Heat-treatment-free die-cast aluminum alloy and preparation method and application thereof

Abstract

To provide a heat-treatment-free die-cast aluminum alloy that improves the strength of the alloy and a preparation method and application thereof.SOLUTION: A heat-treatment-free die-cast aluminum alloy includes: 10.0 to 12.0 wt % of Si, 0.9 to 1.5 wt % of Mg, 2.5 to 3.5 wt % of Cu, 0.4 to 0.8 wt % of Mn, 0.9 to 1.5 wt % of Zn, 0.1 to 0.2 wt % of Ti, 0.03 to 0.06 wt % of Sr, 0.18 wt % or less of Fe, 0.15 wt % or less of a rare earth element, 0.1 wt % or less of an impurity element, and a balance of Al, based on a total weight of the die-cast aluminum alloy. The rare earth elements are Sm and / or Y.EFFECT: The heat-treatment-free die-cast aluminum alloys of the present disclosure have significantly improved ultimate tensile strength and yield strength compared with existing alloys for automotive structural members and therefore are suitable for producing high-strength and lightweight motor structural members of a new energy electric automobile.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to the technical field of die-casting aluminum alloys, and in particular to a die-casting aluminum alloy that does not require heat treatment and its manufacturing method and applications. [Background technology]

[0002] Aluminum alloys are widely used in motor die-casting housings due to their low density, high thermal conductivity and excellent flow properties. At present, the most widely used die-casting aluminum alloy material in the industry is the Al-Si-Cu alloy, which has excellent casting performance and good mechanical properties. In high-power motors, the balance disk is subjected to large tensile stress, and stresses of more than 300 MPa may occur locally. At the same time, an elongation rate of ≥ 1% is required. If ordinary materials are used, the thickness must be increased to meet the use requirements of castings with high strength requirements, such as the balance disk of the motor of new energy vehicles and the end cover of the resolver. High-performance aluminum alloy materials such as AlSi10MnMg and AlMg5Si2 can obtain excellent mechanical properties by controlling the content of alloy elements and the heat treatment process, but such alloys need to be made of high-purity new materials, which are expensive, and for large and complex die-casting parts, heat treatment will cause local deformation in the uneven thickness of the die-casting parts due to the quenching process, which will require finishing processing, which will take time and effort. At present, all the die-casting aluminum alloy materials in the related art have disadvantages such as low strength and low weight reduction effect. Summary of the Invention [Problem to be solved by the invention]

[0003] The present disclosure aims to provide a die-cast aluminum alloy that does not require heat treatment and that improves the strength of the die-cast aluminum alloy, as well as a manufacturing method and uses thereof. [Means for solving the problem]

[0004] In order to achieve the above object, a first aspect of the present disclosure provides a die-cast aluminum alloy that does not require heat treatment, the die-cast aluminum alloy containing, based on a total weight of the die-cast aluminum alloy, 10.0 to 12.0 wt.% Si, 0.9 to 1.5 wt.% Mg, 2.5 to 3.5 wt.% Cu, 0.4 to 0.8 wt.% Mn, 0.9 to 1.5 wt.% Zn, 0.1 to 0.2 wt.% Ti, 0.03 to 0.06 wt.% Sr, 0.18 wt.% or less Fe, 0.15 wt.% or less rare earth elements, 0.1 wt.% or less other impurity elements, and the balance Al, wherein the rare earth elements are Sm and / or Y.

[0005] Optionally, based on the total weight of the die cast aluminum alloy, the die cast aluminum alloy comprises 10.0 to 12.0 wt.% Si, 1.0 to 1.4 wt.% Mg, 3.0 to 3.3 wt.% Cu, 0.03 to 0.06 wt.% Y, 0.03 to 0.06 wt.% Sm, 0.4 to 0.55 wt.% Mn, 0.9 to 1.5 wt.% Zn, 0.1 to 0.2 wt.% Ti, 0.03 to 0.06 wt.% Sr, 0.12 to 0.16 wt.% Fe, 0.05 wt.% or less of other impurity elements, and the balance Al.

[0006] Optionally, the weight ratio of Sm to Y is (0.8 to 1.2):1, and the weight ratio of Mg to Cu is (0.32 to 0.45):1.

[0007] Optionally, the die cast aluminum alloy has a yield strength of 240 to 280 MPa, an ultimate tensile strength of 330 to 380 MPa, and an elongation of 1 to 4%.

[0008] A second aspect of the present disclosure provides a method for producing a die-cast aluminum alloy not requiring heat treatment according to the first aspect of the present disclosure, the method including the steps of melting aluminum in a smelting furnace, adding silicon, a Zn raw material, a Cu raw material, and a Mn raw material to perform a first smelting to obtain a first molten metal, performing a refining process and a slag removal process on the first molten metal to obtain a second molten metal, adding a Ti raw material, a Sr raw material, a rare earth raw material, and a Mg raw material to the second molten metal to perform a second smelting to obtain a molten aluminum alloy, and then performing component detection after the component detection has passed, to obtain a third molten metal, wherein the rare earth raw material includes a Sm raw material and / or a Y raw material, performing a degassing process on the third molten metal to obtain a fourth molten metal, and performing component detection on the fourth molten metal, and performing high-pressure die casting after the fourth molten metal has passed the component detection, to obtain a die-cast aluminum alloy not requiring heat treatment.

[0009] Selectively, the Zn raw material is an Al-Zn based alloy, the Cu raw material is an Al-Cu based alloy, the Mn raw material is an Al-Mn based alloy, the Ti raw material is an Al-Ti based alloy, the Sr raw material is an Al-Sr based alloy, the Sm raw material is an Al-Sm based alloy, the Mg raw material is a magnesium ingot and / or an Mg-Y based alloy, and the Y raw material is an Mg-Y based alloy and / or an Al-Y based alloy.

[0010] Optionally, the Al-Zn based alloy is an Al-10Zn intermediate alloy, the Al-Cu based alloy is an Al-50Cu intermediate alloy, the Al-Mn based alloy is an Al-20Mn intermediate alloy, the Al-Ti based alloy is an Al-5Ti intermediate alloy, the Al-Sr based alloy is an Al-5Sr intermediate alloy, the Al-Sm based alloy is an Al-20Sm intermediate alloy, and the Mg-Y based alloy is an Mg-30Y intermediate alloy.

[0011] Optionally, the temperature of the first smelt is from 770 to 790°C and the temperature of the second smelt is from 750 to 760°C.

[0012] Optionally, the refining process includes: introducing an inert gas atmosphere or nitrogen containing a refining agent powder into the first molten metal to perform a first refining process; and after an interval of 50 to 60 minutes, again introducing the inert gas atmosphere or nitrogen containing the refining agent powder to perform a second refining process; the temperatures of the first refining and the second refining are 750 to 760°C, respectively, the inert gas is argon gas; and the conditions of the degassing process include a temperature of 750 to 760°C and a time of 10 to 15 minutes.

[0013] Optionally, the high pressure die casting conditions include: die casting temperature is 690 to 700°C, pressure is 35 to 40MPa, high speed position is 220 to 230mm, injection time is 6 to 8s, cooling time is 8 to 10s, and thickness of die casting mold is 3 to 7mm.

[0014] A third aspect of the present disclosure provides an automotive body structural component comprising the heat treatment-free die-cast aluminum alloy according to the first aspect of the present disclosure. Effect of the Invention

[0015] According to the above technical solution, the heat treatment-free die-casting aluminum alloy provided by the present disclosure has significantly improved ultimate tensile strength and yield strength compared with conventional alloys for automobile structural parts, and is suitable for manufacturing high-strength and lightweight motor structural parts for new energy electric vehicles.

[0016] Other features and advantages of the present disclosure are described in detail in the Detailed Description section below. The drawings are provided for a further understanding of the present disclosure, constitute a part of the specification, and, together with the following detailed description, are used to explain the present disclosure and are not intended to limit the disclosure. [Brief description of the drawings]

[0017] [Figure 1] 1 shows a process flow chart of the manufacturing method of the present disclosure of a heat treatment-free die-cast aluminum alloy. [Diagram 2]1 shows stress-strain graphs of aluminum alloy castings of Examples 1 and 2 of the present disclosure and Comparative Examples 1 and 2. [Diagram 3] FIG. 1 shows an exploded view of a structure in which the heat treatment-free die-cast aluminum alloy of the present disclosure is used for a motor balance disk. [Figure 4] 1 shows a sample of a flat mold in an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, specific embodiments of the present disclosure will be described in detail in conjunction with the drawings. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present disclosure and are not intended to limit the present disclosure.

[0019] A first aspect of the present disclosure provides a heat treatment-free die cast aluminum alloy, the die cast aluminum alloy comprising, based on a total weight of the die cast aluminum alloy, 10.0 to 12.0 wt. % Si (silicon), 0.9 to 1.5 wt. % Mg (magnesium), 2.5 to 3.5 wt. % Cu (copper), 0.4 to 0.8 wt. % Mn (manganese), 0.9 to 1.5 wt. % Zn (zinc), 0.1 to 0.2 wt. % Ti (titanium), 0.03 to 0.06 wt. % Sr (strontium), 0.18 wt. % or less Fe (iron), 0.15 wt. % or less rare earth elements, 0.1 wt. % or less other impurity elements, and the balance Al (aluminum), the rare earth elements being Sm (samarium) and / or Y (yttrium).

[0020] The present disclosure obtains a high-strength aluminum alloy by controlling the content of each element in the alloy, especially the content of Si, Mg, and Cu, and adding rare earth elements Y and / or Sm, which can obtain excellent mechanical properties without heat treatment, and the ultimate tensile strength and yield strength are significantly improved compared with conventional automotive electric drive structural component alloys.

[0021] In the heat treatment-free die-cast aluminum alloy disclosed herein, the addition of Si element can improve the casting fluidity and corrosion resistance of the alloy, play a role in solid solution strengthening, and can form a hypoeutectic alloy when the Si content is 10.0 to 12.0 wt%. Mg element, as an important aging strengthening element in Si-containing aluminum alloys, can form new heterogeneous crystal nuclei with Si to form Mg2Si phase, contribute to the refinement of crystals, and significantly contribute to the improvement of yield strength. Cu element can form θ(CuAl2) with Al, and is an important strengthening element in aluminum alloys. The addition of Fe element can improve the sticking phenomenon of die-cast aluminum alloys to the mold, and an Fe content of 0.18 wt% or less contributes to the reduction of the formation of needle-shaped β-Al5FeSi phase, avoiding the hindrance of metal flow. The addition of Mn element can interact with the iron-containing phase hardened by quenching, reduce the harm of the Fe phase, and improve the heat resistance and denseness of the aluminum alloy, contributing to the improvement of the mold release property of the aluminum alloy. The addition of Zn element contributes to solid solution strengthening and improvement of fluidity. The addition of Ti element increases the nucleation of primary crystal (Al) particles and contributes to realizing grain refinement, but if the content is too high, the nucleation particles become coarse, the refinement effect is weakened, and the performance is reduced. The addition of Sr element can change eutectic Si from lamellar to fine grain, improving the plasticity of aluminum alloy. The addition of rare earth elements can form stable intermetallic compounds with Al, contributing to the refinement of the structure and playing a metamorphic effect, as well as reducing the hydrogen content in the molten metal, and playing the role of refining, purifying, and alloying. In particular, the synergistic effect of Sm and Y elements can greatly refine the microstructure of the alloy, not only changing the primary crystal α-Al from dendritic crystals to fine cellular crystals or equiaxed crystals, but also changing the lump eutectic silicon into fine fibrous or granular.

[0022] In an exemplary embodiment of the present disclosure, based on the total weight of the die-casting aluminum alloy, the die-casting aluminum alloy includes 10.0 to 12.0 wt% Si, 1.0 to 1.4 wt% Mg, 3.0 to 3.3 wt% Cu, 0.03 to 0.06 wt% Y, 0.03 to 0.06 wt% Sm, 0.4 to 0.55 wt% Mn, 0.9 to 1.5 wt% Zn, 0.1 to 0.2 wt% Ti, 0.03 to 0.06 wt% Sr, 0.12 to 0.16 wt% Fe, 0.05 wt% or less of other impurity elements, and the balance Al. The above blending ratio contributes to further improving the strength of the die-casting aluminum alloy.

[0023] In a preferred embodiment, the weight ratio of Sm to Y is (0.8 to 1.2):1, and the weight ratio of Mg to Cu is (0.32 to 0.45):1, and the above blending ratios contribute to further improving the strength of the die-cast aluminum alloy.

[0024] According to the present disclosure, the die-cast aluminum alloy can have a yield strength of 240 to 280 MPa, an ultimate tensile strength of 330 to 380 MPa, and an elongation of 1 to 4%, for example 1.1 to 2.5%. The heat-treatment-free die-cast aluminum alloy of the present disclosure meets the performance requirements for structural parts in the automotive industry and is suitable for manufacturing high-strength and lightweight motor structural parts for new energy electric vehicles.

[0025] A second aspect of the present disclosure provides a method for producing a die-cast aluminum alloy that does not require heat treatment, and refers to FIG. 1 . The method includes the steps of melting aluminum in a smelting furnace, adding silicon, a Zn raw material, a Cu raw material, and a Mn raw material to perform a first smelting to obtain a first molten metal, performing a refining process and a slag removal process on the first molten metal to obtain a second molten metal, adding magnesium, a Ti raw material, a Sr raw material, a rare earth raw material, and a Mg raw material to the second molten metal to perform a second smelting to obtain a molten aluminum alloy, and then performing a component detection after the component detection is passed to obtain a third molten metal, where the rare earth raw material includes a Sm raw material and / or a Y raw material, performing a degassing process on the third molten metal to obtain a fourth molten metal, and performing a component detection on the fourth molten metal, and performing a high-pressure die casting after the component detection is passed to obtain a die-cast aluminum alloy that does not require heat treatment.

[0026] The manufacturing method of the present disclosure for die-casting aluminum alloys that does not require heat treatment can obtain excellent performance without heat treatment processes, which not only solves the problems of deformation and bubbles in castings caused by heat treatment, but also helps to simplify the integrated die-casting process and improve yields.

[0027] According to the present disclosure, the Zn raw material may be an Al-Zn based alloy, the Cu raw material may be an Al-Cu based alloy, the Mn raw material may be an Al-Mn based alloy, the Ti raw material may be an Al-Ti based alloy, the Sr raw material may be an Al-Sr based alloy, the Sm raw material may be an Al-Sm based alloy, the Mg raw material may be a magnesium ingot and / or an Mg-Y based alloy, and the Y raw material may be an Al-Y based alloy and / or an Mg-Y based alloy.

[0028] In one exemplary embodiment of the present disclosure, the Al-Zn based alloy is an Al-10Zn intermediate alloy, the Al-Cu based alloy is an Al-50Cu intermediate alloy, the Al-Mn based alloy is an Al-20Mn intermediate alloy, the Al-Ti based alloy is an Al-5Ti intermediate alloy, the Al-Sr based alloy is an Al-5Sr intermediate alloy, the Al-Sm based alloy is an Al-20Sm intermediate alloy, and the Mg-Y based alloy is an Mg-30Y intermediate alloy.

[0029] According to the present disclosure, the temperature of the first smelting may be 770 to 790°C and the temperature of the second smelting may be 750 to 760°C.

[0030] According to the present disclosure, the refining process may include introducing an inert gas atmosphere or nitrogen containing a refining agent powder into the first molten metal to perform the first refining, and then after an interval of 50 to 60 minutes, introducing an inert gas atmosphere or nitrogen containing a refining agent powder again to perform the second refining, the temperature of the first refining and the second refining are 750 to 760°C, respectively, and the inert gas is argon gas. Here, the refining agent powder may be a refining agent specifically for aluminum alloys commonly found in the art, and the type and amount of use are not limited in the present disclosure. The slag removal process may be a conventional method in the art, for example, the specific operation of the slag removal process may be manual slag removal using a ferrous slag removal tool, and the slag removal process is allowed to stand to obtain the second molten metal.

[0031] According to the present disclosure, the conditions of the degassing treatment include performing the degassing treatment using an inert gas (argon gas) atmosphere or nitrogen at a temperature of 750 to 760° C. for a time of 10 to 15 minutes. After the degassing treatment, the mixture is left to stand for 20 to 30 minutes to obtain a fourth molten metal.

[0032] According to the present disclosure, the conditions of high pressure die casting may include: die casting temperature is 690 to 700°C, pressure is 35 to 40 MPa, high speed position is 220 to 230 mm, injection time is 6 to 8 s, cooling time is 8 to 10 s, and thickness of die casting mold is 3 to 7 mm.

[0033] A third aspect of the present disclosure provides an automobile body structural part comprising a die-cast aluminum alloy, the die-cast aluminum alloy being the die-cast aluminum alloy not requiring heat treatment described above, or the die-cast aluminum alloy not requiring heat treatment produced by the production method described above.

[0034] Furthermore, the automobile body structural part may be a motor structural part of a new energy automobile, specifically, a balance disk and / or an end cover of a resolver. Referring to FIG. 3, a first balance disk 2, a rotor 3, and a second balance disk 4 are sequentially attached to a rotor shaft 1, and each of the first balance disk 2 and the second balance disk 4 may include the heat-treatment-free die-cast aluminum alloy of the present disclosure. When the heat-treatment-free die-cast aluminum alloy of the present disclosure is used to manufacture a high-strength motor balance disk of a new energy automobile and an end cover of a resolver, the development needs of the new energy automobile, such as weight reduction and high output torque, can be met. Specifically, not only can weight reduction be achieved by a local thin-wall design, but the stress on the balance disk and the end cover of the resolver also increases with the increase in torque, and the heat-treatment-free die-cast aluminum alloy of the present disclosure can meet the strength performance required for high output and high torque. In addition, the die-cast aluminum alloy of the present disclosure can meet the requirement of high strength without heat treatment, which contributes to improving manufacturing efficiency, reducing manufacturing costs, and further reducing carbon emissions.

[0035] The present invention will now be described in more detail with reference to the following examples. The raw materials used in the examples are commercially available.

[0036] The manufacturing methods of the aluminum alloys according to the examples and comparative examples specifically include a raw material blending step, an alloy smelting step, a refining and slag removal step, an alloy adding step, a furnace degassing step, and a high-pressure die casting step. 0) In the raw material blending step, raw materials are blended based on the blending ratio of the components to prepare an aluminum ingot, industrial silicon, a magnesium ingot, an Al-10Zn intermediate alloy, an Al-50Cu intermediate alloy, an Al-20Mn intermediate alloy, an Al-5Ti intermediate alloy, an Al-5Sr intermediate alloy, an Al-20Sm intermediate alloy, and an Mg-30Y intermediate alloy. 1) In the alloy smelting step, firstly, the aluminum ingot is put into the furnace and smelted, and the smelting temperature is controlled at 680 to 690°C. After the aluminum ingot is completely melted, the temperature is increased and the temperature is controlled at 770 to 790°C. Then, industrial silicon, Al-10Zn intermediate alloy, Al-50Cu intermediate alloy, and Al-20Mn intermediate alloy are added to perform the first smelting to obtain the first molten metal. 2) In the refining and slag removal step, the temperature is maintained at 750 to 760°C, a refining agent specially for aluminum alloys is added to perform the first powder spray refining, and a rotary jet device is used to introduce high-purity nitrogen containing refining agent powder into the first molten metal to perform the second refining, and the high-purity N2 is supplied at a pressure of 0.5±0.1MPa and a flow rate of 2.0±0.1m 3 / h, and after refining, the slag is removed and the mixture is allowed to stand to obtain the second molten metal. 3) In the alloy addition step, magnesium ingot, Al-5Ti intermediate alloy, Al-5Sr intermediate alloy, Al-20Sm intermediate alloy, and Mg-30Y intermediate alloy are added to the second molten metal to perform the second smelting, and when the molten metal temperature is 750 to 760°C, the aluminum alloy molten metal is obtained, and then sampled and analyzed. After passing the component detection, the third molten metal is obtained. 4) In the in-furnace degassing step, the smelting temperature is maintained at 750 to 760°C, and in-furnace degassing is performed using high-purity nitrogen, the degassing time is about 15 minutes, and then the smelting is allowed to stand for 20 to 30 minutes to obtain a fourth molten metal. 5) In the high pressure die casting step, the fourth molten metal is subjected to component detection. After passing the component detection, high pressure casting is performed when the temperature of the molten aluminum is 690 to 700°C, and a die-cast aluminum alloy that does not require heat treatment is obtained. A LiJing DCC500 model die casting machine is used, and the die casting mold is a flat mold (see Figure 4) with a reactive electric drive balance disk thickness of 3 mm, the die casting pressure is 40 MPa, the high speed position is 230 mm, the injection time is 8 s, and the cooling time is 8 s.

[0037] Example 1 The chemical composition of the die-cast aluminum alloy produced in this embodiment, which does not require heat treatment, is 10.45 wt% Si, 0.13 wt% Fe, 3.03 wt% Cu, 0.50 wt% Mn, 1.00 wt% Mg, 1.01 wt% Zn, 0.16 wt% Ti, 0.048 wt% Sr, 0.049 wt% Y, 0.053 wt% Sm, 0.05 wt% or less of other impurity elements, and the balance Al, with the weight ratio of Sm to Y being 1.1 and the weight ratio of Mg to Cu being 0.33.

[0038] Example 2 The chemical composition of the die-cast aluminum alloy produced in this embodiment, which does not require heat treatment, is 10.26 wt% Si, 0.15 wt% Fe, 3.25 wt% Cu, 0.50 wt% Mn, 1.09 wt% Mg, 1.05 wt% Zn, 0.14 wt% Ti, 0.044 wt% Sr, 0.054 wt% Y, 0.049 wt% Sm, 0.05 wt% or less of other impurity elements, and the balance Al, with the weight ratio of Sm to Y being 0.9 and the weight ratio of Mg to Cu being 0.34.

[0039] Example 3 The chemical composition of the die-cast aluminum alloy produced in this embodiment, which does not require heat treatment, is 10.30 wt% Si, 0.16 wt% Fe, 3.22 wt% Cu, 0.51 wt% Mn, 1.39 wt% Mg, 1.05 wt% Zn, 0.15 wt% Ti, 0.042 wt% Sr, 0.052 wt% Y, 0.049 wt% Sm, 0.05 wt% or less of other impurity elements, and the balance Al, with the weight ratio of Sm to Y being 0.9 and the weight ratio of Mg to Cu being 0.43.

[0040] Example 4 The chemical composition of the die-cast aluminum alloy that does not require heat treatment produced in this embodiment is 10.28 wt% Si, 0.16 wt% Fe, 3.01 wt% Cu, 0.49 wt% Mn, 1.39 wt% Mg, 1.02 wt% Zn, 0.16 wt% Ti, 0.042 wt% Sr, 0.037 wt% Y, 0.051 wt% Sm, 0.05 wt% or less of other impurity elements, and the remainder Al, with the weight ratio of Sm to Y being 1.4 and the weight ratio of Mg to Cu being 0.46.

[0041] Example 5 The chemical composition of the die-cast aluminum alloy produced in this embodiment, which does not require heat treatment, is 10.09 wt% Si, 0.12 wt% Fe, 3.30 wt% Cu, 0.55 wt% Mn, 1.01 wt% Mg, 1.06 wt% Zn, 0.12 wt% Ti, 0.045 wt% Sr, 0.046 wt% Y, 0.031 wt% Sm, 0.05 wt% or less of other impurity elements, and the balance Al, with the weight ratio of Sm to Y being 0.7 and the weight ratio of Mg to Cu being 0.31.

[0042] Example 6 The chemical composition of the die-cast aluminum alloy produced in this embodiment, which does not require heat treatment, is 10.04 wt% Si, 0.10 wt% Fe, 2.66 wt% Cu, 0.67 wt% Mn, 1.46 wt% Mg, 1.07 wt% Zn, 0.12 wt% Ti, 0.044 wt% Sr, 0.014 wt% Y, 0.027 wt% Sm, 0.05 wt% or less of other impurity elements, and the balance Al, with the weight ratio of Sm to Y being 1.92 and the weight ratio of Mg to Cu being 0.55.

[0043] Example 7 The chemical composition of the die-cast aluminum alloy that does not require heat treatment produced in this embodiment is 10.30 wt% Si, 0.17 wt% Fe, 2.52 wt% Cu, 0.56 wt% Mn, 0.97 wt% Mg, 1.24 wt% Zn, 0.13 wt% Ti, 0.051 wt% Sr, 0.062 wt% Y, 0.081 wt% Sm, 0.05 wt% or less of other impurity elements, and the balance Al, with the weight ratio of Sm to Y being 1.31 and the weight ratio of Mg to Cu being 0.38.

[0044] Comparative Example 1 The die-cast aluminum alloy in this comparative example is the commonly used ADC12, whose chemical composition is 10.31 wt% Si, 0.80 wt% Fe, 2.30 wt% Cu, 0.26 wt% Mn, 0.18 wt% Mg, 0.84 wt% Zn, 0.03 wt% Ti, 0.02 wt% Sr, 0.05 wt% or less of other impurity elements, and the balance Al.

[0045] Comparative Example 2 The die-cast aluminum alloy in this comparative example is the commonly used A380, and its chemical composition is 8.51 wt% Si, 1.03 wt% Fe, 3.06 wt% Cu, 0.17 wt% Mn, 0.03 wt% Mg, 0.21 wt% Zn, 0.07 wt% Ti, 0.05 wt% or less of other impurity elements, and the balance Al.

[0046] Comparative Example 3 The chemical composition of the die-cast aluminum alloy that did not require heat treatment produced in this comparative example was 10.49 wt% Si, 0.13 wt% Fe, 3.08 wt% Cu, 0.51 wt% Mn, 1.08 wt% Mg, 1.07 wt% Zn, 0.14 wt% Ti, 0.05 wt% Sr, 0.051 wt% Sm, 0.05 wt% or less of other impurity elements, and the balance Al.

[0047] Comparative Example 4 The chemical composition of the die-cast aluminum alloy that did not require heat treatment produced in this comparative example was 10.45 wt% Si, 0.13 wt% Fe, 3.06 wt% Cu, 0.53 wt% Mn, 1.06 wt% Mg, 1.01 wt% Zn, 0.16 wt% Ti, 0.048 wt% Sr, 0.052 wt% Y, 0.05 wt% or less of other impurity elements, and the balance Al.

[0048] Comparative Example 5 The chemical composition of the die-cast aluminum alloy that did not require heat treatment produced in this comparative example was 9.50 wt% Si, 0.12 wt% Fe, 2.49 wt% Cu, 0.50 wt% Mn, 1.00 wt% Mg, 1.60 wt% Zn, 0.15 wt% Ti, 0.035 wt% Sr, 0.083 wt% Sm, 0.05 wt% or less of other impurity elements, and the balance Al.

[0049] Comparative Example 6 The heat treatment-free die-cast aluminum alloy and manufacturing method of this comparative example refer to Example 6 of CN105463269A, and its chemical composition is 15 wt% Si, 1 wt% Fe, 0.5 wt% Cu, 1 wt% Mn, 0.6 wt% Mg, 1 wt% Zn, 0.1 wt% Sr, 0.15 wt% Gd, 0.15 wt% La, 0.13 wt% Y, 0.12 wt% Nd, 0.2 wt% Sm, 0.1 wt% Er, 0.2 wt% Yb, with the remainder being Al and unavoidable impurities.

[0050] Comparative Example 7 The chemical composition of the die-cast aluminum alloy produced in this comparative example, which does not require heat treatment, is 10.45% by weight Si, 0.13% by weight Fe, 3% by weight Cu, 0.50% by weight Mn, 0.5% by weight Mg, 0.16% by weight Ti, a total of less than 1% by weight of mixed rare earths La, Ce, Sm, and Nd (each of the elements La, Ce, Sm, and Nd is less than 0.35% by weight), less than 0.01% by weight of other impurity elements, and the balance Al.

[0051] Comparative Example 8 The chemical composition of the die-cast aluminum alloy that did not require heat treatment produced in this comparative example was 8.5 wt.% Si, 0.14 wt.% Fe, 2.0 wt.% Cu, 0.54 wt.% Mn, 1.5 wt.% Mg, 0.72 wt.% Zn, 0.08 wt.% Ti, 0.14 wt.% Zr, 0.03 wt.% Sr, 0.01 wt.% or less of other impurity elements, and the balance Al.

[0052] Table 1 below shows the components (unit: weight %) of the die-cast aluminum alloys produced in Examples 1 to 7 and Comparative Examples 1 to 5.

[0053] [Table 1]

[0054] (Test Example 1) Mechanical performance testing was carried out on the aluminum alloy castings produced in the examples and comparative examples. The test method referred to GB / T228.1, the strain before yielding was controlled to 0.00025 / s, and the displacement strain after yielding was controlled to 0.001 / s. The test results are shown in Table 2.

[0055] [Table 2]

[0056] As can be seen from Table 2 above, compared with conventional aluminum alloy castings, the aluminum alloy castings disclosed herein have significantly improved yield strength and ultimate tensile strength, and the die-cast aluminum alloys disclosed herein can be used to manufacture motor structural parts for new energy vehicles, and the thin-walled design can effectively realize lightweight construction.

[0057] The above describes in detail preferred embodiments of the present disclosure in conjunction with the drawings, but the present disclosure is not limited to the specific parts of the above embodiments. Within the scope of the technical idea of ​​the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and all of these simple modifications fall within the scope of protection of the present disclosure.

[0058] It should be noted that each of the specific technical features described in the above specific embodiments can be combined in any suitable manner, provided there is no contradiction, and in order to avoid unnecessary repetition, the present disclosure omits various possible combination manners.

[0059] Furthermore, different embodiments of the present disclosure may be combined in any manner, and should be considered as being disclosed in the present disclosure as well, unless they are contrary to the spirit of the present disclosure. [Explanation of symbols]

[0060] 1 Rotor shaft 2. First balance disc 3 Rotor 4. Second Balance Disc

Claims

1. A die-cast aluminum alloy that does not require heat treatment, % of Zn, 0.1 to 0.2 wt. % of Ti, 0.03 to 0.06 wt. % of Sr, 0.18 wt. % or less of Fe, 0.15 wt. % or less of rare earth elements, 0.1 wt. % or less of other impurity elements, and the balance Al, based on a total weight of the die-cast aluminum alloy, wherein the rare earth elements are Sm and / or Y.

2. 2. The die cast aluminum alloy of claim 1, wherein the die cast aluminum alloy comprises 10.0 to 12.0 wt.% Si, 1.0 to 1.4 wt.% Mg, 3.0 to 3.3 wt.% Cu, 0.03 to 0.06 wt.% Y, 0.03 to 0.06 wt.% Sm, 0.4 to 0.55 wt.% Mn, 0.9 to 1.5 wt.% Zn, 0.1 to 0.2 wt.% Ti, 0.03 to 0.06 wt.% Sr, 0.12 to 0.16 wt.% Fe, 0.05 wt.% or less of other impurity elements, and the balance Al, based on a total weight of the die cast aluminum alloy.

3. 2. The die-cast aluminum alloy according to claim 1, characterized in that the weight ratio of Sm to Y is (0.8 to 1.2):1, and the weight ratio of Mg to Cu is (0.32 to 0.45):

1.

4. 2. The die cast aluminum alloy of claim 1, wherein the die cast aluminum alloy has a yield strength of 240 to 280 MPa, an ultimate tensile strength of 330 to 380 MPa, and an elongation of 1 to 4%.

5. A method for producing a die-cast aluminum alloy that does not require heat treatment according to any one of claims 1 to 4, A step of melting aluminum in a smelting furnace, adding silicon, a Zn raw material, a Cu raw material, and a Mn raw material, and performing a first smelting to obtain a first molten metal; performing a refining process and a slag removing process on the first molten metal to obtain a second molten metal; a step of adding a Ti raw material, a Sr raw material, a rare earth raw material and a Mg raw material to the second molten metal to perform a second smelting to obtain a molten aluminum alloy, and then performing a component detection to obtain a third molten metal after passing the component detection, in which the rare earth raw material includes a Sm raw material and / or a Y raw material; performing a degassing process on the third molten metal to obtain a fourth molten metal; and performing component detection on the fourth molten metal, and after the fourth molten metal passes the component detection, performing high-pressure die casting to obtain a die-cast aluminum alloy that does not require heat treatment.

6. 6. The manufacturing method according to claim 5, wherein the Zn raw material is an Al-Zn based alloy, the Cu raw material is an Al-Cu based alloy, the Mn raw material is an Al-Mn based alloy, the Ti raw material is an Al-Ti based alloy, the Sr raw material is an Al-Sr based alloy, the Sm raw material is an Al-Sm based alloy, the Mg raw material is a magnesium ingot and / or an Mg-Y based alloy, and the Y raw material is an Mg-Y based alloy and / or an Al-Y based alloy.

7. 7. The method according to claim 6, wherein the Al-Zn based alloy is an Al-10Zn intermediate alloy, the Al-Cu based alloy is an Al-50Cu intermediate alloy, the Al-Mn based alloy is an Al-20Mn intermediate alloy, the Al-Ti based alloy is an Al-5Ti intermediate alloy, the Al-Sr based alloy is an Al-5Sr intermediate alloy, the Al-Sm based alloy is an Al-20Sm intermediate alloy, and the Mg-Y based alloy is an Mg-30Y intermediate alloy.

8. The temperature of the first smelting is 770 to 790° C. The method according to claim 5, wherein the temperature of the second smelting is 750 to 760°C.

9. The refining process includes: introducing an inert gas atmosphere or nitrogen containing a refining agent powder into the first molten metal to perform a first refining; and after an interval of 50 to 60 minutes, again introducing the inert gas atmosphere or nitrogen containing the refining agent powder to perform a second refining; the temperatures of the first refining and the second refining are 750 to 760° C., respectively; and the inert gas is argon gas; 6. The method according to claim 5, wherein the degassing conditions include a temperature of 750 to 760[deg.] C. and a time of 10 to 15 minutes.

10. 6. The manufacturing method according to claim 5, wherein the conditions of the high pressure die casting include: die casting temperature is 690 to 700°C, pressure is 35 to 40 MPa, high speed position is 220 to 230 mm, injection time is 6 to 8 s, cooling time is 8 to 10 s, and thickness of the die casting mold is 3 to 7 mm.

11. 5. An automobile body structural part comprising the heat treatment-free die-cast aluminum alloy according to claim 1.

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