Cast aluminum alloy and preparation method and application thereof

Abstract

The invention relates to a cast aluminum alloy and a preparation method and application thereof. The cast aluminum alloy comprises the following components in percentage by weight: 1.5 to 2.5 percent of Fe, 1.05 to 2.0 percent of Ni, 0.005 to 0.08 percent of V, impurities and the balance of aluminum, wherein the content of a single impurity is less than 0.05 percent by weight. According to the cast aluminum alloy, the alloy cost can be reduced, and the cast aluminum alloy has high conductivity and high yield strength and can be used for manufacturing parts such as high-strength and high-conductivity motor rotors.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, specifically to a cast aluminum alloy, its preparation method, and its application. Background Technology

[0002] Aluminum alloys are widely used in various fields such as automobiles, aerospace, and machinery manufacturing due to their excellent specific strength, corrosion resistance, and electrical and thermal conductivity. Taking the automotive industry as an example, aluminum alloys are widely used in body panels and structural components due to their excellent lightweight effect. At the same time, due to their excellent electrical and thermal conductivity, they are also now widely used in the manufacture of motor rotors.

[0003] With the rapid development of new energy vehicles, consumers are increasingly demanding higher performance from their vehicles. Taking power as an example, OEMs typically prioritize technical specifications such as 0-100 km / h acceleration time and top speed. The electric motor is a key component supporting this performance, and the motor rotor plays a crucial role. The motor rotor requires not only good electrical conductivity but also high-temperature yield strength to prevent deformation and rotational instability due to insufficient strength at high temperatures, thus maintaining the motor's high speed. Developing aluminum alloys with higher electrical conductivity and higher high-temperature strength has become a priority for major OEMs and materials companies.

[0004] In one type of die-cast aluminum alloy, a relatively high amount of Ni (4.0~6.0 wt%) is added. However, due to the high price of Ni, the alloy cost is high, which is not conducive to mass production. In another type of high-conductivity and heat-resistant pressure-cast aluminum alloy, Ni is still the main alloying element. Although the Ni content is further reduced (1.8~3.8 wt%), and Fe is limited to 0.25~0.30 wt%, many trace elements such as Cr, V, and Zr need to be added, which to some extent increases the cost of the alloy. Moreover, the yield strength of the alloy is still relatively low (80~100 MPa).

[0005] Therefore, existing cast aluminum alloys suffer from high alloy costs and cannot simultaneously meet the requirements of high electrical conductivity and high-temperature yield strength. Summary of the Invention

[0006] The purpose of this disclosure is to provide a cast aluminum alloy, its preparation method, and its application. The cast aluminum alloy not only has high room temperature strength and electrical conductivity, but also maintains high electrical conductivity, thermal conductivity, and yield strength at extreme operating temperatures; it can also reduce alloy costs.

[0007] To solve the above-mentioned technical problems, the first aspect of this disclosure provides a cast aluminum alloy comprising 1.5 to 2.5% by weight of Fe, 1.05 to 2.0% by weight of Ni, 0.005 to 0.08% by weight of V, impurities, and the balance of aluminum, wherein the content of a single impurity is less than 0.05% by weight.

[0008] This disclosure provides a cast aluminum alloy, which is an Al-Fe alloy. Fe has extremely low solid solubility in the aluminum matrix and precipitates almost entirely as a second phase, effectively reducing the deterioration of the alloy's electrical conductivity due to alloying and maintaining a high conductivity from the source (in aluminum alloys, the deterioration of conductivity due to elemental solid solution is usually much greater than that due to precipitation). A small amount of Ni is introduced into this aluminum alloy, forming a stable AlFeNi phase with Fe, further improving the alloy's room temperature strength. Simultaneously, this phase is morphologically stable at high temperatures, which is beneficial for obtaining high-temperature mechanical properties. In addition to the alloy disclosed herein... In addition to Fe and Ni, trace amounts of V are introduced, which forms a high-temperature stable Al3V phase with Al. This promotes grain refinement and prevents grain coarsening at medium to high temperatures over a long period. Simultaneously, it avoids the impact of excessive element introduction on conductivity, maintaining the high purity of the aluminum alloy and improving its electrical and thermal conductivity. The cast aluminum alloy provided in this disclosure has high yield strength and electrical conductivity, as well as high thermal conductivity, exhibiting excellent comprehensive performance. The main cost element in this alloy is Fe, resulting in low cost and facilitating large-scale application. The cast aluminum alloy provided in this disclosure can be used to manufacture high-strength, high-conductivity motor rotors and other parts.

[0009] In one embodiment, the cast aluminum alloy comprises 1.5-2.3 wt% Fe, 1.05-1.8 wt% Ni, 0.01-0.08 wt% V, impurities, and the balance aluminum, wherein the content of any single impurity is less than 0.05 wt%. When the component content of the cast aluminum alloy is within the preferred range provided in this embodiment, it can have better yield strength, electrical conductivity, and thermal conductivity.

[0010] In one embodiment, the weight ratio of Fe to Ni in the cast aluminum alloy is 1.1 to 1.5:1. By controlling the weight ratio of Fe to Ni within the range of this embodiment, a better synergistic effect can be achieved, resulting in cast aluminum alloys with better yield strength, electrical conductivity, and thermal conductivity, and better overall performance.

[0011] In a preferred embodiment, the cast aluminum alloy does not include Cu, so that the cast aluminum alloy has both excellent alloy strength and electrical and thermal conductivity.

[0012] In a preferred embodiment, the cast aluminum alloy does not contain Mg, so that the cast aluminum alloy has both excellent alloy strength and electrical and thermal conductivity.

[0013] In one embodiment, the cast aluminum alloy has a yield strength of 85~100 MPa and an electrical conductivity of 50~55% IACS at 25°C, and a yield strength of 80 MPa or more at 200°C.

[0014] In one embodiment, the cast aluminum alloy has a thermal conductivity of 190 W / (m·K) or higher at 25°C; and a thermal conductivity of 180 W / (m·K) or higher at temperatures below 200°C.

[0015] A second aspect of this disclosure provides a method for preparing cast aluminum alloys, comprising the following steps: S1. Pure aluminum molten metal is smelted with aluminum-iron master alloy, aluminum-nickel master alloy and aluminum-vanadium master alloy to obtain an alloy mixture. The alloy mixture includes 1.5~2.5% by weight of Fe, 1.05~2.0% by weight of Ni, 0.005~0.08% by weight of V, impurities and the balance of aluminum, wherein the content of a single impurity is less than 0.05% by weight. S2. The alloy mixture is subjected to heat preservation and static treatment, refining treatment and slag removal treatment to obtain alloy melt; S3. The alloy melt is cast.

[0016] This disclosure provides a method for preparing cast aluminum alloys. The alloy is based on the Al-Fe system. By utilizing the low solid solubility of Fe in the aluminum matrix, the degradation of the conductivity of the aluminum alloy by alloying is minimized. By introducing a certain amount of Ni, a stable second phase is formed with Fe, which simultaneously improves the room temperature and medium-high temperature (e.g., 200℃) strength of the alloy. V is used for grain refinement to achieve better conductivity and strength. The preparation is simple, low-cost, and conducive to industrial production.

[0017] In one embodiment, the smelting conditions in step S1 include a temperature of 720~760℃.

[0018] In one embodiment, step S1 further includes: in the smelting process, after the alloy raw material is melted, it is stirred for 5 to 10 minutes to obtain the alloy mixture.

[0019] In one embodiment, in step S2, the conditions for the heat preservation and static treatment include: heat preservation temperature of 720℃~740℃ and static time of 15~30min; The atmosphere for the refining process includes argon.

[0020] This disclosure provides a third aspect of a cast aluminum alloy prepared according to the method described in the second aspect.

[0021] This disclosure provides a fourth aspect of a vehicle high electrical and thermal conductivity component, comprising the cast aluminum alloy described in the first or third aspect of this disclosure.

[0022] The fifth aspect of this disclosure provides an electric motor rotor comprising the cast aluminum alloy described in the first or third aspect of this disclosure.

[0023] The sixth aspect of this disclosure provides a water-cooled plate comprising the cast aluminum alloy described in the first or third aspect of this disclosure.

[0024] The seventh aspect of this disclosure provides a vehicle comprising one or more of the vehicle high electrical and thermal conductivity components described in the fourth aspect of this disclosure, the cast aluminum alloy described in the fifth aspect, and the water-cooled plate described in the sixth aspect.

[0025] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation

[0026] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0027] The first aspect of this disclosure provides a cast aluminum alloy comprising 1.5 to 2.5 wt% Fe, 1.05 to 2.0 wt% Ni, 0.005 to 0.08 wt% V, impurities, and the balance aluminum, wherein the content of any single impurity is less than 0.05 wt%.

[0028] This disclosure provides a cast aluminum alloy, which is an Al-Fe alloy. Fe has extremely low solid solubility in the aluminum matrix and precipitates almost entirely as a second phase, effectively reducing the deterioration of the alloy's electrical conductivity due to alloying and maintaining a high conductivity from the source (in aluminum alloys, the deterioration of conductivity due to elemental solid solution is usually much greater than that due to precipitation). A small amount of Ni is introduced into this aluminum alloy, forming a stable AlFeNi phase with Fe, further improving the alloy's room temperature strength. Simultaneously, this phase is morphologically stable at high temperatures, which is beneficial for obtaining high-temperature mechanical properties. In addition to Fe and Ni, trace amounts of V are introduced into the disclosed alloy. The V forms a high-temperature stable Al3V phase with Al, which can promote grain refinement and prevent grain coarsening at medium and high temperatures over a long period of time. At the same time, it avoids the influence of excessive element introduction on conductivity, maintains the high purity of the aluminum alloy, and is beneficial to improving the alloy's electrical and thermal conductivity. It can also prevent the alloy's casting performance from deteriorating. The cast aluminum alloy provided by this disclosure has high yield strength and electrical conductivity, as well as high thermal conductivity, and has excellent comprehensive performance. The main cost element of the alloy disclosed in this disclosure is Fe, which is low in cost and also conducive to large-scale application.

[0029] In this disclosure, impurities refer to unavoidable impurities introduced due to alloy raw materials and manufacturing processes, including but not limited to Cu, Zn, Si, Mg, Sn, etc. The aluminum alloys in this disclosure contain relatively few unavoidable impurities, with a total impurity content of less than 0.1% by weight, which is negligible.

[0030] In this disclosure, "content of a single impurity" refers to the content of each impurity element present in the impurities of the cast aluminum alloy.

[0031] In this disclosure, "1.5 to 2.5 wt%" includes, but is not limited to, 1.5 wt%, 1.6 wt%, 1.8 wt%, 2.0 wt%, 2.2 wt%, 2.4 wt%, 2.5 wt%, and any range of two values; In this disclosure, "1.05 to 2.0 wt%" includes, but is not limited to, 1.05 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, 2.0 wt%, and any range consisting of any two values; In this disclosure, "0.005 to 0.08 wt%" includes, but is not limited to, 0.005 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, and any range of two values.

[0032] In a preferred embodiment, the cast aluminum alloy comprises 1.5-2.3% by weight Fe, 1.05-1.8% by weight Ni, 0.005-0.08% by weight V, impurities, and the balance aluminum, wherein the content of any single impurity is less than 0.05% by weight. When the component content of the cast aluminum alloy is within the preferred range provided in this embodiment, it can have better yield strength, electrical conductivity, and thermal conductivity.

[0033] In one embodiment, the weight ratio of Fe to Ni in the cast aluminum alloy is 1.1 to 1.5:1, including but not limited to 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, and any two of these ratios. By controlling the weight ratio of Fe to Ni within the range of this embodiment, a better synergistic effect can be achieved, resulting in cast aluminum alloys with better yield strength, electrical conductivity, and thermal conductivity, and thus better overall performance.

[0034] In a preferred embodiment, the cast aluminum alloy does not include Cu, so that the cast aluminum alloy has both excellent alloy strength and electrical and thermal conductivity.

[0035] In a preferred embodiment, the cast aluminum alloy does not contain Mg, so that the cast aluminum alloy has both excellent alloy strength and electrical and thermal conductivity.

[0036] In one specific embodiment, the cast aluminum alloy has a yield strength of 85~100 MPa and an electrical conductivity of 50~55% IACS at 25°C, and a yield strength of over 80 MPa at 200°C. The cast aluminum alloy has a thermal conductivity of 190 W / (m·K) or higher at 25°C; and a thermal conductivity of 180 W / (m·K) or higher at temperatures below 200°C.

[0037] A second aspect of this disclosure provides a method for preparing cast aluminum alloys, comprising the following steps: S1. Pure aluminum molten metal is smelted with aluminum-iron master alloy, aluminum-nickel master alloy, aluminum-vanadium master alloy, and aluminum-strontium master alloy to obtain an alloy mixture. The alloy mixture includes 1.5~2.5% by weight of Fe, 1.05~2.0% by weight of Ni, 0.005~0.08% by weight of V, impurities, and the balance of aluminum, wherein the content of a single impurity is less than 0.05% by weight. S2. The alloy mixture is subjected to heat preservation and static treatment, refining treatment and slag removal treatment to obtain alloy melt; S3. The alloy melt is cast.

[0038] This disclosure provides a method for preparing cast aluminum alloys. The alloy is based on an Al-Fe system. By utilizing the low solid solubility of Fe in the aluminum matrix, the degradation of the conductivity of the aluminum alloy by alloying is minimized. By introducing a certain amount of Ni, a stable second phase is formed with Fe, which simultaneously improves the room temperature and low temperature (e.g., 200℃) strength of the alloy. V is used for grain refinement to achieve better conductivity and strength. The method provided by this disclosure is simple to prepare and is conducive to industrial production.

[0039] In one specific embodiment, in step S1, the conditions for the smelting process include a temperature of 720~760℃.

[0040] In one specific embodiment, step S1 further includes: in the smelting process, after the alloy raw material is melted, it is stirred for 5 to 10 minutes to obtain the alloy mixture, so as to improve the uniformity of the alloy mixture.

[0041] In one specific embodiment, in step S2, the conditions for the heat preservation and static treatment include: a heat preservation temperature of 720℃~740℃ and a static time of 15~30min; the atmosphere for the refining treatment includes argon, and conventional refining agents in the art can be used.

[0042] In this disclosure, in step S3, the casting process can be carried out using conventional processes in the art (including but not limited to high-pressure die casting, centrifugal casting, etc.).

[0043] The third aspect of this disclosure provides cast aluminum alloys prepared according to the method described in the second aspect of this disclosure.

[0044] This disclosure provides a vehicle part comprising the cast aluminum alloy described in the first or third aspect of this disclosure.

[0045] In one specific embodiment, the vehicle parts include, but are not limited to, components such as motor rotors and stators of electric vehicles and heat exchangers that require high alloy strength and conductivity, and may also include parts such as water-cooled plates that require high thermal conductivity.

[0046] The fifth aspect of this disclosure provides an electric motor rotor comprising the cast aluminum alloy described in the first or third aspect of this disclosure.

[0047] The sixth aspect of this disclosure provides a water-cooled plate comprising the cast aluminum alloy described in the first or third aspect of this disclosure.

[0048] The seventh aspect of this disclosure provides a vehicle comprising one or more of the vehicle high electrical and thermal conductivity components described in the fourth aspect of this disclosure, the cast aluminum alloy described in the fifth aspect, and the water-cooled plate described in the sixth aspect.

[0049] The present disclosure is further described in detail below through examples. All raw materials used in the examples are commercially available.

[0050] Example 1 (1) According to the alloy formula listed in the table, aluminum-iron master alloy, aluminum-nickel master alloy, aluminum-vanadium master alloy and aluminum-strontium master alloy are added to the molten pure aluminum solution in sequence for smelting treatment. The smelting treatment conditions include: temperature of 750℃, stirring for 8 minutes after the alloy is completely melted to obtain a uniform alloy mixture. (2) After keeping the temperature at 730℃ and standing for a period of time (15 min) (heating and standing treatment), after the intermediate alloy is fully melted, add refining agent and stir, and pass in high-purity argon gas for refining treatment and slag removal treatment to obtain alloy melt; (3) After the second heat preservation treatment, the casting treatment (die casting process) is carried out. The conditions for die casting treatment include: casting temperature of 720℃, casting pressure of 50MPa, and mold temperature of 160℃; to obtain cast aluminum alloy.

[0051] Examples 2-7 The preparation method in Example 1 is the same as in Example 1, except that the aluminum alloy is prepared by casting according to the aluminum alloy composition in Table 1; the rest of the process is the same as in Example 1.

[0052] Comparative Examples 1-6 The preparation method in Example 1 is the same as in Example 1, except that the aluminum alloy is prepared by casting according to the aluminum alloy composition in Table 1; the rest of the process is the same as in Example 1.

[0053] Table 1

[0054] In Table 1, the balance of the alloy in each embodiment and comparative example is Al; the component content is "-" to indicate that the component was not added; the content of a single impurity in each embodiment and comparative example is less than 0.05% by weight, and the total impurity content is less than 0.1% by weight.

[0055] Test Example 1 This test example is used to test the mechanical, electrical, and thermal properties of the cast aluminum alloys obtained in the above examples and comparative examples.

[0056] The test methods for yield strength include: mechanical property testing according to GB / T 228.1; electrical conductivity was measured using a CON6010 electrical conductivity meter; and thermal conductivity was measured using a NETZSCH LFA 447 laser thermal conductivity meter. The test results are listed in Table 2 below.

[0057] Table 2

[0058] The data in Table 2 shows that: Comparing Comparative Examples 1-6 with Examples 1-7, the composition of the cast aluminum alloys in Examples 1-7 is within the scope of this disclosure. The cast aluminum alloys obtained in Examples 1-7 not only have excellent room temperature strength, electrical conductivity, and thermal conductivity, but also maintain high strength and thermal conductivity at a relatively extreme operating temperature (200°C), which can well meet the requirements of high-performance motor rotors. However, the composition of the cast aluminum alloys in Comparative Examples 1-6 is not within the scope of this disclosure, and the cast aluminum alloys obtained in Comparative Examples 1-6 have the problem that alloy strength and electrical / thermal conductivity cannot be achieved simultaneously. Comparing Examples 1-4 with Examples 5-7, the composition of the cast aluminum alloys in Examples 1-4 is within the preferred range provided in this disclosure, and the cast aluminum alloys obtained in Examples 1-4 have better overall strength and electrical / thermal conductivity. Comparing Example 1 with Examples 5-6, it can be seen that the composition of the cast aluminum alloy and the weight ratio of Fe and Ni in Example 1 are within the preferred range provided in this disclosure, and the cast aluminum alloy of Example 1 has better overall performance.

[0059] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0060] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0061] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A cast aluminum alloy, characterized in that, The cast aluminum alloy comprises 1.5 to 2.5% by weight of Fe, 1.05 to 2.0% by weight of Ni, 0.005 to 0.08% by weight of V, impurities, and the balance of aluminum, wherein the content of any single impurity is less than 0.05% by weight.

2. The cast aluminum alloy according to claim 1, characterized in that, The cast aluminum alloy comprises 1.5 to 2.3% by weight of Fe, 1.05 to 1.8% by weight of Ni, 0.01 to 0.08% by weight of V, impurities, and the balance of aluminum, wherein the content of a single impurity is less than 0.05% by weight.

3. The cast aluminum alloy according to claim 1, characterized in that, In the cast aluminum alloy, the weight ratio of Fe to Ni is 1.1~1.5:

1.

4. The cast aluminum alloy according to claim 1, characterized in that, The cast aluminum alloy does not include Cu.

5. The cast aluminum alloy according to claim 1, characterized in that, The cast aluminum alloy does not contain Mg.

6. The cast aluminum alloy according to claim 1, characterized in that, The cast aluminum alloy has a yield strength of 85~100 MPa and an electrical conductivity of 50~55% IACS at 25℃, and a yield strength of over 80 MPa at 200℃.

7. The cast aluminum alloy according to claim 1, characterized in that, The cast aluminum alloy has a thermal conductivity of 190 W / (m·K) or higher at 25°C; and a thermal conductivity of 180 W / (m·K) or higher at temperatures below 200°C.

8. A method for preparing cast aluminum alloys, characterized in that, Includes the following steps: S1. Pure aluminum molten metal is smelted with aluminum-iron master alloy, aluminum-nickel master alloy and aluminum-vanadium master alloy to obtain an alloy mixture. The alloy mixture includes 1.5~2.5% by weight of Fe, 1.05~2.0% by weight of Ni, 0.005~0.08% by weight of V, impurities and the balance of aluminum, wherein the content of a single impurity is less than 0.05% by weight. S2. The alloy mixture is subjected to heat preservation and static treatment, refining treatment and slag removal treatment to obtain alloy melt; S3. The alloy melt is cast.

9. The method according to claim 8, characterized in that, In step S1, the conditions for the smelting process include a temperature of 720~760℃.

10. The method according to claim 8, characterized in that, Step S1 further includes: in the smelting process, after the alloy raw materials are melted, they are stirred for 5 to 10 minutes to obtain the alloy mixture.

11. The method according to claim 8, characterized in that, In step S2, the conditions for the heat preservation and static treatment include: heat preservation temperature of 720℃~740℃ and static time of 15~30min; The atmosphere for the refining process includes argon.

12. The cast aluminum alloy prepared by the method according to any one of claims 8 to 11.

13. A high electrical and thermal conductivity component for vehicles, characterized in that, Includes the cast aluminum alloy described in any one of claims 1 to 7 and 12.

14. A motor rotor, characterized in that, Includes the cast aluminum alloy described in any one of claims 1 to 7 and 12.

15. A water-cooled plate, characterized in that, Includes the cast aluminum alloy described in any one of claims 1 to 7 and 12.

16. A vehicle, characterized in that, It includes one or more of the vehicle high electrical and thermal conductivity components of claim 13, the motor rotor of claim 14, and the water-cooled plate of claim 15.

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