A cast aluminum alloy and its preparation method, an electric motor rotor, and an automobile

Abstract

This invention provides a cast aluminum alloy, its preparation method, a motor rotor, and an automobile, belonging to the field of cast aluminum alloy technology. Based on a total mass of 100wt%, the cast aluminum alloy comprises the following components: Fe 0.5-2wt%, Ni 0.3-1.5wt%, Cu 0.1-0.8wt%, with the balance being Al and unavoidable impurities. The cast aluminum alloy possesses both high electrical conductivity and excellent yield strength and tensile strength, while also having relatively low production costs, making it suitable for manufacturing high-strength, high-conductivity components such as motor rotors for new energy vehicles.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cast aluminum alloys, and particularly relates to a cast aluminum alloy, a preparation method thereof, a motor rotor and an automobile. BACKGROUND

[0002] The cast aluminum alloy for an automobile motor rotor needs to have high electrical conductivity and excellent mechanical properties and machining properties. However, it is found in actual application that there is always a contradictory change rule between the electrical conductivity and the strength of the aluminum alloy, that is, the electrical conductivity will decrease while the strength increases, and vice versa. The strategies for how to improve the electrical conductivity of the aluminum alloy and how to simultaneously consider excellent mechanical properties are still very limited in the related art. Therefore, it is very meaningful to develop an aluminum alloy with high electrical conductivity and excellent mechanical properties.

[0003] Most high-conductivity high-strength aluminum alloys are aluminum-silicon alloys at present because the aluminum-silicon alloy has excellent castability, good mechanical properties and not bad electrical conductivity. According to the related art [1], when the content of Si in the aluminum alloy reaches 13%, the electrical conductivity of the aluminum alloy at room temperature is less than 40% IACS.

[0004] To solve the above problems, an aluminum alloy without adding Si and adding alloying elements such as Fe and Ni can be selected to improve the electrical conductivity of the aluminum alloy while ensuring that the yield strength and the tensile strength are not reduced too much. For example, the related art [2] discloses a high-strength high-conductivity silicon-free aluminum-iron-nickel alloy, which contains 4.3wt% to 6wt% of Ni, 0.2wt% to 0.8wt% of Fe and 0.01wt% to 1wt% of Ti, and the rest is Al. The electrical conductivity of the aluminum-iron-nickel alloy is 40-50% IACS, the yield strength is not less than 90 MPa, and the ultimate tensile strength is 150 MPa. However, the aluminum-iron-nickel alloy still has the following problems: (1) the alloy product is expensive due to the high price of nickel, which is not conducive to industrial production; (2) the solidification temperature range of the aluminum-iron-nickel alloy is large, coarse dendrites are easy to produce, alloy liquid is difficult to compensate and fill, and the organization density is easy to reduce.

[0005] Therefore, the research on the cast aluminum alloy for a motor rotor is not sufficient enough in the related art, and it is necessary to develop a cast aluminum alloy, a preparation method thereof, a motor rotor and an automobile, which has low cost and high electrical conductivity and high strength.

[0006] [1]KNPrahbu and BNRavishankar.2003.Mater.Sci.Eng.A.[J].Effect ofModification Melt Treatment on Casting / Chill Interfacial Heat Transfer andElectrical Conductivity of Al-13%Si Alloy.360:293-298.

[0007] [2] Patent application document HK40042796A, aluminum alloy for die casting. Summary of the Invention

[0008] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention provide a cast aluminum alloy and its preparation method, a motor rotor, and an automobile, wherein the cast aluminum alloy has low cost and combines high electrical conductivity and high strength.

[0009] This invention provides a cast aluminum alloy, which, based on a total mass of 100 wt%, comprises the following components:

[0010] Fe 0.5-2wt%,

[0011] Ni 0.3-1.5wt%,

[0012] Cu 0.1-0.8wt%,

[0013] The balance consists of Al and unavoidable impurities.

[0014] The advantages and technical effects of the cast aluminum alloy in this invention are as follows:

[0015] (1) The cast aluminum alloy of the present invention does not contain Si element which reduces the electrical conductivity of aluminum alloy, but contains Fe and Ni elements which can improve the strength of aluminum alloy. Therefore, the cast aluminum alloy can improve the electrical conductivity of aluminum alloy while ensuring that the yield strength and tensile strength are not reduced too much.

[0016] (2) The cast aluminum alloy in this embodiment contains Cu, which is dissolved in the α-Al matrix and plays a solid solution strengthening role, and reacts with (Fe,Ni)4Al in the matrix. 13 The combined effect of these phases gives this cast aluminum alloy excellent yield strength and tensile strength;

[0017] (3) Compared with the cast aluminum alloys disclosed in related technologies, the Ni content in the cast aluminum alloy of the present invention is relatively low, so the cost of the cast aluminum alloy is also relatively low.

[0018] In some embodiments, the cast aluminum alloy comprises the following components, based on a total mass of 100 wt%:

[0019] Fe 1-1.5wt%,

[0020] Ni 0.3-1wt%,

[0021] Cu 0.1-0.6wt%,

[0022] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0023] In some embodiments, the total content of Fe and Ni is 0.8-3 wt%.

[0024] In some embodiments, the total content of Fe and Ni is 2-2.5 wt%.

[0025] In some embodiments, the room temperature conductivity of the cast aluminum alloy is above 47% IACS.

[0026] In some embodiments, the yield strength of the cast aluminum alloy is 75 MPa or higher.

[0027] In some embodiments, the tensile strength of the cast aluminum alloy is above 160 MPa.

[0028] In some embodiments, the porosity of the cast aluminum alloy is less than 0.1%.

[0029] In some embodiments, the elongation of the cast aluminum alloy is 13% or more.

[0030] This invention also provides a method for preparing cast aluminum alloy, comprising the following steps: adding aluminum alloy raw materials in proportion and smelting them to obtain an aluminum alloy melt; refining and degassing the aluminum alloy melt successively, and then casting it into a casting mold to obtain the cast aluminum alloy.

[0031] The advantages and technical effects of the method for preparing cast aluminum alloys according to embodiments of the present invention are as follows:

[0032] (1) The preparation method of the present invention has simple steps and is suitable for industrial promotion;

[0033] (2) The cast aluminum alloy obtained by the preparation method of the present invention is not only low in cost, but also has both electrical conductivity and mechanical properties.

[0034] In some embodiments, the casting mold is not preheated and is kept at room temperature.

[0035] In some embodiments, no heat treatment is performed after obtaining the aluminum alloy.

[0036] This invention also provides a motor rotor, which is prepared from the cast aluminum alloy of this invention.

[0037] The advantages and technical effects of the motor rotor in this embodiment of the invention are as follows:

[0038] Because the motor rotor of this embodiment of the invention is made of the cast aluminum alloy of this embodiment, the electronic rotor will not fail even when the speed is as high as 18,000 rpm.

[0039] This invention also provides an automobile, including a motor rotor according to an embodiment of this invention.

[0040] The advantages and technical effects of the automobile in this embodiment of the invention are as follows:

[0041] The automobile of this invention, by using the motor rotor of this invention, can match higher speed and higher energy efficiency. Attached Figure Description

[0042] Figure 1 This is a SEM image of the cast aluminum alloy from Example 3. Detailed Implementation

[0043] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0044] This invention provides a cast aluminum alloy, which, based on a total mass of 100 wt%, comprises the following components:

[0045] Fe 0.5-2wt%,

[0046] Ni 0.3-1.5wt%,

[0047] Cu 0.1-0.8wt%,

[0048] The balance consists of Al and unavoidable impurities.

[0049] The cast aluminum alloy of this invention does not contain Si, therefore its electrical conductivity is significantly improved compared to cast aluminum alloys containing Si in related technologies. Although the absence of Si reduces the strength of the cast aluminum alloy, the presence of Fe, Ni, and Cu in this alloy results in primary phases including (Fe,Ni)₄Al. 13 Phases, α-Al phase and (Fe,Ni)4Al13 The eutectic phase with α-Al, (Fe,Ni)4Al 13 The Cu phase enhances the yield strength and tensile strength of aluminum alloys. Simultaneously, Cu does not react with Fe or Ni to form compounds, but remains dissolved in the α-Al matrix, providing solid solution strengthening and further increasing the yield strength and tensile strength. Therefore, this cast aluminum alloy maintains good electrical conductivity while possessing excellent yield strength and tensile strength. Furthermore, compared to high-Ni-content cast aluminum alloys in related technologies, the Ni content in the cast aluminum alloy of this invention is relatively low, resulting in lower costs and helping companies reduce production costs. The cast aluminum alloy of this invention is suitable for manufacturing high-strength, high-conductivity components such as motor rotors for new energy vehicles.

[0050] Based on a total mass of 100 wt% for the cast aluminum alloy, in the cast aluminum alloy of this embodiment of the invention, the mass fraction of Fe is 0.5-2 wt%, for example, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, 2 wt%, etc., and the mass fraction of Ni is 0.3-1.5 wt%, for example, 0.3 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, etc. When the mass fraction of Fe is less than 0.5 wt% and the mass fraction of Ni is less than 0.3 wt%, it is difficult to form sufficient (Fe,Ni)₄Al. 13 In this phase, cast aluminum alloys exhibit low yield strength and tensile strength. When the mass fraction of Fe exceeds 2 wt%, (Fe,Ni)₄Al 13 Excessive Fe content decreases the electrical conductivity of cast aluminum alloys. When the Ni mass fraction exceeds 1.5 wt%, the cost of the cast aluminum alloy increases accordingly due to the higher cost of Ni. Preferably, the Fe mass fraction is 1-1.5 wt%, and the Ni mass fraction is 0.3-1 wt%.

[0051] Based on a total mass of 100 wt% for the cast aluminum alloy, the Cu content in the cast aluminum alloy of this embodiment is 0.1-0.8 wt%, for example, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, etc. When the Cu content is below 0.1 wt%, it does not provide solid solution strengthening, thus significantly reducing the yield strength and tensile strength of the cast aluminum alloy. When the Cu content is above 0.8 wt%, the electrical conductivity of the cast aluminum alloy decreases. Preferably, the Cu content is 0.1-0.6 wt%.

[0052] In some embodiments, the total content of Fe and Ni is 0.8-3 wt%, for example, 0.8 wt%, 1 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, 2 wt%, 2.2 wt%, 2.4 wt%, 2.6 wt%, 2.8 wt%, 3 wt%, etc. Compared to high-Ni-content cast aluminum alloys in related technologies, the cast aluminum alloys of the embodiments of the present invention have a lower Ni content, and therefore a relatively lower total content of Fe and Ni. This can, on the one hand, reduce the solidification temperature range of the cast aluminum alloy, reduce shrinkage porosity and hot cracking tendency, lower porosity, and increase the density of the cast aluminum alloy, thereby improving its casting performance; on the other hand, it can reduce coarse (Fe,Ni)₄Al₂O₃ particles. 13 The content of the phase increases the elongation of cast aluminum alloys, allowing them to absorb more energy and prevent fracture after impact, while also reducing coarse (Fe,Ni)4Al. 13 The content of the phase can also improve the electrical conductivity of cast aluminum alloys. Preferably, the total content of Fe and Ni is 2-2.5 wt%.

[0053] In some embodiments, the content of a single impurity is ≤0.05 wt.%, and the total impurity content is ≤0.15 wt.%. The impurity content meets the requirements of standard GB / T 8733-2016.

[0054] In some embodiments, the room temperature conductivity of the cast aluminum alloy is above 47% IACS, preferably 47-52% IACS, such as 47% IACS, 48% IACS, 49% IACS, 50% IACS, 51% IACS, 52% IACS, etc.

[0055] In some embodiments, the yield strength of the cast aluminum alloy is 75 MPa or higher, preferably 75-100 MPa, such as 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa, etc.

[0056] In some embodiments, the tensile strength of the cast aluminum alloy is 160 MPa or above, preferably 160-190 MPa, such as 160 MPa, 165 MPa, 170 MPa, 175 MPa, 180 MPa, 185 MPa, 190 MPa, etc.

[0057] In some embodiments, the porosity of the cast aluminum alloy is less than 0.1%, preferably 0.01-0.1%, such as 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, etc.

[0058] In some embodiments, the elongation of the cast aluminum alloy is 13% or more, more preferably 13-20%, such as 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0059] This invention also provides a method for preparing cast aluminum alloy, comprising the following steps:

[0060] Smelting of aluminum alloy melt: Add aluminum alloy raw materials in proportion and smelt to obtain aluminum alloy melt;

[0061] Preparation of cast aluminum alloy: The aluminum alloy melt is refined and degassed successively, and then cast into a casting mold to obtain the cast aluminum alloy.

[0062] The preparation method of this invention is simple and suitable for industrial application. The resulting cast aluminum alloy is not only low in cost but also has both electrical conductivity and mechanical properties.

[0063] In some embodiments, the refined and degassed aluminum alloy melt is cast into a casting mold that is not preheated and is maintained at room temperature. Compared to preheating the casting mold, not preheating the mold increases the temperature gradient between the aluminum alloy melt and the casting mold, thereby increasing the cooling rate, which is beneficial to improving the electrical conductivity, yield strength, tensile strength and elongation of the aluminum alloy in the as-cast state.

[0064] In some embodiments, no heat treatment process is performed after obtaining the cast aluminum alloy. Compared to performing a heat treatment process, skipping the heat treatment process significantly improves the yield strength and tensile strength of the cast aluminum alloy. Heat treatment releases the casting stress in the aluminum alloy, and the decrease in casting stress leads to a decrease in strength. Furthermore, skipping the heat treatment process can greatly reduce energy consumption, optimize the process, lower industrial production costs, and improve economic efficiency.

[0065] In some embodiments, the smelting of aluminum alloy melt specifically includes the following steps: First, the pit furnace is preheated empty to remove water vapor in the furnace. The preheating temperature is above 400°C. At the same time, pure aluminum is preheated. Then, the preheated pure aluminum is placed into the pit furnace for smelting. The smelting temperature is 780-800°C. After the pure aluminum is completely melted, the surface slag is skimmed off and the oxide scale is removed. The melt temperature is maintained, and pure iron, pure nickel, and pure copper are added and completely submerged in the aluminum liquid. After the alloying elements are completely melted, the mixture is allowed to stand for 2-3 hours to obtain the aluminum alloy melt.

[0066] In some embodiments, the preparation of cast aluminum alloy specifically includes the following steps: First, the refining agent is wrapped in aluminum foil and dried, while the stainless steel bell jar is preheated. Then, the preheated refining agent is pressed to the bottom of the aluminum alloy melt using the preheated stainless steel bell jar, and high-purity argon gas is introduced into the aluminum alloy melt to complete the refining and degassing process of the aluminum alloy melt. The casting temperature is maintained at 700-740°C. Next, the aluminum alloy melt is poured into a casting mold that has not been preheated and is kept at room temperature. After the aluminum alloy melt solidifies and cools, the casting is removed from the mold to obtain the cast aluminum alloy. The casting mold is made of cast iron and the casting time is controlled within 30 seconds.

[0067] This invention also provides a motor rotor, which is prepared from the cast aluminum alloy of this invention.

[0068] Because the motor rotor of this embodiment of the invention is made of the cast aluminum alloy of this embodiment, the electronic rotor will not fail even when the speed is as high as 18,000 rpm.

[0069] This invention also provides an automobile, including a motor rotor according to an embodiment of this invention.

[0070] The automobile of this invention, by using the motor rotor of this invention, can match higher speed and higher energy efficiency.

[0071] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0072] Example 1

[0073] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0074] Fe 1wt%,

[0075] Ni 1wt%,

[0076] Cu 0.6wt%,

[0077] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0078] The method for preparing this cast aluminum alloy includes the following steps:

[0079] Smelting of aluminum alloy melt: First, the pit furnace is preheated empty to remove moisture. The preheating temperature is 400℃. At the same time, pure aluminum is preheated. Then, the preheated pure aluminum is placed into the pit furnace for smelting at 780-800℃. After the pure aluminum is completely melted, the surface slag is skimmed off and the oxide scale is removed. The melt temperature is maintained, and pure iron, pure nickel, and pure copper are added and completely submerged in the aluminum liquid. After the alloying elements are completely melted, the mixture is allowed to stand for 2 hours to obtain the aluminum alloy melt.

[0080] Preparation of cast aluminum alloy: First, the refining agent is wrapped in aluminum foil and dried. At the same time, a stainless steel bell jar is preheated. Then, the preheated refining agent is pressed to the bottom of the aluminum alloy melt using the preheated stainless steel bell jar. High-purity argon gas is introduced into the aluminum alloy melt to complete the refining and degassing process. The casting temperature is maintained at 700-740℃. Next, the aluminum alloy melt is poured into a casting mold that is not preheated and kept at room temperature. After the aluminum alloy melt solidifies and cools, the casting is removed from the mold to obtain the cast aluminum alloy. The casting mold is made of cast iron and the casting time is controlled within 30 seconds.

[0081] Example 2

[0082] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0083] Fe 1.5wt%,

[0084] Ni 1wt%,

[0085] Cu 0.6wt%,

[0086] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0087] The preparation method of this cast aluminum alloy is the same as in Example 1.

[0088] Example 3

[0089] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0090] Fe 2wt%,

[0091] Ni 1wt%,

[0092] Cu 0.6wt%,

[0093] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0094] The preparation method of this cast aluminum alloy is the same as in Example 1.

[0095] Example 4

[0096] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0097] Fe 1.5wt%,

[0098] Ni 1wt%,

[0099] Cu 0.6wt%,

[0100] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0101] The only difference between the preparation method of this cast aluminum alloy and Example 1 is that the casting aluminum alloy is also subjected to T6 heat treatment during the preparation process: the obtained cast aluminum alloy is solution treated at 520℃ for 4 hours, taken out and water quenched, and then aged at 180℃ for 3 hours. After the end, it is taken out and air cooled. The interval between the solution treatment and the aging treatment does not exceed 0.5 hours.

[0102] Example 5

[0103] The alloy composition and preparation method used in Example 2 are the same, except that the aluminum alloy melt is poured into a casting mold preheated at 150°C, while all other conditions are the same.

[0104] Example 6

[0105] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0106] Fe 2wt%,

[0107] Ni 1.5wt%,

[0108] Cu 0.6wt%,

[0109] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0110] The preparation method of this cast aluminum alloy is the same as that of Example 1.

[0111] Example 7

[0112] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0113] Fe 1.7wt%,

[0114] Ni 0.5wt%,

[0115] Cu 0.3wt%,

[0116] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0117] The preparation method of this cast aluminum alloy is the same as that of Example 1.

[0118] Comparative Example 1

[0119] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0120] Fe 1.5wt%,

[0121] Ni 1wt%,

[0122] Cu 0,

[0123] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0124] The preparation method of this cast aluminum alloy is the same as in Example 1.

[0125] Comparative Example 2

[0126] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0127] Fe 1.5wt%,

[0128] Ni 1wt%,

[0129] Cu 0.9wt%,

[0130] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0131] The preparation method of this cast aluminum alloy is the same as in Example 1.

[0132] Comparative Example 3

[0133] A cast aluminum alloy, based on a total mass of 100 wt%, comprises the following components:

[0134]

[0135] The balance is Al and unavoidable impurities, with the content of a single impurity ≤0.05 wt.% and the total impurity content ≤0.15 wt.%.

[0136] The preparation method of this cast aluminum alloy is the same as that of Example 1, except that pure iron, pure nickel, pure copper, pure magnesium and aluminum-silicon master alloy are added to the smelting step of the aluminum alloy melt and completely immersed in the aluminum liquid.

[0137] The preparation method of this cast aluminum alloy is the same as that in Example 1.

[0138] The composition and preparation methods of the cast aluminum alloys in Examples 1-7 and Comparative Examples 1-3 are shown in Table 1, and their corresponding performance test data are shown in Table 2. IACS testing was performed using an eddy current conductivity meter (model PZ-60A). Porosity was calculated by metallographic statistical analysis of the void area per unit area. Yield strength, tensile strength, and elongation were obtained according to the GB / T228.1-2010 test standard.

[0139] Table 1. Composition and preparation methods of cast aluminum alloys in Examples 1-7 and Comparative Examples 1-3

[0140]

[0141] Table 2. Performance test results of cast aluminum alloys in Examples 1-7 and Comparative Examples 1-3

[0142]

[0143] As can be seen from Tables 1 and 2, the cast aluminum alloys of Examples 1-7 exhibit good overall performance, maintaining good electrical conductivity (above 47% IACS) while also possessing excellent yield strength (above 76 MPa) and tensile strength (above 160 MPa). Furthermore, compared to high-nickel cast aluminum alloys in related technologies, the cast aluminum alloys of Examples 1-7 of this invention have lower production costs due to their lower nickel content.

[0144] By comparing Examples 1-3, it can be found that when the Fe content is reduced, the electrical conductivity and elongation of the cast aluminum alloy are improved.

[0145] By comparing Examples 2 and 4, it can be found that after the casting alloy of Example 4 is subjected to T6 heat treatment, the electrical conductivity of the casting aluminum alloy decreases slightly, the elongation decreases, and the yield strength and tensile strength also decrease. Overall, the casting aluminum alloy without T6 heat treatment has better comprehensive performance.

[0146] A comparison of Examples 2 and 5 shows that keeping the mold at room temperature during casting is more effective than preheating it. This is because, compared to the preheating method in Example 5, casting the molten aluminum alloy into an unpreheated mold in Example 2 increases the temperature gradient between the molten aluminum alloy and the mold, thereby increasing the cooling rate and improving the electrical conductivity, yield strength, tensile strength, and elongation of the cast aluminum alloy.

[0147] By comparing Example 2 and Comparative Examples 1-2, it can be seen that when the Cu content of Comparative Example 1 is lower than the content range specified in the embodiments of the present invention, the yield strength and tensile strength of the cast aluminum alloy decrease significantly; when the Cu content of Comparative Example 2 is higher than the content range specified in the embodiments of the present invention, although the yield strength and tensile strength of the cast aluminum alloy are excellent, its electrical conductivity is greatly reduced.

[0148] By comparing Example 2 and Comparative Example 3, it can be seen that the addition of Mg and Si and the reduction of Cu content in Comparative Example 3 resulted in a significant decrease in the yield strength, tensile strength and electrical conductivity of the cast aluminum alloy. Therefore, the cast aluminum alloys in the embodiments of the present invention do not include Mg and Si elements.

[0149] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0150] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An electric machine rotor, characterized in that, Prepared from a cast aluminum alloy, the cast aluminum alloy comprises the following components, based on the total mass of the cast aluminum alloy being 100 wt%: Fe 0.5-1.5 wt%, Ni 0.8-1.5 wt%, Cu 0.1-0.8 wt%, the balance being Al and unavoidable impurities; the cast aluminum alloy has a room temperature electrical conductivity of 47-52 % IACS, a yield strength of 75-100 MPa, a tensile strength of 160-190 MPa, a porosity of 0.01-0.1 %, and an elongation of 13-20 %.

2. The motor rotor of claim 1, wherein Prepared from a cast aluminum alloy, the cast aluminum alloy comprises the following components, based on the total mass of the cast aluminum alloy being 100 wt%: Fe 1-1.5 wt%, Ni 0.8-1 wt%, Cu 0.1-0.6 wt%, the balance being Al and unavoidable impurities, the content of a single impurity being ≤0.05 wt.%, and the total content of impurities being ≤0.15 wt.%.

3. The motor rotor of claim 1, wherein The total content of Fe and Ni is 1.3-3 wt%.

4. The motor rotor of claim 3, wherein The total content of Fe and Ni is 2-2.5 wt%.

5. The motor rotor of claim 1, wherein The preparation method of the cast aluminum alloy comprises the following steps: adding aluminum alloy raw materials in proportion, melting to obtain an aluminum alloy melt; after refining and degassing of the aluminum alloy melt, casting into a casting mold to obtain the cast aluminum alloy.

6. The motor rotor of claim 5, wherein, The casting mold is not preheated and kept at room temperature.

7. The motor rotor of claim 5, wherein No heat treatment is performed after the cast aluminum alloy is obtained.

8. An automobile characterized by comprising: An electric machine rotor comprising the cast aluminum alloy of any one of claims 1-7.

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