High-strength rare earth aluminum alloy material and preparation method thereof

Abstract

The application relates to a high-strength rare earth aluminum alloy material and a preparation method thereof, and the preparation method comprises the following steps: step 1, weighing raw materials and mixing into a smelting furnace, heating to smelting, fully stirring to be uniform, and obtaining a first molten liquid; step 2, continuously blowing inert gas from the bottom of the first molten liquid, and performing slagging treatment to obtain a second molten liquid; step 3, adding nanoscale praseodymium yttrium silicide into the second molten liquid, and continuously fully stirring to obtain a third molten liquid; step 4, performing heat preservation and standing treatment on the third molten liquid, and pouring and forming to obtain aluminum alloy rough materials; and step 5, performing annealing treatment on the aluminum alloy rough materials, and obtaining the high-strength rare earth aluminum alloy material after cooling. In addition to conventional iron, copper, manganese and other elements, the rare earth elements praseodymium and yttrium are added, the prepared aluminum alloy material not only has the advantages of high strength and high toughness, but also has excellent corrosion resistance, and is very suitable for use in coastal areas and heavy industrial areas.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloys, and more specifically to a high-strength rare-earth aluminum alloy material and its preparation method. Background Technology

[0002] Large aluminum profiles are widely used in the manufacture of aerospace and ground transportation carriages. High-speed train carriages produced worldwide extensively utilize aluminum alloy profiles, leading to a surge in demand for high-performance aluminum alloy welding wire for these large profiles, which is largely dependent on imports. The composition and proportions of the welding wire directly affect its performance. Adding rare earth elements to aluminum alloys has a positive effect, improving the alloy's microstructure and properties; however, improper addition of rare earth elements can also form coarse intermetallic compounds, significantly reducing mechanical properties and causing substantial resource waste.

[0003] Generally, adding rare earth elements to aluminum alloy welding wire results in either limited and uneven performance improvement—for example, increased tensile strength without improved material plasticity and corrosion resistance, thus limiting the overall performance of the welding wire—or a significant gap in corrosion resistance compared to ordinary aluminum alloys and stainless steel, restricting the application of aluminum alloys and becoming a disadvantage. In practical applications, water, salt, sulfur dioxide, and other environmental factors are unavoidable, especially in coastal areas and some heavy industrial zones where high humidity, high salinity, and heavy pollution make the material's corrosion resistance crucial to product lifespan. Therefore, improving the corrosion resistance of aluminum alloys is particularly important. Summary of the Invention

[0004] To address the problems existing in the prior art, the purpose of this invention is to provide a high-strength rare earth aluminum alloy material and its preparation method.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a high-strength rare-earth aluminum alloy material, comprising the following steps:

[0007] Step 1: Weigh aluminum powder, iron powder, copper powder, silicon powder, magnesium powder, manganese powder and titanium powder, mix them into a furnace, heat to melt, and stir thoroughly to obtain the first molten liquid;

[0008] Step 2: Inert gas is continuously blown into the bottom of the first melt, and slag removal is performed during this process to obtain the second melt.

[0009] Step 3: Add nano-sized praseodymium yttrium silicide to the second melt and continue stirring thoroughly to obtain the third melt;

[0010] Step 4: Keep the third molten liquid at a constant temperature and allow it to stand. Then place it in a mold for casting to obtain aluminum alloy rough material.

[0011] Step 5: Anneal the aluminum alloy rough material and cool it to obtain a high-strength rare earth aluminum alloy material.

[0012] Preferably, in step 1, the purity of aluminum powder, iron powder, copper powder, silicon powder, magnesium powder, manganese powder, and titanium powder is ≥99.99%.

[0013] Preferably, in step 1, the temperature for heating and melting is 735-815℃.

[0014] Preferably, in step 2, the inert gas is at least one of helium, neon, argon, and xenon.

[0015] Preferably, in step 3, the nanoscale praseodymium yttrium silicide has a particle size of 20-30 nm.

[0016] Preferably, in step 4, the settling time is 15-25 minutes.

[0017] Preferably, in step 5, the annealing temperature is 380-450℃ and the annealing time is 1-2 hours.

[0018] Preferably, in step 5, the cooling method is a combination of furnace cooling and air cooling; first, furnace cooling is performed at a rate of 3-5℃ / min, and after the temperature drops to 200℃, air cooling is performed, which is natural cooling to room temperature.

[0019] Preferably, in step 3, the preparation process of nanoscale praseodymium-yttrium silicide includes:

[0020] S1. Weigh out yttrium oxide (Y2O3) and praseodymium oxide (Pr6O3). 11 The silicon powder and other materials are mixed in a grinding mill and then thoroughly ground to obtain a grinding mixture.

[0021] S2. Place the grinding mixture in a crucible, then place the crucible in a graphite furnace, introduce inert gas as a protective gas, heat to 1520-1660℃, hold for 2-4 hours, then cool down to 1250-1300℃ for the first time, hold for 2-4 hours again, and finally cool down to room temperature for the second time to obtain large praseodymium yttrium silicide particles.

[0022] S3. Place the large praseodymium yttrium silicide particles in a nano-scale pulverizer for pulverization, and after sieving, obtain nano-scale praseodymium yttrium silicide.

[0023] Preferably, in S1, the yttrium oxide (Y₂O₃) has a particle size of 1-2 μm and a purity ≥99.99%; the praseodymium oxide (Pr₆O₃) has a particle size of 1-2 μm and a purity ≥99.99%. 11The particle size of the powder is 1-2 μm, and the purity is ≥99.99%; the particle size of the silicon powder is 10-20 μm, and the purity is ≥99.99%.

[0024] Preferably, in S1, the mass ratio of yttrium oxide, praseodymium oxide and silicon powder is 2.3-4.6:10.2-20.4:8.4-25.3.

[0025] More preferably, in S1, the mass ratio of yttrium oxide, praseodymium oxide and silicon powder is 3.2:16.3:16.8.

[0026] Preferably, in step S1, the grinding time is 200-300 r / min, the grinding speed is 1-3 h, and the ball-to-material ratio is 2-3:1.

[0027] Preferably, in step S2, the heating rate is 10-15℃ / min, the first cooling rate is 5-10℃ / min, and the second cooling rate is 10-20℃ / min.

[0028] Secondly, the present invention provides a high-strength rare-earth aluminum alloy material, wherein the rare-earth aluminum alloy material comprises, by mass ratio:

[0029] Mg: 1.64%-1.96%, Si: 0.52%-0.83%, Ti: 0.22%-0.38%, Cu: 0.14%-0.25%, Fe: 0.12%-0.30%, Mn: 0.03%-0.14%, Pr: 0.085%-0.168%, Y: 0.018%-0.036%; balance is aluminum and other unavoidable impurities.

[0030] The beneficial effects of this invention are as follows:

[0031] 1. This invention prepares an aluminum alloy material. In addition to conventional elements such as iron, copper, and manganese, rare earth elements praseodymium and yttrium are added to the aluminum alloy material. The prepared aluminum alloy material not only has the advantages of high strength and high toughness, but also has excellent corrosion resistance, making it very suitable for use in coastal areas and heavy industrial areas.

[0032] 2. The rare earth elements praseodymium and yttrium added to the rare earth aluminum alloy material in this invention are added in the molten liquid as nano-sized praseodymium-yttrium silicide. The nano-sized praseodymium-yttrium silicide can form a coarse dispersed phase, thereby effectively inhibiting crystallization, preventing crack propagation, and improving the ductility and toughness of the aluminum alloy.

[0033] 3. In this invention, two rare earth elements, praseodymium and yttrium, are used to form a composite rare earth silicide. Through experiments, a suitable ratio is obtained. Compared with praseodymium silicide or yttrium silicide alone, it can better enhance the strength and toughness of aluminum alloy materials, especially in terms of corrosion resistance. Detailed Implementation

[0034] The technical solution of the present invention is illustrated below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or defining the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0035] To better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0036] The present invention will be further described below with reference to the following embodiments.

[0037] Example 1

[0038] A high-strength rare-earth aluminum alloy material, calculated by mass ratio, comprises:

[0039] Mg: 1.72%, Si: 0.66%, Ti: 0.25%, Cu: 0.22%, Fe: 0.12%, Mn: 0.1%, Pr: 0.135%, Y: 0.025%; balance is aluminum and other unavoidable impurities.

[0040] The preparation method of the above-mentioned high-strength rare earth aluminum alloy material includes the following steps:

[0041] Step 1: Weigh aluminum powder, iron powder, copper powder, silicon powder, magnesium powder, manganese powder and titanium powder, all with a purity ≥99.99%, mix them in a furnace, heat to 785℃, melt and stir thoroughly to obtain the first molten liquid;

[0042] Step 2: Argon gas is continuously blown into the bottom of the first melt, and slag removal is performed during this process to obtain the second melt;

[0043] Step 3: Add nano-sized praseodymium yttrium silicide with a particle size of 20-30 nm to the second melt, and continue to stir thoroughly to obtain the third melt;

[0044] Step 4: Keep the third molten liquid at a constant temperature for 20 minutes, then place it in a mold for casting to obtain aluminum alloy rough material;

[0045] Step 5: Anneal the aluminum alloy raw material at 420℃ for 1.5h, and then cool it by a combination of furnace cooling and air cooling. That is, first cool it in the furnace at a cooling rate of 4℃ / min, and then cool it naturally to room temperature after the temperature drops to 200℃, to obtain high-strength rare earth aluminum alloy material.

[0046] In step 3 above, the preparation process of nanoscale praseodymium-yttrium silicide includes:

[0047] S1. Weigh out yttrium oxide (Y₂O₃) with a particle size of 1 μm and praseodymium oxide (Pr₆O₃) with a particle size of 1 μm. 11 Yttrium oxide, praseodymium oxide, and silicon powder with a particle size of 10 μm are mixed in a grinding mill. The mass ratio of yttrium oxide, praseodymium oxide, and silicon powder is 3.2:16.3:16.8. The grinding process is carried out at a grinding time of 250 r / min and a grinding speed of 2 h. The ball-to-particle ratio is 2.5:1. After thorough grinding, a grinding mixture is obtained.

[0048] S2. Place the grinding mixture in a crucible, then place the crucible in a graphite furnace, introduce inert gas as a protective gas, heat to 1580℃ at a heating rate of 12℃ / min, and hold for 3 hours. Then, first cool down to 1250℃ at a cooling rate of 8℃ / min, hold for 3 hours again, and finally cool down to room temperature at a cooling rate of 15℃ / min to obtain large praseodymium yttrium silicide particles.

[0049] S3. Place the large praseodymium yttrium silicide particles in a nano-scale pulverizer for pulverization, and after sieving, obtain nano-scale praseodymium yttrium silicide.

[0050] Example 2

[0051] A high-strength rare-earth aluminum alloy material, calculated by mass ratio, comprises:

[0052] Mg: 1.64%, Si: 0.52%, Ti: 0.38%, Cu: 0.14%, Fe: 0.30%, Mn: 0.03%, Pr: 0.085%, Y: 0.018%; balance is aluminum and other unavoidable impurities.

[0053] The preparation method of the above-mentioned high-strength rare earth aluminum alloy material includes the following steps:

[0054] Step 1: Weigh aluminum powder, iron powder, copper powder, silicon powder, magnesium powder, manganese powder and titanium powder, all with a purity ≥99.99%, mix them in a furnace, heat to 735℃, melt and stir thoroughly to obtain the first molten liquid;

[0055] Step 2: Argon gas is continuously blown into the bottom of the first melt, and slag removal is performed during this process to obtain the second melt;

[0056] Step 3: Add nano-sized praseodymium yttrium silicide with a particle size of 20-30 nm to the second melt, and continue to stir thoroughly to obtain the third melt;

[0057] Step 4: Keep the third molten liquid at a constant temperature for 15 minutes, then place it in a mold for casting to obtain aluminum alloy rough material;

[0058] Step 5: Anneal the aluminum alloy raw material at 380℃ for 2 hours, and then cool it by a combination of furnace cooling and air cooling. That is, first cool it in the furnace at a cooling rate of 3℃ / min, and then cool it naturally to room temperature after the temperature drops to 200℃ to obtain high-strength rare earth aluminum alloy material.

[0059] Step 3, the preparation process of nanoscale praseodymium-yttrium silicide includes:

[0060] S1. Weigh out yttrium oxide (Y₂O₃) with a particle size of 2 μm and praseodymium oxide (Pr₆O₃) with a particle size of 2 μm. 11 Yttrium oxide and praseodymium oxide were mixed in a grinding mill with silicon powder having a particle size of 20 μm. The mass ratio of yttrium oxide, praseodymium oxide and silicon powder was 2.3:10.2:8.4. The grinding process was carried out at a time of 200 r / min for 1 hour, with a ball-to-particle ratio of 2:1. After thorough grinding, a grinding mixture was obtained.

[0061] S2. Place the grinding mixture in a crucible, then place the crucible in a graphite furnace, introduce inert gas as a protective gas, heat to 1520℃ at a heating rate of 10℃ / min, and hold for 4 hours. Then, first cool to 1250℃ at a cooling rate of 5℃ / min, hold for 4 hours again, and finally cool to room temperature at a cooling rate of 10℃ / min to obtain large praseodymium yttrium silicide particles.

[0062] S3. Place the large praseodymium yttrium silicide particles in a nano-scale pulverizer for pulverization, and after sieving, obtain nano-scale praseodymium yttrium silicide.

[0063] Example 3

[0064] A high-strength rare-earth aluminum alloy material, calculated by mass ratio, comprises:

[0065] Mg: 1.96%, Si: 0.83%, Ti: 0.22%, Cu: 0.25%, Fe: 0.18%, Mn: 0.14%, Pr: 0.168%, Y: 0.036%; balance is aluminum and other unavoidable impurities.

[0066] The preparation method of the above-mentioned high-strength rare earth aluminum alloy material includes the following steps:

[0067] Step 1: Weigh aluminum powder, iron powder, copper powder, silicon powder, magnesium powder, manganese powder and titanium powder, all with a purity ≥99.99%, mix them in a furnace, heat to 815℃, melt and stir thoroughly to obtain the first molten liquid;

[0068] Step 2: Argon gas is continuously blown into the bottom of the first melt, and slag removal is performed during this process to obtain the second melt;

[0069] Step 3: Add nano-sized praseodymium yttrium silicide with a particle size of 20-30 nm to the second melt, and continue to stir thoroughly to obtain the third melt;

[0070] Step 4: Keep the third molten liquid at a constant temperature for 25 minutes, then place it in a mold for casting to obtain aluminum alloy rough material;

[0071] Step 5: Anneal the aluminum alloy raw material at 450℃ for 1 hour, and then cool it by a combination of furnace cooling and air cooling. That is, first cool it in the furnace at a cooling rate of 5℃ / min, and then cool it naturally to room temperature after the temperature drops to 200℃, to obtain high-strength rare earth aluminum alloy material.

[0072] Step 3, the preparation process of nanoscale praseodymium-yttrium silicide includes:

[0073] S1. Weigh out yttrium oxide (Y₂O₃) with a particle size of 1 μm and praseodymium oxide (Pr₆O₃) with a particle size of 1 μm. 11 Yttrium oxide and praseodymium oxide were mixed in a grinding mill with silicon powder of 10 μm in a mass ratio of 4.6:20.4:25.3. The grinding process was carried out at a grinding time of 300 r / min for 3 h and a ball-to-particle ratio of 3:1. After thorough grinding, a grinding mixture was obtained.

[0074] S2. Place the grinding mixture in a crucible, then place the crucible in a graphite furnace, introduce inert gas as a protective gas, heat to 1660℃ at a heating rate of 15℃ / min, hold for 2 hours, then cool down to 1300℃ for the first time at a cooling rate of 10℃ / min, hold for 2 hours again, and finally cool down to room temperature for the second time at a cooling rate of 20℃ / min to obtain large praseodymium yttrium silicide particles.

[0075] S3. Place the large praseodymium yttrium silicide particles in a nano-scale pulverizer for pulverization, and after sieving, obtain nano-scale praseodymium yttrium silicide.

[0076] Comparative Example 1

[0077] A rare earth aluminum alloy material is prepared in a process that differs from that of Example 1 in that, in step 3, nano-sized praseodymium yttrium silicide is replaced with commercially available nano-sized praseodymium disilicide, while the rest of the process and the amount added are the same as in Example 1.

[0078] Comparative Example 2

[0079] A rare earth aluminum alloy material is prepared in a process that differs from that of Example 1 in that, in step 3, nano-sized praseodymium yttrium silicide is replaced with commercially available nano-sized yttrium disilicide, while the rest of the process and the amount added are the same as in Example 1.

[0080] Comparative Example 3

[0081] A rare earth aluminum alloy material is prepared in a process that differs from that of Example 1 in that, in step 3, nano-sized praseodymium yttrium silicide is replaced with a mixture of commercially available nano-sized praseodymium disilicide and nano-sized yttrium disilicide, with a mass ratio of praseodymium disilicide to yttrium disilicide of 3.2:16.3. The remaining processes and amounts are the same as in Example 1.

[0082] To more clearly illustrate the content of the present invention, the strength, toughness, and corrosion resistance of the rare earth aluminum alloy materials prepared in Example 1 and Comparative Examples 1-3 were tested and compared.

[0083] Among them, tensile strength, yield strength and elongation are tested according to standard GB / T 228.1-2010; elastic modulus is tested according to standard GB / T 5166-2023; impact energy is tested according to standard GB / T 229-2007; corrosion resistance includes intergranular corrosion (tested according to GB / T 7998-2005), exfoliation corrosion (tested according to GB / T 22639-2022) and stress corrosion index (Stress corrosion index Issrt in 3.5% NaCl solution, tested according to HB 7235-1995).

[0084] The results are shown in Table 1 below:

[0085] Table 1. Performance Comparison of Different Rare Earth Aluminum Alloy Materials

[0086]

[0087] As can be seen from Table 1, the rare earth aluminum alloy material prepared in Example 1 of the present invention not only has high strength and good toughness, but also has excellent corrosion resistance.

[0088] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0089] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a high-strength rare-earth aluminum alloy material, characterized in that, Includes the following steps: Step 1: Weigh aluminum powder, iron powder, copper powder, silicon powder, magnesium powder, manganese powder and titanium powder, mix them into a furnace, heat to melt, and stir thoroughly to obtain the first molten liquid; Step 2: Inert gas is continuously blown into the bottom of the first melt, and slag removal is performed during this process to obtain the second melt. Step 3: Add nano-sized praseodymium yttrium silicide to the second melt and continue stirring thoroughly to obtain the third melt; Step 4: Keep the third molten liquid at a constant temperature and allow it to stand. Then place it in a mold for casting to obtain aluminum alloy rough material. Step 5: Anneal the aluminum alloy rough material and cool it to obtain a high-strength rare earth aluminum alloy material.

2. The method for preparing a high-strength rare-earth aluminum alloy material according to claim 1, characterized in that, In step 1, the temperature for heating and melting is 735-815℃.

3. The method for preparing a high-strength rare-earth aluminum alloy material according to claim 1, characterized in that, In step 2, the inert gas is at least one of helium, neon, argon, and xenon.

4. The method for preparing a high-strength rare-earth aluminum alloy material according to claim 1, characterized in that, In step 3, the nanoscale praseodymium yttrium silicon has a particle size of 20-30 nm.

5. The method for preparing a high-strength rare-earth aluminum alloy material according to claim 1, characterized in that, In step 5, the annealing temperature is 380-450℃ and the annealing time is 1-2h; the cooling method is a combination of furnace cooling and air cooling; first, furnace cooling is performed at a cooling rate of 3-5℃ / min, and after the temperature drops to 200℃, air cooling is performed, which is natural cooling to room temperature.

6. The method for preparing a high-strength rare-earth aluminum alloy material according to claim 1, characterized in that, In step 3, the preparation process of nanoscale praseodymium yttrium silicide includes: S1. Weigh yttrium oxide, praseodymium oxide, and silicon powder and mix them in a grinding mill. After thorough grinding, a grinding mixture is obtained. S2. Place the grinding mixture in a crucible, then place the crucible in a graphite furnace, introduce inert gas as a protective gas, heat to 1520-1660℃, hold for 2-4 hours, then cool down to 1250-1300℃ for the first time, hold for 2-4 hours again, and finally cool down to room temperature for the second time to obtain large praseodymium yttrium silicide particles. S3. Place the large praseodymium yttrium silicide particles in a nano-scale pulverizer for pulverization, and after sieving, obtain nano-scale praseodymium yttrium silicide.

7. The method for preparing a high-strength rare-earth aluminum alloy material according to claim 6, characterized in that, In S1, the mass ratio of yttrium oxide, praseodymium oxide, and silicon powder is 2.3-4.6:10.2-20.4:8.4-25.

3.

8. The method for preparing a high-strength rare-earth aluminum alloy material according to claim 6, characterized in that, In step S1, the grinding time is 200-300 r / min, the grinding speed is 1-3 h, and the ball-to-material ratio is 2-3:

1.

9. The method for preparing a high-strength rare-earth aluminum alloy material according to claim 6, characterized in that, In step S2, the heating rate is 10-15℃ / min, the first cooling rate is 5-10℃ / min, and the second cooling rate is 10-20℃ / min.

10. A high-strength rare-earth aluminum alloy material, characterized in that, The rare earth aluminum alloy material is prepared using the preparation method of claim 1, and the rare earth aluminum alloy material comprises, by mass ratio: Mg: 1.64%-1.96%, Si: 0.52%-0.83%, Ti: 0.22%-0.38%, Cu: 0.14%-0.25%, Fe: 0.12%-0.30%, Mn: 0.03%-0.14%, Pr: 0.085%-0.168%, Y: 0.018%-0.036%; balance is aluminum and other unavoidable impurities.

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