A low-cost cast heat-resistant aluminum alloy capable of meeting 350-degree service and its preparation method

Abstract

The present invention belongs to the field of metal materials, and specifically relates to a heat-resistant aluminum alloy capable of service at 350 degrees Celsius and its preparation method. The alloy comprises the following components, measured by mass percentage: 4-16% rare earth, 0-3% Ca, 0-5% Mg, 0-2% Cu, 0-5% Zn, 0-2% Fe, 0.2-0.5% Zr, 0-0.8% Si, 0.5-1.2% Mn, with the total amount of impurity elements ≤ 0.2%, and the balance being Al. In the material composition of the aluminum alloy of the present invention, the main alloying element, Ce or La, a rare earth element, appears in a hypoeutectic, near-eutectic, or hypereutectic form, exhibiting good casting formability and high-temperature heat resistance. Furthermore, the addition of trace alloying elements such as Mg, Cu, and Zn effectively enhances the strength of the base alloy, while the addition of trace Zr and aluminum generates an Al3Zr phase with an L12 structure, further stabilizing its high-temperature performance. The addition of trace Si promotes the precipitation of the Al3Zr phase. The addition of elements such as Ca, Fe, and Mn further controls the content of deleterious phases in the alloy's as-cast structure and enhances the alloy's high-temperature strength by forming other heat-resistant phases with excellent thermal stability. The combined effect of these alloying elements ensures that this heat-resistant aluminum alloy has a higher service temperature while maintaining moderate room-temperature strength and ductility, making it suitable for use in the production of cast aluminum alloys with high service temperature requirements.

Description

Technical Field

[0001] The present invention belongs to the field of metal materials, and in particular relates to a cast heat-resistant aluminum alloy capable of meeting service at 350 degrees Celsius and a preparation method thereof. Background Art

[0002] Aluminum is widely used in industries such as automotive, electronics, aerospace, and weapons. The automotive industry accounts for 12-15% of global aluminum consumption, with cast aluminum alloys accounting for 80% of this total. Cast heat-resistant aluminum alloys are primarily used in parts such as automotive engine cylinders and pistons, helicopter casings, and satellite mounts. These alloys operate at relatively high temperatures, potentially exceeding 350°C in harsh environments. Therefore, in order to improve the strength and heat resistance of cast heat-resistant aluminum alloys, there is an urgent need to develop low-density, high-strength heat-resistant aluminum alloys to meet the production needs of heat-resistant aluminum alloys suitable for service at 350°C.

[0003] Existing cast heat-resistant aluminum alloys mainly include Al-Si heat-resistant aluminum alloys and Al-Cu heat-resistant aluminum alloys. Al-Si alloys have good casting fluidity and resistance to thermal cracking, but Al-Si heat-resistant aluminum alloys have low tensile strength at high temperatures and cannot meet the requirements of service at excessively high temperatures. Al-Cu heat-resistant aluminum alloys have high thermal stability and have good mechanical properties at both room temperature and high temperature after heat treatment. However, Al-Cu alloys have poor casting fluidity, are prone to thermal cracking and casting defects, and have poor corrosion resistance. At the same time, the copper content in Al-Cu heat-resistant aluminum alloys often reaches 3.5-4.5%, which greatly increases the raw material cost of the alloy. In addition, in order to obtain excellent high-temperature performance, the above two types of heat-resistant aluminum alloys often need to add expensive metal Ni and precious rare earth elements such as Sc or Er, which will greatly increase the price of raw materials.

[0004] Among the rare earth elements, Ce and La have the cheapest prices. The price of pure Ce is about the same as that of pure aluminum, and the price of Ce-La mixed rare earth is even lower. The main reason is that the electronic semiconductor industry has a large demand for Nd and Pr, and their mineral deposits are often associated with Ce, La, etc., so when they are used to refine Nd and Pr, by-products Ce and La are often produced, which makes them economical. The applicant's preliminary research on binary Al-Ce alloys found that they have good high-temperature stability, mainly because their eutectic structure does not decompose or coarsen at high temperatures of 350 to 450 degrees. At the same time, the high-temperature diffusion coefficient of Ce in aluminum is extremely low, which is 10 -21 m 2 / s level. The rare earth elements La and Ce have adjacent atomic numbers, similar densities, similar chemical properties, and are also associated with each other. Therefore, developing Al-Ce-La based alloys supplemented with trace strengthening elements to improve microstructural distribution, enhance room temperature performance, and improve high and low temperature plasticity is an ideal approach to developing new heat-resistant aluminum alloys. Summary of the Invention

[0005] The purpose of the present invention is to address the problem that conventional heat-resistant aluminum alloys are difficult to serve in high-temperature environments of 350 degrees and above, and to provide a solution for heat-resistant aluminum alloys that can serve in high-temperature environments of 350 degrees and above. Based on isochronous aging and isothermal aging experiments, the present invention found that the hardness of the Al-Ce eutectic structure at 350 degrees remains stable, and there is no obvious coarsening inside the eutectic structure. In addition, based on the consensus that Ca and rare earth elements improve the heat resistance of aluminum alloys; and the principle that adding trace alloying elements to form an L12 structure further strengthens aluminum alloys; it provides a new idea for the development of heat-resistant aluminum alloys that can serve at 350 degrees.

[0006] The present invention is achieved through the following technical solutions:

[0007] The present invention provides a heat-resistant aluminum alloy capable of meeting service at 350 degrees Celsius, wherein the mass percentages of the alloying elements are as follows:

[0008] 4-16% rare earth (pure Ce or pure La or Ce+La mixture), 0-3% Ca, 0-5% Mg, 0-2% Cu, 0-5% Zn, 0-2% Fe, 0.2-0.5% Zr, 0-0.8% Si, 0.5-1.2% Mn, the total amount of impurity elements ≤0.2%, the balance is Al.

[0009] The working principle of the present invention is as follows: adding rare earth elements Ce or La to Al to form Al-Ce or Al-La eutectic can significantly improve the fluidity and thermal cracking tendency of the molten metal during mold filling, and improve high-temperature thermal stability; and the addition of a small amount of element Ca will also introduce a certain amount of Al-Ca eutectic phase, which can further improve the casting performance and mechanical properties, but it is not advisable to add too much to avoid causing the material to become brittle. Cu can play a strong aging strengthening role in aluminum alloys and improve the room temperature strength of the alloy. The addition of Mg elements will produce solid solution strengthening, and at the same time it is also helpful to improve the heat resistance of aluminum alloys. The trace addition of Zr elements can generate an Al3Zr phase-reinforced matrix with an L12 structure, and trace Si elements can promote the precipitation of Al3Zr phase during high-temperature heat treatment, thereby improving the room temperature performance of the material without affecting the high temperature performance of the alloy.

[0010] The preparation process of the present invention is:

[0011] The raw material metal ingots or master alloys are pretreated in a 300-degree oven to remove the water in them. The clay-graphite crucible used for smelting is sprayed with paint inside and outside and then placed in a smelting furnace to preheat to 300°C. The aluminum ingot is then placed in the crucible and the temperature is raised to above 700°C to melt it.

[0012] After the aluminum ingot is completely melted, add pure rare earth or mixed rare earth metal ingots or aluminum rare earth master alloy, pure Ca ingot or Al-Ca master alloy, pure Cu ingot or Al-Cu master alloy, pure Zn ingot or Al-Zn master alloy, Al-Zr master alloy, Al-Si master alloy, Al-Mn master alloy, keep warm for 5 to 15 minutes, raise the temperature to 750°C, stir clockwise and counterclockwise for about 100 times each, and keep warm for 15 to 20 minutes;

[0013] After all the alloying elements are melted and evenly mixed, the temperature is raised to 760-780°C, and hexachloroethane refining agent is added to refine the molten metal for 10-15 minutes. After the refining is completed, pure Mg ingots or Al-Mg master alloys are added, and the power is turned off and the molten metal is cooled to 730-750°C. The temperature is kept for 15 minutes, and the slag is skimmed to obtain aluminum alloy molten metal with high purity.

[0014] After the molten metal is refined, the appropriate casting process is selected according to the shape, size and service requirements of the casting, including but not limited to metal mold gravity casting, metal mold sand casting, low-pressure metal mold casting, low-pressure sand casting and squeeze casting.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention addresses the problem that heat-resistant aluminum alloys developed in the prior art cannot withstand higher temperatures. By adding inexpensive rare earth elements such as Ce and La, the alloy's heat resistance is enhanced, resulting in a heat-resistant aluminum alloy capable of service at 350°C. The Al-RE-Mg-Cu-Zn-Fe-Ca-Zr-Si-Mn alloy proposed in this invention combines excellent casting fluidity with resistance to hot cracking, and exhibits higher heat resistance, room temperature, and high-temperature strength, promising promising industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0018] Figure 1 Schematic diagram of the optical metallographic structure of the material sample obtained by melting Al-4RE-3Ca-0.5Zr-0.8Si-1.2Mn alloy (RE is Ce) using sand mold gravity casting;

[0019] Figure 2Schematic diagram of the optical metallographic structure of the material sample obtained by melting the Al-8RE-5Mg-0.5Cu-1Fe-1Zn-0.2Zr-0.5Mn alloy (RE is La) using a metal mold gravity casting method;

[0020] Figure 3 Schematic diagram of the optical microstructure of the material sample obtained by melting Al-12RE-5Mg-2Cu-1Fe-1Zn-0.2Zr-0.5Mn alloy (RE is 70% Ce + 30% La) using sand mold low pressure casting;

[0021] Figure 4 Schematic diagram of the optical microstructure of the material sample obtained by melting Al-16RE-2Mg-2Fe-5Zn-0.2Zr-0.3Si-0.5Mn alloy (RE is 40% Ce + 60% La) and low-pressure casting using a metal mold;

[0022] Figure 5 Schematic diagram of the optical microstructure of the material sample obtained by melting Al-16RE-0.5Ca-3Mg-2Fe-3Zn-0.4Zr-0.5Si-0.8Mn alloy (RE is 50% Ce + 50% La) by squeeze casting;

[0023] Figure 6 For the above Figures 1 to 5 Corresponding age hardening curves of each alloy when subjected to isothermal aging heat treatment at 350 degrees Celsius. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0025] The aluminum alloy used in the embodiment of the present invention is an Al-RE heat-resistant aluminum alloy, including the following components in percentage: 4-16% rare earth, 0-3% Ca, 0-5% Mg, 0-2% Cu, 0-5% Zn, 0-2% Fe, 0.2-0.5% Zr, 0-0.8% Si, 0.5-1.2% Mn, the total amount of impurity elements is ≤0.2%, and the balance is Al.

[0026] The specific embodiments are as follows:

[0027] Example 1:

[0028] This embodiment provides a heat-resistant aluminum alloy capable of meeting service temperatures of 350°C. The alloy comprises the following components by mass: 4% rare earth, 3% Ca, 0.5% Zr, 0.8% Si, 1.2% Mn, with the total amount of impurity elements being ≤0.2% and the balance being Al. The preparation process is as follows:

[0029] The raw material metal ingots or master alloys are pretreated in a 300-degree oven to remove the water in them. The clay-graphite crucible used for smelting is sprayed with paint inside and outside and then placed in a smelting furnace to preheat to 300°C. The aluminum ingot is then placed in the crucible and the temperature is raised to above 700°C to melt it.

[0030] After the aluminum ingot is completely melted, add pure rare earth metal ingots, pure Ca ingots, Al-Zr master alloy, Al-Si master alloy, and Al-Mn master alloy, keep them warm for 5 to 15 minutes, raise the temperature to 750°C, stir clockwise and counterclockwise for about 100 times each, and keep them warm for 15 to 20 minutes;

[0031] After all the alloy elements are melted and evenly mixed, the temperature is raised to 760-780° C., and hexachloroethane refining agent is added to refine the molten metal for 10-15 minutes. After the refining is completed, the slag is skimmed off to obtain aluminum alloy molten metal with higher purity.

[0032] The experiment was carried out by sand gravity casting. The optical microstructure diagram of the aluminum alloy prepared in this embodiment is shown in FIG. Figure 1 As shown in Figure 2, it can be seen that there is a larger volume fraction of the primary phase α-Al and a smaller volume fraction of the eutectic structure. Its 350°C isothermal aging hardening curve is shown in Figure 2. Figure 6 As shown in the figure, due to the presence of Zr and Si elements, its hardness quickly reaches a peak and then slowly decreases.

[0033] Example 2:

[0034] This embodiment provides a heat-resistant aluminum alloy capable of meeting service temperatures of 350°C. The alloy comprises the following components by mass: 8% rare earth, 5% Mg, 0.5% Cu, 1% Zn, 1% Fe, 0.2% Zr, and 0.5% Mn. The total amount of impurity elements is ≤0.2%, with the remainder being Al. The preparation process is as follows:

[0035] The raw material metal ingots or master alloys are pretreated in a 300-degree oven to remove the water in them. The clay-graphite crucible used for smelting is sprayed with paint inside and outside and then placed in a smelting furnace to preheat to 300°C. The aluminum ingot is then placed in the crucible and the temperature is raised to above 700°C to melt it.

[0036] After the aluminum ingot is completely melted, add pure rare earth metal ingot, pure Cu ingot, Al-Zn master alloy, Al-Zr master alloy, Al-Mn master alloy, keep them warm for 5 to 15 minutes, raise the temperature to 750°C, stir clockwise and counterclockwise for about 100 times each, and keep them warm for 15 to 20 minutes;

[0037] After all the above alloy elements are melted and evenly mixed, the temperature is raised to 760-780°C, and hexachloroethane refining agent is added to refine the molten metal for 10-15 minutes. After the refining is completed, pure Mg ingots are added, and the power is turned off and the molten metal is cooled to 730-750°C. The temperature is kept for 15 minutes and the slag is skimmed off to obtain aluminum alloy molten metal with higher purity.

[0038] The experiment was carried out by gravity casting using a metal mold. The optical metallographic structure of the aluminum alloy prepared in this embodiment is shown in FIG. Figure 2 As shown in Figure 1, the primary phase α-Al with a larger volume fraction is significantly reduced compared to Example 1, while the volume fraction of the eutectic structure is significantly increased. Figure 6 As shown in FIG. 1 , compared with Example 1, the addition of Cu element significantly increases the as-cast hardness, and as time goes by, the hardness slowly decreases, but is still higher than that of other alloys without Cu element added.

[0039] Example 3:

[0040] This embodiment provides a heat-resistant aluminum alloy capable of meeting service temperatures of 350°C. The alloy comprises the following components by mass: 12% rare earth, 5% Mg, 2% Cu, 1% Zn, 1% Fe, 0.2% Zr, and 0.5% Mn. The total amount of impurity elements is ≤ 0.2%, with the remainder being Al. The preparation process is as follows:

[0041] The raw material metal ingots or master alloys are pretreated in a 300-degree oven to remove the water in them. The clay-graphite crucible used for smelting is sprayed with paint inside and outside and then placed in a smelting furnace to preheat to 300°C. The aluminum ingot is then placed in the crucible and the temperature is raised to above 700°C to melt it.

[0042] After the aluminum ingot is completely melted, add mixed rare earth metal ingot, pure Cu ingot, Al-Zn master alloy, Al-Zr master alloy, Al-Mn master alloy, keep them warm for 5 to 15 minutes, raise the temperature to 750°C, stir clockwise and counterclockwise for about 100 times each, and keep them warm for 15 to 20 minutes;

[0043] After all the above alloy elements are melted and evenly mixed, the temperature is raised to 760-780°C, and hexachloroethane refining agent is added to refine the molten metal for 10-15 minutes. After the refining is completed, pure Mg ingots are added, and the power is turned off and the molten metal is cooled to 730-750°C. The temperature is kept for 15 minutes and the slag is skimmed off to obtain aluminum alloy molten metal with higher purity.

[0044] The experiment was carried out by sand mold low pressure casting. The optical metallographic structure diagram of the aluminum alloy prepared in this embodiment is shown in FIG. Figure 3 As shown in Figure 2, compared with Examples 1 and 2, a larger volume fraction of eutectic structure and a small amount of hypereutectic phase can be seen. Its 350°C isothermal aging hardening curve is shown in Figure 2. Figure 6 As shown, compared with Example 2, its cast hardness is higher, and its hardness is always higher than Example 2 in the process of slowly decreasing hardness with time. It can be seen that the addition of rare earth and alloying elements can greatly improve the strength of the alloy.

[0045] Example 4:

[0046] This embodiment provides a heat-resistant aluminum alloy capable of meeting service temperatures of 350°C. The alloy comprises the following components by mass: 16% rare earth, 2% Mg, 5% Zn, 2% Fe, 0.2% Zr, 0.3% Si, and 0.5% Mn. The total amount of impurity elements is ≤ 0.2%, with the remainder being Al. The preparation process is as follows:

[0047] The raw material metal ingots or master alloys are pretreated in a 300-degree oven to remove the water in them. The clay-graphite crucible used for smelting is sprayed with paint inside and outside and then placed in a smelting furnace to preheat to 300°C. The aluminum ingot is then placed in the crucible and the temperature is raised to above 700°C to melt it.

[0048] After the aluminum ingot is completely melted, add mixed rare earth metal ingot, Al-Zn master alloy, Al-Zr master alloy, Al-Si master alloy, Al-Mn master alloy, keep warm for 5 to 15 minutes, raise the temperature to 750°C, stir clockwise and counterclockwise for about 100 times each, and keep warm for 15 to 20 minutes;

[0049] After all the above alloy elements are melted and evenly mixed, the temperature is raised to 760-780°C, and hexachloroethane refining agent is added to refine the molten metal for 10-15 minutes. After the refining is completed, pure Mg ingots are added, and the power is turned off and the molten metal is cooled to 730-750°C. The temperature is kept for 15 minutes and the slag is skimmed off to obtain aluminum alloy molten metal with higher purity.

[0050] The experiment was carried out by low-pressure casting with a metal mold. The optical metallographic structure of the aluminum alloy prepared in this embodiment is shown in FIG. Figure 4 As shown in Figure 2, compared with Example 3, as the rare earth content increases, the volume fraction of the hypereutectic phase increases and the volume fraction of the eutectic structure decreases. The 350-degree isothermal aging hardening curve of the alloy is shown in Figure 2. Figure 6 As shown in the figure, due to the absence of Cu element addition, the cast hardness is lower than that of Examples 2 and 3. However, due to the presence of Zr and Si elements, there are obvious peaks compared with Example 1, and the hardness is higher than that of Example 1.

[0051] Example 5:

[0052] This embodiment provides a heat-resistant aluminum alloy capable of meeting service temperatures of 350°C. The alloy comprises the following components by mass: 16% rare earth, 0.5% Ca, 3% Mg, 3% Zn, 2% Fe, 0.4% Zr, 0.5% Si, and 0.8% Mn. The total amount of impurity elements is ≤0.2%, with the remainder being Al. The preparation process is as follows:

[0053] The raw material metal ingots or master alloys are pretreated in a 300-degree oven to remove the water in them. The clay-graphite crucible used for smelting is sprayed with paint inside and outside and then placed in a smelting furnace to preheat to 300°C. The aluminum ingot is then placed in the crucible and the temperature is raised to above 700°C to melt it.

[0054] After the aluminum ingot is completely melted, add mixed rare earth metal ingots, pure Ca ingots, Al-Zn master alloy, Al-Zr master alloy, Al-Si master alloy, and Al-Mn master alloy, keep them warm for 5 to 15 minutes, raise the temperature to 750°C, stir clockwise and counterclockwise for about 100 times each, and keep them warm for 15 to 20 minutes;

[0055] After all the above alloy elements are melted and evenly mixed, the temperature is raised to 760-780°C, and hexachloroethane refining agent is added to refine the molten metal for 10-15 minutes. After the refining is completed, pure Mg ingots are added, and the power is turned off and the molten metal is cooled to 730-750°C. The temperature is kept for 15 minutes and the slag is skimmed off to obtain aluminum alloy molten metal with higher purity.

[0056] The experiment was carried out by extrusion casting. The optical microstructure diagram of the aluminum alloy prepared in this embodiment is shown in FIG. Figure 5 As shown in FIG, compared with Example 4, due to the same rare earth content, its metallographic structure is relatively similar. Its 350 degree isothermal aging hardening curve is as follows Figure 6 As shown in FIG, due to the increased content of trace alloy elements, the hardening curve is higher than that of Example 4, and both reach a peak at 2 h and then slowly decrease.

[0057] Based on the verification of the above embodiment, its 350 degree isothermal aging hardening curve is as follows Figure 6 shown.

[0058] In summary, the present invention provides a heat-resistant aluminum alloy suitable for service at 350°C (140°F) and comprises the following composition, by mass percentage: 4-16% rare earth elements, 0-3% Ca, 0-5% Mg, 0-2% Cu, 0-5% Zn, 0-2% Fe, 0.2-0.5% Zr, 0-0.8% Si, and 0.5-1.2% Mn. The total amount of impurity elements is ≤ 0.2%, with the balance being Al. This alloy significantly improves both room-temperature and high-temperature performance while maintaining high plasticity, offering promising applications.

[0059] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A cast heat-resistant aluminum alloy capable of serving at 350 degrees, characterized in that: In the heat-resistant aluminum alloy that can meet the service requirements at 350 degrees, the mass percentages of the alloying elements are as follows: 4~16% rare earth, 0~3% Ca, 0~5% Mg, 0~2% Cu, 0~5% Zn, 0~2% Fe, 0.2~0.5% Zr, 0~0.8% Si, 0.5~1.2% Mn, the total amount of impurity elements ≤0.2%, and the balance is Al.

2. The cast heat-resistant aluminum alloy according to claim 1, wherein The rare earth is one of rare earth elements Ce and La, or a mixture of Ce and La. If it is a mixture, the total amount thereof shall not exceed the range specified in claim 1.

3. The cast heat-resistant aluminum alloy according to claim 1, wherein The raw materials of rare earth, elements Ca, Mg, Cu, Zn and Si can be added in the form of metal elements or master alloys, and the elements Fe, Zr and Mn are added in the form of master alloys.

4. The cast heat-resistant aluminum alloy according to claim 1, wherein For the rare earth raw materials, if the target alloy contains only one rare earth element of Ce or La, the additive used for alloying is a metal ingot of pure Ce or pure La or an Al-Ce and Al-La intermediate alloy; if the target alloy contains two rare earth elements, Ce and La, either a metal ingot of pure Ce or pure La or an Al-Ce and Al-La intermediate alloy can be used, or a Ce-La mixed rare earth or its intermediate alloy with aluminum can be used, or a Ce-La-Nd-Pr mixed rare earth or its intermediate alloy with aluminum can be used; if a mixed rare earth containing other light rare earth elements such as Nd and Pr is used, it is stipulated that the content of other rare earths except Ce and La in the total rare earth amount is less than 5%.

5. The cast heat-resistant aluminum alloy according to claim 1, wherein The production and preparation process includes two steps: smelting and casting.

6. The cast heat-resistant aluminum alloy according to claim 1, wherein The smelting process comprises the following specific steps: The raw material metal ingots or master alloys are pre-treated in a 300-degree oven to remove the water in them. The clay-graphite crucible used for smelting is sprayed with paint inside and outside and then placed in a smelting furnace to preheat to 300°C. The aluminum ingot is then placed in the crucible and heated to above 700°C to melt it. After the aluminum ingot is completely melted, add pure rare earth or mixed rare earth metal ingots or aluminum rare earth master alloy, pure Ca ingot or Al-Ca master alloy, pure Cu ingot or Al-Cu master alloy, pure Zn ingot or Al-Zn master alloy, Al-Zr master alloy, Al-Mn master alloy, keep warm for 5-15 minutes, raise the temperature to 750℃, stir clockwise and counterclockwise for about 100 times each, and keep warm for 15-20 minutes; After all the above alloying elements are melted and evenly mixed, the temperature is raised to 760-780°C, and hexachloroethane refining agent is added to refine the molten metal for 10-15 minutes. After the refining is completed, pure Mg ingots or Al-Mg master alloys are added, and the power is turned off and the molten metal is cooled to 730-750°C. The temperature is kept for 15 minutes, and the slag is skimmed to obtain a relatively pure aluminum alloy molten metal.

7. The cast heat-resistant aluminum alloy according to claim 1, wherein The casting process can be prepared by metal mold gravity casting, metal mold sand casting, low-pressure metal mold casting, low-pressure sand casting or squeeze casting technology.

8. The cast heat-resistant aluminum alloy according to claim 1, wherein The metal mold gravity casting is performed after refining and standing, and the temperature of the molten metal is maintained at 700-750°C. The steel or copper metal mold cavity is sprayed with paint and preheated to 200-250°C. The molten metal is cast into the mold to obtain an alloy ingot; the casting temperature is 700-750°C, and the mold retention time is 60s.

9. The cast heat-resistant aluminum alloy according to claim 1, wherein After refining and standing, the metal mold sand casting maintains the temperature of the molten metal at 700~750℃, sprays the resin sand or quartz sand mold cavity with coating, and casts the molten metal into the mold to obtain an alloy ingot; the casting temperature is 700~780℃, and the mold retention time is determined by the size of the casting.

10. The cast heat-resistant aluminum alloy according to claim 1, wherein After refining and stabilization, the low-pressure metal mold casting transfers the molten metal to a holding furnace to maintain the temperature of the molten aluminum at 700~750℃; the low-pressure metal mold cavity is sprayed with paint and preheated to 180~300℃, and the molten metal flows into the mold through a booster pipe and is held under pressure for solidification at a holding pressure of 0.5~2 kPa; the temperature of the molten aluminum before casting is 700~750℃.

11. The cast heat-resistant aluminum alloy according to claim 1, wherein After refining and stabilization, the low-pressure sand casting molten metal is transferred to a holding furnace to maintain the aluminum liquid temperature at 700-750°C. The low-pressure sand mold cavity is sprayed with paint, and the molten metal flows into the mold through a booster pipe and is maintained under pressure for solidification. The holding pressure is 0.5-2 kPa. The aluminum liquid temperature before casting is 700-780°C.

12. The cast heat-resistant aluminum alloy according to claim 1, wherein After refining and standing, the temperature of the aluminum liquid in the crucible is maintained between 700 and 750 degrees Celsius. The molten metal is transferred to the pressure chamber of the squeeze casting machine using a ladle. The aluminum liquid is formed and solidified under pressure. The metal mold cavity of the low-pressure squeeze casting is sprayed with paint and preheated to 180~300℃; the solidification holding pressure is 50~200 MPa.

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