A heat treatment free high-strength and high-toughness die-casting aluminum alloy and a preparation method thereof

Abstract

The application relates to a heat-treatment-free high-strength and high-toughness die-casting aluminum alloy and a preparation method thereof, wherein the weight percentage of each component in the die-casting aluminum alloy is as follows: Si: 8.2-10.5 wt.%; Fe: 0.08-0.6 wt.%; Cu: 1.4-3.2 wt.%; Mn: 0.3-1.0 wt.%; Mg: 0.5-2.0 wt.%; Zn: 1.2-2.1 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0-0.15 wt.%; Er: 0-0.15 wt.%; Sb: 0-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of metal materials, in particular to a heat-treatment-free high-strength and high-toughness die-casting aluminum alloy and a preparation method thereof. BACKGROUND

[0002] With the deepening of the low-carbon policy, new energy vehicles have higher requirements for the casting performance and mechanical properties of materials in terms of weight reduction and carbon reduction, and aluminum alloys are widely used in the automobile and electronic communication fields as lightweight materials due to their low density, high specific strength, excellent electrical conductivity and thermal conductivity, and recyclable characteristics. In order to meet the production process of different wall thicknesses and large batches of castings, the die-casting forming process is the simplest and most efficient way.

[0003] Traditional die-casting structural parts need to be heat treated by solid solution aging to improve their strength and elongation and other indicators after the die-casting process due to the limitation of the used materials, so as to meet the requirements of automobile collision safety. The heating and cooling process of heat treatment will cause the deformation of the parts, and professional equipment or manual correction is needed to ensure the dimensional accuracy. The heat-treatment-free material has excellent thermal stability and mechanical properties, and the use of the heat-treatment-free material can save the heat treatment process after the die-casting of the parts, thereby reducing the carbon emission and meeting the requirements of carbon neutralization, energy saving and emission reduction trend.

[0004] The most widely used ADC12 die-casting aluminum alloy has a tensile strength lower than 260 MPa, a yield strength lower than 150 MPa and an elongation lower than 2%, and the common A380 aluminum alloy has a tensile strength of about 300 MPa, a yield strength of about 160 MPa and an elongation of about 3.5% in the as-cast state. The performance of the ordinary die-casting aluminum alloy cannot meet the demand of the market for high-strength aluminum alloy: the as-cast tensile strength of the sample of the die-casting part is greater than or equal to 350 MPa, the yield strength is greater than or equal to 250 MPa, and the elongation is greater than or equal to 2%.

[0005] Patent document CN104831129B discloses a non-heat-treatment self-strengthening aluminum-silicon alloy developed by Shanghai Jiaotong University. The alloy is based on Al-Si-Mg and contains Cu, La, Ce, Sm and Nd rare earth elements. The strength and toughness of the alloy are determined by the molar ratio of the rare earth elements and Mn elements. The yield strength of the alloy at room temperature is only 170 MPa.

[0006] Patent document CN110257675A discloses a high-strength die-casting aluminum alloy and a preparation method thereof. The content of Cu element in the alloy is increased to 3.2-3.8%, and Sn element and Ni element are also added to the alloy. After the die-casting of the alloy is completed, the die-castings are subjected to aging heat treatment, which needs to be kept at a temperature of 188-192℃ for 5h and then cooled at room temperature. The obtained tensile strength is greater than 300MPa, the yield strength reaches 240MPa, but the elongation is less than 2%. The alloy needs to be subjected to heat treatment for a long time to meet the mechanical property requirements of the product, and cannot meet the mass application of the castings. In addition, it is pointed out that the alloy emphasizes high strength, but does not point out that the increase of copper content will cause the die-casting hot cracking tendency of the alloy.

[0007] Patent document CN110157959B is a high-strength and high-toughness die-casting aluminum alloy developed by Zhaoqing Nandu Regenerated Aluminum Industry Co., Ltd. The alloy adds content of 8.0-12.0 wt.% on the basis of Al-Si-Mg-Mn. Excessive Zn will produce hot cracking tendency during die-casting, which reduces the yield of the castings.

[0008] The above-mentioned aluminum alloy improves the mechanical properties of the alloy to some extent, but the casting properties of the alloy, especially the fluidity and hot cracking property, cannot meet the production requirements, and it is difficult to produce castings with different wall thicknesses and complex structures. SUMMARY

[0009] The application discloses a heat treatment-free high-strength and high-toughness die-casting aluminum alloy and a preparation method thereof. The weight percentage of each component in the die-casting aluminum alloy is as follows: Si: 8.2-10.5 wt.%; Fe: 0.08-0.6 wt.%; Cu: 1.4-3.2 wt.%; Mn: 0.3-1.0 wt.%; Mg: 0.5-2.0 wt.%; Zn: 1.2-2.1 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0-0.15 wt.%; Er: 0-0.15 wt.%; Sb: 0-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al, and it is limited that Si:(Cu+Mg+Zn)=(1.5-3):1; the sum of Zr, Yb and Er is 0.03-0.3%.

[0010] The application also discloses a preparation method of the heat treatment-free high-strength and high-toughness die-casting aluminum alloy.

[0011] (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to obtain aluminum alloy melt.

[0012] (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ and stirred evenly. A special aluminum alloy refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining processes is controlled at 50~60min. After each refining process, slag is removed to remove the flux and slag on the liquid surface.

[0013] (3) Adding elements that are easily burned: When the melt temperature is 740~760℃, add Mg metal and Al-Sr intermediate alloy ingots to the furnace, and then take samples for analysis after obtaining aluminum alloy melt.

[0014] (4) Degassing and standing: The melting temperature is maintained at 740~760℃. Nitrogen is used to degas the furnace for about 30~50 minutes, followed by standing for 15~30 minutes.

[0015] (5) Composition analysis: After the settling period, aluminum liquid was taken from the furnace and poured into a small sample mold. After the aluminum liquid solidified and cooled, the chemical composition of the casting sample was analyzed.

[0016] (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0017] Preferably, a heat-treatable high-strength and high-toughness die-cast aluminum alloy is provided, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.2-9.1 wt.%; Fe: 0.08-0.15 wt.%; Cu: 1.4-1.8 wt.%; Mn: 0.3-0.50 wt.%; Mg: 0.5-1.0 wt.%; Zn: 1.2-1.5 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0-0.15 wt.%; Er: 0-0.15 wt.%; Sb: 0-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0018] Preferably, a heat-free, high-strength, high-toughness die-cast aluminum alloy is provided, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.1-9.8 wt.%; Fe: 0.15-0.25 wt.%; Cu: 1.8-2.2 wt.%; Mn: 0.50-0.75 wt.%; Mg: 1.0-1.6 wt.%; Zn: 1.5-1.8 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0-0.15 wt.%; Er: 0-0.15 wt.%; Sb: 0-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0019] Preferably, a heat-treatable high-strength and high-toughness die-cast aluminum alloy is provided, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.8-10.5 wt.%; Fe: 0.25-0.6 wt.%; Cu: 2.2-3.2 wt.%; Mn: 0.75-1.0 wt.%; Mg: 1.6-2.0 wt.%; Zn: 1.8-2.1 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0-0.15 wt.%; Er: 0-0.15 wt.%; Sb: 0-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0020] Preferably, a heat-treatable high-strength and high-toughness die-cast aluminum alloy is provided, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.2 wt.%; Fe: 0.08 wt.%; Cu: 3.2 wt.%; Mn: 0.3 wt.%; Mg: 0.5 wt.%; Zn: 1.2 wt.%; Ti: 0.1 wt.%; Sr: 0.01 wt.%; Zr: 0.02 wt.%; Cr: 0.013 wt.%; V: 0.013 wt.%; Yb: 0.01 wt.%; Er: 0.02 wt.%; Sb: 0.003 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0021] Preferably, a heat-treasure-free high-strength and high-toughness die-cast aluminum alloy is provided, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.1 wt.%; Fe: 0.2 wt.%; Cu: 2.2 wt.%; Mn: 0.55 wt.%; Mg: 1.0 wt.%; Zn: 1.5 wt.%; Ti: 0.15 wt.%; Sr: 0.035 wt.%; Zr: 0.039 wt.%; Cr: 0.015 wt.%; V: 0.015 wt.%; Yb: 0.02 wt.%; Er: 0.03 wt.%; Sb: 0.004 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0022] Preferably, a heat-treatable high-strength and high-toughness die-cast aluminum alloy is provided, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.3 wt.%; Fe: 0.15 wt.%; Cu: 2.1 wt.%; Mn: 0.5 wt.%; Mg: 1.2 wt.%; Zn: 1.6 wt.%; Ti: 0.13 wt.%; Sr: 0.03 wt.%; Zr: 0.041 wt.%; Cr: 0.015 wt.%; V: 0.015 wt.%; Yb: 0.02 wt.%; Er: 0.02 wt.%; Sb: 0.003 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0023] Preferably, a heat-treatable high-strength and high-toughness die-cast aluminum alloy is provided, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 10.5 wt.%; Fe: 0.4 wt.%; Cu: 1.4 wt.%; Mn: 1.0 wt.%; Mg: 2.0 wt.%; Zn: 2.1 wt.%; Ti: 0.2 wt.%; Sr: 0.1 wt.%; Zr: 0.052 wt.%; Cr: 0.014 wt.%; V: 0.014 wt.%; Yb: 0.05 wt.%; Er: 0.01 wt.%; Sb: 0.005 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0024] This invention discloses a heat-free high-strength and high-toughness die-cast aluminum alloy and its preparation method. The heat-free high-strength and high-toughness die-cast aluminum alloy has a tensile strength of 382 MPa or above, a yield strength of 273 MPa or above, and an elongation of 4% or above in the die-cast state at room temperature.

[0025] The Si element content of this invention is located near the Al-Si eutectic composition point, which improves the fluidity of the alloy and ensures that the alloy has good casting performance. Strict control of the Fe and Mn ratio can change the morphology of the needle-like or lath-like harmful β-Al5FeSi phase in the Al-Si-Mg casting alloy, transforming it from needle-like or lath-like into a well-distributed Chinese character-shaped Mn-containing Al5Si2(FeMn)3 phase, reducing the harmful effect of Fe on the alloy and thus improving the alloy's ductility and shrinkage characteristics.

[0026] The main role of Sr is to modify eutectic Si. Increasing the Sr content can transform the eutectic Si structure from coarse needle-like structures to fine fibrous structures, reduce the aspect ratio of eutectic silicon, and significantly increase the number of α-Al dendrites, thereby improving the strength and toughness of the material. The addition of appropriate amounts of Ti can also improve the tensile strength and fracture toughness of the alloy.

[0027] The added Zr element acts as a heterogeneous nucleation site, increasing the nucleation of α-Al grains and achieving grain refinement. Rare earth Er elements can form coherent or semi-coherent Al3Er phases in the alloy, significantly improving the alloy's mechanical properties. Rare earth Yb can form Yb-containing coherent dispersed phases in the alloy, thereby inhibiting recrystallization of the matrix alloy and improving the alloy's strength and fracture toughness.

[0028] Adding Cr can transform the acicular Fe-containing phase in the alloy into a granular form, reducing its cutting effect and preventing stress concentration under stress, thereby improving the alloy's elongation.

[0029] Adding an appropriate amount of vanadium (V) can improve tensile strength and elongation. A suitable amount of V can reduce the secondary dendrite spacing of the alloy, playing a role in grain refinement and strengthening, thereby improving the alloy's strength and plasticity. Attached Figure Description

[0030] Figure 1 Figure (a) shows the metallographic images of the die-cast aluminum alloy obtained in Example 6, where Figure (a) is a 200X metallographic image and Figure (b) is a 500X metallographic image.

[0031] Figure 2 This is a SEM image of the fracture surface in Example 6.

[0032] Figure 3 The tensile stress-strain curves of the die-cast aluminum alloys obtained in Example 6 and Comparative Example 4 are shown. Detailed Implementation

[0033] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention. Example 1

[0034] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.2 wt.%; Fe: 0.08 wt.%; Cu: 3.2 wt.%; Mn: 0.3 wt.%; Mg: 0.5 wt.%; Zn: 1.2 wt.%; Ti: 0.1 wt.%; Sr: 0.01 wt.%; Zr: 0.02 wt.%; Cr: 0.01 wt.%; V: 0.013 wt.%; Yb: 0.15 wt.%; Sb: 0.003 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0035] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, chromium powder and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, slag is removed to remove the flux and dross on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0036] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 386 MPa, yield strength of 273 MPa, and elongation of 5.5%. Example 2

[0037] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.5 wt.%; Fe: 0.15 wt.%; Cu: 2.3 wt.%; Mn: 0.32 wt.%; Mg: 0.8 wt.%; Zn: 1.2 wt.%; Ti: 0.11 wt.%; Sr: 0.029 wt.%; Zr: 0.032 wt.%; Cr: 0.012 wt.%; V: 0.013 wt.%; Yb: 0.08 wt.%; Er: 0.03 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0038] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, chromium powder, and rare earth Er are added in sequence to obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0039] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 388 MPa, yield strength of 275 MPa, and elongation of 5.2%. Example 3

[0040] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.7 wt.%; Fe: 0.25 wt.%; Cu: 2 wt.%; Mn: 0.35 wt.%; Mg: 0.7 wt.%; Zn: 1.4 wt.%; Ti: 0.12 wt.%; Sr: 0.025 wt.%; Zr: 0.035 wt.%; Cr: 0.013 wt.%; V: 0.014 wt.%; Yb: 0.04 wt.%; Er: 0.09 wt.%; Sb: 0.005 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0041] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0042] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 389 MPa, yield strength of 274 MPa, and elongation of 5.3%. Example 4

[0043] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.0 wt.%; Fe: 0.4 wt.%; Cu: 1.4 wt.%; Mn: 0.53 wt.%; Mg: 0.9 wt.%; Zn: 1.5 wt.%; Ti: 0.15 wt.%; Sr: 0.036 wt.%; Zr: 0.046 wt.%; Cr: 0.014 wt.%; V: 0.015 wt.%; Er: 0.15 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0044] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-V master alloy, chromium powder, and rare earth Er are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0045] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 387 MPa, yield strength of 279 MPa, and elongation of 4.9%. Example 5

[0046] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.1 wt.%; Fe: 0.11 wt.%; Cu: 2.5 wt.%; Mn: 0.59 wt.%; Mg: 1.0 wt.%; Zn: 1.6 wt.%; Ti: 0.15 wt.%; Sr: 0.035 wt.%; Zr: 0.039 wt.%; Cr: 0.012 wt.%; V: 0.015 wt.%; Sb: 0.004 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0047] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-V master alloy, chromium powder and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0048] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 382 MPa, yield strength of 283 MPa, and elongation of 5.9%. Example 6

[0049] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.3 wt.%; Fe: 0.12 wt.%; Cu: 2.3 wt.%; Mn: 0.65 wt.%; Mg: 1.2 wt.%; Zn: 1.7 wt.%; Ti: 0.13 wt.%; Sr: 0.033 wt.%; Zr: 0.038 wt.%; Cr: 0.013 wt.%; V: 0.014 wt.%; Sb: 0.004 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0050] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-V master alloy, chromium powder and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0051] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 385 MPa, yield strength of 280 MPa, and elongation of 5.6%. Example 7

[0052] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.5 wt.%; Fe: 0.15 wt.%; Cu: 2 wt.%; Mn: 0.68 wt.%; Mg: 1.3 wt.%; Zn: 1.6 wt.%; Ti: 0.13 wt.%; Sr: 0.031 wt.%; Zr: 0.041 wt.%; Cr: 0.011 wt.%; V: 0.015 wt.%; Yb: 0.15 wt.%; Er: 0.15 wt.%; Sb: 0.003 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0053] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0054] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 390 MPa, yield strength of 285 MPa, and elongation of 5.5%. Example 8

[0055] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.7 wt.%; Fe: 0.25 wt.%; Cu: 1.8 wt.%; Mn: 0.7 wt.%; Mg: 1.0 wt.%; Zn: 1.8 wt.%; Ti: 0.10 wt.%; Sr: 0.042 wt.%; Zr: 0.043 wt.%; Cr: 0.023 wt.%; V: 0.013 wt.%; Er: 0.03 wt.%; Sb: 0.003 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0056] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0057] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 391 MPa, yield strength of 285 MPa, and elongation of 4.9%. Example 9

[0058] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.8 wt.%; Fe: 0.3 wt.%; Cu: 2.0 wt.%; Mn: 0.73 wt.%; Mg: 1.2 wt.%; Zn: 1.6 wt.%; Ti: 0.15 wt.%; Sr: 0.053 wt.%; Zr: 0.055 wt.%; Cr: 0.032 wt.%; V: 0.015 wt.%; Yb: 0.02 wt.%; Er: 0.04 wt.%; Sb: 0.003 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0059] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0060] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 390 MPa, yield strength of 287 MPa, and elongation of 4.6%. Example 10

[0061] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.9 wt.%; Fe: 0.4 wt.%; Cu: 1.4 wt.%; Mn: 0.75 wt.%; Mg: 1.4 wt.%; Zn: 1.9 wt.%; Ti: 0.17 wt.%; Sr: 0.055 wt.%; Zr: 0.043 wt.%; Cr: 0.025 wt.%; V: 0.014 wt.%; Yb: 0.06 wt.%; Er: 0.05 wt.%; Sb: 0.006 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0062] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0063] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 392 MPa, yield strength of 289 MPa, and elongation of 4.5%. Example 11

[0064] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 10.0 wt.%; Fe: 0.35 wt.%; Cu: 2.4 wt.%; Mn: 0.82 wt.%; Mg: 1.3 wt.%; Zn: 2.0 wt.%; Ti: 0.15 wt.%; Sr: 0.062 wt.%; Zr: 0.058 wt.%; Cr: 0.042 wt.%; V: 0.014 wt.%; Yb: 0.08 wt.%; Er: 0.09 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0065] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, chromium powder, and rare earth Er are added in sequence to obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0066] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 395 MPa, yield strength of 288 MPa, and elongation of 4.2%. Example 12

[0067] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 10.2 wt.%; Fe: 0.25 wt.%; Cu: 2.2 wt.%; Mn: 0.93 wt.%; Mg: 1.8 wt.%; Zn: 1.2 wt.%; Ti: 0.20 wt.%; Sr: 0.073 wt.%; Zr: 0.069 wt.%; Cr: 0.053 wt.%; V: 0.014 wt.%; Er: 0.15 wt.%; Sb: 0.005 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0068] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0069] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 390 MPa, yield strength of 288 MPa, and elongation of 4.1%. Example 13

[0070] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 10.5 wt.%; Fe: 0.4 wt.%; Cu: 1.4 wt.%; Mn: 1.0 wt.%; Mg: 2.0 wt.%; Zn: 2.1 wt.%; Ti: 0.16 wt.%; Sr: 0.1 wt.%; Zr: 0.1 wt.%; Cr: 0.1 wt.%; V: 0.015 wt.%; Yb: 0.05 wt.%; Er: 0.07 wt.%; Sb: 0.006 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0071] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to melt and obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0072] The sampled properties of the die-cast part obtained in this embodiment are: tensile strength of 392 MPa, yield strength of 289 MPa, and elongation of 4.0%.

[0073] Comparative Example 1

[0074] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.2 wt.%; Fe: 0.08 wt.%; Cu: 3.2 wt.%; Mn: 0.3 wt.%; Mg: 0.5 wt.%; Zn: 1.2 wt.%; Ti: 0.1 wt.%; Sr: 0.01 wt.%; Zr: 0.01 wt.%; Cr: 0.01 wt.%; V: 0.013 wt.%; Sb: 0.004 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0075] A method for preparing a heat-free high-strength and high-toughness die-cast aluminum alloy includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-V master alloy, and chromium powder are added in sequence to obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ for uniform stirring and aluminum alloy special refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining is controlled at 50~60min. After each refining is completed, the slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg and Al-Sr intermediate alloy ingots to the furnace, and take samples for analysis after obtaining aluminum alloy melt. (4) Degassing and settling: The melting temperature is maintained at 740~760℃, and nitrogen is used to degas the furnace for about 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After settling, aluminum liquid is taken from the furnace and poured into a composition sample mold. After the aluminum liquid solidifies and cools, the chemical composition of the casting sample is analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

[0076] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 366 MPa, yield strength of 251 MPa, and elongation of 5.0%.

[0077] Comparative Example 2

[0078] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.1 wt.%; Fe: 0.11 wt.%; Cu: 2.5 wt.%; Mn: 0.59 wt.%; Mg: 1.0 wt.%; Zn: 1.6 wt.%; Ti: 0.15 wt.%; Sr: 0.035 wt.%; Cr: 0.012 wt.%; V: 0.015 wt.%; Sb: 0.004 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0079] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0080] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 353 MPa, yield strength of 230 MPa, and elongation of 4.3%.

[0081] Comparative Example 3

[0082] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 10.5 wt.%; Fe: 0.4 wt.%; Cu: 1.4 wt.%; Mn: 1.0 wt.%; Mg: 2.0 wt.%; Zn: 2.1 wt.%; Ti: 0.16 wt.%; Sr: 0.1 wt.%; Zr: 0.1 wt.%; Cr: 0.1 wt.%; V: 0.015 wt.%; Yb: 0.15 wt.%; Er: 0.15 wt.%; Sb: 0.006 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0083] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0084] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 383 MPa, yield strength of 265 MPa, and elongation of 2.9%.

[0085] Comparative Example 4

[0086] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.2 wt.%; Fe: 0.08 wt.%; Cu: 4.0 wt.%; Mn: 0.3 wt.%; Mg: 3.0 wt.%; Zn: 2.0 wt.%; Ti: 0.10 wt.%; Sr: 0.01 wt.%; Zr: 0.02 wt.%; Cr: 0.01 wt.%; V: 0.013 wt.%; Yb: 0.15 wt.%; Sb: 0.003 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0087] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0088] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 377 MPa, yield strength of 266 MPa, and elongation of 0.6%.

[0089] Comparative Example 5

[0090] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.1 wt.%; Fe: 0.11 wt.%; Cu: 0.5 wt.%; Mn: 0.59 wt.%; Mg: 0.5 wt.%; Zn: 1.0 wt.%; Ti: 0.15 wt.%; Sr: 0.035 wt.%; Zr: 0.039 wt.%; Cr: 0.012 wt.%; V: 0.015 wt.%; Sb: 0.004 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0091] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0092] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 379 MPa, yield strength of 245 MPa, and elongation of 3.9%.

[0093] Comparative Example 6

[0094] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 10.5 wt.%; Fe: 0.4 wt.%; Cu: 1.0 wt.%; Mn: 1.0 wt.%; Mg: 0.5 wt.%; Zn: 1.2 wt.%; Ti: 0.16 wt.%; Sr: 0.1 wt.%; Zr: 0.1 wt.%; Cr: 0.1 wt.%; V: 0.015 wt.%; Yb: 0.05 wt.%; Er: 0.07 wt.%; Sb: 0.006 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0095] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0096] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 382 MPa, yield strength of 236 MPa, and elongation of 4.8%.

[0097] Comparative Example 7

[0098] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 7.0 wt.%; Fe: 0.1 wt.%; Cu: 1.0 wt.%; Mn: 0.65 wt.%; Mg: 1.8 wt.%; Zn: 1.7 wt.%; Ti: 0.13 wt.%; Sr: 0.03 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0099] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0100] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 380 MPa, yield strength of 185 MPa, and elongation of 1.8%.

[0101] Comparative Example 8

[0102] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.0 wt.%; Fe: 0.4 wt.%; Cu: 4.0 wt.%; Mn: 0.65 wt.%; Mg: 1.2 wt.%; Zn: 1.7 wt.%; Ti: 0.13 wt.%; Sr: 0.03 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0103] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0104] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 275 MPa, yield strength of 160 MPa, and elongation of 0.9%.

[0105] Comparative Example 9

[0106] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 11.0 wt.%; Fe: 0.1 wt.%; Cu: 2.0 wt.%; Mn: 0.65 wt.%; Mg: 1.8 wt.%; Zn: 1.7 wt.%; Ti: 0.13 wt.%; Sr: 0.03 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0107] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0108] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 328 MPa, yield strength of 159 MPa, and elongation of 1.2%.

[0109] Comparative Example 10

[0110] A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 12.0 wt.%; Fe: 0.4 wt.%; Cu: 3.0 wt.%; Mn: 0.65 wt.%; Mg: 1.2 wt.%; Zn: 1.7 wt.%; Ti: 0.13 wt.%; Sr: 0.03 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al.

[0111] The preparation method of this comparative example is the same as that of comparative example 1, except that the raw materials added are different.

[0112] The sampled properties of the die-cast part obtained in this comparative example are: tensile strength of 335 MPa, yield strength of 153 MPa, and elongation of 0.8%.

[0113] Table 1 records the composition of the alloys involved in Examples 1-13 and Comparative Examples 1-10.

[0114] Table 2 records the mechanical properties of the alloys involved in Examples 1-13 and Comparative Examples 1-10.

[0115] As shown in Tables 1 and 2, in Comparative Example 1, the sum of Zr, Yb, and Er added is less than 0.03%, resulting in a 22 MPa decrease in yield strength compared to Example 1. Comparative Example 2 differs from Example 2 in that it does not contain Zr, Yb, and Er, leading to a 43 MPa decrease in yield strength and a 1.6% decrease in elongation. In Comparative Example 3, the sum of Zr, Yb, and Er added is greater than 0.3%, resulting in a 24 MPa decrease in yield strength and a 1.1% decrease in elongation. Based on Examples 1, 2, and 3, we can conclude that the sum of Zr, Yb, and Er added to the alloy must be between 0.03% and 0.3% to ensure the alloy's mechanical properties. Furthermore, as shown in Comparative Examples 4, 5, and 6, when the ratio of Si added to Cu, Mg, and Zn in the alloy is greater than or less than (1.5-3):1, the mechanical properties obtained by the alloy cannot meet the requirements for high strength.

[0116] Comparative Example 7 designed an alloy with low Si, low Fe, and low Cu; Comparative Example 8 is an alloy with low Si, high Fe, and high Cu; Comparative Example 9 is an alloy with high Si and low Fe; and Comparative Example 10 is an alloy with high Si and high Fe. The Si content of these four alloys is outside the range of silicon content in this invention. The strength and elongation obtained by these four alloys are lower than the mechanical properties of Examples 1 to 13 in this invention, and none of them can meet the requirements for high performance of alloys.

[0117] In summary, the present invention discloses a heat-free, high-strength, high-toughness die-cast aluminum alloy. The weight percentages of the components in this die-cast aluminum alloy are as follows: Si: 8.2-10.5 wt.%; Fe: 0.08-0.6 wt.%; Cu: 1.4-3.2 wt.%; Mn: 0.3-1.0 wt.%; Mg: 0.5-2.0 wt.%; Zn: 1.2-2.1 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0-0.15 wt.%; Er: 0-0.15 wt.%; Sb: 0-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, and the balance is Al. The ratio of Si:(Cu+Mg+Zn) is further specified as (1.5-3):1; the sum of Zr, Yb, and Er elements is between 0.03-0.3%. Within this range, the tensile strength of this die-cast alloy at room temperature can reach 390 MPa, the yield strength can reach 285 MPa, and the elongation is above 4%.

[0118] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

[0119] .

[0120] .

Claims

1. A heat-treatable, high-strength, high-toughness die-cast aluminum alloy, wherein the weight percentages of each component in the die-cast aluminum alloy are as follows: Si:8.2-10.5 wt.%;Fe:0.08-0.6 wt.%;Cu:1.4-3.2 wt.%;Mn:0.3-1.0 wt.%; Mg: 0.5-2.0 wt.%; Zn: 1.2-2.1 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0.01-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0.02-0.15 wt.%; Er: 0.03-0.15 wt.%; Sb: 0.003-0.1 wt.%; The total content of other impurities is less than or equal to 0.3 wt.%, with the balance being Al; Further specified Si:(Cu+Mg+Zn)=(1.5-3):1; The sum of Zr, Yb, and Er elements is between 0.03-0.3%; This heat-free high-strength and high-toughness die-cast aluminum alloy has a tensile strength of up to 382 MPa, a yield strength of up to 273 MPa, and an elongation of over 4% in the room temperature die-cast state.

2. The heat-treasure-free high-strength and high-toughness die-cast aluminum alloy according to claim 1, characterized in that, The weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.2-9.1 wt.%; Fe: 0.08-0.15 wt.%; Cu: 1.4-1.8 wt.%; Mn: 0.3-0.50 wt.%; Mg: 0.5-1.0 wt.%; Zn: 1.2-1.5 wt.%; wt.%; Zr: 0.02-0.1wt.%; Cr: 0.01-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0.02-0.15 wt.%; Er: 0.03-0.15 wt.%; Sb: 0.003-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, with the balance being Al; further specified Si:(Cu+Mg+Zn)=(1.5-3):1; the sum of Zr, Yb, and Er elements is between 0.03-0.3%.

3. The heat-treasure-free high-strength and high-toughness die-cast aluminum alloy according to claim 1, characterized in that, The weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.1-9.8 wt.%; Fe: 0.15-0.25 wt.%; Cu: 1.8-2.2 wt.%; Mn: 0.50-0.75 wt.%; Mg: 1.0-1.6 wt.%; Zn: 1.5-1.8 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0.01-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0.02-0.15 wt.%; Er: 0.03-0.15 wt.%; Sb: 0.003-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, with the balance being Al; further specified Si:(Cu+Mg+Zn)=(1.5-3):1; the sum of Zr, Yb, and Er elements is between 0.03-0.3%.

4. The heat-treasure-free high-strength and high-toughness die-cast aluminum alloy according to claim 1, characterized in that, The weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.8-10.5 wt.%; Fe: 0.25-0.6 wt.%; Cu: 2.2-3.2 wt.%; Mn: 0.75-1.0 wt.%; Mg: 1.6-2.0 wt.%; Zn: 1.8-2.1 wt.%; Ti: 0.1-0.2 wt.%; Sr: 0.01-0.1 wt.%; Zr: 0.02-0.1 wt.%; Cr: 0.01-0.1 wt.%; V: 0.01-0.04 wt.%; Yb: 0.02-0.15 wt.%; Er: 0.03-0.15 wt.%; Sb: 0.003-0.1 wt.%; the total content of other impurities is less than or equal to 0.3 wt.%, with the balance being Al; further specified Si:(Cu+Mg+Zn)=(1.5-3):1; the sum of Zr, Yb, and Er elements is between 0.03-0.3%.

5. The heat-treasure-free high-strength and high-toughness die-cast aluminum alloy according to claim 1, characterized in that, The weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 8.2 wt.%; Fe: 0.08 wt.%; Cu: 3.2 wt.%; Mn: 0.3 wt.%; Mg: 0.5 wt.%; Zn: 1.2 wt.%; Ti: 0.1 wt.%; Sr: 0.01 wt.%; Zr: 0.02 wt.%; Cr: 0.013 wt.%; V: 0.013 wt.%; Yb: 0.01 wt.%; Er: 0.02 wt.%; Sb: 0.003 wt.%; The total content of other impurities is less than or equal to 0.3 wt.%, with the balance being Al.

6. The heat-treasure-free high-strength and high-toughness die-cast aluminum alloy according to claim 1, characterized in that, The weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.1 wt.%; Fe: 0.2 wt.%; Cu: 2.2 wt.%; Mn: 0.55 wt.%; Mg: 1.0 wt.%; Zn: 1.5 wt.%; Ti: 0.15 wt.%; Sr: 0.035 wt.%; Zr: 0.039 wt.%; Cr: 0.015 wt.%; V: 0.015 wt.%; Yb: 0.02 wt.%; Er: 0.03 wt.%; Sb: 0.004 wt.%; The total content of other impurities is less than or equal to 0.3 wt.%, with the balance being Al.

7. The heat-treasure-free high-strength and high-toughness die-cast aluminum alloy according to claim 1, characterized in that, The weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 9.3 wt.%; Fe: 0.15 wt.%; Cu: 2.1 wt.%; Mn: 0.5 wt.%; Mg: 1.2 wt.%; Zn: 1.6 wt.%; Ti: 0.13 wt.%; Sr: 0.03 wt.%; Zr: 0.041 wt.%; Cr: 0.015 wt.%; V: 0.015 wt.%; Yb: 0.02 wt.%; Er: 0.02 wt.%; Sb: 0.003 wt.%; The total content of other impurities is less than or equal to 0.3 wt.%, with the balance being Al.

8. The heat-treasure-free high-strength and high-toughness die-cast aluminum alloy according to claim 1, characterized in that, The weight percentages of each component in the die-cast aluminum alloy are as follows: Si: 10.5 wt.%; Fe: 0.4 wt.%; Cu: 1.4 wt.%; Mn: 1.0 wt.%; Mg: 2.0 wt.%; Zn: 2.1 wt.%; Ti: 0.2 wt.%; Sr: 0.1 wt.%; Zr: 0.052 wt.%; Cr: 0.014 wt.%; V: 0.014 wt.%; Yb: 0.05 wt.%; Er: 0.01 wt.%; Sb: 0.005 wt.%; The total content of other impurities is less than or equal to 0.3 wt.%, with the balance being Al.

9. A method for preparing a heat-treasure-free high-strength and high-toughness die-cast aluminum alloy as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Batching and melting: Pure aluminum ingots or recycled aluminum are added to the melting furnace in sequence according to the element ratio for melting. The melting temperature is controlled at 670~690℃. After all the aluminum ingots are melted, the temperature is raised to 760~780℃. Then, industrial silicon, metallic Zn, Al-Mn master alloy, metallic Fe, Al-Cu, Al-Ti, Al-Zr, Al-Yb, Al-V master alloy, as well as chromium powder, rare earth Er and pure Sb powder are added in sequence to obtain aluminum alloy melt. (2) Refining and slag removal: The temperature of the aluminum alloy melt is controlled at 740~760℃ and stirred evenly. A special aluminum alloy refining agent is added for primary powder spraying refining and secondary powder spraying refining. The interval between the two refining processes is controlled at 50~60min. After each refining process, slag is removed to remove the flux and slag on the liquid surface. (3) Adding elements that are easily burned off: When the melt temperature is 740~760℃, add Mg metal and Al-Sr master alloy ingots to the furnace, and then take samples for analysis after obtaining aluminum alloy melt; (4) Degassing and settling: The melting temperature is maintained at 740~760℃. Nitrogen is used to degas the furnace for 30~50 minutes, followed by settling for 15~30 minutes. (5) Composition analysis: After the settling period, aluminum liquid was taken from the furnace and poured into a small sample mold. After the aluminum liquid solidified and cooled, the chemical composition of the casting sample was analyzed. (6) High pressure die casting: After the composition analysis is qualified, high pressure die casting is carried out at an aluminum liquid temperature of 660~670℃, the injection speed is 4~5m / s, the vacuum degree is less than 50mbar, the mold temperature is 180℃, and a die casting with a wall thickness of 3~5mm is obtained.

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