A method for preparing hypereutectic aluminum-silicon alloy material by extrusion casting
By combining extrusion casting technology with modified alloy refining agents, the problem of coarse primary silicon phase in hypereutectic aluminum-silicon alloys was solved, achieving refinement of alloy microstructure and improvement of mechanical properties, making it suitable for engine parts manufacturing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TAIYUAN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2023-12-21
- Publication Date
- 2026-05-26
AI Technical Summary
The high silicon content in hypereutectic aluminum-silicon alloys results in sharp edges and large sizes of primary silicon phases in the alloy microstructure, which cuts through the matrix, reduces the mechanical properties of the alloy, and limits its applications.
By employing a squeeze casting process, combined with the use of Al-30Si master alloy, refining agent, and grain refiner, including Al-4.5P and Al-10Sr modified alloys, and by controlling the melting temperature and pressure casting parameters, the primary silicon and matrix grains are refined.
It significantly refines the primary silicon and matrix grains, improves the mechanical properties of the alloy, enhances the bonding strength between the primary silicon and the aluminum matrix, simplifies the smelting process, and reduces equipment costs.
Smart Images
Figure CN117737484B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of hypereutectic aluminum-silicon alloy material preparation technology, and in particular to a method for preparing hypereutectic aluminum-silicon alloy materials by extrusion casting. Background Technology
[0002] Hypereutectic aluminum-silicon alloys possess advantages such as high strength, good wear resistance, and good dimensional stability, making them ideal alloys for manufacturing high-performance engine parts and capable of solving problems such as cylinder scoring, cylinder seizure, and oil leakage. However, the silicon content in hypereutectic aluminum-silicon alloys reaches 13% to 30%, and their microstructure is prone to the formation of sharp-edged and coarse-sized primary silicon phases, which can easily fracture the matrix and reduce the mechanical properties of the alloy. This severely limits the application of hypereutectic aluminum-silicon alloys. Summary of the Invention
[0003] Based on the above, the present invention provides a method for preparing hypereutectic aluminum-silicon alloy materials by extrusion casting.
[0004] To achieve the above objectives, the present invention provides the following solution:
[0005] One of the technical solutions of this invention is a method for preparing a hypereutectic aluminum-silicon alloy material by extrusion casting, comprising the following steps:
[0006] After melting ZL109 aluminum alloy, Al-30Si master alloy is added, and the temperature is raised to 820~850℃ and held for 15~20 minutes. Then, a refining agent is added for refining. The temperature is lowered to 750~770℃, a refining agent is added, and the temperature is held. The mixture is then cast into a mold for extrusion casting to obtain hypereutectic aluminum-silicon alloy material.
[0007] The second technical solution of this invention is a hypereutectic aluminum-silicon alloy material prepared according to the above-mentioned preparation method, wherein the elements, by mass percentage, include silicon (Si): 14.0-16.0%; copper (Cu): 0.4-1.3%; magnesium (Mg): 0.6-1.1%; nickel (Ni): 0.6-1.3%; phosphorus (P): 0.03-0.033%; strontium (Sr): 0.03-0.033%; aluminum (Al): balance; impurities <1%.
[0008] The third technical solution of the present invention is the application of the above-mentioned hypereutectic aluminum-silicon alloy material in an engine.
[0009] The fourth technical solution of the present invention is a method for refining the primary silicon size and matrix grain size in hypereutectic aluminum-silicon alloy materials, which adopts the above-mentioned extrusion casting method for preparing hypereutectic aluminum-silicon alloy materials.
[0010] The present invention discloses the following technical effects:
[0011] This invention uses a common gravity casting process (squeeze casting), and the equipment is inexpensive.
[0012] The Al-30Si master alloy added in this invention generates a large amount of primary silicon and eutectic silicon in the aluminum alloy microstructure, resulting in a refined alloy microstructure. Furthermore, the extrusion casting process significantly refines the size and grain size of the primary silicon, enhancing the bonding strength between the primary silicon, eutectic silicon, and the aluminum matrix. This process not only refines the alloy microstructure but also greatly improves the mechanical properties of the hypereutectic aluminum-silicon alloy.
[0013] The method of this invention simplifies the smelting steps, obtains a uniform hypereutectic aluminum-silicon alloy structure, greatly refines the grain size and the size of primary silicon, and improves the mechanical properties of the hypereutectic aluminum-silicon alloy material. Attached Figure Description
[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0015] Figure 1 This is a microstructure diagram of the hypereutectic aluminum-silicon alloy material obtained in Example 1 of the present invention.
[0016] Figure 2 This is a microstructure diagram of the hypereutectic aluminum-silicon alloy material obtained in Comparative Example 1 of the present invention.
[0017] Figure 3 This is a microstructure diagram of the hypereutectic aluminum-silicon alloy material obtained in Comparative Example 2 of the present invention.
[0018] Figure 4 This is a microstructure diagram of the hypereutectic aluminum-silicon alloy material obtained in Comparative Example 3 of the present invention.
[0019] Figure 5 This is a microstructure diagram of the hypereutectic aluminum-silicon alloy material obtained in Comparative Example 4 of the present invention. Detailed Implementation
[0020] Various exemplary embodiments of the present invention will now be described in detail. 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 embodiments of the present invention.
[0021] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0023] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0024] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0025] The first aspect of this invention provides a method for preparing a hypereutectic aluminum-silicon alloy material by extrusion casting, comprising the following steps:
[0026] After melting ZL109 aluminum alloy, Al-30Si master alloy is added, and the temperature is raised to 820~850℃ and held for 15~20 minutes. Then, a refining agent is added for refining. The temperature is lowered to 750~770℃, a refining agent is added, and the temperature is held. The mixture is then cast into a mold for extrusion casting to obtain hypereutectic aluminum-silicon alloy material.
[0027] Al-30Si master alloy is inexpensive, does not easily float in aluminum alloy melt, is easy to add, has good wettability between its alloy blocks and ZL109 aluminum alloy melt, does not easily agglomerate in ZL109 aluminum alloy melt, can be evenly distributed in ZL109 aluminum alloy melt in a short time, and has relatively high thermal stability.
[0028] In a preferred embodiment of the present invention, the melt is cooled to 670°C before being poured into the mold (cooling to 670°C is to pour and extrude the molten metal near the liquidus line, which can reduce the formation and growth of dendrites in the molten metal structure and avoid coarse dendrites as much as possible); the mold is preheated to 300°C before casting (the purpose of preheating the mold is to: 1. prevent the molten metal from rapidly decreasing its fluidity due to rapid cooling, resulting in increased surface roughness and shrinkage cracks; 2. reduce the thermal fatigue stress of the mold and prevent the mold from cracking due to rapid heating; 3. adjust the sliding fit clearance between molds through preheating to prevent more molten metal from penetrating the gap; 4. prevent the molten metal from cooling too quickly after being poured into the mold, so as to avoid reduced plasticity and increased deformation resistance); the mold material is hot work die steel 3Cr2W8V.
[0029] In a preferred embodiment of the present invention, the Al-30Si master alloy needs to be polished and preheated at 200°C for 2 hours before being added to the ZL109 aluminum alloy melt.
[0030] In a preferred embodiment of the present invention, the melting temperature of ZL109 aluminum alloy is 580~610℃; the refining specifically involves first holding at 820~850℃ for 10~15 minutes, removing slag, and then cooling to 750~770℃ to add a refining agent; the holding time after adding the refining agent is 15~30 minutes.
[0031] In a preferred embodiment of the present invention, the mass ratio of the ZL109 aluminum alloy to the Al-30Si master alloy is (4.9-5.1):1.
[0032] In a preferred embodiment of the present invention, the refining agent is C2Cl6; the amount of the refining agent added is 0.05 to 0.1% of the sum of the masses of ZL109 aluminum alloy and Al-30Si master alloy.
[0033] In a preferred embodiment of the present invention, the refining agent is Al-4.5P and / or Al-10Sr modified alloy; the amount of the refining agent added is 0.3-1% of the sum of the mass of ZL109 aluminum alloy and Al-30Si master alloy.
[0034] In a further preferred embodiment of the present invention, the refining agent is an Al-4.5P and Al-10Sr modified alloy; the mass ratio of the Al-4.5P and Al-10Sr modified alloy is (2-2.5):1; when adding the refining agent, Al-10Sr is added first, followed by Al-4.5P; the amount of the refining agent added is 1% of the sum of the mass of ZL109 aluminum alloy and Al-30Si master alloy.
[0035] The grain refiner is an Al-4.5P and Al-10Sr modified alloy in a mass ratio of (2-2.5):1. The refining effect of phosphorus (P) is achieved through the addition of AlP, which acts as a heterogeneous nucleation site for primary silicon. Sr, on the other hand, refines the eutectic silicon through a poisoning mechanism. Sr first reacts with AlP to form Sr3P2. Adding Sr first ensures sufficient refinement of the eutectic silicon. Then, sufficient P is added, allowing the generated AlP to react with the remaining Sr. The remaining AlP can then fully serve as a heterogeneous nucleation site for primary silicon, resulting in a refining effect. At the aforementioned Al-4.5P and Al-10Sr ratio, sufficient P is available to refine the primary silicon grains. Exceeding this ratio range will weaken the refining effect to varying degrees.
[0036] Adding a finer agent in amounts exceeding the 0.3-1% mentioned above will weaken the finer effect and increase the grain size, whether the amount is too high or too low.
[0037] Al-4.5P and Al-10Sr modified alloys are inexpensive and easy to prepare. This invention uses Al-4.5P and / or Al-10Sr modified alloys as refining agents, which significantly refines primary silicon and can greatly optimize the microstructure of hypereutectic aluminum-silicon alloys.
[0038] In a preferred embodiment of the present invention, the melt in the mold is extruded and cast using a press to obtain a hypereutectic aluminum-silicon alloy material; the extrusion pressure of the extrusion casting is 600~700MPa, the extrusion speed is 0.1~0.15mm / s, and the holding time is 15~20s.
[0039] If the extrusion parameters are below the above range, the specific pressure is too low, the pressure is insufficient to refine the grains, and the grains cannot be fully crushed. If the extrusion speed is too low, sufficient pressure cannot be guaranteed inside the molten metal before solidification, and there may be pores or looseness inside the molten metal after solidification. If the holding time is too short, the pressure does not have enough time to refine the grains, and the grains cannot be crushed sufficiently within the effective time. If the extrusion parameters are above the above range, the specific pressure is too high, and the effect is similar to the grain refining effect within this range. If the extrusion speed is too high, the residual gas inside the molten metal cannot be fully discharged, and large pores are easily formed inside. If the holding time exceeds the above-described range, the molten metal has already solidified, and the pressure has a weak effect on its grain refining.
[0040] Extrusion casting, due to its advantages over casting and forging, can improve the interfacial bonding force between silicon and the aluminum matrix metal in hypereutectic aluminum-silicon alloys, greatly refine the size of primary silicon and matrix grains, and reduce the porosity of the alloy structure, thereby improving the performance of hypereutectic aluminum-silicon alloys.
[0041] The second aspect of this invention provides a hypereutectic aluminum-silicon alloy material prepared according to the above-described preparation method, wherein, by mass percentage, the elements comprise silicon (Si): 14.0-16.0%; copper (Cu): 0.4-1.3%; magnesium (Mg): 0.6-1.1%; nickel (Ni): 0.6-1.3%; phosphorus (P): 0.03-0.033%; strontium (Sr): 0.03-0.033%; aluminum (Al): balance; impurities <1%.
[0042] The third aspect of this invention provides the application of the above-mentioned hypereutectic aluminum-silicon alloy material in an engine.
[0043] The fourth aspect of the present invention provides a method for refining the primary silicon size and matrix grain size in a hypereutectic aluminum-silicon alloy material, using the above-mentioned extrusion casting method for preparing hypereutectic aluminum-silicon alloy materials.
[0044] Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this invention can be obtained through commercial channels.
[0045] The ZL109 aluminum alloy used in the embodiments and comparative examples of this invention has the following elemental composition by mass percentage: silicon (Si): 11.0-13.0%; copper (Cu): 0.5-1.5%; magnesium (Mg): 0.8-1.3%; nickel (Ni): 0.8-1.5%; aluminum (Al): balance; impurities <1.2%.
[0046] The Al-30Si master alloy used in the embodiments and comparative examples of this invention has the following elemental composition by mass percentage: Silicon (Si): 29.0-31.0%; Copper (Cu): 0.01-0.03%; Magnesium (Mg): 0.02-0.04%; Manganese (Mn): 0.02-0.04%; Zinc (Zn): 0.01-0.03%; Titanium (Ti): 0.05-0.01%; Aluminum (Al): balance.
[0047] The Al-4.5P refining agent (i.e., Al-4.5P modified alloy) used in the embodiments and comparative examples of this invention has the following elemental composition by mass percentage: phosphorus P: 4.5-5%; copper Cu: 0.01-0.03%; magnesium Mg: 0.02-0.04%; aluminum Al: balance.
[0048] The Al-10Sr refining agent (i.e., Al-10Sr modified alloy) used in the embodiments and comparative examples of this invention has the following elemental composition by mass percentage: Strontium (Sr): 10-11%; Copper (Cu): 0.01-0.03%; Magnesium (Mg): 0.02-0.04%; Aluminum (Al): balance.
[0049] The technical solution of the present invention will be further illustrated by the following embodiments.
[0050] Example 1
[0051] Step 1: Preheat the Al-30Si master alloy at 200℃ for 2 hours. Place the crucible in a resistance furnace and preheat to 400℃.
[0052] Step 2: ZL109 aluminum alloy was selected. 666g of ZL109 aluminum alloy was placed in a crucible and heated to 720℃ until completely melted. After removing the slag, 134g of Al-30Si master alloy was added, and the mixture was heated to 820℃ and held for 15 minutes until completely melted. 0.8g of C2Cl6 refining agent was added to refine the melt, and the temperature was held for 10 minutes. After removing the slag, the temperature was lowered to 770℃. First, 2.4g of Al-10Sr refining agent was added and held for 10 minutes, then 5.4g of Al-4.5P refining agent was added and held for 20 minutes. The temperature was then lowered to 670℃ and cast into a mold made of 3Cr2W8V material (the mold had been preheated to 300℃).
[0053] Step 3: Use a press to extrude the melt in the mold. The extrusion pressure is 700 MPa, the extrusion speed is 0.1 mm / s, and the holding time is 15 s. After extrusion, a sample (hypereutectic aluminum-silicon alloy material) is obtained.
[0054] The elemental composition of the hypereutectic aluminum-silicon alloy material prepared in this embodiment, by mass percentage, is as follows: Silicon (Si): 15%; Copper (Cu): 0.9%; Magnesium (Mg): 0.8%; Nickel (Ni): 0.9%; Phosphorus (P): 0.03%; Strontium (Sr): 0.03%; Aluminum (Al): Balance; Impurities <1%.
[0055] Comparative Example 1
[0056] Step 1: Preheat the Al-30Si master alloy at 200℃ for 2 hours. Place the crucible in a resistance furnace and preheat to 400℃.
[0057] Step 2: ZL109 aluminum alloy was selected. 666g of ZL109 aluminum alloy was placed in a crucible and heated to 720℃ until completely melted. After slag removal, 134g of Al-30Si master alloy was added, and the mixture was heated to 820℃ and held for 15 minutes until completely melted. 0.8g of C2Cl6 refining agent was added to refine the melt, and the temperature was held for 10 minutes. After slag removal, the temperature was lowered to 770℃. First, 2.4g of Al-10Sr refining agent was added and held for 10 minutes, then 5.4g of Al-4.5P refining agent was added and held for 20 minutes. The temperature was lowered to 670℃ and cast into a mold of 3Cr2W8V material (the mold had been preheated to 300℃) to obtain a sample (hypereutectic aluminum-silicon alloy material). That is, compared with Example 1, step 3, extrusion casting, was omitted in this comparative example.
[0058] The elemental composition of the hypereutectic aluminum-silicon alloy material prepared in this comparative example is as follows: silicon (Si): 15%; copper (Cu): 0.9%; magnesium (Mg): 0.8%; nickel (Ni): 0.9%; phosphorus (P): 0.03%; strontium (Sr): 0.03%; aluminum (Al): balance; impurities <1%.
[0059] Comparative Example 2
[0060] Step 1: Preheat the Al-30Si master alloy at 200℃ for 2 hours. Place the crucible in a resistance furnace and preheat to 400℃.
[0061] Step 2: ZL109 aluminum alloy was selected. 666g of ZL109 aluminum alloy was placed in a crucible and heated to 720℃ until completely melted. After removing the slag, 134g of Al-30Si master alloy was added, and the mixture was heated to 820℃ and held for 15 minutes until completely melted. 0.8g of C2Cl6 refining agent was added to refine the melt, and the temperature was held for 10 minutes. After removing the slag, the temperature was lowered to 670℃ and cast into a mold made of 3Cr2W8V material (the mold had been preheated to 300℃).
[0062] Step 3: The melt in the mold is extruded using a press. The extrusion pressure is 700 MPa, the extrusion speed is 0.1 mm / s, and the holding time is 15 s. After extrusion, a sample (hypereutectic aluminum-silicon alloy material) is obtained. That is, compared with Example 1, this comparative example omits the step of "first adding 2.4 g of Al-10Sr refining agent and holding for 10 min, then adding 5.4 g of Al-4.5P refining agent and holding for 20 min" in Step 2.
[0063] The elemental composition of the hypereutectic aluminum-silicon alloy material prepared in this comparative example is as follows: silicon (Si): 15%; copper (Cu): 0.9%; magnesium (Mg): 0.8%; nickel (Ni): 0.9%; aluminum (Al): balance; impurities <1%.
[0064] Comparative Example 3
[0065] Step 1: Preheat the Al-30Si master alloy at 200℃ for 2 hours. Place the crucible in a resistance furnace and preheat to 400℃.
[0066] Step 2: ZL109 aluminum alloy was selected. 666g of ZL109 aluminum alloy was placed in a crucible and heated to 720℃ until completely melted. After slag removal, 134g of Al-30Si master alloy was added, and the mixture was heated to 820℃ and held for 15 minutes until completely melted. 0.8g of C2Cl6 refining agent was added to refine the melt, and the temperature was held for 10 minutes. After slag removal, the temperature was lowered to 770℃, and 5.4g of Al-4.5P refining agent (the optimal content of P) was added. The temperature was held for 20 minutes. The temperature was then lowered to 670 minutes and the mixture was cast into a 3Cr2W8V material mold (the mold had been preheated to 300℃) to obtain a sample (hypereutectic aluminum-silicon alloy material). That is, compared with Example 1, this comparative example omits the addition of Al-10Sr refining agent in step 2 and the extrusion casting step in step 3.
[0067] The elemental composition of the hypereutectic aluminum-silicon alloy material prepared in this comparative example is as follows: silicon (Si): 15%; copper (Cu): 0.9%; magnesium (Mg): 0.8%; nickel (Ni): 0.9%; phosphorus (P): 0.03%; aluminum (Al): balance; impurities <1%.
[0068] Comparative Example 4
[0069] Step 1: Preheat the Al-30Si master alloy at 200℃ for 2 hours. Place the crucible in a resistance furnace and preheat to 400℃.
[0070] Step 2: Use ZL109 aluminum alloy. Place 666g of ZL109 aluminum alloy into a crucible and heat to 720°C. o After the carbon is completely melted and the slag is removed, 134g of Al-30Si master alloy is added, and the mixture is heated to 820°C. o Hold at temperature C for 15 minutes until completely melted. Add 0.8g of C2Cl6 refining agent to refine the melt, hold for 10 minutes, remove slag, and hold for another 30 minutes. Cool to 770°C. o C. Add 2.4g of Al-10Sr refining agent (the optimal Sr content), hold at the temperature for 20min; cool to 670min and cast into a 3Cr2W8V material mold (the mold has been preheated to 300℃) to obtain a sample (hypereutectic aluminum-silicon alloy material). That is, compared with Example 1, this comparative example omits the addition of Al-4.5P refining agent in step 2 and the extrusion casting step in step 3.
[0071] The elemental composition of the hypereutectic aluminum-silicon alloy material prepared in this comparative example is as follows: silicon (Si): 15%; copper (Cu): 0.9%; magnesium (Mg): 0.8%; nickel (Ni): 0.9%; strontium (Sr): 0.03%; aluminum (Al): balance; impurities <1%.
[0072] Figure 1The image shows the microstructure of the hypereutectic aluminum-silicon alloy material obtained in Example 1.
[0073] Figure 2 The image shows the microstructure of the hypereutectic aluminum-silicon alloy material obtained in Comparative Example 1.
[0074] Figure 3 The image shows the microstructure of the hypereutectic aluminum-silicon alloy material obtained in Comparative Example 2.
[0075] Figure 4 The image shows the microstructure of the hypereutectic aluminum-silicon alloy material obtained in Comparative Example 3.
[0076] Figure 5 The image shows the microstructure of the hypereutectic aluminum-silicon alloy material obtained in Comparative Example 4.
[0077] The mechanical properties of the extrusion-cast hypereutectic aluminum-silicon alloy materials prepared in Example 1 and Comparative Examples 1-4 were tested. The specific test results are shown in Table 1 (test standard: GB / T 10623-2008).
[0078] Table 1. Mechanical properties of hypereutectic aluminum-silicon alloy materials prepared in Example 1 and Comparative Examples 1-4
[0079]
[0080] The average grain size of the extrusion-cast hypereutectic aluminum-silicon alloy materials prepared in Example 1 and Comparative Examples 1-4 is shown in Table 2.
[0081] Table 2. Average grain size of the hypereutectic aluminum-silicon alloy materials prepared in Example 1 and Comparative Examples 1-4
[0082]
[0083] A comparison of the microstructure and mechanical properties of the hypereutectic aluminum-silicon alloy materials in Example 1 and Comparative Example 1 shows that the microstructure of the hypereutectic aluminum-silicon alloy material prepared by the method of this invention (extrusion casting + modified alloy refining of primary silicon) is significantly refined and homogenized. The size of the primary silicon in the microstructure is greatly reduced, and the bonding strength between the primary silicon and the aluminum matrix in the extruded hypereutectic aluminum-silicon alloy material is greatly improved, with significant increases in tensile strength and hardness. A comparison of the microstructure and mechanical properties of the hypereutectic aluminum-silicon alloy materials in Example 1 and Comparative Example 1 shows that a small amount of large-sized primary silicon remains in the microstructure of Comparative Example 1, while the microstructure of Example 1... Significant refinement was achieved, with both primary and eutectic silicon exhibiting very small sizes, resulting in a substantial improvement in mechanical properties. A comparison of the microstructure and mechanical properties of the hypereutectic aluminum-silicon alloy materials in Example 1 and Comparative Example 2 reveals that the primary silicon in Comparative Example 2 is extremely large, severely disrupting the aluminum matrix and significantly reducing its mechanical properties. Furthermore, a comparison of the microstructure and mechanical properties of the hypereutectic aluminum-silicon alloy materials in Example 1 and Comparative Examples 3 and 4 shows that some large-sized primary silicon particles still exist in the microstructures of Comparative Examples 3 and 4, and their distribution is uneven. In contrast, the primary silicon in Example 1 is not only significantly smaller in size but also more uniformly distributed, resulting in a finer microstructure and a substantial improvement in mechanical properties.
[0084] This invention combines the strengthening effects of extrusion casting, grain refinement, and the refinement of primary silicon by modifiers to further investigate the influence of primary silicon size refinement on the microstructure of hypereutectic aluminum-silicon alloys. The method of this invention highlights the advantages of extrusion casting and Al-4.5P and Al-10Sr modifiers as microstructure refiners, significantly refining the size of primary silicon and improving the mechanical properties of hypereutectic aluminum-silicon alloys.
[0085] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for preparing a hypereutectic aluminum-silicon alloy material by extrusion casting, characterized in that, The steps are as follows: After melting ZL109 aluminum alloy, Al-30Si master alloy is added, and the temperature is raised to 820-850℃ and held for 15-20 minutes. Then, refining agent is added for refining. The temperature is lowered to 750-770℃, refining agent is added, and the temperature is held. The mixture is then poured into a mold for extrusion casting to obtain hypereutectic aluminum-silicon alloy material. The melting temperature of ZL109 aluminum alloy is 580-610℃; the refining process specifically involves first holding at 820-850℃ for 10-15 minutes, then removing slag and cooling to 750-770℃; after adding the refining agent, the holding time is 15-30 minutes. The mass ratio of the ZL109 aluminum alloy to the Al-30Si master alloy is (4.9-5.1):1; The refining agent is an Al-4.5P and Al-10Sr modified alloy; the amount of the refining agent added is 0.3-1% of the sum of the mass of ZL109 aluminum alloy and Al-30Si master alloy; The mass ratio of the Al-4.5P and Al-10Sr modified alloy is (2-2.5):1; when adding the refining agent, Al-10Sr is added first, followed by Al-4.5P; The extrusion casting has an extrusion pressure of 600-700 MPa, an extrusion speed of 0.1-0.15 mm / s, and a holding time of 15-20 s. By mass percentage, the hypereutectic aluminum-silicon alloy material comprises: silicon (Si): 14.0-16.0%; copper (Cu): 0.4-1.3%; magnesium (Mg): 0.6-1.1%; nickel (Ni): 0.6-1.3%; phosphorus (P): 0.03-0.033%; strontium (Sr): 0.03-0.033%; aluminum (Al): balance; impurities <1%.
2. The method for preparing hypereutectic aluminum-silicon alloy material by extrusion casting according to claim 1, characterized in that, The refining agent is C2Cl6; the amount of the refining agent added is 0.05 to 0.1% of the sum of the masses of ZL109 aluminum alloy and Al-30Si master alloy.
3. The hypereutectic aluminum-silicon alloy material prepared by the preparation method according to any one of claims 1-2, characterized in that, By mass percentage, the elements include silicon (Si): 14.0-16.0%; copper (Cu): 0.4-1.3%; magnesium (Mg): 0.6-1.1%; nickel (Ni): 0.6-1.3%; phosphorus (P): 0.03-0.033%; strontium (Sr): 0.03-0.033%; aluminum (Al): balance; impurities <1%.
4. The application of the hypereutectic aluminum-silicon alloy material as described in claim 3 in an engine.
5. A method for refining the primary silicon size and matrix grain size in a hypereutectic aluminum-silicon alloy material, characterized in that, The preparation method of the extrusion casting hypereutectic aluminum-silicon alloy material according to any one of claims 1-2 is adopted.