Low-cost ultrahigh-toughness cast aluminum-silicon alloy material and preparation method thereof

Abstract

The invention relates to the technical field of cast aluminum-silicon alloys, in particular to a low-cost ultrahigh-toughness cast aluminum-silicon alloy material and a preparation method thereof. The aluminum-silicon alloy material comprises the following components in percentage by weight: 7.0%-9.0% of silicon, 0.30%-0.50% of magnesium, 1.60%-2.00% of copper, less than or equal to 0.2% of zinc, less than or equal to 0.2% of iron, 0.20%-0.40% of manganese, less than or equal to 0.2% of chromium, 0.05%-0.3% of zirconium, 0.03%-0.2% of titanium, less than or equal to 0.04% of strontium and the balance of aluminum and other impurities. Wherein the total content of other impurities is less than or equal to 0.15%, and the content of a single impurity is less than or equal to 0.05%. The aluminum-silicon alloy material provided by the invention has relatively excellent comprehensive properties such as tensile strength and elongation and relatively low cost, and can replace traditional cast aluminum, deformed aluminum, medium-low grade ductile iron, gray iron, carbon steel, plates and other materials, so that the weight-reducing and light-weight design of parts is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of cast aluminum-silicon alloys, and in particular to a low-cost ultra-high-strength and tough cast aluminum-silicon alloy material and a preparation method thereof. Background Art

[0002] Cast aluminum alloys are mainly divided into four series according to the system: Al-Si, Al-Cu, Al-Mg, and Al-Zn. Among them, Al-Si casting alloys are widely used in the machinery manufacturing industry because of their good casting processability and suitable mechanical properties. However, after T6 treatment, the tensile strength of Al-Si casting alloys is generally below 350MPa, and the toughness is insufficient, making it difficult to use on parts with high load-bearing requirements. In comparison, Al-Cu, Al-Mg, and Al-Zn casting alloys have higher toughness, especially Al-Cu casting alloys, which can reach a tensile strength of more than 400MPa after T6 treatment. However, Al-Cu, Al-Mg, and Al-Zn casting alloys have shortcomings such as poor casting fluidity, poor corrosion resistance, high tendency to hot cracking, and easy air absorption, which limit their application.

[0003] CN108203780B discloses a liquid die forged high-strength wear-resistant aluminum alloy and its preparation method. The aluminum silicon alloy of the invention is squeeze cast and treated with T6, and the tensile strength can reach 401.6MPa, the elongation after fracture is 6.1%, and the comprehensive strength and toughness are excellent. However, it is necessary to use precious metal components Ni and Re, and add a high content of Cu. CN108251714B discloses an extrusion cast high-strength and toughness aluminum alloy. The obtained aluminum silicon alloy is squeeze cast and treated with T6, and the tensile strength can reach 395.1MPa, the yield strength is 345.2MPa, and the elongation after fracture is 6.2%, but it is necessary to use more expensive elements Te and Yb.

[0004] Existing high-strength and toughness aluminum-silicon alloys mostly achieve high strength and toughness by adding rare earths, precious metals such as Ni, Te, Mo, etc. or adding a large amount of Cu. Adding rare earths and precious metals will lead to high alloy costs, and adding a large amount of Cu will reduce the toughness and plasticity of the alloy, limiting its application. Therefore, it is of great significance to study aluminum-silicon casting alloys and preparation methods that have both low cost and high strength and toughness comprehensive properties to promote the application of aluminum alloy materials. Summary of the invention

[0005] Based on this, it is necessary to provide a low-cost ultra-high-strength cast aluminum-silicon alloy material and its preparation method. The low-cost ultra-high-strength cast aluminum-silicon alloy material of the present application has a cast tensile strength of 330-400MPa, a yield strength of 180-240MPa, and an elongation of 5-13%; after T6 treatment, the tensile strength is 370-500MPa, the yield strength is 270-420MPa, and the elongation is 5-15%. The aluminum-silicon alloy has excellent casting performance and can replace traditional cast aluminum, deformed aluminum, medium and low-grade ductile iron, gray iron, carbon steel and plate materials to achieve weight reduction and lightweight design of parts.

[0006] In a first aspect of the present application, a low-cost, ultra-high strength and toughness cast aluminum-silicon alloy is provided. The low-cost, ultra-high strength and toughness cast aluminum-silicon alloy comprises the following elemental components, measured by weight percentage: silicon 7.0%~9.0%, magnesium 0.30%~0.50%, copper 1.60%~2.00%, zinc ≤0.2%, iron ≤0.2%, manganese 0.20%~0.40%, chromium ≤0.2%, zirconium 0.05%~0.3%, titanium 0.03%~0.2%, strontium ≤0.04%, and the remainder is aluminum and other impurities; wherein the total content of other impurities is ≤0.15%, and the content of a single impurity is ≤0.05%.

[0007] In one embodiment, the low-cost ultra-high strength and toughness cast aluminum-silicon alloy includes the following elemental components by weight percentage: silicon 7.5%~8.5%, magnesium 0.35%~0.45%, copper 1.80%~2.00%, zinc ≤0.2%, iron ≤0.15%, manganese 0.30%~0.40%, chromium 0.05%~0.12%, zirconium 0.05%~0.15%, titanium 0.04%~0.12%, strontium 0.01%~0.03%, other single impurity content ≤0.05%, and other impurity total content ≤0.15%.

[0008] In one embodiment, the ratio of copper content to magnesium content in the low-cost ultra-high strength and toughness cast aluminum-silicon alloy is ≥3.4.

[0009] In one embodiment, TCB seed alloy is used in the casting of the low-cost ultra-high strength and toughness cast aluminum-silicon alloy.

[0010] In one embodiment, the TCB seed alloy is added in an amount of 0.1% to 2% of the total weight of the melt.

[0011] In one embodiment, the as-cast structure of the low-cost ultra-high strength and toughness cast aluminum-silicon alloy has the following characteristics: the eutectic silicon is in the form of fine dots, strips and sheets, and the particle size of the eutectic silicon is ≤5μm; there is a composite strengthening phase composed of AlSiCuMg and Al2Cu strengthening phases in the as-cast structure, and the composite strengthening phase is distributed between α-Al dendrites, around the eutectic silicon and inside the eutectic silicon.

[0012] The second aspect of the present application provides a method for preparing a low-cost ultra-high-strength and tough cast aluminum-silicon alloy, comprising the following steps:

[0013] S1: Prepare raw materials according to elemental composition.

[0014] S2: adding all raw materials except aluminum-strontium alloy and TCB seed alloy into a smelting furnace for smelting, and after the raw materials are melted, adding aluminum-strontium alloy, or aluminum-strontium alloy and TCB seed alloy, stirring, and standing.

[0015] S3: Add refining agent to refine and degas to obtain aluminum-silicon alloy liquid.

[0016] S4: Casting the aluminum-silicon alloy liquid to obtain an ingot.

[0017] S5: The ingot or parts are subjected to solution treatment, cooling treatment and aging treatment in sequence to obtain a low-cost ultra-high strength and toughness cast aluminum-silicon alloy.

[0018] In one embodiment, in S2, the smelting temperature is 680°C to 780°C, and the standing time is 10 min to 30 min.

[0019] In one embodiment, in S3, the refining agent is a sodium-free refining agent; the refining and degassing is performed by adding a refining agent and using argon or nitrogen at 680-730° C.; and the refining and degassing time is 10-30 min.

[0020] The present application also provides another method for preparing a low-cost ultra-high-strength and tough cast aluminum-silicon alloy, comprising the following steps:

[0021] S1: Prepare raw materials according to elemental composition.

[0022] S2: adding all raw materials except the aluminum-strontium alloy and the TCB seed alloy into a smelting furnace for smelting to melt the raw materials.

[0023] S3: After refining and degassing with a refining agent, an aluminum-strontium alloy, or an aluminum-strontium alloy and a TCB seed alloy is added and stirred to obtain an aluminum-silicon alloy liquid.

[0024] Alternatively, during the refining and degassing process with the addition of a refining agent, an aluminum-strontium alloy, or an aluminum-strontium alloy and a TCB seed alloy is added to obtain an aluminum-silicon alloy liquid.

[0025] S4: Casting the aluminum-silicon alloy liquid to obtain an ingot.

[0026] S5: The ingot or parts are subjected to solution treatment, cooling treatment and aging treatment in sequence to obtain a low-cost ultra-high strength and toughness cast aluminum-silicon alloy.

[0027] In one embodiment, in S2, the smelting temperature is 680°C-780°C; in S3, the refining agent is a sodium-free refining agent; the refining and degassing is performed by adding a refining agent and using argon or nitrogen at 680-730°C; the refining and degassing time is 10-30 minutes.

[0028] This application designs the content of the three elements Si, Cu, and Mg and the ratio of copper to magnesium, and regulates the relative content and distribution of the three strengthening phases AlSiCuMg, Al2Cu, and Mg2Si, so that the composite strengthening phase composed of AlSiCuMg and Al2Cu strengthening phases mainly exists in the cast structure, and the composite strengthening phase is distributed between α-Al dendrites, around eutectic silicon, and inside eutectic silicon, thereby achieving ultra-high strength performance of the alloy. Further, by adopting Sr, TCB, Zr composite modification and grain refinement of eutectic silicon and α-aluminum matrix, the ultra-high strength of the alloy is improved, and at the same time, it can also have a high elongation after fracture.

[0029] The low-cost ultra-high-strength cast aluminum-silicon alloy of the present application has a low Cu content and a small amount of Zr, Cr, and Ti elements, and does not contain precious metals such as rare earth, Ni, and Sc, so the cost is relatively favorable. At the same time, the mechanical properties of the low-cost ultra-high-strength cast aluminum-silicon alloy of the present application are close to and exceed those of aluminum-copper, aluminum-zinc, and aluminum-magnesium casting alloys, and are more suitable for replacing traditional cast aluminum, deformed aluminum, medium and low-grade ductile iron, gray iron, carbon steel, and plate materials to achieve weight reduction and lightweight design of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the metallographic structure morphology of the alloy in Example 1 in T6 state.

[0031] Figure 2 1 to 4 are tensile stress-strain curves of the samples of Examples 1 to 4.

[0032] Figure 3 This is the SEM morphology of the alloy in Example 1 in the cast state.

[0033] Figure 4 This is the metallographic structure morphology of the alloy in Example 1 under cast condition.

[0034] Figure 5 This is the SEM morphology of eutectic silicon in the T6 state of alloy in Example 1. DETAILED DESCRIPTION

[0035] References to embodiments of the present application will now be provided in detail, one or more embodiments of which are described below. Each embodiment is provided as an explanation rather than a limitation of the present application. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present application without departing from the scope or spirit of the present application. For example, a feature described or described as part of one embodiment may be used in another embodiment to produce a further embodiment.

[0036] Therefore, it is intended that the present application covers such modifications and variations that fall within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present application are disclosed in or are apparent from the following detailed description. It will be appreciated by those of ordinary skill in the art that this discussion is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the present application.

[0037] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0038] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0039] In this article, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 100~150 ℃ means that the units of the left endpoint "100" and the right endpoint "150" are both ℃ (Celsius).

[0040] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0041] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0042] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, mentioning that the method may also include step (c) means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0043] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0044] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0045] In view of the problem that high strength and toughness aluminum-silicon alloys in traditional technology are mostly achieved by adding rare earths, precious metals such as Ni, Te, etc. or adding a large amount of Cu, which leads to high alloy costs and limited applications, this application proposes a low-cost ultra-high strength and toughness cast aluminum-silicon alloy material and a preparation method to solve the above-mentioned technical problems existing in traditional aluminum-silicon alloys.

[0046] In a first aspect of the present application, a low-cost, ultra-high strength and toughness cast aluminum-silicon alloy is provided. The low-cost, ultra-high strength and toughness cast aluminum-silicon alloy comprises the following elemental components, measured by weight percentage: silicon 7.0%~9.0%, magnesium 0.30%~0.50%, copper 1.60%~2.00%, zinc ≤0.2%, iron ≤0.2%, manganese 0.20%~0.40%, chromium ≤0.2%, zirconium 0.05%~0.3%, titanium 0.03%~0.2%, strontium ≤0.04%, and the remainder is aluminum and other impurities; wherein the total content of other impurities is ≤0.15%, and the content of a single impurity is ≤0.05%.

[0047] In some embodiments, the low-cost ultra-high strength and toughness cast aluminum-silicon alloy includes the following elemental components, measured by weight percentage: silicon 7.5%~8.5%, magnesium 0.35%~0.45%, copper 1.80%~2.00%, zinc ≤0.2%, iron ≤0.15%, manganese 0.30%~0.40%, chromium 0.05%~0.12%, zirconium 0.05%~0.15%, titanium 0.04%~0.12%, strontium 0.01%~0.03%, the content of other individual impurities ≤0.05%, and the total content of other impurities ≤0.15%.

[0048] In one embodiment, a low-cost ultra-high strength and toughness cast aluminum-silicon alloy includes the following elemental components, measured by weight percentage: silicon 7.0%~9.0%, magnesium 0.30%~0.50%, copper 1.60%~2.00%, zinc ≤0.2%, iron ≤0.2%, manganese 0.20%~0.40%, chromium ≤0.2%, zirconium 0.05%~0.3%, titanium 0.03%~0.2%, strontium ≤0.04%, and the remainder is aluminum and other impurities; wherein the total content of other impurities is ≤0.15%, and the content of a single impurity is ≤0.05%; and the ratio of copper content to magnesium content in the low-cost ultra-high strength and toughness cast aluminum-silicon alloy is ≥3.4.

[0049] In some embodiments, the low-cost ultra-high strength and toughness cast aluminum-silicon alloy includes the following elemental components by weight percentage: silicon 7.5%~8.5%, magnesium 0.35%~0.45%, copper 1.80%~2.00%, zinc ≤0.2%, iron ≤0.15%, manganese 0.30%~0.40%, chromium 0.05%~0.12%, zirconium 0.05%~0.15%, titanium 0.04%~0.12%, strontium 0.01%~0.03%, other single impurity content ≤0.05%, other impurity total content ≤0.15%; and the ratio of copper content to magnesium content in the low-cost ultra-high strength and toughness cast aluminum-silicon alloy is ≥3.4, including but not limited to 3.4, 4, 4.5, 5, 5.5, 5.7.

[0050] It can be understood that in the cast structure of the aluminum-silicon alloy of the present application, the eutectic silicon is in the form of fine dots, strips and sheets, and the eutectic silicon particle size is ≤5 microns; and there is a composite strengthening phase composed of AlSiCuMg and Al2Cu strengthening phases in the cast structure, and the composite strengthening phase is distributed between the α-Al dendrites, around the eutectic silicon and inside the eutectic silicon.

[0051] The present application designs the contents of the three elements Si, Cu, and Mg and the ratio of copper to magnesium, and regulates the relative contents and phase distribution positions of the three strengthening phases AlSiCuMg, Al2Cu, and Mg2Si, so that the cast structure mainly contains a composite strengthening phase composed of AlSiCuMg and Al2Cu strengthening phases, and the composite strengthening phase is distributed between α-Al dendrites, around eutectic silicon, and inside eutectic silicon, thereby achieving ultra-high strength performance of the alloy.

[0052] In some embodiments, TCB seed alloy is used in the casting of low cost ultra high strength and toughness cast aluminum silicon alloy.

[0053] In some embodiments, the TCB seed alloy is added in an amount of 0.1% to 2% of the total weight of the melt, including but not limited to 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, and 2%.

[0054] It is understandable that when the content of TCB seed alloy is low, it is difficult to achieve the refinement of the aluminum matrix and improve the microstructure; when the content is too high, in addition to increasing the production cost, it is also easy to form coarse Ti compounds and reduce the plasticity of the aluminum alloy.

[0055] The present application improves the ultra-high strength of the alloy by using Sr, TCB, Zr composite modification and grain refinement of eutectic silicon and α-aluminum matrix, and also enables it to have high elongation after fracture. Among them, TCB and Zr elements are used to refine the aluminum alloy grains to achieve fine grain strengthening; the addition of strontium is used to control the morphology of eutectic silicon.

[0056] The low-cost ultra-high-strength cast aluminum-silicon alloy of the present application has a low Cu content and a small amount of Zr, Cr, and Ti elements, and does not contain precious metals such as rare earth, Ni, and Sc, so the cost is relatively favorable. At the same time, the mechanical properties of the low-cost ultra-high-strength cast aluminum-silicon alloy of the present application are close to and exceed those of aluminum-copper, aluminum-zinc, and aluminum-magnesium casting alloys, and are more suitable for replacing traditional cast aluminum, deformed aluminum, medium and low-grade ductile iron, gray iron, carbon steel, and plate materials to achieve weight reduction and lightweight design of parts.

[0057] The second aspect of the present application provides a method for preparing a low-cost ultra-high-strength and tough cast aluminum-silicon alloy, comprising the following steps:

[0058] S1: Prepare raw materials according to elemental composition.

[0059] S2: Add all raw materials except aluminum strontium alloy and TCB seed alloy into a smelting furnace for smelting. After the raw materials are melted, add aluminum strontium alloy, or aluminum strontium alloy and TCB seed alloy (when TCB is not included, only aluminum strontium alloy is added), stir, and let stand.

[0060] S3: Add refining agent to refine and degas to obtain aluminum-silicon alloy liquid.

[0061] S4: Casting the aluminum-silicon alloy liquid to obtain an ingot.

[0062] S5: The ingot or parts are subjected to solution treatment, cooling treatment and aging treatment in sequence to obtain a low-cost ultra-high strength and toughness cast aluminum-silicon alloy.

[0063] This application does not limit the raw material components, and any raw material that can reach the components of the present invention is within the protection scope of the present invention. For example, in the embodiment of the present invention, the raw materials include: low iron A00 aluminum, 3303 silicon, magnesium ingot, AlCu50, AlMn20, AlCr10, AlZr10, AlSr10, AlTi15, TCB.

[0064] In some embodiments, in S2, the smelting temperature is 680°C to 780°C, including but not limited to 680°C, 690°C, 700°C, 720°C, 740°C, 760°C, and 780°C; the standing time is 10 min to 30 min, including but not limited to 10 min, 15 min, 20 min, 25 min, and 30 min.

[0065] In some embodiments, the amount of TCB seed alloy added is 0.1-2% of the total amount of the melt.

[0066] It is understandable that the present application adds aluminum strontium alloy and TCB after refining and degassing, which can reduce the burning loss of aluminum strontium alloy and TCB alloy and improve the absorption rate of the intermediate alloy.

[0067] In some embodiments, in S3, the refining agent is a sodium-free refining agent.

[0068] In some embodiments, in S3, the amount of refining agent added is 0.1% to 3% of the total amount of the melt, including but not limited to 0.1%, 0.2%, 0.5%, 1%, 2%, and 3%.

[0069] In some embodiments, refining and degassing is performed by adding a refining agent and using argon or nitrogen at 680~730℃; the refining and degassing time is 10~30min, including but not limited to 10min, 15min, 20min, 25min, 30min; the refining and degassing temperature includes but is not limited to 680℃, 690℃, 700℃, 720℃, 730℃.

[0070] It is understandable that the present invention does not limit the conditions of T6 treatment, i.e., solution treatment, cooling treatment and aging treatment, and any treatment conditions that can achieve the effect of the present application are within the protection scope of the present application. Exemplarily, in the present application, the process of T6 treatment is: the temperature of solution treatment is 490℃~530℃, and it is kept warm for 4h~12h. After quenching and water cooling, aging treatment is performed at an aging temperature of 160℃~2000℃, and it is kept warm for 4~12h, and then cooled to room temperature with the furnace. The present invention application can adopt single-stage solution treatment or graded solution treatment; similarly, the present invention can adopt single-stage aging or graded aging.

[0071] The present application also provides another method for preparing a low-cost ultra-high-strength and tough cast aluminum-silicon alloy, comprising the following steps:

[0072] S1: Prepare raw materials according to elemental composition.

[0073] S2: adding all raw materials except the aluminum-strontium alloy and the TCB seed alloy into a smelting furnace for smelting to melt the raw materials.

[0074] S3: After refining and degassing with a refining agent, an aluminum-strontium alloy, or an aluminum-strontium alloy and a TCB seed alloy is added and stirred to obtain an aluminum-silicon alloy liquid.

[0075] Alternatively, a refining agent is added and argon or nitrogen is used for refining and degassing, and an aluminum-strontium alloy, or an aluminum-strontium alloy and a TCB seed alloy is added before the end of refining, and refining is continued to obtain an aluminum-silicon alloy liquid at the end of refining.

[0076] S4: Casting the aluminum-silicon alloy liquid to obtain an ingot.

[0077] S5: The ingot or parts are subjected to solution treatment, cooling treatment and aging treatment in sequence to obtain a low-cost ultra-high strength and toughness cast aluminum-silicon alloy.

[0078] In some embodiments, in S2, the smelting temperature is 680°C to 780°C, including but not limited to 680°C, 690°C, 700°C, 720°C, 740°C, 760°C, and 780°C.

[0079] In some embodiments, in S3, the refining agent is a sodium-free refining agent; the refining and degassing is performed by adding a refining agent and using argon or nitrogen at 680-730°C. The refining and degassing time is 10-30 minutes, including but not limited to 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes; the refining and degassing temperature includes but is not limited to 680°C, 690°C, 700°C, 720°C, and 730°C.

[0080] In some embodiments, the amount of TCB seed alloy added is 0.1-2% of the total amount of the melt, including but not limited to 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2%. The amount of refining agent added is 0.1%-3% of the total amount of the melt, including but not limited to 0.1%, 0.2%, 0.5%, 1%, 2%, 3%.

[0081] It can be understood that S3 also includes the process of standing and slag removal, that is, after adding a refining agent for refining and degassing, adding an aluminum-strontium alloy and a TCB seed alloy, stirring, and then standing, slag removal to obtain an aluminum-silicon alloy liquid. Or after adding a refining agent for refining and degassing, standing, slag removal, and then adding an aluminum-strontium alloy and a TCB seed alloy, stirring to obtain an aluminum-silicon alloy liquid. Or, adding a refining agent, adding an aluminum-strontium alloy and a TCB seed alloy at the same time, passing gas for refining and degassing, standing, and slag removal to obtain an aluminum-silicon alloy liquid.

[0082] The following are specific embodiments.

[0083] Example 1

[0084] A low-cost ultra-high-strength and tough cast aluminum-silicon alloy material, comprising the following components by mass percentage:

[0085] Silicon 7.50%; Magnesium 0.35%; Copper 2.0%; Zinc ≤0.2%; Manganese 0.30%; Iron 0.08%; Zirconium 0.14%; Chromium 0.11%; Strontium 0.010%; Titanium 0.042%, the ratio of copper to magnesium is 5.7:1, the total content of other impurities is ≤0.15%, and the content of a single impurity is ≤0.05%, the balance is aluminum; the amount of TCB added is 0.5% of the total weight of the melt.

[0086] The method for preparing the above-mentioned low-cost ultra-high-strength and tough cast aluminum-silicon alloy material comprises the following steps:

[0087] (1) Prepare the raw materials according to the above ingredients.

[0088] (2) Put all raw materials except aluminum strontium alloy and TCB alloy into a furnace in turn for melting at a temperature of 780°C; after the alloy is melted evenly and completely, add aluminum strontium alloy and 0.5% TCB alloy of the total weight of the melt, stir, and then let stand for 10 minutes.

[0089] (3) Start the degassing refining machine and add 0.5% of the weight of the molten aluminum liquid sodium-free refining agent, and refine and degas the aluminum liquid with nitrogen at 700°C for 15 minutes; after the refining is completed, let it stand for 20 minutes and clean the slag.

[0090] (4) The aluminum liquid was kept at 700°C and the samples were prepared by extrusion casting process.

[0091] (5) After cooling the sample to room temperature, perform T6 heat treatment.

[0092] The specific process of T6 heat treatment is: solution treatment at 520℃ for 4h, rapid quenching and water cooling (water temperature 30℃), followed by aging treatment at 170℃, insulation for 8h, and cooling to room temperature after aging.

[0093] Example 2

[0094] A low-cost ultra-high strength and toughness cast aluminum-silicon alloy material, whose material composition is the same as that of Example 1.

[0095] The preparation method of the low-cost ultra-high strength and toughness cast aluminum-silicon alloy material is basically the same as that of Example 1, except for the parameters of the T6 heat treatment. In this embodiment, the parameters of the T6 heat treatment are: first, solid solution is carried out at 490°C for 6 hours, then solid solution is carried out at 510°C for 4 hours, then quenched and water-cooled (water temperature is 30°C), and finally aged at 170°C for 6 hours and then cooled to room temperature.

[0096] Example 3

[0097] A low-cost ultra-high strength and toughness cast aluminum-silicon alloy material, whose material composition is the same as that of Example 1.

[0098] The preparation method of the low-cost ultra-high strength and toughness cast aluminum-silicon alloy material is basically the same as that in the embodiment, except for the parameters of the T6 heat treatment. In this embodiment, the parameters of the T6 heat treatment are: solution parameters: 530°C, 8h, quenching and water cooling (water temperature 30°C) followed by aging treatment, aging temperature 170°C, insulation for 4h, and then cooling out of the furnace to room temperature.

[0099] Example 4

[0100] A low-cost ultra-high-strength and tough cast aluminum-silicon alloy material, comprising the following components by mass percentage:

[0101] Silicon 7.65%; Magnesium 0.45%; Copper 1.8%; Zinc ≤0.2%; Manganese 0.38%; Iron 0.10%; Zirconium 0.11%; Chromium 0.11%; Strontium 0.028%; Titanium 0.12%, the ratio of copper to magnesium is 4.0:1, the total content of other impurities is ≤0.15%, the content of other single impurities is ≤0.05%, and the balance is aluminum; the TCB addition amount is 0.9% of the total weight of the melt.

[0102] The method for preparing the above-mentioned low-cost ultra-high-strength and tough cast aluminum-silicon alloy material comprises the following steps:

[0103] (1) Provide the raw materials according to the above composition.

[0104] (2) Put all raw materials except aluminum strontium alloy and TCB alloy into a furnace in sequence for melting at a melting temperature of 760°C.

[0105] (3) After the alloy is evenly melted, start the degassing refining machine and add 0.5% of the weight of the molten aluminum to the sodium-free refining agent. Refine and degas the aluminum liquid with nitrogen at 710°C for 20 minutes. Add aluminum-strontium alloy and 0.9% of the total weight of the melt to the TCB alloy 5 minutes before the end of refining and degassing. After refining and degassing, let it stand for 15 minutes and remove the slag.

[0106] (4) The aluminum liquid is kept at 700°C, and the samples are prepared by high vacuum die casting process.

[0107] (5) After the sample is cooled to room temperature, T6 heat treatment is performed.

[0108] The specific process of T6 heat treatment is: solution temperature 520℃, insulation for 8h, quenching and water cooling (water temperature 30℃) followed by aging treatment, aging temperature 160℃, insulation for 12h, and then cooling out of the furnace to room temperature.

[0109] Example 5

[0110] A low-cost ultra-high-strength and tough cast aluminum-silicon alloy material, whose composition is substantially the same as that of Example 1, except that no TCB is added, comprises the following components by mass percentage:

[0111] Silicon 7.50%; Magnesium 0.35%; Copper 2.0%; Zinc ≤0.2%; Manganese 0.30%; Iron 0.08%; Zirconium 0.14%; Chromium 0.11%; Strontium 0.010%; Titanium 0.042%, the ratio of copper to magnesium is 5.7:1, the total content of other impurities ≤0.15%, and the content of a single impurity ≤0.05%, the balance is aluminum.

[0112] The preparation method of the above low-cost ultra-high-strength cast aluminum-silicon alloy material is basically the same as that of Example 1, except that TCB is not added. The specific preparation process is as follows:

[0113] The method for preparing the above-mentioned low-cost ultra-high-strength and tough cast aluminum-silicon alloy material comprises the following steps:

[0114] (1) Prepare the raw materials according to the above ingredients.

[0115] (2) Put all raw materials except aluminum-strontium alloy into the furnace in turn for melting at a temperature of 780°C. After the alloy is melted evenly and completely, add aluminum-strontium alloy, stir, and then let stand for 10 minutes.

[0116] (3) Start the degassing refining machine and add 0.5% of the weight of the molten aluminum liquid sodium-free refining agent, and refine and degas the aluminum liquid with nitrogen at 700°C for 15 minutes; after the refining is completed, let it stand for 20 minutes and clean the slag.

[0117] (4) The aluminum liquid was kept at 700°C and the samples were prepared by extrusion casting process.

[0118] (5) After cooling the sample to room temperature, perform T6 heat treatment.

[0119] The specific process of T6 heat treatment is: solution treatment at 520℃ for 4h, rapid quenching and water cooling (water temperature 30℃), followed by aging treatment at 170℃, insulation for 8h, and cooling to room temperature after aging.

[0120] Example 6

[0121] A low-cost ultra-high-strength and tough cast aluminum-silicon alloy material, comprising the following components by mass percentage:

[0122] Silicon 9.0%; Magnesium 0.3%; Copper 1.6%; Zinc ≤0.2%; Manganese 0.33%; Iron 0.11%; Zirconium 0.13%; Chromium 0.12%; Strontium 0.025%; Titanium 0.04%, the ratio of copper to magnesium is 5.3:1, the total content of other impurities is ≤0.15%, and the content of a single impurity is ≤0.05%, the balance is aluminum, no TCB is added.

[0123] The method for preparing the above-mentioned low-cost ultra-high-strength and tough cast aluminum-silicon alloy material comprises the following steps:

[0124] (1) Prepare the raw materials according to the above ingredients.

[0125] (2) Put all raw materials except aluminum-strontium alloy into the furnace in turn for melting at a temperature of 760°C. After the alloy is melted evenly and completely, add aluminum-strontium alloy, stir, and then let stand for 10 minutes.

[0126] (3) Start the degassing refining machine and add 0.5% of the weight of the molten aluminum liquid sodium-free refining agent, and refine and degas the aluminum liquid with nitrogen at 710°C for 15 min; after the refining is completed, let it stand for 20 minutes and clean the slag.

[0127] (4) The aluminum liquid was kept at 700°C and the samples were prepared by extrusion casting process.

[0128] (5) After cooling the sample to room temperature, perform T6 heat treatment.

[0129] The specific process of T6 heat treatment is: solution temperature 520℃, insulation for 4h, quenching and water cooling (water temperature 30℃) followed by aging treatment, aging temperature 170℃, insulation for 8h, and cooling to room temperature.

[0130] Example 7

[0131] A low-cost ultra-high-strength and tough cast aluminum-silicon alloy material, comprising the following components by mass percentage:

[0132] Silicon 8.9%; Magnesium 0.5%; Copper 1.7%; Zinc ≤0.2%; Manganese 0.28%; Iron 0.11%; Zirconium 0.22%; Chromium 0.16%; Strontium 0.025%; Titanium 0.18%, the ratio of copper to magnesium is 3.4:1, the total content of other impurities is ≤0.15%, and the content of a single impurity is ≤0.05%, the balance is aluminum, no TCB is added.

[0133] The preparation method of the above-mentioned low-cost ultra-high strength and toughness cast aluminum-silicon alloy material is the same as that in Example 6.

[0134] Example 8

[0135] A low-cost ultra-high strength and toughness cast aluminum-silicon alloy material, whose alloy composition and preparation method are basically the same as those of Example 4, except that the copper:magnesium ratio is 5.7:1, wherein the copper content is 1.7% and the magnesium content is 0.3%.

[0136] The composition of each element by mass percentage includes: silicon 7.65%; magnesium 0.3%; copper 1.7%; zinc ≤0.2%; manganese 0.38%; iron 0.10%; zirconium 0.11%; chromium 0.11%; strontium 0.028%; titanium 0.12%, the ratio of copper to magnesium is 5.7:1, the total content of other impurities is ≤0.15%, the content of other single impurities is ≤0.05%, and the balance is aluminum; the TCB addition amount is 0.9% of the total weight of the melt.

[0137] Comparative Example 1

[0138] An aluminum-silicon alloy, whose material composition, preparation process and T6 heat treatment process refer to Example 1 in patent CN115852214B.

[0139] Comparative Example 2

[0140] An aluminum-silicon alloy, whose material composition, preparation process and T6 heat treatment process refer to Example 2 in patent CN108251714B.

[0141] Comparative Example 3

[0142] An aluminum-silicon alloy, whose material composition, preparation process and T6 heat treatment process refer to Example 1 in patent CN116445774A.

[0143] Comparative Example 4

[0144] An aluminum-silicon alloy material, whose alloy composition and preparation method are basically the same as those of Example 4, except that the copper:magnesium ratio is 3.2:1, wherein the copper content is 1.6% and the magnesium content is 0.5%.

[0145] The composition of each element by mass percentage includes: silicon 7.65%; magnesium 0.5%; copper 1.6%; zinc ≤0.2%; manganese 0.38%; iron 0.10%; zirconium 0.11%; chromium 0.11%; strontium 0.028%; titanium 0.12%, the ratio of copper to magnesium is 4.0:1, the total content of other impurities is ≤0.15%, the content of other single impurities is ≤0.05%, and the balance is aluminum; the TCB addition amount is 0.9% of the total weight of the melt.

[0146] Test example:

[0147] The tensile strength, yield strength and elongation after fracture properties of the aluminum-silicon alloys of the embodiment and the comparative example were tested, and the results are shown in Table 1.

[0148] Table 1 Mechanical properties test of embodiments and comparative examples

[0149]

[0150] As can be seen from Table 1, compared with the comparative example, the ultra-high strength and toughness aluminum-silicon alloy of the present application can reach a tensile strength of 400MPa and above, a yield strength of 300MPa and above, and an elongation of 5.0% or above after T6 treatment. Among them, Examples 1 and 4 obtained ultra-high strength and toughness aluminum-silicon alloys with a tensile strength of more than 480MPa, a yield strength of more than 390MPa, and an elongation of 5-8%. The mechanical properties of the alloy are close to and exceed those of aluminum-copper, aluminum-zinc, and aluminum-magnesium casting alloys.

[0151] From the comparison between Example 1 and Comparative Example 1, it can be seen that after adding a small amount of Zr, Cr and TCB, the alloy of the present invention has both higher strength and higher elongation after fracture. From the comparison between each embodiment and Comparative Example 2 and Comparative Example 3, it can be seen that the alloy of the present invention has higher tensile strength and yield strength under the condition of similar elongation after fracture.

[0152] Figure 2 The tensile stress-strain curves of the alloys prepared in Examples 1-4 of the present application show that after the alloy of Example 1 is treated with T6, the tensile strength is 483MPa and the elongation after fracture is 5.8%, which has high plasticity. The alloy composition of Example 2 and Example 3 is the same as that of Example 1. Only by adjusting the T6 treatment process, the elongation after fracture is greatly improved to 11.3% and 9.7%, respectively, but the tensile strength is significantly reduced compared with Example 1. By adjusting the alloy composition and heat treatment process, Example 4 has an ultra-high plasticity of 8.1% elongation after fracture while maintaining a tensile strength of 486MPa, and has excellent comprehensive performance.

[0153] Figure 1 , Figure 5 They are the metallographic structure morphology of the alloy T6 prepared in Example 1 and the SEM morphology of eutectic silicon. Figure 1 and Figure 5 It can be seen that eutectic silicon is in the shape of tiny dots, spheres and short rods, evenly distributed on the substrate.

[0154] Figure 3 , Figure 4 They are the SEM morphology and metallographic structure morphology of the alloy prepared in Example 1 under cast state. Figure 3 We can see the distribution of tiny dots, strips and flakes of eutectic silicon, and we can also see the AlSiCuMg and Al2Cu strengthening phases distributed inside and around the eutectic silicon. Figure 4 It can be seen that the alloy structure in the cast state is mainly composed of a rose-shaped α-Al matrix, fine eutectic silicon distributed between the α-Al matrix, and a small amount of light gray strengthening phase.

[0155] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0156] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A low-cost ultra-high-strength cast aluminum-silicon alloy, characterized in that: Measured in percentage by weight, the low-cost, ultra-high-strength and tough cast aluminum-silicon alloy includes the following elemental components: silicon 7.0%~9.0%, magnesium 0.30%~0.50%, copper 1.60%~2.00%, zinc ≤0.2%, iron ≤0.2%, manganese 0.20%~0.40%, chromium ≤0.2%, zirconium 0.05%~0.3%, titanium 0.03%~0.2%, strontium ≤0.04%, and the remainder is aluminum and other impurities; wherein the total content of other impurities is ≤0.15%, and the content of a single impurity is ≤0.05%.

2. The low-cost ultra-high-strength cast aluminum-silicon alloy according to claim 1, characterized in that: The low-cost, ultra-high-strength and tough cast aluminum-silicon alloy includes the following elemental components by weight percentage: silicon 7.5%~8.5%, magnesium 0.35%~0.45%, copper 1.80%~2.00%, zinc ≤0.2%, iron ≤0.15%, manganese 0.30%~0.40%, chromium 0.05%~0.12%, zirconium 0.05%~0.15%, titanium 0.04%~0.12%, strontium 0.01%~0.03%, the content of other individual impurities ≤0.05%, and the total content of other impurities ≤0.15%.

3. The low-cost ultra-high-strength cast aluminum-silicon alloy according to any one of claims 1-2, characterized in that: The ratio of copper content to magnesium content in the low-cost ultra-high strength and toughness cast aluminum-silicon alloy is ≥3.

4.

4. The low-cost ultra-high-strength and tough cast aluminum-silicon alloy according to any one of claims 1-2, characterized in that: The low-cost ultra-high-strength and tough cast aluminum-silicon alloy uses a TCB seed alloy; the amount of the TCB seed alloy added is 0.1% to 2% of the total weight of the melt.

5. The low-cost ultra-high-strength and tough cast aluminum-silicon alloy according to any one of claims 1-2, characterized in that: The cast structure of the low-cost ultra-high-strength and tough cast aluminum-silicon alloy has the following characteristics: the eutectic silicon is in the form of fine dots, strips and sheets, and the particle size of the eutectic silicon is ≤5μm; there is a composite strengthening phase composed of AlSiCuMg and Al2Cu strengthening phases in the cast structure, and the composite strengthening phase is distributed between α-Al dendrites, around the eutectic silicon and inside the eutectic silicon.

6. A method for preparing a low-cost ultra-high-strength and tough cast aluminum-silicon alloy, characterized in that: The steps include: S1: Prepare raw materials according to elemental composition; S2: adding all raw materials except aluminum-strontium alloy and TCB seed alloy into a smelting furnace for smelting, and after the raw materials are melted, adding aluminum-strontium alloy, or aluminum-strontium alloy and TCB seed alloy, stirring, and standing; S3: adding a refining agent for refining and degassing to obtain aluminum-silicon alloy liquid; S4: Casting the aluminum-silicon alloy liquid to obtain an ingot; S5: The ingot or parts are subjected to solution treatment, cooling treatment and aging treatment in sequence to obtain a low-cost ultra-high strength and toughness cast aluminum-silicon alloy.

7. The preparation method according to claim 6, characterized in that: In S2, the smelting temperature is 680°C to 780°C, and the standing time is 10 min to 30 min.

8. The preparation method according to claim 6, characterized in that: In S3, the refining agent is a sodium-free refining agent; the refining and degassing is performed by adding a refining agent and using argon or nitrogen at 680-730° C.; and the refining and degassing time is 10-30 min.

9. A method for preparing a low-cost ultra-high-strength and tough cast aluminum-silicon alloy, characterized in that: The steps include: S1: Prepare raw materials according to elemental composition; S2: adding all raw materials except aluminum strontium alloy and TCB seed alloy into a smelting furnace for smelting to melt the raw materials; S3: After refining and degassing with a refining agent, an aluminum-strontium alloy or an aluminum-strontium alloy and a TCB seed alloy are added and stirred to obtain an aluminum-silicon alloy liquid; or, In the process of adding a refining agent for refining and degassing, an aluminum-strontium alloy, or an aluminum-strontium alloy and a TCB seed alloy is added to obtain an aluminum-silicon alloy liquid; S4: Casting the aluminum-silicon alloy liquid to obtain an ingot; S5: The ingot or parts are subjected to solution treatment, cooling treatment and aging treatment in sequence to obtain a low-cost ultra-high strength and toughness cast aluminum-silicon alloy.

10. The preparation method according to claim 9, characterized in that: In S2, the smelting temperature is 680°C to 780°C; In S3, the refining agent is a sodium-free refining agent; the refining and degassing is performed by adding a refining agent and using argon or nitrogen at 680-730° C.; and the refining and degassing time is 10-30 min.

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