a specific technique or condition is specified in the embodiments, the technique or condition described in the literature in the art or according to the product instruction is used. The reagent or instrument not specified by the manufacturer is a conventional product that can be obtained by market purchase.

[0090] Embodiment 1 A 7-series aluminum alloy ingot, the mass percentage of Zn is 5.5% to 6.5%, the mass percentage of Mg is 2% to 2.5%, and the mass percentage of Cu is 1.5% to 2.5% based on the total mass of the aluminum alloy ingot; wherein the total mass percentage of impurities (Cr, Mn, Fe, Si) is less than or equal to 0.2%, and the balance is aluminum.

[0091] As shown in Figure 3 The preparation method of the 7-series aluminum alloy ingot of the present embodiment 1 includes the following steps: S101, according to the components and the amount of each component of the 7-series aluminum alloy ingot, the raw materials Al, Zn, Mg and Cu are prepared. Among them, Al adopts Al particles with a purity greater than or equal to 99.9% and is prepared by magnetron directional solidification treatment of electrolytic aluminum.

[0092] S102, turn on the intermediate frequency induction furnace, open the water pump switch to cool the intermediate frequency induction furnace, first add the Al particles prepared in step S101 to the intermediate frequency induction furnace, after the Al particles are completely melted, add Zn and Cu, and finally put the Mg block into the aluminum liquid with a metal clamp, wherein the metal clamp needs to be preheated.

[0093] S103, pour the melted aluminum liquid into the mold, and cut the metal block in the mold into an aluminum alloy ingot with a shape suitable for the cavity of the crucible, for example, a cylindrical shape, and polish the metal oxide layer on the surface of the aluminum alloy ingot with sandpaper.

[0094] Example 2 A preparation method of a directional solidification aluminum alloy, comprising the following steps: S110, place the 7-series aluminum alloy ingot sample of example 1 into a corundum crucible, and place the bottom of the sample into a corundum gasket to prevent the bottom temperature from being too low. Put the corundum crucible on the sample table, put the high-temperature-resistant glue on the top of the sample table, and the purpose of putting the high-temperature-resistant glue is to prevent the metal liquid from adhering to the sample table and fix the corundum crucible, and obtain the workpiece to be melted; S120, start the directional solidification equipment (for example, use a high-vacuum magnetic control directional solidification furnace k24-412), open the water pump switch, inert gas switch (for example, argon switch), set the operation and power switch. Adjust the equipment to manual mode, open the air inlet valve. Remove the screws of the melting chamber, and use the manual remote control to lower the melting chamber to the limit. Fix the workpiece to be melted in step S110 on the machine cooling table, and raise the melting chamber to the fixed position to fix the screws.

[0095] S130, set the automatic process parameters: first close the air inlet valve, open the vacuum valve and mechanical pump, when the vacuum in the melting chamber is extracted to 10 Pa; open the molecular pump until the vacuum degree in the melting chamber is extracted to 5x10 -3 Pa, stop vacuum extraction, wait for 10 minutes when the rotating speed of the molecular pump is reduced to 0, close the molecular pump. Open the Ar gas valve, then fill high-purity Ar gas into the melting chamber, and observe the air pressure in the melting chamber, when the vacuum degree reaches 750-800 Pa, stop filling gas, and close the Ar gas valve. Use the mode of segmented heating to gradually increase the temperature in the corundum crucible. When the temperature of the aluminum alloy melt in the crucible reaches the set melting temperature (900℃), keep warm for 60 minutes.

[0096] S140, control the crucible containing the aluminum alloy melt to operate at a pulling speed of 30 μm / s, after the pulling is completed, when the temperature in the melting chamber is lowered to 100℃, adjust the equipment to manual mode, open the air inlet valve. Remove the screws of the melting chamber, and use the manual remote control to lower the melting chamber to the limit. Take out the corundum crucible and the internal metal sample, and obtain the initial aluminum alloy.

[0097] S150. The initial aluminum alloy is held at 460℃~465℃ for 6~10 h, then held at 470℃~475℃ for 20~30 h for secondary homogenization treatment, and then water-quenched; then aged at 120℃ for 12~36 h, the top area is removed, and the remaining part is the directionally solidified aluminum alloy.

[0098] In this Example 2, the elemental composition of the aluminum alloy after homogenization treatment was measured to be 6.1% Zn, 2.1% Mg, 1.9% Cu, and the content of other impurity elements (Cr, Mn, Fe, Si) should be <0.2%.

[0099] Combination Figure 5c and Figure 5d As shown, in the directional solidified aluminum alloy prepared in Example 2, the area ratio of columnar crystals is large, at least greater than or equal to 70%.

[0100] like Figure 4 The tensile curves of the initial aluminum alloy obtained in step S140 (corresponding to the as-cast curve), the aluminum alloy after homogenization treatment (corresponding to the homogenization curve), the directionally solidified aluminum alloy A obtained after aging for 12 hours (corresponding to the 12-hour aging curve), the directionally solidified aluminum alloy B obtained after aging for 24 hours (corresponding to the 24-hour aging curve), and the directionally solidified aluminum alloy C obtained after aging for 36 hours (corresponding to the 36-hour aging curve) show that the tensile strength of the as-cast initial aluminum alloy obtained solely through direction solidification is 375 MPa, and the elongation after fracture is 6.8%. After further heat treatment, the tensile strength and plasticity of the homogenized aluminum alloy are 410 MPa and 15%, respectively. After aging at 120℃ for 24 hours, the tensile strength increases to 548 MPa, and the elongation after fracture is 9.5%, which is a 46.1% increase in tensile strength and a 39.7% increase in elongation after fracture compared to the directionally solidified as-cast aluminum alloy. The tensile strength of directional solidified aluminum alloy C after aging treatment for 36 hours reaches about 510 MPa, but the elongation after fracture decreases significantly, making it suitable for applications where elongation after fracture is not a high requirement.

[0101] Figure 5a The image shows the metallographic structure of the initial aluminum alloy obtained in step S140. As can be seen from the metallographic observation, there are many blocky second phases distributed within the grains and at the grain boundaries. Although the distribution of the second phases is relatively uniform, the size of the second phases is relatively large. Figure 5b The image shows the metallographic structure of the aluminum alloy after homogenization treatment. It can be seen from the image that the blocky second phase is significantly reduced, and some of the second phase is distributed along the grain boundaries. Figure 5c The image shows the metallographic structure of the directionally solidified aluminum alloy A obtained after aging for 12 hours. It can be seen that the size of the second phase in the directionally solidified aluminum alloy A has changed significantly, but there are some smaller, randomly distributed second phases.Figure 5d It can be seen from the figure that the strip-shaped grain boundary second phase is distributed along the grain boundary, and the fine black second phase is uniformly distributed in the grain after the directional solidification aluminum alloy B is corroded after aging treatment for 24 hours.

[0102] Example 3 A method for preparing a directional solidification aluminum alloy, different from example 2, in step S140, the crucible containing the aluminum alloy melt is controlled to be operated at a pulling speed of 50 μm / s; in step S150, the aging treatment is performed at 120℃ for 24h. The remaining steps and parameters are the same as example 2.

[0103] In this example 3, the measured element composition of the aluminum alloy after homogenization treatment is that the content of Zn is 6.0%, the content of Mg is 2.1%, the content of Cu is 1.8%, and the content of other impurity elements (Cr, Mn, Fe, Si) should be <0.2%.

[0104] In this example 3, it can be known from the tensile test that the tensile strength of the as-cast initial aluminum alloy obtained only by directional solidification is 365MPa, and the elongation after fracture is 7.6%; while the tensile strength of the directional solidification aluminum alloy after further homogenization treatment, quenching and aging treatment (aging treatment at 120℃ for 24h) is 505MPa, and the elongation after fracture is 8.4%.

[0105] Example 4 A method for preparing a directional solidification aluminum alloy, different from example 2, in step S140, the crucible containing the aluminum alloy melt is controlled to be operated at a pulling speed of 70 μm / s; in step S150, the aging treatment is performed at 120℃ for 24h. The remaining steps and parameters are the same as example 2.

[0106] In this example 4, the measured element composition of the aluminum alloy after homogenization treatment is that the content of Zn is 5.9%, the content of Mg is 2.1%, the content of Cu is 1.8%, and the content of other impurity elements (Cr, Mn, Fe, Si) should be <0.2%.

[0107] The tensile test is performed on the directional solidification aluminum alloy after aging treatment, and the tensile strength of the directional solidification aluminum alloy after aging treatment at 120℃ for 24h is 509MPa, and the elongation after fracture is 7.4%.

[0108] Example 5 A method for preparing a directional solidification aluminum alloy, different from example 2, in step S150, the aging treatment is performed at 100℃ for 24h. The remaining steps and parameters are the same as example 2.

[0109] The directional solidification aluminum alloy after aging treatment is subjected to tensile test, and the tensile strength of the directional solidification aluminum alloy after aging treatment at 100℃ for 24h is 483MPa, and the elongation after fracture is 8.3%.

[0110] Example 6 A preparation method of a directional solidification aluminum alloy, different from example 2, is that the aging treatment at 150℃ for 24h is performed in step S150. The remaining steps and parameters are the same as those in example 2.

[0111] The directional solidification aluminum alloy after aging treatment is subjected to tensile test, and the tensile strength of the directional solidification aluminum alloy after aging treatment at 150℃ for 24h is 498MPa, and the elongation after fracture is 7.2%.

[0112] Comparative Example 1 An aluminum alloy ingot comparison, different from example 1, is that in step S101, the raw material aluminum adopts conventional aluminum particles with a purity of 99.85%, and in the obtained aluminum alloy ingot comparison, the impurity elements Fe and Si content >0.4%, and the C and Mn content >0.3%.

[0113] Comparative Example 2 Different from example 2, the comparative example 3 performs the operations of steps S110 to S140 of example 2, wherein in step S110, the aluminum alloy ingot comparison sample of comparative example 1 is used instead of the 7-series aluminum alloy ingot sample in step S110 of example 1, and an as-cast initial alloy comparison A is obtained.

[0114] Through tensile test, the tensile strength of the as-cast initial alloy comparison A is 355MPa, and the elongation after fracture is 4.6%. The tensile strength and the elongation after fracture are worse than those of the as-cast aluminum alloy obtained in step S140 of example 2, and it can be inferred that the tensile strength and the elongation after fracture of the directional solidification aluminum alloy after homogenization treatment, quenching and aging treatment are also significantly lower than those of the directional solidification aluminum alloy obtained in example 2.

[0115] Comparative Example 3 Different from example 2, the comparative example 3 performs the operations of steps S110 to S140 of example 2, wherein in step S140, the crucible containing the aluminum alloy melt is controlled to perform the downward drawing operation at a downward drawing speed of 20μm / s, and an as-cast initial alloy comparison B is obtained.

[0116] Through tensile test, the tensile strength of the as-cast initial alloy comparison B is 305MPa, and the elongation after fracture is 6.5%. The tensile strength and the elongation after fracture are worse than those of the as-cast aluminum alloy obtained in step S140 of example 2, and it can be inferred that the tensile strength and the elongation after fracture of the directional solidification aluminum alloy after homogenization treatment, quenching and aging treatment are also significantly lower than those of the directional solidification aluminum alloy obtained in example 2.

[0117] Comparative Example 4 Different from Example 2, Comparative Example 4 carried out the operation of steps S110 to S140 of Example 2, wherein in step S140, the crucible containing the molten aluminum alloy was controlled to carry out the down-drawing operation at a down-drawing speed of 80 μm / s, and the as-cast initial alloy Comparative C was obtained.

[0118] Through the tensile test, the tensile strength of the as-cast initial alloy Comparative C was 366 MPa, and the elongation after fracture was 5.7%. The tensile strength and the elongation after fracture were worse than those of the as-cast aluminum alloy obtained in step S140 of Example 2, and it could be inferred that the tensile strength and the elongation after fracture of the directionally solidified aluminum alloy after the homogenization treatment, quenching and aging treatment were also significantly lower than those of the directionally solidified aluminum alloy obtained in Example 2.

[0119] Comparative Example 5 The preparation method of a directionally solidified aluminum alloy Comparative D in Comparative Example 5 was different from Example 2 in that in step S150, the initial aluminum alloy was kept at 475 ℃ for 6-10 h, then kept at 485 ℃ for 20-30 h for the secondary homogenization treatment, then quenched by water cooling; and then aged at 120 ℃ for 24 h. The other steps and parameters were the same as those in Example 2.

[0120] In Comparative Example 5, the element composition of the aluminum alloy after the homogenization treatment was measured as follows: the content of Zn was 5.8%, the content of Mg was 2.0%, the content of Cu was 1.9%, and the content of other impurity elements (Cr, Mn, Fe, Si) should be <0.2%.

[0121] Through the tensile test, the tensile strength of the directionally solidified aluminum alloy Comparative D obtained in Comparative Example 5 was 456 MPa, and the elongation after fracture was 4.8%. It was found through analysis that the material was overburned during the homogenization treatment, and the homogenization temperature should not be too high.

[0122] Comparative Example 6 The preparation method of a directionally solidified aluminum alloy Comparative in Comparative Example 6 was different from Example 2 in that in step S150, after the homogenization treatment, the step of quenching by water cooling was not carried out, and the aging treatment was directly carried out at 120 ℃. The other steps and parameters were the same as those in Example 2.

[0123] The tensile test was performed on the obtained directional solidification aluminum alloy in Comparative Example 6. The tensile strength of the directional solidification aluminum alloy Comparative Example E without quenching and directly aged at 120℃ for 12h was 469MPa, and the elongation after fracture was 7.6%. The tensile strength of the directional solidification aluminum alloy Comparative Example F without quenching and directly aged at 120℃ for 24h was 448MPa, and the elongation after fracture was 5.6%. It can be seen that the material without quenching reached the peak aging in 12 hours, and the performance further decreased with the increase of aging time. In the embodiments of the present disclosure, the test method of the tensile test comprises: using an MTS tensile machine, the tensile direction is the same as the downward direction, the tensile speed is 1×10 -3 / s.

[0124] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present disclosure.

[0125] The above-mentioned embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as the limitation of the patent scope of the present application. It should be pointed out that, for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A method of producing a directionally solidified aluminium alloy characterised in that, The preparation method comprises the following steps: placing a crucible containing an aluminum alloy ingot in a smelting chamber with an inert atmosphere and a certain vacuum degree, heating and melting, and holding to obtain an aluminum alloy melt; controlling the crucible containing the aluminum alloy melt to perform a down-drawing operation at a preset down-drawing speed, and after the down-drawing is completed, taking out the crucible after cooling in the smelting chamber to obtain an initial aluminum alloy; after homogenization treatment and quenching of the initial aluminum alloy, performing aging treatment to obtain a directionally solidified aluminum alloy.

2. The preparation method according to claim 1, wherein: the total mass percentage of impurity elements in the aluminum alloy ingot is less than or equal to 0.2%; and / or the aluminum alloy ingot comprises an Al-Zn alloy, an Al-Cu alloy, an Al-Mg alloy or an Al-Si alloy; and / or the aluminum alloy ingot is prepared by using a raw material comprising aluminum with a purity greater than or equal to 99.9%; and / or the vacuum degree comprises 500-900 Pa; or the vacuum degree comprises 600-850 Pa; or the vacuum degree comprises 700-850 Pa; or the vacuum degree comprises 750-800 Pa; and / or the heating and melting comprises stepwise heating to the melting temperature of the aluminum alloy ingot; and / or the holding comprises holding for 40-100 min.

3. The preparation method according to claim 1, wherein: the preset down-drawing speed is 30-70 μm / s; or the preset down-drawing speed is 30-60 μm / s; or the preset down-drawing speed is 30-50 μm / s; and / or during the down-drawing, the temperature gradient is maintained at 30-70 k / cm; or the temperature gradient is maintained at 40-65 k / cm; or the temperature gradient is maintained at 50-65 k / cm.

4. The preparation method according to claim 1, wherein: the homogenization treatment comprises holding at 460-480 ℃ for 20-40 h; or the homogenization treatment comprises holding at a first temperature for a first time length, and then holding at a second temperature for a second time length; wherein the first temperature is less than the second temperature, and both the first temperature and the second temperature are within the temperature range of 460-480 ℃; or the homogenization treatment comprises holding at 460-470 ℃ for 6-12 h, and then holding at 470-480 ℃ for 12-36 h.

5. The preparation method according to claim 1, wherein: the aging treatment comprises aging at 100-150 ℃ for 20-30 h; or the aging treatment comprises aging at 100-130 ℃ for 20-30 h; or the aging treatment comprises aging at 110-130 ℃ for 22-28 h.

6. The preparation method according to any one of claims 1-5, wherein: after the aging treatment, the method further comprises removing a top region of the aluminum alloy after the aging treatment, and the remaining part is used as the directionally solidified aluminum alloy; and / or The smelting chamber with inert atmosphere and certain vacuum is obtained by keeping the inlet valve of the smelting chamber closed, then vacuumizing the smelting chamber to (1-9)×10 -3 Pa, stopping vacuumizing, then opening the inlet valve to let inert gas into the smelting chamber, and closing the inlet valve when the vacuum of the smelting chamber reaches 500-900 Pa.

7. The preparation method according to any one of claims 1-5, wherein: The mass percentage of Zn in the aluminum alloy ingot is 5% to 6.5%, the mass percentage of Mg is 2% to 3%, and the mass percentage of Cu is 1% to 2.5%, based on the total mass of the aluminum alloy ingot; wherein the total mass percentage of impurities is less than or equal to 0.2%.

8. The production method according to claim 7, characterized in that the mass percentage of Zn is 5.5% to 6.3%; or the mass percentage of Zn is 5.9% to 6.2%; and / or the mass percentage of Mg is 2% to 2.5%; or the mass percentage of Mg is 2.0% to 2.2%; and / or the mass percentage of Cu is 1.5% to 2.5%; or the mass percentage of Cu is 1.8% to 2.1%.

9. A directionally solidified aluminium alloy characterised in that, obtained by the production method of the directionally solidified aluminum alloy according to any one of claims 1 to 8.

10. An aluminum alloy member characterized by, the directionally solidified aluminum alloy obtained by the production method of the directionally solidified aluminum alloy according to any one of claims 1 to 8, or the directionally solidified aluminum alloy according to claim 9.

11. An end product comprising the aluminum alloy member according to claim 10.

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