Manufacturing method for high-strength composite modified aluminum silicon magnesium alloy parts

Abstract

The present invention provides a high-strength composite modified aluminum alloy part and a manufacturing method thereof. The manufacturing method includes step S1 of providing a molten aluminum alloy, step S2 of providing a modifier, step S3 of adding the modifier to the molten aluminum alloy and smelting the molten aluminum alloy under an inert gas atmosphere to obtain a molten modified aluminum alloy, step S4 of casting the molten aluminum alloy to obtain the cast aluminum alloy blank, and step S5 of heat treating the modified aluminum alloy blank, in which the heat treatment is performed by heating the aluminum alloy blank to 530 to 550°C. and step S5 including a solution treatment in which the aluminum alloy blank after the solution treatment is placed in a water bath having a temperature of 60-70°C and water-quenched for 2-4 minutes, and an aging treatment in which the aluminum alloy blank after the water-quenching treatment is kept at 150-165°C for 120-280 minutes, then cooled to 110-130°C and kept at that temperature for 30-120 minutes, and then naturally cooled to room temperature to obtain the high-strength composite-modified aluminum alloy part.

Description

[Technical Field]

[0001] The present invention relates to alloy materials and manufacturing technologies, and more particularly to high-strength composite modified aluminum alloy parts and methods for manufacturing the same. [Background technology]

[0002] Aluminum alloys are the most widely used non-ferrous metal structural materials industrially, with extensive applications in aerospace, automotive, machinery manufacturing, shipbuilding, and the chemical industry. Cast aluminum alloys possess excellent casting fluidity and airtightness, low shrinkage rate, and a low tendency to thermal cracking, making them suitable materials for lightweighting automotive hubs.

[0003] However, people's demands for aluminum alloys are increasing, and they need to possess not only their inherent lightweight properties but also a certain level of strength, especially for automotive parts and industrial production. For large-scale parts made of cast aluminum alloy, it is necessary to have high strength, moderate toughness, and the ability to solve mechanical property problems.

[0004] For this reason, a process has been proposed in which the alloy is modified using a modifier such as aluminum strontium alloy, and then refined by bonding a refinement agent. However, conventional modification methods have not been able to obtain the ideal strength and plasticity. Furthermore, research is underway on heat treatment of cast aluminum alloys. However, the heat treatment process differs depending on the composition of the aluminum alloy parts, and current heat treatments require high temperatures, resulting in high energy consumption, long processing times, increased processing costs, and, because the treatment is performed directly at high temperatures, it is unfavorable for the interconversion of the states of each substance and the uniformity of dissolution, leading to non-uniformity of the mechanical properties of the alloy.

[0005] Therefore, it is necessary to provide a manufacturing process that can further increase the mechanical strength of aluminum alloy parts. [Overview of the Initiative]

[0006] In view of this, the present invention provides a high-strength composite modified aluminum alloy part and a method for manufacturing the same, which can further improve the mechanical strength of the aluminum alloy.

[0007] To solve the above technical problems, the present invention employs the following technical means.

[0008] A method for manufacturing a high-strength composite modified aluminum alloy part according to the first embodiment of the present invention is: Step S1 provides molten aluminum alloy, Step S2 involves providing a modifier, The aforementioned modifier is a combination of rare earth aluminum alloy, aluminum strontium intermediate alloy, aluminum titanium, or aluminum titanium boron intermediate alloy. Alternatively, the modifier is a combination of a composite rare-earth aluminum alloy, an aluminum-titanium or aluminum-titanium-boron intermediate alloy, wherein the composite rare-earth aluminum alloy contains strontium, titanium or titanium-boron, and a rare earth metal. Step S2, wherein the rare earth metal in the rare earth aluminum alloy or the composite rare earth aluminum alloy is one or more of lanthanum, cerium, and yttrium. Step S3 involves adding the modifying agent to the molten aluminum alloy under an inert gas atmosphere and smelting it to obtain a modified molten aluminum alloy. Step S4 involves casting using the modified aluminum alloy molten metal to obtain the modified aluminum alloy blank, Step S5 is to heat-treat the modified aluminum alloy blank, wherein the heat treatment is performed The modified aluminum alloy blank is heated to 530-550°C and then kept warm for 100-300 minutes in a solution treatment, The aluminum alloy blank, after undergoing solution treatment, is placed in a water bath at a temperature of 60-70°C and water-quenched for 2-4 minutes in a water quenching treatment. Step S5 includes an aging treatment in which an aluminum alloy blank, after undergoing a water quenching treatment, is heated at 150-165°C for 120-280 minutes, then cooled to 110-130°C and heated for 30-120 minutes, and then naturally cooled to room temperature to obtain the high-strength composite modified aluminum alloy part.

[0009] Furthermore, step S1 is, To provide aluminum alloy master ingots, The scale layer on the surface of the aforementioned aluminum alloy master ingot is removed, and then it is cleaned and dried. The process includes smelting a dried aluminum alloy master ingot, refining it, removing slag, and obtaining the molten aluminum alloy, The composition of the aforementioned aluminum alloy master ingot is either a hypoeutectic aluminum alloy or a eutectic aluminum alloy.

[0010] According to some embodiments of the present invention, the modifier is a combination of a rare earth aluminum alloy, an aluminum strontium intermediate alloy, aluminum titanium, or an aluminum titanium boron intermediate alloy, wherein the aluminum strontium intermediate alloy and the aluminum titanium or aluminum titanium boron intermediate alloy are added at intervals. The rare earth aluminum alloy is added first, or added together with the first one added, or added between the timing of adding the aluminum strontium intermediate alloy and the timing of adding the aluminum titanium or aluminum titanium boron intermediate alloy.

[0011] Furthermore, step S3 is, Step S301 involves adding the rare-earth aluminum alloy to the molten aluminum alloy and smelting it to obtain a first homogeneous mixed molten metal, Step S302 involves adding the aluminum strontium intermediate alloy to the first homogeneous mixed molten metal and continuing to smelt it to obtain a second homogeneous mixed molten metal, The process includes step S303, which involves adding the aluminum-titanium or aluminum-titanium-boron intermediate alloy to the second homogeneous mixed molten metal and continuing to smelt it to obtain the modified aluminum alloy.

[0012] According to some other embodiments of the present invention, the modifier is a combination of a composite rare-earth aluminum alloy, aluminum titanium, or aluminum titanium boron intermediate alloy, and step S3 is, Step S310 involves adding the composite rare-earth aluminum alloy to the molten aluminum alloy and smelting it to obtain a fourth homogeneous mixed molten metal, The process includes step S320, which involves adding the aluminum-titanium or aluminum-titanium-boron intermediate alloy to the fourth homogeneous mixed molten metal and continuing to smelt it to obtain the modified aluminum alloy.

[0013] Furthermore, the manufacturing of the aforementioned composite rare-earth aluminum alloy is Step S211, which provides the molten aluminum, Step S212 provides an aluminum strontium intermediate alloy, an aluminum titanium or aluminum titanium boron intermediate alloy, and a rare earth aluminum intermediate alloy, wherein the rare earth metal in the rare earth aluminum intermediate alloy is one or more selected from lanthanum, cerium, and yttrium. The process includes step S213, in which, under an inert gas atmosphere, the molten aluminum is sequentially smelted with the rare-earth aluminum intermediate alloy, aluminum strontium intermediate alloy, aluminum titanium, or aluminum titanium boron intermediate alloy to obtain the composite rare-earth alloy.

[0014] Furthermore, the modifier accounts for 0.4 to 0.6 wt% of the total amount of the modified aluminum alloy molten metal, and the mass ratio of the total amount of the rare earth metal:strontium:titanium or titanium boron is 1:(0.1 to 1.2):(0.1 to 1.2).

[0015] Furthermore, in step S5, the heating rate during the solution heat treatment is controlled to be 1.5 - 3 °C / min, and the holding time is controlled to be 120 - 180 min.

[0016] Furthermore, the solution heat treatment, the quenching treatment, and the aging treatment are continuous processes. The water bath is a circulating water bath. After the quenching treatment and before the aging treatment, the temperature of the cast aluminum alloy blank is maintained at 55 °C or higher.

[0017] Furthermore, in the aging treatment stage, the cooling rate from 150 - 165 °C to 110 - 130 °C is controlled to be 2 - 5 °C / min.

[0018] The high-strength composite modified aluminum alloy part according to the second embodiment of the present invention is obtained by manufacturing with the manufacturing method described in any one of the above embodiments. The tensile strength of the high-strength composite modified aluminum alloy part is 300 MPa or more, the yield strength is 230 MPa or more, and the elongation is 6% or more.

[0019] The above technical means of the present invention has at least one of the following beneficial effects.

[0020] The manufacturing method of the high-strength composite modified aluminum alloy part according to the embodiment of the present invention modifies the aluminum alloy by introducing rare earth metals, and combines with specific heat treatment processes to process the casting, thereby enhancing its mechanical strength to meet the needs of the aviation, aerospace, automotive fields, etc., while enhancing its toughness and reducing the occurrence of embrittlement and the like.

Brief Description of the Drawings

[0021] [Figure 1] Figure 1 is a photograph of a high-strength composite modified aluminum alloy part, i.e., a hub, manufactured in the embodiment. [Figure 2] Figure 2 is a metallographic structure image of the rib part of the hub shown in Figure 1, where (a) is a low-magnification image, (b) is a medium-magnification image, and (c) is a high-magnification image. [Modes for carrying out the invention]

[0022] To clarify the purpose, technical means, and advantages of the embodiments of the present invention, the technical means of the present invention will be described clearly and completely below, along with the embodiments of the present invention. Clearly, the embodiments described are only some, not all, embodiments of the present invention. Any other embodiments obtained by those skilled in the art based on the embodiments of the present invention described are also within the scope of protection of the present invention.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention must have the ordinary meaning that would be understood by a person with ordinary skill in the art to which this invention belongs. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but merely distinguish different components. Similarly, similar terms such as "one" or "one" do not indicate a limit on quantity, but indicate that there is at least one.

[0024] First, a method for manufacturing high-strength composite modified aluminum alloy parts according to an embodiment of the present invention will be described below, with reference to specific embodiments.

[0025] A method for manufacturing a high-strength composite modified aluminum alloy part according to an embodiment of the present invention includes the following steps. Step S1: Provide molten aluminum alloy. In other words, first prepare the molten aluminum alloy.

[0026] Alternatively, molten aluminum alloy can be produced by directly heating and melting commercially available high-purity aluminum alloy ingots, or the aluminum alloy ingots can be further refined. The refining process may involve the following steps, for example: Step S11 provides an aluminum alloy ingot, Step S12 involves removing the scale layer from the surface of the aluminum alloy ingot, Step S13 involves washing and drying the aluminum alloy ingot from which the scale layer has been removed. Step S14 involves smelting the dried aluminum alloy ingot to obtain an initial molten metal, The step may include refining the initial molten metal to obtain the aluminum alloy molten metal (step S15).

[0027] In other words, for aluminum alloy ingots, the first step is to remove the scale layer from the surface, then wash it to remove surface scum, dry it, and then smelt the molten metal. The specific smelting process will be described in detail later.

[0028] After the above purification process, unwanted impurities such as Fe and oxides can be removed. This leads to further improvement in the alteration and refinement of rare earth alloys.

[0029] Furthermore, the Fe and its oxides within this material can be removed by adding, for example, manganese or an aluminum-manganese alloy, which forms a surface scum.

[0030] Examples of modified substrates, i.e., molten aluminum alloys, include aluminum-magnesium alloys, aluminum-silicon alloys, and aluminum-silicon-magnesium alloys, but the present invention is not limited to these.

[0031] Step S2: Provide a modifier.

[0032] Among these, the modifier is a combination of rare earth aluminum alloy, aluminum strontium intermediate alloy, aluminum titanium, or aluminum titanium boron intermediate alloy, or the modifier is a combination of composite rare earth aluminum alloy, aluminum titanium, or aluminum titanium boron intermediate alloy.

[0033] The aforementioned composite rare-earth aluminum alloy contains strontium, titanium or titanium boron, and a rare-earth metal.

[0034] The rare earth metal in the rare earth aluminum alloy and the composite rare earth aluminum alloy is one or more of lanthanum, cerium, and yttrium.

[0035] In other words, there are two embodiments as follows:

[0036] Regarding Embodiment 1, The aforementioned modifier is a combination of rare earth aluminum alloy, aluminum strontium intermediate alloy, aluminum titanium, or aluminum titanium boron intermediate alloy.

[0037] In this configuration, the aluminum strontium intermediate alloy is the alteration agent, and the aluminum titanium intermediate alloy or aluminum titanium boron intermediate alloy is the refinement agent. In other words, ordinary alteration agents and refinement agents may also be used.

[0038] Furthermore, the aforementioned altering agent and / or the aforementioned refining agent may be commercially available, or it may be manufactured by weighing the corresponding metallic strontium, titanium, and titanium & boron, respectively, and melting them in molten aluminum to form a uniform alloy.

[0039] Furthermore, by incorporating a rare-earth aluminum alloy in addition to the usual alteration agent and refinement agent, the limitations on mechanical performance due to "poisoning" reactions between the alteration agent and refinement agent can be overcome. As the rare-earth metal in the rare-earth aluminum alloy, considering strontium in the alteration agent and titanium and boron in the refinement agent, a Group IIIB element with an intervening electronic structure may be selected. Considering stability, resources, etc., it is preferable to use one or more of yttrium, lanthanum from the lanthanum group of metals, and cerium. As the rare-earth aluminum alloy, for example, one or more of commercially available Al-10Ce, Al-20Ce, Al-20La, Al-10La, Al-20Y, and Al-10Y may be used.

[0040] Alternatively, rare-earth aluminum alloys may be manufactured in-house, for example, by the following method.

[0041] Under an inert atmosphere, the rare earth metal or an intermediate alloy containing the rare earth metal is added to the molten aluminum and stirred while heating until it is completely dissolved. After complete dissolution, continue to keep warm for 10-20 minutes to homogenize. The homogenized molten metal is refined. After refining, the mixture is left to stand for a predetermined time, then poured to obtain the rare earth aluminum alloy.

[0042] Here, the molten aluminum may be prepared using commercially available high-purity aluminum ingots, and subjected to appropriate processing based on the refining process for the aluminum alloy ingots described above; however, this explanation will be omitted here.

[0043] In addition, commercially available aluminum strontium intermediate alloys, aluminum titanium intermediate alloys, or aluminum titanium boron intermediate alloys, and rare earth aluminum alloys may be subjected to descaling, ultrasonic cleaning, and refining treatments in that order. This further removes undesirable impurities and oxides, thereby enhancing the refinement and transformation of the composite rare earth alloy as a product.

[0044] Regarding Embodiment 2, The aforementioned modifier is a combination of a composite rare-earth aluminum alloy, aluminum titanium, or aluminum titanium boron intermediate alloy.

[0045] The composite rare-earth aluminum alloy may be manufactured by smelting and refining the above-mentioned rare-earth aluminum alloy, aluminum strontium intermediate alloy, aluminum titanium or aluminum titanium boron intermediate alloy, and molten aluminum.

[0046] For example, the manufacturing of the composite rare-earth aluminum alloy is Step S211 provides molten aluminum, Step S212 provides an aluminum strontium intermediate alloy, an aluminum titanium or aluminum titanium boron intermediate alloy, and a rare earth aluminum alloy, wherein the rare earth metal in the rare earth aluminum alloy is one or more selected from lanthanum, cerium, and yttrium. The process may also include step S213, in which the molten aluminum is smelted with the rare-earth aluminum alloy, aluminum strontium intermediate alloy, aluminum titanium, or aluminum titanium boron intermediate alloy under an inert gas atmosphere to obtain the composite rare-earth alloy.

[0047] Here, the aluminum strontium intermediate alloy and the aluminum titanium or aluminum titanium boron intermediate alloy are added at intervals, and the rare earth aluminum alloy is added before the aluminum strontium intermediate alloy and the aluminum titanium or aluminum titanium boron intermediate alloy, or together with the first one added, or between the timing of adding the aluminum strontium intermediate alloy and the timing of adding the aluminum titanium or aluminum titanium boron intermediate alloy.

[0048] Preferably, the rare earth aluminum alloy, the aluminum strontium intermediate alloy, and the aluminum titanium or aluminum titanium boron intermediate alloy are added to the molten aluminum in sequence at intervals.

[0049] Step S3: In an inert gas atmosphere, the modifying agent is added to the molten aluminum alloy and smelted to obtain the modified molten aluminum alloy.

[0050] In other words, after preparing molten aluminum and a modifier, the modifier is added to the molten aluminum under an inert gas atmosphere and further smelted to obtain modified aluminum alloy molten metal.

[0051] The manufacturing method according to the embodiment of the present invention overcomes the mutual poisoning effect between the altering agent and the refinement agent to a great extent by incorporating rare earth metals into the modifier, thereby increasing the amount of altering agent and refinement agent added, and enhancing the effects of alteration and refinement.

[0052] The following smelting procedures are performed on each of the two combinations of modifiers described above.

[0053] Regarding the combination of the modifier being a rare earth aluminum alloy, an aluminum strontium intermediate alloy, aluminum titanium, or an aluminum titanium boron intermediate alloy, specifically, each rare earth aluminum alloy, aluminum strontium intermediate alloy, aluminum titanium, or aluminum titanium boron intermediate alloy and its pretreatment may refer to step S2 above.

[0054] In this combination, the aluminum strontium intermediate alloy and the aluminum titanium or aluminum titanium boron intermediate alloy are added at intervals, the rare earth aluminum alloy is added first, then added together with the first one added, or added between the timing of adding the aluminum strontium intermediate alloy and the timing of adding the aluminum titanium or aluminum titanium boron intermediate alloy.

[0055] More preferably, step S3 specifically means, Step S301 involves adding the rare-earth aluminum alloy to the molten aluminum and smelting it to obtain a first homogeneous mixed molten metal, Step S302 involves adding the aluminum strontium intermediate alloy to the first homogeneous mixed molten metal and continuing to smelt it to obtain a second homogeneous mixed molten metal, The process may also include step S303, in which the aluminum-titanium or aluminum-titanium-boron intermediate alloy is added to the second homogeneous mixed molten metal and subsequently smelted to obtain the modified aluminum alloy.

[0056] In other words, by first adding a rare-earth aluminum alloy and smelting it, and then sequentially adding an aluminum strontium intermediate alloy as a modification agent, and an aluminum titanium intermediate alloy or aluminum titanium boron intermediate alloy as a refiner at intervals, the poisoning effects of strontium and boron can be better resolved, and a modified aluminum alloy with higher refinement, greater uniformity, and superior mechanical properties can be obtained.

[0057] Furthermore, if the modifier is a combination of a composite rare-earth aluminum alloy, aluminum titanium, or aluminum titanium boron intermediate alloy, step S3 is performed as follows: Step S310 involves adding the composite rare-earth aluminum alloy to the molten aluminum and smelting it to obtain a fourth homogeneous mixed molten metal, The process includes step S320, which involves adding the aluminum-titanium or aluminum-titanium-boron intermediate alloy to the fourth homogeneous mixed molten metal and continuing to smelt it to obtain the modified aluminum alloy.

[0058] In other words, if a composite rare-earth aluminum alloy is obtained by smelting a rare-earth aluminum alloy, a modifier, a refiner, and aluminum beforehand, it can be manufactured by adding it to the molten aluminum in one step. Of course, in the case of high-temperature smelting, abnormal growth of crystal grains is likely to occur, which does not improve the mechanical performance. Therefore, it is preferable to further add a refiner, i.e., an aluminum-titanium intermediate alloy or an aluminum-titanium-boron intermediate alloy, to the composite rare-earth aluminum alloy once it has been completely melted and uniformly mixed with the aluminum alloy, in order to control the growth of crystal grains.

[0059] As a modifier, the amount added is appropriately designed according to the needs of use, with different content levels of each active ingredient in the intermediate alloy. For example, when incorporated into a composite rare-earth alloy (with a mass ratio of the total amount of rare-earth elements contained therein:strontium:titanium or titanium-boron = 1:(0.1~1.2):(0.1~1.2)), the modifier preferably accounts for 0.4~0.6 wt% of the total amount of the modified aluminum alloy.

[0060] Furthermore, any one of the above steps of refining—that is, refining in the process of purifying molten aluminum, refining in the process of manufacturing rare-earth aluminum alloys, and refining each molten metal in a composite rare-earth aluminum alloy—may be carried out in the following manner.

[0061] The smelting agent was blown in with an inert gas and held for 3 to 10 minutes. After that, a slag remover was added and stirred for 5 to 10 minutes to remove the surface scum.

[0062] Furthermore, the amount of the refining agent added accounts for 0.1 to 0.3% of the mass of the molten metal added, and the amount of the slag remover added accounts for 0.1 to 0.3% of the mass of the molten metal added.

[0063] The components of the aforementioned refining agent, when calculated by mass, It contains potassium chloride: 10-15 parts by mass, sodium chloride: 15-25 parts by mass, calcium fluoride: 8-15 parts by mass, sodium carbonate: 15-25 parts by mass, sodium sulfate: 8-12 parts by mass, sodium fluoroaluminate: 10-20 parts by mass, and hexachloroethane: 8-12 parts by mass.

[0064] The components of the aforementioned slag remover, when calculated by mass, It contains 25-30 parts by mass of sodium chloride, 25-30 parts by mass of potassium chloride, 5-10 parts by mass of sodium carbonate, 5-10 parts by mass of sodium sulfate, 1-5 parts by mass of sodium fluoroaluminate, 5-10 parts by mass of sodium fluorosilicate, 5-10 parts by mass of calcium fluoride, 1-5 parts by mass of potassium nitrate, and 5-10 parts by mass of potassium fluorosilicate.

[0065] Furthermore, the decision of whether or not to continue refining may be made by monitoring the hydrogen content of the molten metal. In this invention, the hydrogen content is estimated by testing the density of the molten metal; that is, the closer the molten metal density is to the theoretical density, the higher the hydrogen content (this varies slightly depending on the components contained in the alloy, but is generally around 2.7 g / cm³). 3(To a certain extent) it indicates that the hydrogen content will be lower. For example, if the density of the molten metal is 2.65 g / cm³ 3 If the density is less than 2.65 g / cm³, the refining process is performed, and the molten metal density is 2.65 g / cm³. 3 If the above conditions are met, the system may be configured to either not perform the refining process or to terminate the refining process.

[0066] Step S4: The modified aluminum alloy molten metal is poured to obtain a cast aluminum alloy blank.

[0067] In other words, after smelting, the resulting modified aluminum alloy molten metal is cast into a mold to obtain the cast aluminum alloy blank.

[0068] The specific casting process may be the same as that of a standard casting process; however, a detailed description of this process is omitted here.

[0069] Step S5, the aluminum alloy blank is heat-treated.

[0070] In other words, after obtaining an aluminum alloy blank through casting, the inventors repeatedly conducted research and developed the following heat treatment process to further increase its mechanical strength.

[0071] Specifically, the heat treatment described above is: The aluminum alloy blank is heated to 530-550°C and kept warm for 100-300 minutes in a solution treatment, The aluminum alloy blank, after undergoing solution treatment, is placed in a water bath at a temperature of 60-70°C and water-quenched for 2-4 minutes in a water quenching treatment. The process includes aging treatment to obtain the high-strength composite modified aluminum alloy part, which involves heating an aluminum alloy blank after water quenching at 150-165°C for 120-280 minutes, then lowering the temperature to 110-130°C and heating for 30-120 minutes, and then allowing it to cool naturally to room temperature.

[0072] In other words, the aluminum alloy blank is subjected to a series of treatments: solution treatment, water quenching, and aging treatment.

[0073] By designing the above solution treatment, it is possible to eliminate stress caused by the cooling rate during crystal solidification of a casting due to the casting structure (for example, uneven wall thickness and large thickness at intermediate points), improve the mechanical strength and hardness of the alloy, improve the metal structure, eliminate intergrain and component segregation, and make the structure uniform.

[0074] In addition, by designing the water quenching process described above, the casting is rapidly cooled, allowing the strengthening elements to dissolve to the maximum extent in the alloy, and then fixed at room temperature for storage.

[0075] By designing the aging process described above, as the temperature increases and the time is extended, several steps occur, such as the recombination of atoms within the supersaturated solid solution lattice to create a solute atom-enriched region (called the G-PI region), the disappearance of the G-PI region and the uneven distribution of atoms in the second phase to create the G-PII region, the creation of a metastable second phase (transition phase), the bonding of a large amount of the G-PII region with a small amount of the metastable phase, and the conversion of the metastable phase into a stable phase, causing the mass points of the second phase to aggregate.

[0076] Furthermore, according to the manufacturing method of the present invention, high strength can be ensured by first using high-temperature aging treatment to induce a phase transition between the β' region and the β'' region.

[0077] Preferably, the heating rate in the solution treatment is controlled to 1.5 to 3°C / min, and the holding time is controlled to 120 to 180 min. By controlling the heating rate and holding time of the solution treatment, the amount of loose α-Al phase and rolled spherical α-Al phase can be further increased, the primary α-Al phase can be subdivided, and the number of dendritic crystals can be reduced.

[0078] Furthermore, the solution treatment, water quenching treatment, and aging treatment are continuous processes, the water bath is a circulating water bath, and the temperature of the cast aluminum alloy blank is maintained at 55°C or higher after the water quenching treatment and before the aging treatment. Continuous processing not only improves production efficiency but also avoids unnecessary defects caused by process interruptions. In addition, the minimum temperature during the period is controlled to avoid defects caused by rapid cooling.

[0079] Furthermore, in the aging treatment stage, the cooling rate is controlled to 2-5°C / min, from 150-165°C to 110-130°C. By controlling the cooling rate in the aging treatment stage, the inclusion of defects can be greatly reduced, further increasing the mechanical strength and maintaining a high level of properties. The manufacturing method according to the present invention will be described in more detail below with reference to specific examples.

[0080] Example 1 Aluminum alloy: Aluminum silicon magnesium alloy (A356) (purchased from Shandong Weiqiao File Industry) was used. High-purity aluminum ingot (purchased from China Aluminum Co. Ltd., composition: Al (99.99%), Fe < 0.1%, impurities < 0.05%) Refining agent: Ingredients: Potassium chloride: 15 parts by mass, sodium chloride: 20 parts by mass, CaF2: 10 parts by mass, Na2CO3: 20 parts by mass, Na2SO4: 10 parts by mass, Na3AlF6: 15 parts by mass, C2Cl6: 10 parts by mass. Slag remover: Ingredients: Sodium chloride: 25 parts by mass, potassium chloride: 25 parts by mass, sodium carbonate: 5 parts by mass, sodium sulfate: 5 parts by mass, sodium fluoroaluminate: 5 parts by mass, sodium fluorosilicate: 10 parts by mass, calcium fluoride: 10 parts by mass, potassium nitrate: 5 parts by mass, potassium fluorosilicate: 10 parts by mass.

[0081] 1) Production of molten aluminum alloy Melting: First, the preheated aluminum-silicon-magnesium alloy A356 was added to a preheated smelting furnace and heated to within 760 degrees Celsius to melt it and obtain molten aluminum. Degassing and slag removal: After the aluminum molten, nitrogen gas (or argon gas) was passed through, then a smelting agent (0.3 wt% smelting agent) was blown into the aluminum molten, and the aeration time was controlled to 15 minutes. Standing: The molten aluminum in S3 was allowed to stand for 10 minutes, and the temperature was controlled to below 760 degrees Celsius to cleanly remove slag impurities from the surface of the molten aluminum. During this time, we sampled the molten aluminum that had been left to stand, measured its chemical composition, and estimated the amount of hydrogen gas. The hydrogen content was estimated using the density method, and the density was 2.65 g / cm³. 3 The above is required. The higher the density, the better (2.7 g / cm³). 3 The closer the location, the lower the hydrogen content is thought to be.

[0082] 2) Refining process of the intermediate alloy 2.1) Aluminum strontium intermediate alloy: Purchased from Nantong Angshen Metal Materials Co., Ltd., composition: Al-10Sr, Fe<0.05. Pretreatment: The scale and surface of the aluminum strontium intermediate alloy were cleaned using a grinder. Ultrasonic cleaning: The pre-treated aluminum strontium intermediate alloy was placed in an ultrasonic cleaning tank and subjected to ultrasonic treatment. Drying: The washed aluminum strontium intermediate alloy was placed in an oven and dried at 60-100°C for 30-60 minutes. Smelting: The aluminum strontium intermediate alloy was placed in a preheated crucible and melted at 760-780°C. Refining Process: After melting the aluminum strontium intermediate alloy, a refining process was carried out. An Ar+graphite automatic degassing stirring rod was introduced to refine the molten high-purity aluminum. Ar was blown in as a refining agent for 5-10 minutes at 730-750°C, with the amount of refining agent blown in being 0.1-0.3% of the molten metal. This was held for 3-5 minutes, and no boiling bubbles should be present on the surface of the molten aluminum during the refining process. Surface scum removal: 0.1-0.3% slag remover was added and uniformly dispersed for 15-20 minutes to remove surface scum. Standing: After removing the residue, the mixture was left to stand at 740-760°C for 8-15 minutes. 2.2) Refining agent: Refining treatment of aluminum titanium boron intermediate alloy Aluminum-titanium-boron intermediate alloy: Purchased from Nantong Angshen Metal Materials Co., Ltd. (Composition and content: Ti: 5%, B: 1%, remainder: Al) The aluminum-titanium-boron intermediate alloy, used as a refiner, underwent the same treatment as described above.

[0083] 3) Manufacturing of composite rare-earth aluminum alloys 3.1) Smelting of high-purity rare-earth aluminum intermediate alloys a) Production of high-purity molten aluminum Pretreatment: The scale and surface layer of the high-purity aluminum ingot were cleaned using a grinder. Ultrasonic cleaning: High-purity aluminum ingots, after pretreatment, were placed in a cleaning agent and subjected to ultrasonic treatment. Drying: After ultrasonic cleaning, the high-purity aluminum ingots were placed in an oven and dried at 60-100°C for 30-60 minutes. Melting: After drying, high-purity aluminum was placed in a preheated crucible and heated to 760-780°C to melt it. Refining Process: After melting high-purity aluminum, a refining process was performed. Specifically, the melted high-purity aluminum was refined using an Ar + graphite automatic degassing and stirring rod. Ar was blown in as a refining agent for 5-10 minutes at 740-760°C, with the amount of refining agent blown in being 0.1-0.3% of the molten metal, and this was held for 3-5 minutes. After this, it was left to stand for 10-20 minutes, and then 0.1-0.3% of a slag remover was added and uniformly dispersed to remove surface scum. Standing: After removing the residue, the mixture was left to stand at 740-760°C for 8-15 minutes.

[0084] b) Smelting of rare-earth aluminum alloys: The temperature of the high-purity aluminum obtained in a) above was adjusted to 780-820°C, and after heating and completely melting it, a rare-earth aluminum lanthanum alloy (purchased from Baotou Rare Earth Research Institute, composition: Al-10La, Fe<0.05) was added in a set mass%, i.e., so that the lanthanum content in the rare-earth aluminum alloy was 0.2±0.02 wt%. It was then heated at 780-820°C under an argon atmosphere and completely melted. Stirring and heat retention: After melting, the molten metal was stirred for 3-5 minutes to make it uniform, and then kept warm at 760-780°C for 10-20 minutes. Refining Process: In the entire process, the rare-earth aluminum lanthanum alloy was melted under protection of an argon atmosphere and then refined. An Ar+graphite automatic degassing and stirring rod was introduced to refine the melted material. The refining agent was blown in with Ar at 760-780°C for 5-10 minutes, with an amount of refining agent of 0.1-0.3% of the molten metal, and held for 3-5 minutes. During the refining process, there should be no boiling bubbles on the surface of the molten aluminum. Removal of Molten Metal Surface Scum: 0.1-0.3% of a slag remover was added and uniformly dispersed for 15-20 minutes to remove the surface scum. Standing: After removing the residue, the mixture was left to stand at 720-730°C for 10-15 minutes.

[0085] 3.2) Manufacturing of composite rare earth alloys As described above, molten aluminum, rare-earth aluminum alloy, aluminum strontium intermediate alloy, and aluminum titanium boron intermediate alloy were prepared, and then mixed smelting was performed on them to obtain a composite rare-earth alloy.

[0086] In this embodiment, the addition sequence was as follows: first, a rare-earth aluminum alloy was added to the molten aluminum; then, an aluminum strontium alloy was added; and finally, an aluminum titanium boron alloy was added. Specifically, the sequence was as follows:

[0087] Step 1, Mixing the raw materials: The high-purity aluminum, aluminum-titanium-boron intermediate alloy, aluminum-strontium intermediate alloy, and rare-earth aluminum alloy obtained above were weighed in the required mass % and then preheated.

[0088] The total amount per 100 parts by weight contains: high-purity aluminum: 4.8 parts by weight, aluminum-titanium-boron intermediate alloy: 0.2 parts by weight, aluminum-strontium intermediate alloy: 60 parts by weight, and rare-earth aluminum alloy: 35 parts by weight.

[0089] Step 2, Adding and melting rare earth aluminum alloy: First, the rare earth aluminum alloy that has undergone the above purification process is heated to 780-820°C to soften it before melting. Then, the temperature of the entire molten aluminum is controlled to 760-780°C, and the rare earth aluminum alloy is added to the molten aluminum and kept warm.

[0090] Throughout the entire process, the rare-earth aluminum alloy was melted under protection in an argon atmosphere.

[0091] Step 3: After the rare-earth aluminum alloy had completely melted, the mixture was stirred for 5-10 minutes while the temperature was controlled to 750-770°C.

[0092] Throughout the entire process, the system was protected under an argon atmosphere, and a graphite material was used for the stirring rod. The system was preheated to 400-500°C before stirring.

[0093] In other words, by slightly lowering the temperature after the rare-earth aluminum alloy has completely melted, it is possible to prevent the subsequent coarsening of crystal grains caused by overheating.

[0094] Step 4: The molten metal was kept at 740-760°C for 5-20 minutes. At this stage, the alloying reaction occurred.

[0095] Step 5, Refining: After the heat preservation ended, refining was carried out, including degassing and slag removal. 0.3% of a refining agent was blown into the molten metal with argon gas, and the ventilation time was controlled within 3 - 8 minutes. Then, 0.2% of a slag removal agent was added, and it was stirred for 5 minutes and left to stand to remove the slag and impurities on the surface of the molten metal. The whole process was protected under an argon atmosphere.

[0096] Before and during refining, samples of the aluminum molten metal were taken, and its density was measured to estimate the hydrogen content. The measurement method used was the density method (compared with the theoretical value of aluminum, 2.70 g / cm 3 ). The closer the measured sample was to 2.7 g / cm 3 , the lower the hydrogen content inside the aluminum was indicated. Usually, it was less than 2.7 g / cm 3 . When the density test of the sample was about 2.65 g / cm 3 , the hydrogen content could be estimated. Vacuum pumping treatment was required during this process. If the hydrogen content was unqualified, further refining was carried out, that is, the refining agent and slag removal agent were repeatedly added and refined again.

[0097] Step 6, Standing: The molten metal after adding and refining the rare earth aluminum alloy was left to stand for 3 - 5 minutes, and the temperature was controlled at 740 - 760 degrees.

[0098] Step 7, Adding and dissolving the aluminum - strontium master alloy: The aluminum - strontium master alloy after the above - mentioned refining was added to the molten metal in Step 6, and the temperature was controlled at 780 - 820 °C to completely dissolve the aluminum - strontium master alloy. The whole process was protected under an argon atmosphere while dissolving the aluminum - strontium master alloy.

[0099] After the aluminum - strontium master alloy was dissolved, the temperature was controlled at 740 - 760 °C, and it was stirred for 3 - 8 minutes to achieve homogenization. The whole process was protected under an argon atmosphere, a graphite material was used for the stirring rod, and it was pre - heated to 400 - 500 °C before stirring.

[0100] Step 9: Next, the samples were insulated at 725-750°C. The insulation time was controlled to 15-30 minutes.

[0101] Step 10, Smelting, Degassing & Slag Removal: After the molten metal has been kept warm, argon gas is introduced, then 0.3% smelting agent is blown into the molten aluminum rare earth composite, and the aeration time is controlled to 5-10 minutes. 0.2% slag remover is added to the molten aluminum and stirred for 5 minutes to remove slag and impurities from the surface of the molten aluminum rare earth composite. The entire process was protected under an argon atmosphere.

[0102] Molten aluminum was sampled before and during refining, and its hydrogen content was measured (hydrogen content: 2.65 g / cm³). 3 (The above is required.) The hydrogen measurement process requires vacuuming, and if the hydrogen content is unsatisfactory, further refining is performed, that is, refining agents and slag removers are repeatedly added and refining is carried out again.

[0103] Step 11, Adding the aluminum-titanium-boron intermediate alloy: The aluminum-titanium-boron intermediate alloy was added to the molten metal after processing in Step 10, heated to completely dissolve, and then stirred uniformly for 3-5 minutes to homogenize it.

[0104] Step 12, Insulation: After stirring, the molten metal was kept warm for 8-12 minutes, controlling the temperature to 715-725°C.

[0105] Step 13, Purification, Degassing & Slag Removal: After the molten metal has been kept warm, argon gas is introduced, and 0.3% of the refining agent is blown into the aluminum rare earth composite molten metal. The aeration time is controlled to 5-10 minutes, and 0.2% of the slag remover is added to the aluminum molten metal and stirred for 5 minutes to remove slag and impurities from the surface of the aluminum rare earth composite molten metal. The entire process was protected under an argon atmosphere.

[0106] Molten aluminum was sampled before and during refining, and its hydrogen content was measured (hydrogen content: 2.65 g / cm³). 3(The above is required.) The hydrogen measurement process requires vacuuming, and if the hydrogen content is unsatisfactory, further refining is performed until it passes, that is, refining agents and slag removers are repeatedly added and refining is performed again.

[0107] Step 14, Casting: The mold was preheated to 300-400°C. The temperature of the molten composite rare-earth alloy obtained in Step 13 above was controlled to 715-725°C for casting.

[0108] Preferably, during casting, the oxides on the surface layer of the molten aluminum rare earth composite are thoroughly filtered using a glass fiber filter mesh, and the molten aluminum rare earth composite is filtered before each casting.

[0109] Preferably, the cooling control of the mold for casting involves cooling the molten aluminum rare earth composite poured into the mold using a water cooling method, controlling the solidification rate of the molten aluminum at 50-100°C / s during cooling, and sequentially solidifying the material.

[0110] The specific weights of the rare earth metal:strontium:titanium or titanium boron in the composite rare earth aluminum alloy are not limited to the above examples. For example, the mass ratio of the weights of the rare earth metal:strontium:titanium or titanium boron may be 1:(0.1~1.2):(0.1~1.2).

[0111] 4) Manufacturing of modified aluminum alloy blanks Aluminum alloy, composite rare earth aluminum alloy, and aluminum titanium boron intermediate alloy were prepared with a mass ratio of 99.4:0.4:0.2 for aluminum alloy, composite rare earth aluminum alloy, and aluminum titanium boron intermediate alloy.

[0112] The smelting process then proceeded in the following steps.

[0113] Mixing: In the above proportions, the composite rare-earth aluminum alloy obtained in 3) was first added to the molten aluminum-silicon-magnesium alloy treated in 1) above, while the temperature was controlled to 740±5 degrees. Stirring: The molten metal, to which the composite rare-earth aluminum alloy has been added, must be stirred using a graphite mixer. The stirring process must be carried out uniformly and continuously for 8 minutes. Incubation: After stirring, the temperature was controlled to 735 degrees Celsius and the incubation period was controlled to 20 minutes. Smelting: After the heating period was complete, argon gas was introduced, then a slag remover was blown into the molten aluminum, and the aeration time was controlled to 15 minutes. Addition of refinement agent: A 0.2% aluminum-titanium-boron intermediate alloy was added to the refined molten aluminum, dissolved, stirred, and the refining process was continued. Heat retention and standing: After the refining was completed, the molten aluminum flowed into the heat retention cell, and the temperature was controlled to 710±3 degrees Celsius. After standing for 10±2 minutes, the slag and impurities on the surface of the molten aluminum were removed. Casting: When the preheated mold was 250-400 degrees Celsius, the refined modified aluminum alloy, with its temperature controlled to 700±5 degrees Celsius, was cast into the mold and cooled to obtain a modified aluminum alloy blank. The thickness of this modified aluminum alloy blank was 30 mm.

[0114] 5) Heat treatment Solution treatment: The modified aluminum alloy blank described above was placed in a heating furnace and heated to 540°C at a heating rate of 2°C / min, and then kept warm for 120 minutes. Water quenching treatment: The modified aluminum alloy blank, after the above solution treatment, was placed in a circulating water bath at a temperature of 65°C and water quenched for 3 minutes. Aging treatment: After undergoing water quenching, the modified aluminum alloy blank was placed directly into a 150°C insulated box and kept warm for 120 minutes. Then, it was cooled to 110°C at a rate of 2°C / min and kept warm for 30 minutes, after which it was allowed to cool naturally to room temperature to obtain the high-strength composite modified aluminum alloy part.

[0115] Figure 1 is a photograph of a high-strength composite modified aluminum alloy part, namely a hub, manufactured in the example. Figure 2 is a metallographic image of the rib portion of the hub shown in Figure 1, where (a) is a low-magnification image, (b) is a medium-magnification image, and (c) is a high-magnification image. As can be seen from Figure 2, the metallographic structure of the aluminum alloy after modification and heat treatment in this example shows a further increase in relatively rounded spherical α-Al phases, with the primary α-Al phase and dendritic crystals almost invisible. In other words, the crystal grains have become more homogenized, and the microstructure has become more uniform. In addition, the spherical α-Al phase is uniformly distributed at the grain boundaries.

[0116] Furthermore, the mechanical performance of the A356 aluminum alloy (referred to as "before modification"), the modified blank (referred to as "modified alloy 1"), and the heat-treated part (referred to as "Example 1") was evaluated. The evaluation results are shown in Table 1 below.

[0117] [Table 1]

[0118] As can be seen from Table 1, the heat treatment of this embodiment 1 significantly improves the strength even after heat treatment. In addition to the heat treatment, the yield strength and tensile strength (yield strength and tensile strength increased by approximately 4 times and approximately 3 times, respectively, compared to an unmodified, unheat-treated aluminum alloy master ingot) were greatly increased, and a high level of elongation (increased to more than 5 times compared to an untreated aluminum alloy master ingot) was also maintained, resulting in a significant improvement in overall mechanical performance.

[0119] Example 2 In this example, the method is the same as in Example 1, except that a combination of rare earth aluminum alloy, aluminum strontium intermediate alloy, aluminum titanium, or aluminum titanium boron intermediate alloy was used as the modifier.

[0120] The following describes only the differences in the treatment of molten modified aluminum alloy.

[0121] 4) Manufacturing of modified aluminum alloy blanks Aluminum alloy: Rare earth aluminum alloy (the refining process for the rare earth aluminum alloy is the same as in Example 1): Aluminum strontium alloy: Aluminum titanium boron intermediate alloy were prepared in a mass ratio of 99.4:0.2:0.2:0.2.

[0122] The smelting process then proceeded in the following steps. Mixing: In the aluminum-silicon-magnesium alloy molten metal treated in 1) above, the temperature was controlled to 740±5 degrees Celsius, and first, the rare earth aluminum alloy was added. Stirring: The molten metal containing the rare-earth aluminum alloy is stirred using a graphite mixer, ensuring uniform stirring during the stirring process, and continuous stirring for 8 minutes. Insulation: After stirring, the temperature was controlled to 735 degrees Celsius and the insulation time was controlled to 20 minutes. Smelting: After the heating period was complete, argon gas was introduced, then a slag remover was blown into the molten aluminum, and the aeration time was controlled to 15 minutes. Addition of aluminum strontium intermediate alloy: 0.2% aluminum strontium intermediate alloy was added to the refined molten aluminum, and the refining process was continued by dissolving and stirring. Homogenization: After the aluminum strontium intermediate alloy was completely melted, the temperature was controlled to 740-760°C and the mixture was stirred for 3-8 minutes to achieve homogenization. Insulation: Next, the samples were insulated at 725-750°C for 15-30 minutes. Addition of a refining agent: A 0.2% aluminum-titanium-boron intermediate alloy was added to the refined molten aluminum, and after melting, the refining process was continued with stirring. Heat retention and standing: After the refining was completed, the molten aluminum flowed into the heat retention cell, and the temperature was controlled to 710±3 degrees Celsius. After standing for 10±2 minutes, slag and impurities on the surface of the molten aluminum were removed. Casting: When the preheated mold was at 250-400 degrees Celsius, the refined modified aluminum alloy, whose temperature was controlled to 700±5 degrees Celsius, was poured into the mold and cooled to obtain a modified aluminum alloy blank.

[0123] The microstructure image of the product obtained in this embodiment is similar to that of Example 1, so it will not be described in detail here.

[0124] [Table 2]

[0125] Here, modified alloy 2 represents the modified blank, and no heat treatment was performed.

[0126] As can be seen from Table 2, the heat treatment in this Example 2 can also yield results similar to those in Example 1.

[0127] At the same time, compared to Example 2, it was found that a composite rare-earth aluminum alloy was first produced by smelting a rare-earth aluminum alloy and an aluminum strontium intermediate alloy, and that the composite modified aluminum alloy parts modified with this composite rare-earth aluminum alloy had higher overall mechanical performance.

[0128] Example 3 In this embodiment, the only difference from Embodiment 1 is that ZL111 is used instead of A356.

[0129] For specific manufacturing details, please refer to Example 1; a detailed explanation is omitted here.

[0130] Furthermore, the mechanical performance of the ZL111 aluminum alloy (referred to as "before modification"), the modified blank (referred to as "modified alloy 3"), and the heat-treated part (referred to as "Example 3") was evaluated. The evaluation results are shown in Table 3 below.

[0131] [Table 3]

[0132] As can be seen from Table 3, the heat treatment in this Example 3 can also yield results similar to those in Examples 1 and 2. In other words, the manufacturing process of the present invention can be similarly applied to eutectic aluminum alloys, resulting in better strength and higher toughness.

[0133] While preferred embodiments of the present invention have been described above, those skilled in the art will understand that some improvements and modifications are possible without departing from the aforementioned principles of the present invention, and these improvements and modifications should also be considered to fall within the scope of protection of the present invention.

Claims

1. In a method for manufacturing high-strength composite modified aluminum silicon magnesium alloy parts, Step S1 provides molten aluminum silicon magnesium alloy, Step S2 provides a modifier, wherein the modifier accounts for 0.4 to 0.6 wt% of the total amount of molten aluminum silicon magnesium alloy. The modifier is a combination of a composite rare-earth aluminum alloy and an aluminum-titanium intermediate alloy, or a combination of a composite rare-earth aluminum alloy and an aluminum-titanium-boron intermediate alloy, wherein the composite rare-earth aluminum alloy contains strontium, titanium or titanium-boron, and rare earth metals, and the mass ratio of the total amount of the rare earth metal:strontium:titanium or titanium-boron in the composite rare-earth aluminum alloy is 1:(0.1-1.2):(0.1-1.2). The rare earth metal in the aforementioned composite rare earth aluminum alloy is one or more of lanthanum, cerium, and yttrium. The manufacturing of the aforementioned composite rare-earth aluminum alloy is Step S211, which provides the molten aluminum-silicon-magnesium alloy, Step S212 provides an aluminum strontium intermediate alloy, an aluminum titanium or aluminum titanium boron intermediate alloy, and a rare earth aluminum intermediate alloy, wherein the rare earth metal in the rare earth aluminum intermediate alloy is one or more selected from lanthanum, cerium, and yttrium. Step S2 includes step S213, in which, under an inert gas atmosphere, the rare earth aluminum intermediate alloy, aluminum strontium intermediate alloy, aluminum titanium, or aluminum titanium boron intermediate alloy are sequentially added to the molten aluminum silicon magnesium alloy to obtain the composite rare earth aluminum alloy. Step S3 involves adding the modifier to the molten aluminum-silicon-magnesium alloy under an inert gas atmosphere and smelting it to obtain the modified aluminum-silicon-magnesium alloy molten metal. Step S4 involves casting using the modified aluminum-silicon-magnesium alloy molten metal to obtain a modified aluminum-silicon-magnesium alloy blank, Step S5 involves heat-treating the modified aluminum silicon magnesium alloy blank, The heat treatment comprises a solution treatment in which the modified aluminum silicon magnesium alloy blank is heated to 530 to 550°C and held at that temperature for 100 to 300 minutes. The modified aluminum-silicon-magnesium alloy blank, after undergoing solution treatment, is placed in a water bath at a temperature of 60-70°C and water-quenched for 2-4 minutes in a water quenching treatment. A method for manufacturing a high-strength composite modified aluminum silicon magnesium alloy part, characterized by comprising step S5, which includes: heating a modified aluminum silicon magnesium alloy blank after water quenching at 150 to 165°C for 120 to 280 mins, then lowering the temperature to 110 to 130°C and heating for 30 to 120 mins, and then allowing it to cool naturally to room temperature to obtain the high-strength composite modified aluminum silicon magnesium alloy part.

2. Step S1 is, To provide aluminum silicon magnesium alloy master ingots, The scale layer on the surface of the aluminum-silicon-magnesium alloy master ingot is removed, and then the ingot is cleaned and dried. The process includes smelting a dried aluminum-silicon-magnesium alloy master ingot, refining it, removing slag, and obtaining the molten aluminum-silicon-magnesium alloy. The manufacturing method according to claim 1, characterized in that the aluminum-silicon-magnesium alloy master ingot is composed of a hypoeutectic aluminum alloy or a eutectic aluminum alloy.

3. Step S3 is, Step S310 involves adding the composite rare-earth aluminum alloy to the aluminum-silicon-magnesium alloy molten metal and smelting it to obtain a homogeneous mixed molten metal, The manufacturing method according to claim 1, characterized by comprising step S320, which involves adding the aluminum-titanium or aluminum-titanium-boron intermediate alloy to the homogeneous mixed molten metal and continuing to smelt it to obtain the modified aluminum-silicon-magnesium alloy molten metal.

4. The manufacturing method according to claim 1, characterized in that in step S5, the heating rate during the solution treatment is controlled to 1.5 to 3°C / min and the holding time is controlled to 120 to 180 min.

5. The aforementioned solution treatment, water quenching treatment, and aging treatment are continuous processes. The manufacturing method according to claim 1, characterized in that the water bath is a circulating water bath, and after the water quenching treatment and before the aging treatment, the temperature of the modified aluminum silicon magnesium alloy blank is maintained at 55°C or higher.

6. The manufacturing method according to claim 1, characterized in that, in the aging treatment stage, the cooling rate from 150 to 165°C to 110 to 130°C is controlled to 2 to 5°C / min.

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