Microcrystal aluminum alloy and preparation method and application thereof

Abstract

The invention discloses a microcrystalline aluminum alloy and a preparation method and application thereof, and belongs to the technical field of microcrystalline aluminum alloy material preparation. The microcrystalline aluminum alloy disclosed by the invention comprises Al and the following components in percentage by weight: 0.5 to 4.0 percent of Si, 0.5 to 4.5 percent of Mg, 0.5 to 5.0 percent of Fe, 0.5 to 6.0 percent of Cu, 0.5 to 8.0 percent of Ni, 0 to 5.0 percent of Mn, 0 to 4.0 percent of Mo, 0 to 4.0 percent of Zr and inevitable impurities. The grain size of the microcrystalline aluminum alloy is smaller than 5 microns, the hardness is larger than or equal to 150 HB, the room-temperature tensile strength is larger than or equal to 450 MPa, the high-temperature tensile strength (200 DEG C) is larger than 200 MPa, and the flatness is smaller than or equal to 5 microns.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of microcrystalline aluminum alloy materials, and particularly relates to a microcrystalline aluminum alloy and its preparation method and application. Background Art

[0002] Aluminum alloy has the characteristics of low density, low thermal expansion coefficient, high elastic modulus, strong deformability, etc. Moreover, aluminum alloy has a large machining space and can adapt to various material processing technologies, and is an excellent material for preparing optical reflectors.

[0003] Currently, the casting process (steps include: metal melting, mold manufacturing, pouring and solidification, and demolding and cleaning) is generally used to prepare microcrystalline aluminum alloy. However, there are a large number of casting defects (shrinkage porosity, gas holes, inclusions) in the microcrystalline aluminum alloy produced by the casting process, and many problems such as uneven composition will also be caused, which cannot meet the actual production and application requirements. Summary of the Invention

[0004] The purpose of the present invention is to provide a microcrystalline aluminum alloy and its preparation method and application to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above purpose, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention: A microcrystalline aluminum alloy, by weight percentage, includes Al and the following components: Si 0.5 - 4.0%, Mg 0.5 - 4.5%, Fe 0.5 - 5.0%, Cu 0.5 - 6.0%, Ni 0.5 - 8.0%, Mn 0 - 5.0%, Mo 0 - 4.0%, Zr 0 - 4.0% and unavoidable impurities.

[0007] Preferably, the microcrystalline aluminum alloy, by weight percentage, includes Al and the following components: Si 0.5 - 3.8%, Mg 0.5 - 4.0%, Fe 0.5 - 4.8%, Cu 0.5 - 5.5%, Ni 0.5 - 7.5%, Mn 0 - 4.5%, Mo 0 - 3.5%, Zr 0 - 3.5% and unavoidable impurities.

[0008] More preferably, the total weight percentage of the impurities is less than 0.15%, and the weight percentage of each impurity element is less than 0.05%.

[0009] Si in the present invention has a relatively high liquid surface tension. By adjusting the addition amount of Si element in the microcrystalline aluminum alloy (0.5 - 4.0%), the alloy melt can have good fluidity during melting, which is beneficial to the gas atomization powder making process. By adjusting the addition amount of Mg element in the microcrystalline aluminum alloy (0.5 - 4.5%), the strength of the alloy is improved. And the Si element and Mg element can form Mg2Si phase. When Mg2Si phase is dissolved in the matrix, it can cause lattice distortion and hinder dislocation movement, thereby improving the hardness of the alloy. By adding an appropriate amount of Cu element (0.5 - 6.0%) in the microcrystalline aluminum alloy, the plasticity during hot working is improved and the strengthening effect of heat treatment is enhanced.

[0010] The combined action of Mn element and Cu element in the microcrystalline aluminum alloy can improve the elongation rate of the alloy, enhance the plasticity of the alloy and improve the flatness.

[0011] In the present invention, by adjusting the addition amount of Fe element in the microcrystalline aluminum alloy (0.5 - 5.0%), the grain refinement is achieved, the purity of the melt is controlled, the surface roughness of the alloy is improved, and the processing flatness is enhanced. By adding an appropriate amount of Ni element (0.5 - 8.0%) in the microcrystalline aluminum alloy, the tensile strength and hardness of the alloy are increased.

[0012] The combined action of Zr element and Mn element in the microcrystalline aluminum alloy can increase the recrystallization temperature of the alloy, refine the grains, and further improve the processing flatness.

[0013] Zr element and Mo element in the microcrystalline aluminum alloy can form insoluble phases in the alloy, pin the dislocations and prevent grain growth, which can improve the hardness of the alloy.

[0014] The second technical solution of the present invention: A preparation method of the above microcrystalline aluminum alloy, comprising the following steps:

[0015] Mix the raw materials of the components and then carry out homogenization treatment, powder making, forming and rolling in sequence to obtain the microcrystalline aluminum alloy.

[0016] Further, the homogenization treatment includes: mixing and melting the raw materials of the components and then stirring to obtain a homogenized melt;

[0017] The height of the tumbling during the stirring is 5 - 20 cm, the power is 10 - 200 kW, and the time is 10 min.

[0018] Preferably, the powder making includes: making powder from the homogenized melt by vacuum gas atomization method to obtain microcrystalline aluminum material powder.

[0019] Preferably, the atomization temperature of the vacuum gas atomization method is 800 - 1200 °C, the atomization time is 15 - 45 min, and the atomization pressure is 3 - 8 MPa.

[0020] Preferably, the forming includes: subjecting the microcrystalline aluminum alloy material powder to hot isostatic pressing to obtain an ingot.

[0021] Preferably, the heating-up time of the hot isostatic pressing is 2.5 - 3.5 h, the temperature is 450 - 650 °C, and the heat preservation time is 3 - 12 h.

[0022] Preferably, the temperature of the rolling is 250 - 400 °C, the deformation amount is 80 - 90%, and the rolling speed is 10 - 50 mm / s.

[0023] The third technical solution of the present invention: an application of the above-mentioned microcrystalline aluminum alloy in the preparation of a reflector of an optical precision instrument.

[0024] The present invention discloses the following technical effects:

[0025] (1) The grain size of the microcrystalline aluminum alloy of the present invention is < 5 μm, the hardness is ≥ 150 HB, the tensile strength at room temperature is ≥ 450 MPa, the tensile strength at high temperature (200 °C) is > 200 MPa, and the flatness is ≤ 5 μm.

[0026] (2) By adjusting the composition and preparation process (vacuum gas atomization powder making, hot isostatic pressing) of the present invention, the grain size in the microcrystalline aluminum alloy is reduced, the uniformity of the composition is improved, and the problems of a large number of casting defects (shrinkage porosity, gas holes, inclusions) and non-uniform composition existing in the production of microcrystalline aluminum alloy by the casting process are solved.

[0027] (3) The present invention uses the method of vacuum gas atomization powder making to prepare powder raw materials, and then uses the method of hot isostatic pressing to form the powder raw materials into an ingot, which not only ensures that the microcrystalline aluminum alloy blank has extremely high purity, but also can improve the density, strength and other properties of the material.

[0028] (4) By using the method of the present invention, microcrystalline aluminum alloy bars with different diameters can be produced by adjusting the deformation amount. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is a metallographic picture of the microcrystalline aluminum alloy bar prepared in Example 3 of the present invention. Detailed Embodiments

[0031] The various exemplary embodiments of the present invention will be described in detail below. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and implementation manners of the present invention.

[0032] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0033] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0034] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0035] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0036] It should be noted that the aspects not described in detail in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0037] In a first aspect of the present invention, there is provided a microcrystalline aluminum alloy, which, by weight percentage, comprises Al and the following components: Si 0.5 - 4.0%, Mg 0.5 - 4.5%, Fe 0.5 - 5.0%, Cu 0.5 - 6.0%, Ni 0.5 - 8.0%, Mn 0 - 5.0%, Mo 0 - 4.0%, Zr 0 - 4.0%, and inevitable impurities.

[0038] Preferably, the microcrystalline aluminum alloy, by weight percentage, comprises Al and the following components: Si 0.5 - 3.8%, Mg 0.5 - 4.0%, Fe 0.5 - 4.8%, Cu 0.5 - 5.5%, Ni 0.5 - 7.5%, Mn 0 - 4.5%, Mo 0 - 3.5%, Zr 0 - 3.5% and inevitable impurities.

[0039] More preferably, the total weight percentage of the impurities is less than 0.15%, and the weight percentage of each impurity element is less than 0.05%.

[0040] In the second aspect of the present invention, a method for preparing a microcrystalline aluminum alloy is provided, comprising the following steps:

[0041] (1) Initial batching: Carry out batching according to the component ratio;

[0042] (2) Homogenization treatment: Mix the raw materials of the components, melt them, and then use the electromagnetic induction stirring of the intermediate frequency furnace (the tumbling height is 5 - 20 cm, the power is 10 - 200 kW, and the time is 10 min) to stir the melt to obtain a homogenized melt;

[0043] (3) Preparing microcrystalline aluminum material powder: Place the homogenized melt in a vacuum gas atomization furnace, evacuate to ensure that the vacuum degree in the vacuum gas atomization furnace reaches within 10 Pa. After evacuation, fill the vacuum gas atomization furnace with an inert gas, the filling pressure is 0 - 50 kPa, the filling time is 10 - 30 min, then heat up to 800 - 1200 °C, increase the pressure to 3 - 8 MPa, and carry out vacuum gas atomization treatment for 15 - 45 min to obtain microcrystalline aluminum material powder;

[0044] The particle size range of the microcrystalline aluminum material powder is 0.5 - 150 μm, the oxygen content ≤ 0.10%, the loose bulk density ≥ 1.5 g / cm 3 , and the tapped density ≥ 1.8 g / cm 3 ;

[0045] (4) Forming: Carry out hot isostatic pressing on the microcrystalline aluminum material powder (the heating time of hot isostatic pressing is 2.5 - 3.5 h, the temperature is 450 - 650 °C, and the holding time is 3 - 12 h) to obtain an ingot blank;

[0046] (5) Rolling: Carry out hot rolling on the ingot blank together with a pure aluminum sheath (the temperature is 250 - 400 °C, the deformation amount is 80 - 90%, and the rolling speed is 10 - 50 mm / s). After hot rolling, remove the sheath to obtain a microcrystalline aluminum alloy with a diameter of 10 - 200 mm;

[0047] The grain size of the microcrystalline aluminum alloy < 5 μm, the hardness ≥ 150 HB, the room temperature tensile strength ≥ 450 MPa, the high temperature tensile strength (200 °C) > 200 MPa, and the flatness ≤ 5 μm.

[0048] In the third aspect of the present invention, there is provided an application of the above-mentioned microcrystalline aluminum alloy in the preparation of a reflector for an optical precision instrument.

[0049] Example 1

[0050] A method for preparing a microcrystalline aluminum alloy bar:

[0051] (1) The microcrystalline aluminum alloy bar is composed of the following components by weight percentage: Si 0.5%, Mg 0.5%, Fe 0.5%, Cu 0.5%, Ni 0.5%, and the balance is Al and inevitable impurities, and the weight percentage of impurities is less than 0.15%, and the weight percentage of each impurity element is less than 0.05%.

[0052] (2) Initial batching: Batching is carried out according to the component ratio;

[0053] (3) Homogenization treatment: After all the raw materials are melted, the electromagnetic induction of the intermediate frequency furnace itself is used to stir (tumble) the molten liquid in the furnace. The tumbling height is 5 cm, the tumbling power is 50 kW, and the time is 10 min to obtain a homogenized melt. The fluidity of the melt is 600 mm.

[0054] (4) Preparing microcrystalline aluminum material powder: The homogenized melt is placed in a vacuum atomization furnace, evacuated to ensure that the vacuum degree in the furnace reaches within 10 Pa. After evacuation, nitrogen is filled into the vacuum atomization furnace. The filling pressure is 50 kPa, and the filling time is 10 min. Then it is heated to 1000 °C and the pressure is increased to 4 MPa for 30 min of vacuum atomization treatment to obtain microcrystalline aluminum material powder.

[0055] The particle size range of the microcrystalline aluminum material powder is 0.5 - 150 μm, the oxygen content is 0.05%, and the loose bulk density is 1.56 g / cm 3 , and the tapped density is 1.85 g / cm 3 .

[0056] (5) Powder metallurgy forming: The microcrystalline aluminum material powder is subjected to hot isostatic pressing (the heating time of hot isostatic pressing is 2.5 h, the temperature is 450 °C, and the holding time is 8 h) to obtain an ingot blank with a size of φ250×800 mm;

[0057] (6) The ingot blank together with the pure aluminum sheath is hot-rolled (the temperature is 300 °C, the deformation amount is 80%, and the rolling speed is 10 mm / s). After hot rolling, the sheath is removed to obtain a microcrystalline aluminum alloy bar with a diameter of 30 mm.

[0058] The grain size of the microcrystalline aluminum alloy bar prepared in this example is 4.5 μm, the hardness is 150 HB, the tensile strength at room temperature is 450 MPa, the tensile strength at high temperature (200 °C) is 230 MPa, the flatness is 4.5 μm, and the density is 2.73 g / cm 3 , the coefficient of thermal expansion is 22.38 ppm / °C, and the elastic modulus is 69.32 GPa.

[0059] Example 2

[0060] A preparation method of a microcrystalline aluminum alloy bar:

[0061] (1) The microcrystalline aluminum alloy bar is composed of the following components by weight percentage: Si 3.0%, Mg 0.5%, Fe 0.5%, Cu 0.5%, Ni 0.5%, Mn 0.5%, Mo 0.5%, Zr 0.5%, and the balance is Al and inevitable impurities, and the weight percentage of impurities is less than 0.15%, and the weight percentage of each impurity element is less than 0.05%.

[0062] (2) Initial batching: Carry out batching according to the component ratio;

[0063] (3) Homogenization treatment: After all the raw materials are melted, the molten liquid in the furnace is stirred (tumbled) by the electromagnetic induction of the intermediate frequency furnace itself. The height of the tumbling is 5 cm, the power of the tumbling is 50 kW, and the time is 10 min. After cooling, a homogenized melt is obtained, and the melt fluidity is 650 mm.

[0064] (4) Prepare microcrystalline aluminum material powder: Place the homogenized melt in a vacuum atomization furnace, evacuate to ensure that the vacuum degree in the furnace reaches within 10 Pa. After evacuation, fill nitrogen into the vacuum atomization furnace, the filling pressure is 40 kPa, and the filling time is 15 min. Then heat up to 1000 °C and increase the pressure to 4 MPa, and carry out vacuum atomization treatment for 30 min to obtain microcrystalline aluminum material powder.

[0065] The particle size range of the microcrystalline aluminum material powder is 0.5 - 150 μm, the oxygen content is 0.08%, and the loose bulk density is 1.58 g / cm 3 , and the tapped density is 1.9 g / cm 3 .

[0066] (5) Powder metallurgy forming: Perform hot isostatic pressing on the microcrystalline aluminum material powder (the heating-up time of hot isostatic pressing is 2.5 h, the temperature is 500 °C, and the holding time is 8 h) to obtain an ingot blank with a size of φ250×800 mm.

[0067] (6) The billet and the pure aluminum cladding are hot-rolled together (temperature: 350 °C, deformation: 80%, rolling speed: 20 mm / s). After hot rolling, the cladding is removed to obtain a microcrystalline aluminum alloy bar with a diameter of 35 mm.

[0068] The grain size of the microcrystalline aluminum alloy bar prepared in this example is 4.5 μm, the hardness is 157 HB, the tensile strength at room temperature is 463 MPa, the tensile strength at high temperature (200 °C) is 242 MPa, the flatness is 4.3 μm, and the density is 2.75 g / cm 3 , the coefficient of thermal expansion is 22.00 ppm / °C, and the elastic modulus is 71.44 GPa.

[0069] Example 3

[0070] A preparation method of a microcrystalline aluminum alloy bar:

[0071] (1) The microcrystalline aluminum alloy bar is composed of the following components by weight percentage: Si 1.5%, Mg 1.5%, Fe 2.0%, Cu 2.0%, Ni 2.0%, Mn 0.5%, Mo 0.5%, Zr 0.5%, the balance is Al and unavoidable impurities, and the weight percentage of impurities is less than 0.15%, and the weight percentage of each impurity element is less than 0.05%.

[0072] (2) Initial batching: Batching is carried out according to the component ratio;

[0073] (3) Homogenization treatment: After all the raw materials are melted, the electromagnetic induction of the intermediate frequency furnace itself is used to stir (tumble) the molten liquid in the furnace. The tumbling height is 5 cm, the tumbling power is 50 kW, the time is 10 min, and after cooling, a homogenized melt is obtained. The fluidity of the melt is 630 mm.

[0074] (4) Preparing microcrystalline aluminum material powder: The homogenized melt is placed in a vacuum atomization furnace, evacuated to ensure that the vacuum degree in the furnace reaches within 10 Pa. After evacuation, nitrogen is filled into the vacuum atomization furnace, the filling pressure is 20 kPa, the filling time is 20 min, then it is heated to 1000 °C and the pressure is increased to 4 MPa, and vacuum atomization treatment is carried out for 30 min to obtain microcrystalline aluminum material powder.

[0075] The particle size range of the microcrystalline aluminum material powder is 0.5 - 150 μm, the oxygen content is 0.075%, and the loose bulk density is 1.6 g / cm 3 , and the tapped density is 1.87 g / cm 3 .

[0076] (5) Powder metallurgy forming: The microcrystalline aluminum material powder is subjected to hot isostatic pressing (the heating-up time of hot isostatic pressing is 2.5 h, the temperature is 550 °C, and the heat preservation time is 8 h) to obtain an ingot blank with a size of φ250×800 mm.

[0077] (6) The ingot blank together with the pure aluminum sheath is subjected to hot rolling (the temperature is 400 °C, the deformation amount is 85%, and the rolling speed is 30 mm / s). After hot rolling, the sheath is removed to obtain a microcrystalline aluminum alloy rod with a diameter of 40 mm.

[0078] The metallographic picture of the microcrystalline aluminum alloy rod prepared in this example is shown in Figure 1 .

[0079] The grain size of the microcrystalline aluminum alloy rod prepared in this example is 4.0 μm, the hardness is 165 HB, the tensile strength at room temperature is 470 MPa, the tensile strength at high temperature (200 °C) is 250 MPa, the flatness is 4.0 μm, and the density is 2.82 g / cm 3 , the thermal expansion coefficient is 22.25 ppm / °C, and the elastic modulus is 79.63 GPa.

[0080] Example 4

[0081] A preparation method of a microcrystalline aluminum alloy rod:

[0082] (1) The microcrystalline aluminum alloy rod is composed of the following components by weight percentage: Si 1.5%, Mg 1.5%, Fe 2.0%, Cu 2.0%, Ni 2.0%, Mn 1.5%, Mo 1.5%, Zr 1.5%, and the balance is Al and inevitable impurities, and the weight percentage of impurities is less than 0.15%, and the weight percentage of each impurity element is less than 0.05%.

[0083] (2) Initial batching: Batching is carried out according to the component ratio;

[0084] (3) Homogenization treatment: After all the raw materials are melted, the electromagnetic induction of the intermediate frequency furnace itself is used to stir (tumble) the molten liquid in the furnace. The height of tumbling is 5 cm, the power of tumbling is 50 kW, and the time is 10 min. After cooling, a homogenized melt is obtained, and the fluidity of the melt is 630 mm.

[0085] (4) Preparation of microcrystalline aluminum material powder: The homogenized melt is placed in a vacuum atomization furnace, evacuated to ensure that the vacuum degree in the furnace reaches within 10 Pa. After evacuation, nitrogen is filled into the vacuum atomization furnace, the filling pressure is 15 kPa, the filling time is 25 min, and then the temperature is raised to 1000 °C and the pressure is raised to 4 MPa for 30 min of vacuum atomization treatment to obtain microcrystalline aluminum material powder.

[0086] The particle size range of the microcrystalline aluminum material powder is 0.5 - 150 μm, the oxygen content is 0.07%, and the apparent density is 1.58 g / cm 3 , and the tapped density ≥ 1.86 g / cm 3 .

[0087] (5) Powder metallurgy forming: The microcrystalline aluminum material powder is subjected to hot isostatic pressing (the heating-up time of hot isostatic pressing is 2.5 h, the temperature is 500 °C, and the holding time is 8 h) to obtain an ingot blank with dimensions of φ250 × 800 mm.

[0088] (6) The ingot blank together with the pure aluminum sheath is hot-rolled (the temperature is 400 °C, the deformation amount is 85%, and the rolling speed is 40 mm / s). After hot rolling, the sheath is removed to obtain a microcrystalline aluminum alloy bar with a diameter of 35 mm.

[0089] The grain size of the microcrystalline aluminum alloy bar prepared in this example is 3.5 μm, the hardness is 160 HB, the tensile strength at room temperature is 485 MPa, the tensile strength at high temperature (200 °C) is 210 MPa, the flatness is 3.0 μm, and the density is 2.84 g / cm 3 , the thermal expansion coefficient is 22.22 ppm / °C, and the elastic modulus is 80.42 GPa.

[0090] Example 5

[0091] A preparation method of a microcrystalline aluminum alloy bar:

[0092] (1) The microcrystalline aluminum alloy bar, by weight percentage, consists of the following components: Si 3.0%, Mg 3.5%, Fe 5.0%, Cu 6.0%, Ni 8.0%, Mn 5.0%, Mo 3.0%, Zr 3.0%, the balance being Al and unavoidable impurities, and the weight percentage of impurities is less than 0.15%, and the weight percentage of each impurity element is less than 0.05%.

[0093] (2) Initial batching: Batching is carried out according to the component ratio;

[0094] (3) Homogenization treatment: After all the raw materials are melted, the molten liquid in the furnace is stirred (tumbled) by the electromagnetic induction of the intermediate frequency furnace itself. The tumbling height is 10 cm, the tumbling power is 80 kW, and the time is 10 min. After cooling, a homogenized melt is obtained, and the melt fluidity is 650 mm.

[0095] (4) Preparation of microcrystalline aluminum material powder: Place the homogenized melt in a vacuum gas atomization furnace, evacuate the air to ensure that the vacuum degree in the furnace reaches within 10 Pa. After evacuation, fill the vacuum gas atomization furnace with nitrogen, with a filling pressure of 10 kPa and a filling time of 30 min. Then, heat up to 900 °C and increase the pressure to 4 MPa, and perform vacuum gas atomization treatment for 45 min to obtain microcrystalline aluminum material powder.

[0096] The particle size range of the microcrystalline aluminum material powder is 0.5 - 150 μm, the oxygen content is 0.085%, and the loose bulk density is 1.62 g / cm 3 , and the tapped density ≥ 1.88 g / cm 3 .

[0097] (5) Powder metallurgy forming: Perform hot isostatic pressing on the microcrystalline aluminum material powder (the heating-up time for hot isostatic pressing is 3 h, the temperature is 600 °C, and the holding time is 9 h) to obtain an ingot blank with dimensions of φ250 × 800 mm.

[0098] (6) Hot roll the ingot blank together with a pure aluminum jacket (the temperature is 400 °C, the deformation amount is 90%, and the rolling speed is 50 mm / s). After hot rolling, remove the jacket to obtain a microcrystalline aluminum alloy bar with a diameter of 40 mm.

[0099] The grain size of the microcrystalline aluminum alloy bar prepared in this example is 4.0 μm, the hardness is 150 HB, the room temperature tensile strength is 510 MPa, the high temperature tensile strength (200 °C) is 225 MPa, the flatness is 2.5 μm, and the density is 3.33 g / cm 3 , the coefficient of thermal expansion is 22.02 ppm / °C, and the elastic modulus is 132.36 GPa.

[0100] Comparative Example 1

[0101] The difference from Example 1 is only that the microcrystalline aluminum alloy bar is prepared by a casting process, with a casting temperature of 680 °C, a mold temperature of 135 °C, and a pouring temperature of 795 °C.

[0102] The grain size of the microcrystalline aluminum alloy bar prepared in this comparative example is 100 μm, the hardness is 88 HB, the room temperature tensile strength is 196 MPa, the high temperature tensile strength (200 °C) is 115 MPa, the flatness is 50 μm, and the density is 2.69 g / cm 3 , the coefficient of thermal expansion is 24.12 ppm / °C, and the elastic modulus is 65.46 GPa.

[0103] Comparative Example 2

[0104] The difference from Example 2 is only that the process of powder metallurgy forming is hot pressing, with a pressure of 50 MPa, a temperature of 400 °C, and a holding time of 4 h.

[0105] The grain size of the microcrystalline aluminum alloy bar prepared in this comparative example is 68 μm, the hardness is 95 HB, the tensile strength at room temperature is 450 MPa, the tensile strength at high temperature (200 °C) is 202 MPa, and the flatness is 20 μm. The density is 2.72 g / cm 3 , and the coefficient of thermal expansion is 23.45 ppm / °C, and the elastic modulus is 67.36 GPa.

[0106] Comparative Example 3

[0107] The difference from Example 2 is only that the microcrystalline aluminum alloy bar, by weight percentage, consists of the following components: Si 10.0%, Mg 6.0%, the contents of the remaining elements are the same, the balance is Al and unavoidable impurities, and the weight percentage of impurities is less than 0.15%, and the weight percentage of each impurity element is less than 0.05%.

[0108] The grain size of the microcrystalline aluminum alloy bar prepared in this comparative example is 75 μm, the hardness is 83 HB, the tensile strength at room temperature is 465 MPa, the tensile strength at high temperature (200 °C) is 189 MPa, the flatness is 8 μm, and the density is 2.72 g / cm 3 , and the coefficient of thermal expansion is 23.69 ppm / °C, and the elastic modulus is 68.46 GPa.

[0109] The components of the microcrystalline aluminum alloy bars prepared in Examples 1 to 5 are shown in Table 1, and the components of the microcrystalline aluminum alloy bars prepared in Comparative Examples 1 to 3 are shown in Table 2.

[0110] Table 1 Components of Microcrystalline Aluminum Alloy Bars

[0111]

[0112]

[0113] Table 2 Components of Microcrystalline Aluminum Alloy Bars

[0114]

[0115] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A microcrystalline aluminum alloy, characterized in that, By weight percentage, it comprises Al and the following components: Si 0.5 - 4.0%, Mg 0.5 - 4.5%, Fe 0.5 - 5.0%, Cu 0.5 - 6.0%, Ni 0.5 - 8.0%, Mn 0 - 5.0%, Mo 0 - 4.0%, Zr 0 - 4.0% and unavoidable impurities.

2. The microcrystalline aluminum alloy according to claim 1, wherein, By weight percentage, it comprises Al and the following components: Si 0.5 - 3.8%, Mg 0.5 - 4.0%, Fe 0.5 - 4.8%, Cu 0.5 - 5.5%, Ni 0.5 - 7.5%, Mn 0 - 4.5%, Mo 0 - 3.5%, Zr 0 - 3.5% and unavoidable impurities.

3. A method for preparing the microcrystalline aluminum alloy according to any one of claims 1 to 2, characterized in that, It comprises the following steps: Mix the raw materials of the components and then successively carry out homogenization treatment, powder making, forming and rolling to obtain the microcrystalline aluminum alloy.

4. The preparation method according to claim 3, characterized in that, The homogenization treatment includes: mixing and melting the raw materials of the components and then stirring to obtain a homogenized melt; And / or, the tumbling height of the stirring is 5 - 20 cm, the power is 10 - 200 kW, and the time is 10 min.

5. The preparation method according to claim 4, characterized in that, The powder making includes: making powder from the homogenized melt by vacuum gas atomization to obtain microcrystalline aluminum material powder.

6. The preparation method according to claim 5, characterized in that, The atomization temperature of the vacuum gas atomization method is 800 - 1200 °C, the atomization time is 15 - 45 min, and the atomization pressure is 3 - 8 MPa.

7. The preparation method according to claim 5, wherein The forming includes: performing hot isostatic pressing on the microcrystalline aluminum material powder to obtain a billet.

8. The preparation method according to claim 7, characterized in that, The heating-up time of the hot isostatic pressing is 2.5 - 3.5 h, the temperature is 450 - 650 °C, and the heat preservation time is 3 - 12 h.

9. The preparation method according to claim 3, characterized in that, The temperature of the rolling is 250 - 400 °C, the deformation amount is 80 - 90%, and the rolling speed is 10 - 50 mm / s.

10. Application of the microcrystalline aluminum alloy according to any one of claims 1 - 2 in the preparation of a reflector of an optical precision instrument.

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