Aluminum alloy refiner as well as preparation method and application thereof

Abstract

The invention provides an aluminum alloy refiner and a preparation method and application thereof, and relates to the technical field of aluminum alloys, and the preparation method of the aluminum-titanium-boron-rare earth composite refiner comprises the following steps that aluminum, an Al-Ti intermediate alloy, an Al-rare earth intermediate alloy and an Al-B intermediate alloy are subjected to melting treatment and stirred to be uniform, and then an aluminum alloy melt is obtained; the aluminum alloy melt is subjected to degassing treatment, slagging-off and heating to obtain aluminum alloy liquid, and the aluminum alloy liquid is subjected to casting, annealing and cooling to obtain the aluminum-titanium-boron-rare earth composite refiner. The aluminum-titanium-boron-rare earth composite refiner can reduce the average grain size of the aluminum alloy.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, specifically to aluminum alloy refining agents, their preparation methods, and applications. Background Technology

[0002] Aluminum alloys are metallic materials with excellent properties, obtained by adding one or more alloying elements such as copper, silicon, magnesium, zinc, and manganese to aluminum as the base material and then heat-treating them. Their density is approximately 2.7 g / cm³. 3 After alloying and heat treatment, aluminum alloys exhibit a very high strength-to-weight ratio, making them important raw materials for the transportation, construction, power, and packaging industries. According to the classic Hall-Page relation, the strength of a metallic material is inversely proportional to the square root of its grain size; therefore, the finer the grains, the higher the material's strength and hardness. Aluminum alloy grain refiners are additives used to refine grain size and improve the microstructure and mechanical properties of aluminum alloys. The addition of grain refiners significantly increases the nucleation rate during solidification, transforming coarse grains into fine equiaxed grains, thereby increasing the strength of the aluminum alloy.

[0003] Currently, aluminum-titanium-boron (ATiB) grain refiners are the most widely used grain refiners in the aluminum alloy industry. The TiB2 crystal structure of ATiB is highly compatible with aluminum, resulting in low interfacial energy; therefore, TiB2 can efficiently promote α-Al nucleation. However, when Zr and Cr are present in the melt, these elements adsorb onto the surface of TiB2 particles and react with TiB2 to form a solid solution coating. Therefore, the presence of zirconium and chromium in the alloy severely weakens the effect of ATiB. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an aluminum alloy refining agent, its preparation method, and its application, solving the technical problem that the effectiveness of aluminum-titanium-boron refining agents is affected by zirconium and chromium elements.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing an aluminum-titanium-boron-rare earth composite refining agent, comprising the following steps: melting aluminum, Al-Ti master alloy, Al-rare earth master alloy, and Al-B master alloy and stirring them evenly to obtain an aluminum alloy melt; degassing the aluminum alloy melt, removing slag, and heating it to obtain an aluminum alloy liquid; and obtaining the aluminum alloy liquid as an aluminum-titanium-boron-rare earth composite refining agent after casting, annealing, and cooling.

[0007] Preferably, the Al-rare earth master alloy is selected from Al-La master alloy, Al-Ce master alloy or Al-Y master alloy.

[0008] Preferably, the melting temperature is 800℃-850℃.

[0009] Preferably, the annealing process includes treatment at 550-570°C for 5-7 hours.

[0010] In a second aspect, the present invention provides an aluminum-titanium-boron-rare earth composite refining agent, which is prepared by the preparation method described in the first aspect.

[0011] Preferably, the aluminum-titanium-boron-rare earth composite refining agent comprises the following components in parts by weight: Ti 5%-6%, B 1%-1.5%, rare earth elements 0.5%-1%, and Al balance.

[0012] Preferably, the aluminum-titanium-boron-rare earth composite refining agent comprises the following components in parts by weight: Ti 5%, B 1%, rare earth elements 0.5%, and Al balance.

[0013] Thirdly, the present invention provides an application of the aluminum-titanium-boron-rare earth composite refining agent as described in the second aspect in the preparation of aluminum alloys, wherein the aluminum alloys include at least one of Zr and Cr.

[0014] Preferably, the amount of the aluminum-titanium-boron-rare earth composite refining agent is 0.1%-0.3% of the mass of aluminum in the aluminum alloy.

[0015] Compared with existing technologies, it has the following beneficial effects:

[0016] The preparation method of the aluminum-titanium-boron-rare earth composite grain refiner of the present invention includes the following steps: aluminum, Al-Ti master alloy, Al-rare earth master alloy, and Al-B master alloy are melted and stirred evenly to obtain an aluminum alloy melt. The aluminum alloy melt is then degassed, slag is removed, and the temperature is raised to obtain an aluminum alloy liquid. The aluminum alloy liquid is then cast, annealed, and cooled to obtain the aluminum-titanium-boron-rare earth composite grain refiner. The addition of rare earth elements, due to their high atom activity, consumes some free B and Ti to form rare earth compounds. Furthermore, the rare earth elements react with Zr and Cr already adsorbed on the surface of TiB2 particles to form a more stable rare earth-zirconium / chromium-boron / titanium composite phase, thereby changing the interface composition and structure of the aluminum alloy, reducing the average grain size of the aluminum alloy, and improving the strength of the aluminum alloy. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] To better understand the above technical solution, the following will provide a detailed explanation of the above technical solution in conjunction with specific implementation methods.

[0019] I. Preparation Method

[0020] Example 1

[0021] This embodiment provides a method for preparing an aluminum-titanium-boron-rare earth composite refining agent, comprising the following steps:

[0022] The furnace was cleaned and Al ingots were added and heated to 800°C. Al-Ti master alloy was then added to the furnace and stirred until homogeneous. Al-La master alloy was then added and the furnace temperature was stabilized at 820°C. Al-B master alloy was then added, and the mixture was melted and stirred until homogeneous to obtain aluminum alloy melt. The aluminum alloy melt was sampled and analyzed quickly. The temperature of the aluminum liquid mixture during sampling should be higher than 760°C. The chemical composition of the target aluminum alloy profile was adjusted by adding metal elements (see Table 1 for details). High-purity argon gas was introduced through a rotary spray gun for degassing. After slag removal and heating, aluminum alloy liquid was obtained, with its temperature controlled at 760°C.

[0023] Molten aluminum alloy is poured into a mold, and the casting temperature is controlled at 740℃. The casting is carried out at a speed of 120 mm / min, with a casting depth of 100 m. 3 The cooling water flow rate is / h. After casting, it is subjected to homogenization annealing at 550℃ for 6 hours. Finally, it is cooled to room temperature by cooling water spray to obtain aluminum alloy ingot, namely aluminum-titanium-boron-rare earth composite refining agent.

[0024] Example 2

[0025] This embodiment provides a method for preparing an aluminum-titanium-boron-rare earth composite refining agent, comprising the following steps:

[0026] The furnace was cleaned and Al ingots were added and heated to 810°C. Al-Ti master alloy was then added to the furnace and stirred until homogeneous. Al-Ce master alloy was then added and the furnace temperature was stabilized at 830°C. Aluminum-boron master alloy was then added, and the mixture was melted and stirred until homogeneous to obtain an aluminum alloy melt. The aluminum alloy melt was sampled for rapid testing and analysis. The temperature of the aluminum liquid mixture during sampling must be higher than 770°C. The chemical composition of the target aluminum alloy profile was adjusted by adding metal elements (see Table 1 for details). High-purity argon gas was introduced through a rotating spray gun for degassing. After slag removal and heating, the aluminum alloy liquid was obtained, and its temperature was controlled at 770°C.

[0027] Molten aluminum alloy is poured into a mold, and the casting temperature is controlled at 750℃. The casting is carried out at a speed of 120 mm / min, with a casting depth of 100 m / s.3 The cooling water flow rate is / h. After casting, it is subjected to homogenization annealing at 560℃ for 7 hours. Finally, it is cooled to room temperature by cooling water spray to obtain aluminum alloy ingot, namely aluminum-titanium-boron-rare earth composite refining agent.

[0028] Example 3

[0029] This embodiment provides a method for preparing an aluminum-titanium-boron-rare earth composite refining agent, comprising the following steps:

[0030] The furnace was cleaned and Al ingots were added and heated to 820°C. Al-Ti master alloy was then added to the furnace and stirred until homogeneous. Al-Y master alloy was then added and the furnace temperature was stabilized at 840°C. Aluminum-boron master alloy was then added, and the mixture was melted and stirred until homogeneous to obtain an aluminum alloy melt. The aluminum alloy melt was sampled for rapid testing and analysis. The temperature of the aluminum liquid mixture during sampling must be higher than 780°C. The chemical composition of the target aluminum alloy profile was adjusted by adding metal elements (see Table 1 for details). High-purity argon gas was introduced through a rotating spray gun for degassing. After slag removal and heating, the aluminum alloy liquid was obtained, and its temperature was controlled at 780°C.

[0031] Molten aluminum alloy is poured into a mold, and the casting temperature is controlled at 760℃. The casting is carried out at a speed of 120 mm / min, with a casting depth of 100 m. 3 The cooling water flow rate is / h. After casting, it is subjected to homogenization annealing at 570℃ for 5 hours. Finally, it is cooled to room temperature by cooling water spray to obtain aluminum alloy ingot, namely aluminum-titanium-boron-rare earth composite refining agent.

[0032] Comparative Example 1

[0033] The difference between this comparative example and Example 1 is that no aluminum-rare earth intermediate alloy is added; otherwise, they are the same as in Example 1.

[0034] Table 1. Components of aluminum-titanium-boron-rare earth (RE) composite refining agents prepared in examples and comparative examples.

[0035]

[0036] II. Testing Methods

[0037] Preparation of the test sample:

[0038] The furnace was cleaned, and 99.7% pure aluminum ingots were added and heated to melt. Al-Zr and Al-Cr master alloys were then added to the furnace, and the mixture was melted and stirred until homogeneous to obtain an aluminum alloy melt. The Zr content and Cr content were both 0.1% of the pure aluminum ingot mass. High-purity argon gas was introduced through a rotary torch for degassing. After slag removal and heating, a liquid aluminum alloy was obtained. The temperature was raised to 720°C, and 0.2% of the aluminum-titanium-boron-rare earth composite refining agent prepared in Examples 1-3 and Comparative Example 1 (by weight of the pure aluminum ingot) was added to the liquid aluminum alloy. The mixture was melted, stirred until homogeneous, and allowed to stand for 3 minutes. The liquid aluminum was then poured into a mold, and the casting temperature was controlled at 715°C. The casting speed was 120 mm / min, and the cooling water flow rate was 100 m³ / min. 3 The temperature is increased by 50°C / h, then cooled to 200°C by strong air cooling, and finally cooled to room temperature by cooling water spray to obtain aluminum casting rods. The aluminum casting rods are then subjected to homogenization treatment under the following conditions: first, the temperature is increased from 50°C / h to 580°C and held for 8 hours, and then cooled to room temperature by air cooling to obtain the sample to be tested.

[0039] 1. Average grain size: The average grain size of the test samples of Examples 1-3 and Comparative Example 1 was determined according to ASTM E112 standard (comparative method).

[0040] 2. Tensile strength: The tensile strength of the test samples of Examples 1-3 and Comparative Example 1 was tested using a universal testing machine in accordance with GB / T 228.1.

[0041] III. Test Results

[0042] The test results of the samples to be tested in Examples 1-3 and Comparative Example 1 are shown in Table 2.

[0043] Table 2 Test results of samples from Examples 1-3 and Comparative Example 1

[0044]

[0045] As shown in Table 2, the average grain size of the sample prepared in Example 1 was 200 µm, while the average grain size of the sample prepared in Comparative Example 1 was 800 µm. Therefore, the average grain size of the aluminum alloy prepared by adding the aluminum-titanium-boron-rare earth composite refining agent prepared in Example 1 was significantly smaller. This is because when the aluminum-titanium-boron-rare earth composite refining agent is added to the aluminum melt, the rare earth atoms are highly active. On the one hand, they consume some of the free B and Ti to form rare earth compounds. On the other hand, the rare earth elements react with Zr and Cr already adsorbed on the surface of TiB2 particles to form a more stable rare earth-zirconium / chromium-boron / titanium composite phase, thereby changing the interface composition and structure of the aluminum alloy, reducing the average grain size of the aluminum alloy, and improving the strength of the aluminum alloy.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0048] The present invention has been illustrated with the above embodiments to describe the detailed process flow of the present invention. However, the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an aluminum-titanium-boron-rare earth composite refining agent, characterized in that, The process includes the following steps: melting aluminum, Al-Ti master alloy, Al-rare earth master alloy, and Al-B master alloy and stirring them evenly to obtain an aluminum alloy melt; degassing the aluminum alloy melt, removing slag, and heating it to obtain an aluminum alloy liquid; and casting, annealing, and cooling the aluminum alloy liquid to obtain an aluminum-titanium-boron-rare earth composite refining agent.

2. The preparation method of the aluminum-titanium-boron-rare earth composite refining agent as described in claim 1, characterized in that, The Al-rare earth master alloy is selected from Al-La master alloy, Al-Ce master alloy or Al-Y master alloy.

3. The preparation method of the aluminum-titanium-boron-rare earth composite refining agent as described in claim 1, characterized in that, The melting temperature is 800℃-850℃.

4. The preparation method of the aluminum-titanium-boron-rare earth composite refining agent as described in claim 1, characterized in that, The annealing process includes treatment at 550-570°C for 5-7 hours.

5. An aluminum-titanium-boron-rare earth composite refining agent, characterized in that, It is prepared by the preparation method according to any one of claims 1-4.

6. The aluminum-titanium-boron-rare earth composite refining agent as described in claim 5, characterized in that, The aluminum-titanium-boron-rare earth composite refining agent comprises the following components in parts by weight: Ti 5%-6%, B 1%-1.5%, rare earth elements 0.5%-1%, and Al balance.

7. The aluminum-titanium-boron-rare earth composite refining agent as described in claim 5, characterized in that, The aluminum-titanium-boron-rare earth composite refining agent comprises the following components in parts by weight: Ti 5%, B 1%, rare earth elements 0.5%, and Al balance.

8. The application of the aluminum-titanium-boron-rare earth composite refining agent as described in any one of claims 5-7 in the preparation of aluminum alloys, characterized in that, The aluminum alloy includes at least one of Zr and Cr.

9. The application as described in claim 8, characterized in that, The amount of the aluminum-titanium-boron-rare earth composite refining agent is 0.1%-0.3% of the mass of aluminum in the aluminum alloy.

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