Smelting and casting method for enhancing A390 aluminum alloy through carbon nanotubes

Abstract

The invention belongs to the technical field of A390 material smelting application, and particularly discloses a smelting and casting method for enhancing A390 aluminum alloy through carbon nanotubes, which comprises the following steps: step 1, preparing an additive; 2, when an A390 material is smelted, the additive prepared in the step 1 is added; and 3, the A390 material solution smelted in the step 2 is used for pouring. The preparation method has the beneficial effects that 1, the carbon nanotubes and the aluminum powder are physically mixed and then pressed into small blocks, the density of the small blocks is similar to that of aluminum melt, the small blocks can be better dispersed in an aluminum matrix in the smelting process, and the uniformity and the reinforcing effect of the material are ensured; and 2, when the additive is made into a block shape, the additive can sink into the bottom of an A390 material smelting solution, the additive is continuously molten in the sinking process, and uniform smelting of the additive and the A390 material is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of A390 material smelting application, and in particular relates to a smelting and casting method of A390 aluminum alloy reinforced by carbon nanotubes. Background Art

[0002] A390 aluminum alloy is a high-silicon hypereutectic aluminum alloy with good wear resistance, corrosion resistance, low linear expansion coefficient, good thermal conductivity, especially good high-temperature mechanical properties and high-temperature dimensional stability. In addition, its Si content is relatively high, and its density is lower than that of eutectic and hypoeutectic aluminum alloys.

[0003] When casting aluminum parts with A390 materials, the strength of the casting directly affects the service life of the manufactured products. According to analysis, in the process of metal aluminum casting, adding carbon nanotubes to the aluminum melt when casting aluminum parts or aluminum ingots can significantly enhance the strength of aluminum alloy products. However, due to the light weight and high surface area of ​​carbon nanotubes, they are easy to float on the surface of the aluminum melt and are not easy to disperse evenly.

[0004] Therefore, based on the above problems, the present invention provides a melting and casting method for reinforcing A390 aluminum alloy by carbon nanotubes. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a melting and casting method of A390 aluminum alloy reinforced by carbon nanotubes to solve the technical problems existing in the background technology.

[0006] Technical solution: A smelting and casting method for A390 aluminum alloy reinforced by carbon nanotubes of the present invention comprises the following steps: step 1, preparing additives; step 2, adding the additives prepared in step 1 when smelting the A390 material; step 3, casting using the A390 material solution smelted in step 2; wherein, in step 1, the additives and the A390 material are first crushed separately, and then the mixed and crushed additives are homogeneously mixed with the A390 material, and finally pressed into blocks by a pressing device, and in step 2, the A390 material is first added to the smelting equipment, and then the pressed additives and A390 material blocks are put into the smelting equipment, and finally smelted and stirred.

[0007] In the technical solution of the present invention, the additive in step 1 is carbon nanotubes.

[0008] In the technical solution of the present invention, the content of the additive is 2-5%, and the content of the A390 material is 95-98%.

[0009] In the technical solution, the additive in block form is pressed by pressing equipment, and the A390 material has a size of 5-10 mm and a thickness of 1-3 mm.

[0010] In the technical solution, the A390 material after crushing in step 1 is 99.9% aluminum powder with a mesh size of 200.

[0011] Compared with the prior art, the beneficial effects of the smelting and casting method of A390 aluminum alloy reinforced by carbon nanotubes of the present invention are: 1. By physically mixing carbon nanotubes with aluminum powder and pressing them into small pieces, the density of the small pieces is similar to that of aluminum melt, and they can be better dispersed in the aluminum matrix during the smelting process, ensuring the uniformity and reinforcement effect of the material; 2. When the additive is made into a block, it can sink to the bottom of the A390 material molten liquid, and continuously melt during the sinking process, thereby achieving uniform smelting with the A390 material. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 The figure is a comparison diagram of aluminum castings cast by the molten metal liquid (a1-a3) with the traditional addition of carbon nanotubes and the molten metal liquid (b1-b3) with the present invention adding carbon nanotube alloy blocks. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0015] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "top", "bottom", "one side", "the other side", "front", "back", "middle part", "inside", "top end", "bottom end", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0016] Example

[0017] A smelting and casting method of A390 aluminum alloy reinforced by carbon nanotubes of the present invention comprises the following steps:

[0018] Step 1, preparing additives;

[0019] Step 2, adding the additive prepared in step 1 during melting of the A390 material;

[0020] Step 3, casting using the A390 material solution melted in step 2;

[0021] Among them, in step 1, the additive and the A390 material are first crushed separately, and then the mixed and crushed additive and the A390 material are homogeneously mixed (crushed and mixed using an agate mortar), and finally pressed into blocks using a pressing device. In step 2, the A390 material is first added to the smelting equipment, and then the pressed additive and A390 material blocks are put into the smelting equipment, and finally smelted and stirred.

[0022] In addition, preferably, the additive in step 1 is carbon nanotubes.

[0023] In addition, preferably, the content of the additive is 2-5%, and the content of the A390 material is 95-98%.

[0024] In addition, preferably, the additive is pressed into block form using a pressing device, with the A390 material having a size of 5-10 mm and a thickness of 1-3 mm (tablet size).

[0025] In addition, it is preferred that the A390 material after crushing in step 1 is 99.9% aluminum powder of 200 mesh.

[0026] In addition, the composition ratio and preparation method of the additive block are as follows:

[0027] Composition ratio: The mass ratio of carbon nanotubes (CNT) to aluminum powder is 1:10 to 1:20, and the specific ratio is adjusted according to experimental optimization. The content of carbon nanotubes is generally controlled between 0.5% and 2% of the total mass of the aluminum alloy.

[0028] Production method: After mixing carbon nanotubes with aluminum powder, use pressure molding equipment to press them into small blocks (about 1-3 mm thick and 5-10 mm in diameter). During the block forming process, a binder (such as epoxy resin) can be appropriately added to ensure the strength and shape stability of the formed block.

[0029] The volume of the additive block: The size of each block should be controlled within the range that is easy to handle and dissolve, usually 5-10mm in diameter and 1-3mm in thickness. The volume of the block should be appropriate so that it can be evenly dispersed during the smelting process.

[0030] Timing and temperature of putting into A390 aluminum alloy melt:

[0031] Temperature: The temperature of the aluminum alloy melt should be controlled between 750-800℃ to ensure good fluidity and avoid excessive oxidation.

[0032] Time to add: After smelting is completed, when the aluminum melt reaches a uniform liquid state, slowly add the prefabricated additive block. Avoid vigorous stirring when adding, and it is recommended to add gradually.

[0033] Stirring time and method: After adding the additives, use a medium frequency furnace for uniform stirring for 5-10 minutes. The temperature can be moderately increased during the stirring process (not exceeding 850°C) to help the block fully dissolve and combine with the aluminum alloy matrix. The purpose of stirring is to ensure the uniform distribution of carbon nanotubes and aluminum alloy matrix while avoiding the generation of excessive bubbles.

[0034] Drawing requirements:

[0035] Traditional casting method: If the traditional casting method is used, the casting speed must be controlled within the range of 0.1-1m / s, and the temperature must be kept stable during the casting process (about 720℃-750℃) to avoid pores or cracks caused by excessive cooling of the material.

[0036] New casting method: If a new casting method is used, the uniformity of the material structure can be further improved by controlling the casting speed and temperature gradient. At the same time, a thermal field control system can be added during the casting process to optimize the crystallization process.

[0037] Final casting properties:

[0038] like Figure 1 As shown, after adding carbon nanotubes to A390 aluminum alloy, the tensile strength and hardness of the material should be significantly improved, while achieving a weight reduction effect. According to experiments, if the content of carbon nanotubes is 1-2%, a weight reduction of up to 15-20% can be achieved, and the wear resistance and oxidation resistance of the material can be enhanced.

[0039] When BNNT is combined with an aluminum alloy matrix, its excellent elastic modulus and tensile strength can be utilized to improve the mechanical properties while reducing the thermal expansion difference and enhancing the high-temperature stability of the material.

[0040] The present invention can achieve weight reduction and reinforcement of A390 aluminum alloy through this method, which not only improves the mechanical properties of the material, but can also be applied to structural parts in the aviation field to achieve a higher lightweight goal. The key point of this patent solution is the introduction method of carbon nanotubes. By pressing them into blocks, the problem of carbon nanotubes floating on the surface of the melt in the traditional method is avoided, thereby effectively achieving uniform distribution and ensuring the final performance of the aluminum alloy.

[0041] The aluminum castings cast by the present invention have excellent tensile strength and yield strength, and are suitable for manufacturing cylinders, impellers, connecting rods, rocker arms, missile rudders, pump bodies, pump casings, gear box components, etc. The aluminum-based master alloy is reinforced with boron nitride nanotubes to nearly double its strength.

[0042] It should be noted that, in this article, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0043] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A melting and casting method for strengthening A390 aluminum alloy by carbon nanotubes, characterized in that: The following steps are included: Step 1, preparing additives; Step 2, adding the additive prepared in step 1 during melting of the A390 material; Step 3, casting using the A390 material solution melted in step 2; Among them, in step 1, the additive and the A390 material are first crushed separately, and then the mixed and crushed additive and the A390 material are homogeneously mixed, and finally pressed into blocks by a pressing device. In step 2, the A390 material is first added to the smelting equipment, and then the pressed additive and A390 material blocks are put into the smelting equipment, and finally smelted and stirred.

2. The method for melting and casting A390 aluminum alloy reinforced with carbon nanotubes according to claim 1, characterized in that: The additive in step 1 is carbon nanotubes.

3. The method for melting and casting A390 aluminum alloy reinforced with carbon nanotubes according to claim 2, characterized in that: The content of the additive is 2-5%, and the content of the A390 material is 95-98%.

4. The method for melting and casting A390 aluminum alloy reinforced with carbon nanotubes according to claim 1, characterized in that: The block-shaped additive is made by pressing equipment, and the size of the A390 material is 5-10 mm and the thickness is 1.3 mm.

5. The method for melting and casting A390 aluminum alloy reinforced with carbon nanotubes according to claim 1, characterized in that: The A390 material after crushing in the step 1 is 99.9% aluminum powder with a mesh size of 200.

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