Heat-treatment-free high-performance die-casting rare earth aluminum alloy as well as preparation method and application thereof

Abstract

The invention discloses a heat-treatment-free high-performance die-casting rare earth aluminum alloy which comprises the following chemical components in percentage by mass: 3.0 to 6.2 percent of Mg, 2.0 to 8.3 percent of Si, 1.0 to 2.8 percent of Cu, 0.13 to 0.8 percent of Mn, 0.03 to 0.56 percent of Ta, 0.03 to 0.62 percent of Zr, 0.01 to 0.26 percent of Ag, 0.01 to 0.32 percent of Hf, 0.01 to 0.24 percent of Ti, 0.0001 to 0.0050 percent of Be, less than or equal to 0.2 percent of Fe, 0.1 to 1.2 percent of total content of rare earth elements, less than or equal to 0.03 percent of other inevitable single impurity elements, less than or equal to 0.15 percent of total impurity elements and the balance of aluminum. After the die-casting rare earth aluminum alloy is subjected to high-pressure casting forming, heat treatment is not needed, the yield strength of the die-casting rare earth aluminum alloy is not lower than 280 MPa, the tensile strength of the die-casting rare earth aluminum alloy is not lower than 320 MPa, the percentage elongation after fracture of the die-casting rare earth aluminum alloy is not lower than 7.0%, and the die-casting rare earth aluminum alloy can be used for manufacturing complex-shape structural parts in the industries of electric motorcycles, automobiles, mechanical equipment and the like

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy materials and casting, and specifically relates to a heat treatment-free high-performance die-casting rare earth aluminum alloy, a preparation method and applications thereof. Background Art

[0002] With the continuous advancement of technology and industry, a series of electric vehicles represented by new energy vehicles are becoming more and more popular, and related industries are developing rapidly. The lightweighting of new energy vehicles and related vehicles has become the focus of attention and research in the aluminum alloy material industry. There are many parts with complex shapes, large wall thickness variations, and long molding processes in new energy vehicles and related vehicles. In order to achieve the goals of cost reduction, efficiency improvement and lightweighting, aluminum alloy high-pressure casting (referred to as "die casting") technology has been widely used in various fields of manufacturing because of its ability to obtain workpieces close to the final shape and size, high production efficiency, and good performance of the castings produced. However, the performance of the widely used die-cast aluminum alloy materials is relatively low, and some die-castings still need heat treatment to achieve the goal of improving performance, which can no longer meet the manufacturing industry's development needs for the performance of die-castings. This is because the aluminum alloy castings produced by the die-casting process are usually complex in appearance and thin in wall thickness. Once solution treatment is performed, it will cause a large degree of deformation of the workpiece, seriously affecting the yield and economic benefits. Therefore, there is an urgent need for an aluminum alloy material that has high strength, plasticity and toughness without heat treatment and excellent die-casting formability to meet the needs of various fields of the manufacturing industry. Summary of the invention

[0003] In view of the above-mentioned deficiencies, the present invention discloses a high-performance die-cast rare earth aluminum alloy that does not require heat treatment, a preparation method and an application thereof. By rationally optimizing alloying elements and adding an appropriate amount of rare earth elements for micro-alloying, an aluminum alloy material with excellent comprehensive performance can be obtained in the die-casting state (F state) without heat treatment. The aluminum alloy material can be used for the production of die-cast parts with complex shapes and appearances, meeting the requirements of the new energy vehicle industry for aluminum alloy die-cast parts that do not require heat treatment.

[0004] The present invention is achieved by adopting the following technical solutions: A heat treatment-free high-performance die-cast rare earth aluminum alloy, comprising the following chemical components in mass fractions: Mg: 3.0-6.2%, Si: 2.0-8.3%, Cu: 1.0-2.8%, Mn: 0.13-0.8%, Ta: 0.03-0.56%, Zr: 0.03-0.62%, Ag: 0.01-0.26%, Hf: 0.01-0.32%, Ti: 0.01-0.24%, Be: 0.0001-0.0050%, Fe≤0.2%, total rare earth element content 0.1-1.2%, of which rare earth elements are Ce, Y and Yb, other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, balance is aluminum.

[0005] The main alloy elements used in the present invention are Mg, Si and Cu. When Mg and Si are added in the above ratio, the alloy will undergo L→α-Al+Mg during the solidification process. 2 The eutectic reaction of Si generates Mg 2 The eutectic structure is mainly Si+α-Al. During the solidification process, the eutectic reaction can improve the fluidity and filling property of the alloy melt, and the Mg formed by the eutectic reaction 2 Si is small in size and dispersed in distribution, replacing the fibrous, granular, and blocky eutectic Si structures formed by the Al-Si eutectic reaction, improving the strength and plasticity of the alloy. In addition, the main effects of adding Cu elements are twofold. On the one hand, Cu atoms form a supersaturated solid solution in the α-Al matrix, producing a solid solution strengthening effect; on the other hand, they form Al 2 Cu precipitates into the phase, producing precipitation strengthening effect, which improves the strength of the alloy material from two aspects.

[0006] At the same time, the Mn, Ta, Zr, Ag, Hf, and Ti used in the present invention are micro-alloying elements. The main function of the Mn element is to inhibit the chemical reaction between the aluminum liquid and the mold during the die-casting process, and reduce the risk of "sticking to the mold" during the die-casting process of the alloy material. On the one hand, Ta, Zr, Ag, Hf, and Ti elements can form a series of complex intermediate phases with each other, which plays a role in refining the grains; on the other hand, they can improve the Mg formed by the eutectic reaction. 2 The organizational morphology of the Si phase is refined and homogenized.

[0007] Moreover, the present invention uses three rare earth elements, namely Ce, Y and Yb. On the one hand, they can form an intermediate phase with the Al element in the aluminum alloy melt. The crystal structure of these intermediate phases is the same as that of α-Al, and the lattice size is similar to that of α-Al, with a small mismatch, and they are good α-Al grain refiners, which can produce good grain refinement effects; on the other hand, the intermediate phases formed by the rare earth elements and Al have a strong affinity to Mg. 2 The Si phase also has good adaptability and can be used as a Mg 2 The nucleation core of Si phase can effectively refine Mg2 In addition, Ce, Y, and Yb, which exist in the aluminum alloy melt in atomic state, can be adsorbed on Mg due to their high activity. 2 Si phase surface, inhibiting Mg 2 The growth rate of Si phase along certain directions can improve the Mg 2 The morphology of Si phase plays a metamorphic role.

[0008] In addition, the present invention uses the alkaline earth metal element Be, which can inhibit the burning of the Mg element, reduce the burning rate, and reduce the risk of hydrogen absorption.

[0009] Furthermore, the heat treatment-free high-performance die-cast rare earth aluminum alloy comprises the following chemical components in mass fraction: Mg: 3.2-6.0%, Si: 2.2-7.5%, Cu: 1.5-2.5%, Mn: 0.2-0.7%, Ta: 0.10-0.45%, Zr: 0.10-0.50%, Ag: 0.05-0.20%, Hf: 0.05-0.26%, Ti: 0.02-0.16%, Be: 0.0005-0.0040%, Fe≤0.12%, total rare earth element content 0.1-1.0%, wherein the rare earth elements are Ce, Y, and Yb, and the ratio between the three rare earth elements is (4-6): (2-4): (1-2), other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, and the balance is aluminum. The present invention further limits the usage ratio of Ce, Y, and Yb, so that the three elements can form a suitable intermediate phase to obtain grain refinement and refinement of Mg. 2 Si equal effect.

[0010] The method for preparing the heat-treatment-free high-performance die-cast rare earth aluminum alloy comprises the following steps: (1) weighing raw materials in proportion, wherein the raw materials include aluminum ingots, magnesium ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-beryllium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys; (2) placing aluminum ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys in a melting furnace, and then stirring and melting at 760-840° C. to obtain a melt A; (3) subjecting the melt A obtained in step (2) to a first refining treatment at 760-800° C. for 30-60 minutes, allowing the melt to stand after the first refining treatment, and then skimming off the slag to obtain a melt B; (4) adding aluminum-beryllium master alloy to the melt B obtained in step (3), then stirring and smelting at 720-780° C., then adding magnesium ingot, stirring and smelting at 700-760° C. to obtain melt C, sampling from melt C for chemical composition analysis, and if there is a deviation in the composition, adjusting the composition using the raw materials described in step (1) and sampling again for analysis until all elements reach the expected indicators; (5) The melt C obtained in step (4) is subjected to a second refining treatment at 720-760° C. for 20-40 minutes. After the second refining treatment, the melt C is allowed to stand, and then the slag is removed to obtain a melt D. Samples are taken from the melt D for analysis. If the composition is still within the expected index range, no treatment is required to proceed to the next step. If the composition deviates, the composition is adjusted until all elements reach the expected composition range before proceeding to the next step. (6) The melt D obtained in step (5) is discharged from the bottom of the furnace for casting, wherein the melt D is subjected to double-stage filtration treatment and then enters an automatic casting machine for casting to obtain a high-performance die-cast rare earth aluminum alloy without heat treatment.

[0011] The obtained heat treatment-free high-performance die-cast rare earth aluminum alloy can achieve the following performance parameters: yield strength ≥280MPa, tensile strength ≥320MPa, and elongation after fracture ≥8.0%.

[0012] Furthermore, in step (2), the smelting time is 1 to 4 hours, and the stirring speed is 20 to 100 r / min.

[0013] Furthermore, the first refining treatment and the second refining treatment both use a mixed gas made by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99%, wherein high-purity argon accounts for 90%, high-purity nitrogen accounts for 9%, and high-purity chlorine accounts for 1%.

[0014] Furthermore, in step (6), the first filter plate of the double-stage filtration is 60 mesh, and the second filter plate is 80 mesh; the furnace temperature of the melt D is 640-740°C.

[0015] The application of the heat-treatment-free high-performance die-cast rare earth aluminum alloy in die-cast products is to prepare die-castings using the heat-treatment-free high-performance die-cast rare earth aluminum alloy, which specifically includes the following steps: S1, placing the heat treatment-free high-performance die-cast rare earth aluminum alloy into an aluminum melting furnace, stirring and remelting at 720-760° C. to obtain an alloy melt; S2. Refining the alloy melt obtained in step S1 at 700-740° C. for 10-30 minutes, then letting it stand and removing slag, and then keeping the aluminum alloy melt warm at 660-740° C. for standby use; transferring the alloy melt to a cold chamber die-casting machine by a robotic arm for die-casting, and obtaining a die-casting after cooling.

[0016] Furthermore, in step S1, a mixed gas prepared by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99% is used in the refining, wherein the high-purity argon accounts for 90%, the high-purity nitrogen accounts for 9%, and the high-purity chlorine accounts for 1%.

[0017] Furthermore, in step S2, the die-casting molding refers to high-pressure die-casting. During the die-casting process, the first-stage injection speed is 0.1-0.5 m / s, the second-stage injection speed is 0.2-1.5 m / s, the third-stage injection speed is 2.5-10 m / s, the die-casting pressure is 50-100 MPa, and the pressure is maintained for 10-40 seconds.

[0018] Compared with the prior art, this technical solution has the following beneficial effects: 1. At present, the commonly used die-cast aluminum alloy materials in China are Al-Si aluminum alloys, and the commonly used grades are ADC12, A380, 46500, etc. These aluminum alloys usually have a certain strength in the die-cast state (F state), but poor plasticity, resulting in poor impact resistance and fatigue resistance, which makes it difficult to meet the development requirements of the new energy vehicle industry for the high comprehensive performance of heat-free aluminum alloy die-castings. In view of the above problems, the present invention uses rare earth microalloying as a means to develop a high-performance die-cast rare earth aluminum alloy without heat treatment with high strength, plasticity and toughness to meet the development needs of various fields of manufacturing.

[0019] 2. The heat-treatment-free high-performance die-cast rare earth aluminum alloy obtained by the present invention has excellent formability and is suitable for the production of die-cast parts with complex shapes and appearances. After high-pressure casting, it has high strength, plasticity and toughness in the F state, with a yield strength of not less than 280MPa, a tensile strength of not less than 320MPa, and an elongation after fracture of not less than 7.0%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The metallographic phase diagram is 200 times that of the heat treatment-free high-performance die-cast rare earth aluminum alloy ingot obtained in Example 1.

[0021] Figure 2 This is a 500-fold metallographic image of the die casting obtained in Example 1.

[0022] Figure 3 This is a 1000-fold metallographic image of the die casting obtained in Example 1.

[0023] Figure 4 It is the stress-strain curve obtained by tensile testing of the die casting obtained in Example 1. DETAILED DESCRIPTION

[0024] The present invention is further described by the following examples, but is not intended to be limiting of the present invention. Specific experimental conditions and methods not specified in the following examples are conventional methods commonly known to those skilled in the art.

[0025] Embodiment 1: A high-performance die-cast rare earth aluminum alloy without heat treatment, comprising the following chemical components in mass fractions: Mg: 6.0%, Si: 2.8%, Cu: 1.8%, Mn: 0.6%, Ta: 0.24%, Zr: 0.16%, Ag: 0.09%, Hf: 0.13%, Ti: 0.04%, Be: 0.0020%, Fe: 0.11%, the total content of rare earth elements is 0.6%, of which the rare earth elements are Ce, Y and Yb, and the ratio between the three rare earth elements is 5:3:2, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, and the balance is aluminum.

[0026] The method for preparing the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, wherein the raw materials include aluminum ingots, magnesium ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-beryllium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys; (2) placing aluminum ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys in a smelting furnace, and then stirring and smelting at 800° C. to obtain a melt A; the smelting time is 3.5 hours, and the stirring speed is 60 r / min; (3) The melt A obtained in step (2) is subjected to a first refining treatment at 765° C. for 50 minutes. After the first refining treatment, the melt is allowed to stand for 30 minutes, and then the melt is skimmed to obtain a melt B; (4) adding aluminum-beryllium master alloy to the melt B obtained in step (3), then stirring and melting at 760° C., then adding magnesium ingot, stirring and melting at 730° C. to obtain melt C, sampling from melt C for chemical composition analysis, and if there is a deviation in the composition, adjusting the composition using the raw materials described in step (1) and sampling again for analysis until all elements reach the expected indicators; (5) The melt C obtained in step (4) is subjected to a second refining treatment at 740°C for 20 minutes. After the second refining treatment, the melt C is allowed to stand, and then the slag is removed to obtain a melt D. Samples are taken from the melt D for analysis. If the composition is still within the expected index range, no treatment is required to proceed to the next step. If the composition deviates, the composition is adjusted until all elements reach the expected composition range before proceeding to the next step. (6) discharging the melt D obtained in step (5) from the bottom of the furnace for casting, wherein the melt D is subjected to double-stage filtration and then enters an automatic casting machine for casting to obtain a high-performance die-cast rare earth aluminum alloy without heat treatment; the first-stage filter plate of the double-stage filtration is 60 mesh, and the second-stage filter plate is 80 mesh; the temperature of the melt D out of the furnace is 710°C; The first refining treatment and the second refining treatment both use a mixed gas made by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99%, wherein high-purity argon accounts for 90%, high-purity nitrogen accounts for 9%, and high-purity chlorine accounts for 1%.

[0027] The application of the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment in die-cast products is to use the heat-treatment-free high-performance die-cast rare earth aluminum alloy to prepare die-castings, which specifically includes the following steps: S1. The heat-treatment-free high-performance die-cast rare earth aluminum alloy is placed in an aluminum melting furnace and stirred and remelted at 750° C. to obtain an alloy melt; in the refining, a mixed gas is used, which is a mixture of 99.99% high-purity argon, 99.99% high-purity nitrogen and 99.99% high-purity chlorine, wherein the high-purity argon accounts for 90%, the high-purity nitrogen accounts for 9%, and the high-purity chlorine accounts for 1%; S2. Refining the alloy melt obtained in step S1 at 720°C for 20 minutes, then letting it stand and skimming off the slag, and then keeping the aluminum alloy melt warm at 700-720°C for standby use; using a robotic arm to transfer the alloy melt to a cold chamber die-casting machine for die-casting, and obtaining a die-casting after cooling; the die-casting refers to high-pressure die-casting, and during the die-casting process, the first-stage injection speed is 0.2m / s, the second-stage injection speed is 1.0m / s, the third-stage injection speed is 5.0m / s, the die-casting pressure is 86MPa, and the pressure is maintained for 20 seconds.

[0028] Embodiment 2: A high-performance die-cast rare earth aluminum alloy without heat treatment, comprising the following chemical components in mass fractions: Mg: 3.8%, Si: 6.7%, Cu: 2.2%, Mn: 0.34%, Ta: 0.19%, Zr: 0.36%, Ag: 0.11%, Hf: 0.23%, Ti: 0.08%, Be: 0.0030%, Fe: 0.10%, the total content of rare earth elements is 0.8%, of which the rare earth elements are Ce, Y and Yb, and the ratio between the three rare earth elements is 5.4:3.2:1.4, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, and the balance is aluminum.

[0029] The method for preparing the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, wherein the raw materials include aluminum ingots, magnesium ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-beryllium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys; (2) placing aluminum ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys in a smelting furnace, and then stirring and smelting at 780° C. to obtain a melt A; the smelting time is 4 hours, and the stirring speed is 45 r / min; (3) subjecting the melt A obtained in step (2) to a first refining treatment at 770° C. for 40 minutes, standing the melt for 30 minutes after the first refining treatment, and then skimming off the slag to obtain melt B; (4) adding aluminum-beryllium master alloy to the melt B obtained in step (3), then stirring and melting at 740° C., then adding magnesium ingot, stirring and melting at 720° C. to obtain melt C, sampling from melt C for chemical composition analysis, and if there is a deviation in the composition, adjusting the composition using the raw materials described in step (1) and sampling again for analysis until all elements reach the expected indicators; (5) The melt C obtained in step (4) is subjected to a second refining treatment at 745°C for 20 minutes. After the second refining treatment, the melt C is allowed to stand, and then the slag is removed to obtain a melt D. Samples are taken from the melt D for analysis. If the composition is still within the expected index range, no treatment is required to proceed to the next step. If the composition deviates, the composition is adjusted until all elements reach the expected composition range before proceeding to the next step. (6) discharging the melt D obtained in step (5) from the bottom of the furnace for casting, wherein the melt D is subjected to double-stage filtration treatment and then enters an automatic casting machine for casting to obtain a high-performance die-cast rare earth aluminum alloy without heat treatment; the first-stage filter plate of the double-stage filtration is 60 mesh, and the second-stage filter plate is 80 mesh; the temperature of the melt D out of the furnace is 700°C; The first refining treatment and the second refining treatment both use a mixed gas made by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99%, wherein high-purity argon accounts for 90%, high-purity nitrogen accounts for 9%, and high-purity chlorine accounts for 1%.

[0030] The application of the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment in die-cast products is to use the heat-treatment-free high-performance die-cast rare earth aluminum alloy to prepare die-castings, which specifically includes the following steps: S1. The heat-treatment-free high-performance die-cast rare earth aluminum alloy is placed in an aluminum melting furnace and stirred and remelted at 755° C. to obtain an alloy melt; in the refining, a mixed gas is used which is a mixture of 99.99% high-purity argon, 99.99% high-purity nitrogen and 99.99% high-purity chlorine, wherein the high-purity argon accounts for 90%, the high-purity nitrogen accounts for 9%, and the high-purity chlorine accounts for 1%; S2. Refining the alloy melt obtained in step S1 at 710°C for 15 minutes, then letting it stand and removing the slag, and then keeping the aluminum alloy melt warm at 680-690°C for standby use; using a robotic arm to transfer the alloy melt to a cold chamber die-casting machine for die-casting, and obtaining a die-casting after cooling; the die-casting refers to high-pressure die-casting, and the first-stage injection speed during the die-casting process is 0.25m / s, the second-stage injection speed is 1.3m / s, the third-stage injection speed is 6.010m / s, the die-casting pressure is 90MPa, and the pressure is maintained for 30 seconds.

[0031] Embodiment 3: A high-performance die-cast rare earth aluminum alloy without heat treatment, comprising the following chemical components in mass fractions: Mg: 3.4%, Si: 7.4%, Cu: 1.9%, Mn: 0.66%, Ta: 0.28%, Zr: 0.45%, Ag: 0.19%, Hf: 0.21%, Ti: 0.08%, Be: 0.0025%, Fe: 0.12%, the total content of rare earth elements is 0.75%, of which the rare earth elements are Ce, Y and Yb, and the ratio between the three rare earth elements is 5.1:3:1.9, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, and the balance is aluminum.

[0032] The method for preparing the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, wherein the raw materials include aluminum ingots, magnesium ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-beryllium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys; (2) placing aluminum ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys in a smelting furnace, and then stirring and smelting at 800° C. to obtain a melt A; the smelting time is 4 hours, and the stirring speed is 60 r / min; (3) The melt A obtained in step (2) is subjected to a first refining treatment at 765° C. for 60 minutes. After the first refining treatment, the melt A is allowed to stand and then slag is removed to obtain a melt B. (4) adding aluminum-beryllium master alloy to the melt B obtained in step (3), then stirring and melting at 745° C., then adding magnesium ingot, stirring and melting at 720° C. to obtain melt C, sampling from melt C for chemical composition analysis, and if there is a deviation in the composition, adjusting the composition using the raw materials described in step (1) and sampling again for analysis until all elements reach the expected indicators; (5) The melt C obtained in step (4) is subjected to a second refining treatment at 755°C for 20 minutes. After the second refining treatment, the melt C is allowed to stand, and then the slag is removed to obtain a melt D. Samples are taken from the melt D for analysis. If the composition is still within the expected index range, no treatment is required to proceed to the next step. If the composition deviates, the composition is adjusted until all elements reach the expected composition range before proceeding to the next step. (6) discharging the melt D obtained in step (5) from the bottom of the furnace for casting, wherein the melt D is subjected to double-stage filtration and then enters an automatic casting machine for casting to obtain a high-performance die-cast rare earth aluminum alloy without heat treatment; the first-stage filter plate of the double-stage filtration is 60 mesh, and the second-stage filter plate is 80 mesh; the temperature of the melt D out of the furnace is 710°C; The first refining treatment and the second refining treatment both use a mixed gas made by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99%, wherein high-purity argon accounts for 90%, high-purity nitrogen accounts for 9%, and high-purity chlorine accounts for 1%.

[0033] The application of the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment in die-cast products is to use the heat-treatment-free high-performance die-cast rare earth aluminum alloy to prepare die-castings, which specifically includes the following steps: S1. The heat-treatment-free high-performance die-cast rare earth aluminum alloy is placed in an aluminum melting furnace and stirred and remelted at 745° C. to obtain an alloy melt; in the refining, a mixed gas is used which is a mixture of 99.99% high-purity argon, 99.99% high-purity nitrogen and 99.99% high-purity chlorine, wherein the high-purity argon accounts for 90%, the high-purity nitrogen accounts for 9%, and the high-purity chlorine accounts for 1%; S2. Refining the alloy melt obtained in step S1 at 710°C for 10 to 30 minutes, then letting it stand and removing the slag, and then keeping the aluminum alloy melt warm at 660 to 670°C for standby use; using a robotic arm to transfer the alloy melt to a cold chamber die-casting machine for die-casting, and obtaining a die-casting after cooling; the die-casting refers to high-pressure die-casting, and the first-stage injection speed during the die-casting process is 0.15m / s, the second-stage injection speed is 0.8m / s, the third-stage injection speed is 4.0m / s, the die-casting pressure is 65MPa, and the pressure is maintained for 30 seconds.

[0034] Embodiment 4: A high-performance die-cast rare earth aluminum alloy without heat treatment, comprising the following chemical components in mass fractions: Mg: 3.0%, Si: 2.0%, Cu: 1.0%, Mn: 0.13%, Ta: 0.03%, Zr: 0.03%, Ag: 0.01%, Hf: 0.01%, Ti: 0.01%, Be: 0.0001%, Fe: 0.15%, total rare earth element content 0.1%, of which rare earth elements are Ce, Y and Yb, and the ratio between the three rare earth elements is 4:2:1, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, and the balance is aluminum.

[0035] The method for preparing the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, wherein the raw materials include aluminum ingots, magnesium ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-beryllium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys; (2) placing aluminum ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys in a smelting furnace, and then stirring and smelting at 760° C. to obtain a melt A; the smelting time is 4.5 hours, and the stirring speed is 40 r / min; (3) The melt A obtained in step (2) is subjected to a first refining treatment at 765° C. for 30 minutes. After the first refining treatment, the melt A is allowed to stand and then slag is removed to obtain a melt B. (4) adding aluminum-beryllium master alloy to the melt B obtained in step (3), then stirring and melting at 720° C., then adding magnesium ingot, stirring and melting at 700° C. to obtain melt C, taking samples from melt C for chemical composition analysis, and if there is a deviation in the composition, adjusting the composition using the raw materials described in step (1) and taking samples for analysis again until all elements reach the expected indicators; (5) The melt C obtained in step (4) is subjected to a second refining treatment at 750°C for 20 minutes. After the second refining treatment, the melt C is allowed to stand, and then the slag is removed to obtain a melt D. Samples are taken from the melt D for analysis. If the composition is still within the expected index range, no treatment is required to proceed to the next step. If the composition deviates, the composition is adjusted until all elements reach the expected composition range before proceeding to the next step. (6) discharging the melt D obtained in step (5) from the bottom of the furnace for casting, wherein the melt D is subjected to double-stage filtration and then enters an automatic casting machine for casting to obtain a high-performance die-cast rare earth aluminum alloy without heat treatment; the first-stage filter plate of the double-stage filtration is 60 mesh, and the second-stage filter plate is 80 mesh; the temperature of the melt D out of the furnace is 640°C; The first refining treatment and the second refining treatment both use a mixed gas made by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99%, wherein high-purity argon accounts for 90%, high-purity nitrogen accounts for 9%, and high-purity chlorine accounts for 1%.

[0036] The application of the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment in die-cast products is to use the heat-treatment-free high-performance die-cast rare earth aluminum alloy to prepare die-castings, which specifically includes the following steps: S1. The heat-treatment-free high-performance die-cast rare earth aluminum alloy is placed in an aluminum melting furnace and stirred and remelted at 720° C. to obtain an alloy melt; in the refining, a mixed gas is used which is a mixture of 99.99% high-purity argon, 99.99% high-purity nitrogen and 99.99% high-purity chlorine, wherein the high-purity argon accounts for 90%, the high-purity nitrogen accounts for 9%, and the high-purity chlorine accounts for 1%; S2. Refining the alloy melt obtained in step S1 at 700°C for 30 minutes, then letting it stand and skimming off the slag, and then keeping the aluminum alloy melt warm at 660-670°C for standby use; using a robotic arm to transfer the alloy melt to a cold chamber die-casting machine for die-casting, and obtaining a die-casting after cooling; the die-casting refers to high-pressure die-casting, and the first-stage injection speed during the die-casting process is 0.1m / s, the second-stage injection speed is 0.2m / s, the third-stage injection speed is 2.5m / s, the die-casting pressure is 50MPa, and the pressure is maintained for 40 seconds.

[0037] Embodiment 5: A high-performance die-cast rare earth aluminum alloy without heat treatment, comprising the following chemical components in mass fractions: Mg: 6.2%, Si: 8.3%, Cu: 2.8%, Mn: 0.8%, Ta: 0.56%, Zr: 0.62%, Ag: 0.26%, Hf: 0.32%, Ti: 0.24%, Be0.0050%, Fe: 0.2%, the total content of rare earth elements is 1.2%, of which the rare earth elements are Ce, Y and Yb, and the ratio between the three rare earth elements is 6:4:2, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, and the balance is aluminum.

[0038] The method for preparing the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, wherein the raw materials include aluminum ingots, magnesium ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-beryllium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys; (2) placing aluminum ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys in a smelting furnace, and then stirring and smelting at 840° C. to obtain a melt A; the smelting time is 3 hours, and the stirring speed is 20 r / min; (3) The melt A obtained in step (2) is subjected to a first refining treatment at 760° C. for 60 minutes. After the first refining treatment, the melt A is allowed to stand and then slag is removed to obtain a melt B. (4) adding aluminum-beryllium master alloy to the melt B obtained in step (3), then stirring and smelting at 780° C., then adding magnesium ingot, stirring and smelting at 760° C. to obtain melt C, taking samples from melt C for chemical composition analysis, and if there is a deviation in the composition, adjusting the composition using the raw materials described in step (1) and taking samples for analysis again until all elements reach the expected indicators; (5) The melt C obtained in step (4) is subjected to a second refining treatment at 745°C for 40 minutes. After the second refining treatment, the melt C is allowed to stand, and then the slag is removed to obtain a melt D. Samples are taken from the melt D for analysis. If the composition is still within the expected index range, no treatment is required to proceed to the next step. If the composition deviates, the composition is adjusted until all elements reach the expected composition range before proceeding to the next step. (6) discharging the melt D obtained in step (5) from the bottom of the furnace for casting, wherein the melt D is subjected to double-stage filtration and then enters an automatic casting machine for casting to obtain a high-performance die-cast rare earth aluminum alloy without heat treatment; the first-stage filter plate of the double-stage filtration is 60 mesh, and the second-stage filter plate is 80 mesh; the temperature of the melt D out of the furnace is 740°C; The first refining treatment and the second refining treatment both use a mixed gas made by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99%, wherein high-purity argon accounts for 90%, high-purity nitrogen accounts for 9%, and high-purity chlorine accounts for 1%.

[0039] The application of the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment in die-cast products is to use the heat-treatment-free high-performance die-cast rare earth aluminum alloy to prepare die-castings, which specifically includes the following steps: S1. The heat-treatment-free high-performance die-cast rare earth aluminum alloy is placed in an aluminum melting furnace and stirred and remelted at 760° C. to obtain an alloy melt; in the refining, a mixed gas is used which is a mixture of 99.99% high-purity argon, 99.99% high-purity nitrogen and 99.99% high-purity chlorine, wherein the high-purity argon accounts for 90%, the high-purity nitrogen accounts for 9%, and the high-purity chlorine accounts for 1%; S2. Refining the alloy melt obtained in step S1 at 740°C for 10 minutes, then letting it stand and skimming off the slag, and then keeping the aluminum alloy melt warm at 720-740°C for standby use; using a robotic arm to transfer the alloy melt to a cold chamber die-casting machine for die-casting, and obtaining a die-casting after cooling; the die-casting refers to high-pressure die-casting, and during the die-casting process, the first-stage injection speed is 0.5m / s, the second-stage injection speed is 1.5m / s, the third-stage injection speed is 10m / s, the die-casting pressure is 100MPa, and the pressure is maintained for 10 seconds.

[0040] Embodiment 6: A high-performance die-cast rare earth aluminum alloy without heat treatment, comprising the following chemical components in mass fractions: Mg: 3.5%, Si: 5.3%, Cu: 1.8%, Mn: 0.38%, Ta: 0.36%, Zr: 0.42%, Ag: 0.12%, Hf: 0.22%, Ti: 0.14%, Be: 0.0032%, Fe: 0.18%, the total content of rare earth elements is 0.8%, of which the rare earth elements are Ce, Y and Yb, and the ratio between the three rare earth elements is 8:1:1, other unavoidable single impurity elements ≤0.03%, the total amount of impurity elements ≤0.15%, and the balance is aluminum.

[0041] The method for preparing the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment comprises the following steps: (1) weighing raw materials in proportion, wherein the raw materials include aluminum ingots, magnesium ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-beryllium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys; (2) placing aluminum ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys in a smelting furnace, and then stirring and smelting at 800° C. to obtain a melt A; the smelting time is 1 hour, and the stirring speed is 100 r / min; (3) The melt A obtained in step (2) is subjected to a first refining treatment at 758° C. for 50 minutes. After the first refining treatment, the melt is allowed to stand for 30 minutes, and then the melt is skimmed to obtain a melt B; (4) adding aluminum-beryllium master alloy to the melt B obtained in step (3), then stirring and melting at 760° C., then adding magnesium ingot, stirring and melting at 730° C. to obtain melt C, sampling from melt C for chemical composition analysis, and if there is a deviation in the composition, adjusting the composition using the raw materials described in step (1) and sampling again for analysis until all elements reach the expected indicators; (5) The melt C obtained in step (4) is subjected to a second refining treatment at 739° C. for 20 minutes. After the second refining treatment, the melt C is allowed to stand, and then the melt D is obtained by slagging. Samples are taken from the melt D for analysis. If the composition is still within the expected index range, no treatment is required to proceed to the next step. If the composition deviates, the composition is adjusted until all elements reach the expected composition range before proceeding to the next step. (6) discharging the melt D obtained in step (5) from the bottom of the furnace for casting, wherein the melt D is subjected to double-stage filtration and then enters an automatic casting machine for casting to obtain a high-performance die-cast rare earth aluminum alloy without heat treatment; the first-stage filter plate of the double-stage filtration is 60 mesh, and the second-stage filter plate is 80 mesh; the temperature of the melt D out of the furnace is 710°C; The first refining treatment and the second refining treatment both use a mixed gas made by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99%, wherein high-purity argon accounts for 90%, high-purity nitrogen accounts for 9%, and high-purity chlorine accounts for 1%.

[0042] The application of the heat-treatment-free high-performance die-cast rare earth aluminum alloy described in this embodiment in die-cast products is to use the heat-treatment-free high-performance die-cast rare earth aluminum alloy to prepare die-castings, which specifically includes the following steps: S1. The heat-treatment-free high-performance die-cast rare earth aluminum alloy is placed in an aluminum melting furnace and stirred and remelted at 750° C. to obtain an alloy melt; in the refining, a mixed gas is used, which is a mixture of 99.99% high-purity argon, 99.99% high-purity nitrogen and 99.99% high-purity chlorine, wherein the high-purity argon accounts for 90%, the high-purity nitrogen accounts for 9%, and the high-purity chlorine accounts for 1%; S2. Refining the alloy melt obtained in step S1 at 720°C for 20 minutes, then letting it stand and skimming off the slag, and then keeping the aluminum alloy melt warm at 700-720°C for standby use; using a robotic arm to transfer the alloy melt to a cold chamber die-casting machine for die-casting, and obtaining a die-casting after cooling; the die-casting refers to high-pressure die-casting, and during the die-casting process, the first-stage injection speed is 0.2m / s, the second-stage injection speed is 1.0m / s, the third-stage injection speed is 5.0m / s, the die-casting pressure is 86MPa, and the pressure is maintained for 20 seconds.

[0043] Comparative Example 1: Comparison is made with die castings produced using ADC12 alloy, the composition mass percentage of the ADC12 alloy is: Si: 10.8%, Mg: 0.23%, Cu: 1.6%, Mn: 0.36%, Zn: 0.43%, Ti: 0.04%, Fe: 0.89%, other unavoidable single impurity elements ≤ 0.03%, the total amount of impurity elements ≤ 0.15%, and the balance is aluminum. The die casting temperature of the ADC12 alloy is 650°C, the first-stage injection speed is 0.4m / s, the second-stage injection speed is 4.5m / s, the third-stage injection speed is 12.0m / s, the die casting pressure is 100MPa, and the die casting is obtained after cooling.

[0044] Comparative Example 2: A die casting produced by A380 alloy is used for comparison. The mass percentage of the A380 alloy composition is: Si: 8.3%, Mg: 0.03%, Cu: 3.2%, Mn: 0.46%, Ni: 0.32%, Zn: 1.6%, Ti: 0.03%, Fe: 0.87%, other unavoidable single impurity elements ≤ 0.03%, the total amount of impurity elements ≤ 0.15%, and the balance is aluminum. The die casting temperature of the A380 alloy is 670°C, the first-stage injection speed is 0.4m / s, the second-stage injection speed is 4.5m / s, the third-stage injection speed is 12.0m / s, the die casting pressure is 100MPa, and the die casting is obtained after cooling.

[0045] Comparative Example 3: The heat treatment-free high-performance die-cast rare earth aluminum alloy described in this comparative example is different from the aluminum alloy described in Example 1 only in that Ce is not added to the aluminum alloy composition.

[0046] Comparative Example 4: The heat treatment-free high-performance die-cast rare earth aluminum alloy described in this comparative example is different from the aluminum alloy described in Example 1 only in that Y is not added to the aluminum alloy composition.

[0047] Comparative Example 5: The heat treatment-free high-performance die-cast rare earth aluminum alloy described in this comparative example is different from the aluminum alloy described in Example 1 only in that Yb is not added to the aluminum alloy composition.

[0048] Experimental Example 1: Die castings were prepared according to the methods described in Examples 1 to 6 and Comparative Examples 1 to 5, and then mechanical properties were tested to examine their yield strength, tensile strength, and elongation after fracture. The results are shown in Table 1.

[0049] Table 1 Mechanical properties test results

[0050] It can be seen from Table 1 that the mechanical properties and plasticity of the die castings obtained by the present invention are better than those of the die castings prepared using ADC12 and A380 alloys, and have excellent performance.

[0051] Experimental Example 2: Aluminum alloy materials were prepared according to the methods described in Examples 1 to 6 and Comparative Examples 1 to 5, and the crystal structure and lattice parameters of the aluminum alloy materials were detected. The results are shown in Table 2.

[0052] Table 2 Test results of aluminum alloy materials

[0053] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high-performance die-cast rare earth aluminum alloy without heat treatment, characterized in that: The chemical components include the following mass fractions: Mg: 3.0-6.2%, Si: 2.0-8.3%, Cu: 1.0-2.8%, Mn: 0.13-0.8%, Ta: 0.03-0.56%, Zr: 0.03-0.62%, Ag: 0.01-0.26%, Hf: 0.01-0.32%, Ti: 0.01-0.24%, Be: 0.0001-0.0050%, Fe≤0.2%, total rare earth element content 0.1-1.2%, of which rare earth elements are Ce, Y and Yb, other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, balance is aluminum.

2. The heat treatment-free high-performance die-cast rare earth aluminum alloy according to claim 1, characterized in that: The heat treatment-free high-performance die-cast rare earth aluminum alloy comprises the following chemical components in mass fraction: Mg: 3.2-6.0%, Si: 2.2-7.5%, Cu: 1.5-2.5%, Mn: 0.2-0.7%, Ta: 0.10-0.45%, Zr: 0.10-0.50%, Ag: 0.05-0.20%, Hf: 0.05-0.26%, Ti: 0.02-0.16%, Be: 0.0005-0.0040%, Fe≤0.12%, total rare earth element content 0.1-1.0%, of which rare earth elements are Ce, Y and Yb, and the ratio between the three rare earth elements is (4-6):(2-4):(1-2), other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, and the balance is aluminum.

3. The method for preparing a heat-treatment-free high-performance die-cast rare earth aluminum alloy as claimed in claim 1 or 2, characterized in that: The following steps are involved: (1) weighing raw materials in proportion, wherein the raw materials include aluminum ingots, magnesium ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-beryllium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys; (2) placing aluminum ingots, industrial silicon, copper ingots, aluminum-manganese master alloys, aluminum-tantalum master alloys, aluminum-zirconium master alloys, aluminum-silver master alloys, aluminum-hafnium master alloys, aluminum-titanium master alloys, aluminum-cerium master alloys, aluminum-yttrium master alloys, and aluminum-ytterbium master alloys in a melting furnace, and then stirring and melting at 760-840° C. to obtain a melt A; (3) subjecting the melt A obtained in step (2) to a first refining treatment at 740-800° C. for 30-60 minutes, allowing the melt to stand after the first refining treatment, and then skimming off the slag to obtain a melt B; (4) adding aluminum-beryllium master alloy to the melt B obtained in step (3), then stirring and smelting at 720-780° C., then adding magnesium ingot, stirring and smelting at 700-760° C. to obtain melt C, sampling from melt C for chemical composition analysis, and if there is a deviation in the composition, adjusting the composition using the raw materials described in step (1) and sampling again for analysis until all elements reach the expected indicators; (5) The melt C obtained in step (4) is subjected to a second refining treatment at 720-760° C. for 20-40 minutes. After the second refining treatment, the melt C is allowed to stand, and then the slag is removed to obtain a melt D. Samples are taken from the melt D for analysis. If the composition is still within the expected index range, no treatment is required to proceed to the next step. If the composition deviates, the composition is adjusted until all elements reach the expected composition range before proceeding to the next step. (6) The melt D obtained in step (5) is discharged from the bottom of the furnace for casting, wherein the melt D is subjected to double-stage filtration treatment and then enters an automatic casting machine for casting to obtain a high-performance die-cast rare earth aluminum alloy without heat treatment.

4. The method for preparing the heat treatment-free high-performance die-cast rare earth aluminum alloy according to claim 3, characterized in that: In step (2), the smelting time is 1 to 4 hours, and the stirring speed is 20 to 100 r / min.

5. The method for preparing the heat treatment-free high-performance die-cast rare earth aluminum alloy according to claim 3, characterized in that: The first refining treatment and the second refining treatment both use a mixed gas made by mixing high-purity argon with a concentration of 99.99%, high-purity nitrogen with a concentration of 99.99% and high-purity chlorine with a concentration of 99.99%, wherein high-purity argon accounts for 90%, high-purity nitrogen accounts for 9%, and high-purity chlorine accounts for 1%.

6. The method for preparing the heat treatment-free high-performance die-cast rare earth aluminum alloy according to claim 3, characterized in that: In step (6), the first filter plate of the double-stage filtration is 60 mesh, and the second filter plate is 80 mesh; the furnace temperature of the melt D is 640-740°C.

7. Application of the heat-treatment-free high-performance die-cast rare earth aluminum alloy as claimed in claim 1 or 2 in die-cast products, characterized in that: The method of preparing a die casting using the heat treatment-free high-performance die-cast rare earth aluminum alloy specifically comprises the following steps: S1, placing the heat treatment-free high-performance die-cast rare earth aluminum alloy into an aluminum melting furnace, stirring and remelting at 720-760° C. to obtain an alloy melt; S2. Refining the alloy melt obtained in step S1 at 700-740° C. for 10-30 minutes, then letting it stand and removing slag, and then keeping the aluminum alloy melt warm at 660-740° C. for standby use; transferring the alloy melt to a cold chamber die-casting machine by a robotic arm for die-casting, and obtaining a die-casting after cooling.

8. The use of the heat-treatment-free high-performance die-cast rare earth aluminum alloy in die-cast products according to claim 7, characterized in that: In step S1, a mixed gas prepared by mixing high-purity argon gas with a concentration of 99.99%, high-purity nitrogen gas with a concentration of 99.99% and high-purity chlorine gas with a concentration of 99.99% is used in the refining, wherein the high-purity argon gas accounts for 90%, the high-purity nitrogen gas accounts for 9%, and the high-purity chlorine gas accounts for 1%.

9. The use of the heat-treatment-free high-performance die-cast rare earth aluminum alloy in die-cast products according to claim 7, characterized in that: In step S2, the die casting refers to high-pressure die casting. During the die casting process, the first-stage injection speed is 0.1-0.5 m / s, the second-stage injection speed is 0.2-1.5 m / s, the third-stage injection speed is 2.5-10 m / s, the die casting pressure is 50-100 MPa, and the pressure is maintained for 10-40 seconds.

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