Heat-resistant cast aluminum alloy
By controlling the Cu and Ca content and process processing in Al-Cu alloy, a specific eutectic phase is formed, which solves the thermal cracking problem of the alloy during casting and improves its room temperature and high temperature mechanical properties, satisfying aerospace and other application requirements in the field.
Patent Information
- Application Number
- CN202411278442.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2024-12-13
AI Technical Summary
Al-Cu alloys are prone to thermal cracking and shrinkage during casting, and their high-temperature mechanical properties have not been effectively improved, making it difficult to meet the engineering application needs in aerospace and other fields.
By controlling the Cu content between 5-12 wt.%, the Ca content between 0.5-2.0 wt.%, RE≤0.8 wt.%, Mn≤0.3 wt.%, Ti≤0.5 wt.%, casting, solid solution and Aging process forms the Al8Cu4Ca ternary eutectic phase and the θ'-Al2Cu binary eutectic phase, and optimizes the microstructure of the alloy to improve casting and mechanical properties.
It significantly improves the casting performance and room temperature and high temperature mechanical strength of aluminum alloy, reduces the tendency of thermal cracking, extends the solidification range, and enhances the heat resistance of the alloy.
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Figure CN119121009A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of high-performance aluminum alloys, and in particular relates to a heat-resistant cast aluminum alloy. Background Art
[0002] Aluminum alloys are widely used in aerospace, automobile, shipbuilding and other fields. Among them, Al-Cu alloys have the advantages of high strength, good thermal stability, and excellent heat treatment strengthening effect. However, due to the large solidification range of Al-Cu alloys, the casting performance of the alloy is poor. During the solidification process, problems such as hot cracking and shrinkage are very likely to occur, which seriously limits its application. In order to further improve the room temperature and high temperature mechanical properties of Al-Cu alloys, researchers have added trace elements such as Ag and Sc. However, the addition of trace elements has little effect on the eutectic temperature of Al-Cu alloys, and it is difficult to improve the casting performance of the alloy.
[0003] Ca has the advantages of low cost and low density. In aluminum alloys, Ca easily increases the viscosity of aluminum liquid and causes brittleness at room temperature. Therefore, the content of Ca is generally strictly limited in industrial aluminum alloys. Studies have found that adding Ca to aluminum-based alloys can form (Al)+Al 4 Ca eutectic structure, Al-Ca alloy can obtain excellent casting performance and heat resistance, but because the solid solubility of Ca in aluminum is very small, the strength of the alloy is not high. Patent CN116987937A discloses an Al-Cu-Mn-Ca alloy and its preparation method. The alloy contains Cu: 4% to 5%, Mn: 0.5% to 1%, Ca: 0.5% to 1%, Ti: 0.1% to 0.3%, and the balance is Al. Due to the eutectic reaction, nanoscale Al 4 Ca colonies improve the casting properties of Al-Cu-Mn alloys and greatly improve the plasticity of the alloys. However, the tensile strength of the alloy is less than 350 MPa. And the high-temperature mechanical properties have not been improved. Therefore, it is urgent to develop aluminum alloys with excellent casting properties and room temperature and high temperature mechanical properties to expand their engineering applications. Summary of the invention
[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides a heat-resistant cast aluminum alloy.
[0005] To achieve the above object, the technical solution adopted by the present invention is: a heat-resistant cast aluminum alloy, comprising the following elements in percentage by weight: Cu: 5-12wt.%, Ca: 0.5-2.0wt.%, RE≤0.8wt.%, Mn≤0.3wt.%, Ti≤0.5wt.%, the remainder being Al and unavoidable impurities; RE is Ce, La, Sc or Er;
[0006] The preparation method of the heat-resistant cast aluminum alloy comprises the following steps:
[0007] (1) preparing pure Al, Al-Cu, Al-Ca, Al-RE, Al-Mn and Al-Ti master alloys, melting pure Al, then adding Al-Cu, Al-Ca, Al-RE, Al-Mn and Al-Ti master alloys and stirring to obtain a uniform melt;
[0008] (2) adding a refining agent to the melt, then purifying and standing the melt to obtain an alloy liquid;
[0009] (3) cooling the alloy liquid and then casting it to obtain an ingot;
[0010] (4) The ingot is subjected to solution treatment and aging treatment to obtain a heat-resistant cast aluminum alloy.
[0011] In the present invention, the content of Cu is controlled within 5-12wt.%, and the content of Ca is controlled within 0.5-2.0wt.%, which can improve the casting performance of the heat-resistant cast aluminum alloy, and improve the mechanical properties of the alloy while ensuring that the alloy has excellent casting performance.
[0012] As a preferred embodiment of the present invention, the atomic percentage ratio of Cu / Ca in the heat-resistant cast aluminum alloy is ≥4:1.
[0013] In the present invention, the mass ratio of Cu / Ca is controlled to be ≥7:1, and the casting, solid solution and aging processes are combined to form Al at the grain boundary of the alloy. 8 Cu 4 Ca ternary eutectic phase and needle-shaped θ'-Al 2 Cu binary eutectic phase, on the one hand, reduces the alloy's thermal cracking tendency and improves the casting performance of Al-Cu alloy; on the other hand, it makes the alloy have good room temperature and high temperature mechanical strength. If the Cu / Ca mass ratio is less than 7:1, there is only Al in the alloy. 8 Cu 4 Ca ternary eutectic phase, lacking binary eutectic θ'-Al 2 Cu phase makes the room temperature and high temperature mechanical strength of the alloy poor.
[0014] As a preferred embodiment of the present invention, the heat-resistant cast aluminum alloy contains the following elements in percentage by mass: Cu: 9-10.5wt.%, Ca: 1.0-1.1wt.%, Mn: 0.18-0.27wt.%, 0.28≤RE≤0.45wt.%, Ti≤0.25wt.%, and the balance is Al and unavoidable impurities.
[0015] As a preferred embodiment of the present invention, the melting temperature is 740-760°C.
[0016] As a preferred embodiment of the present invention, the melt temperature is adjusted to 730-780°C before adding the refining agent.
[0017] As a preferred embodiment of the present invention, the alloy melt is purified using a degassing device and then allowed to stand for 10-30 minutes.
[0018] As a preferred embodiment of the present invention, the alloy liquid is cooled to 700-720° C. for casting.
[0019] As a preferred embodiment of the present invention, the solution temperature is 520-580°C, the holding time is 12-30 hours, and the hot water quenching is 60-80°C.
[0020] As a preferred embodiment of the present invention, the aging treatment is a single-stage aging treatment or a regression aging treatment;
[0021] The temperature of the single-stage aging treatment is 165-250° C., and the time is 5-48 hours.
[0022] The regression aging treatment specifically includes: aging at a temperature of 200-350° C. for 5-25 hours, then aging at a temperature of 450-550° C. for 10-300 minutes, and then aging at 150-300° C. for 5-25 hours.
[0023] The supersaturated solid solution obtained by the ingot solution treatment of the present invention uniformly precipitates metastable θ'-Al in the Al matrix during the single-stage aging process. 2 Cu phase, which is in the form of fine needles, has a good strengthening effect. After solid solution and single-stage aging treatment, the alloy has good room temperature mechanical properties. 2 The Cu phase has poor thermal stability and is prone to coarsening at temperatures above 200°C, which weakens its strengthening effect, resulting in limited high temperature resistance of the alloy. Therefore, a more preferred solution of the present invention is to use regression aging treatment after solution treatment, which can not only improve the room temperature mechanical properties of the alloy, but also improve the high temperature mechanical properties of the alloy.
[0024] Compared with the prior art, the present invention has the following beneficial effects: the present invention controls the microstructure by controlling the type and amount of microalloys and optimizing the alloy preparation method, so that the second phase in the heat-resistant cast aluminum alloy is mainly Al at the grain boundary. 8 Cu 4 Ca ternary eutectic phase and θ'-Al in Al matrix 2 The Cu phase not only enhances the heat treatment strengthening effect of the alloy, and improves the room temperature and high temperature mechanical strength of the heat-resistant cast aluminum alloy while ensuring the elongation; it also effectively reduces the thermal cracking tendency of the alloy, shortens the solidification range of the alloy, and improves the casting performance of the alloy. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 The following are typical microstructure diagrams and DSC curve diagrams of the cast aluminum alloy prepared in Example 5.
[0026] Figure 2 The typical microstructure and DSC curve of the cast aluminum alloy prepared in Comparative Example 1. DETAILED DESCRIPTION
[0027] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0028] Example 1
[0029] The raw materials of the heat-resistant cast aluminum alloy include, by weight percentage, 5.2% Cu, 0.6% Ca, and the balance Al.
[0030] A method for preparing a heat-resistant cast aluminum alloy comprises the following steps:
[0031] S1. Dry the calculated weight of pure Al, Al-50Cu master alloy and Al-10Ca master alloy.
[0032] S2. Put pure Al into a smelting furnace to melt, and maintain the melt temperature at 750°C after it is completely melted.
[0033] S3. Put the dried Al-50Cu master alloy and Al-10Ca master alloy into the molten aluminum liquid, and stir and remove slag after the master alloy is melted.
[0034] S4. Adjust the solution temperature to 740°C, add a refining agent to the melt, stir and remove the slag.
[0035] S5. Adjust the solution temperature to 720°C, use a degassing device to purify the alloy melt, and then let it stand for 20 minutes.
[0036] S7. Cast into a steel mold preheated to 200°C.
[0037] S8, the alloy taken out from the mold is subjected to solution aging treatment, with the solution temperature being 525°C for 20 hours and the aging temperature being 180°C for 8 hours.
[0038] The heat-resistant cast aluminum alloy prepared in Example 1 has a tensile strength of 386 MPa and a yield strength of 246 MPa at room temperature; a tensile strength of 238 MPa and a yield strength of 173 MPa at a high temperature of 250° C., an elongation of more than 6% at room temperature, and an elongation of more than 10% at a high temperature of 250° C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0039] Only the single-stage aging treatment after the solution treatment in step S8 in the preparation method of the heat-resistant cast aluminum alloy described in Example 1 is replaced with a regression aging treatment: aging at 220°C for 18 hours, aging at 480°C for 150 minutes, and then aging at 250°C for 6 hours. The room temperature strength of the prepared heat-resistant cast aluminum alloy is similar to that of Example 1, but the high temperature strength is enhanced.
[0040] Example 2
[0041] The raw materials of the heat-resistant cast aluminum alloy include, by weight percentage, Cu: 6%, Ca: 0.8%, Mn: 0.23%, and the balance is Al.
[0042] A method for preparing a heat-resistant cast aluminum alloy comprises the following steps:
[0043] S1. Dry the calculated weight of pure Al, Al-50Cu master alloy, Al-Mn and Al-10Ca master alloy.
[0044] S2. Put pure Al into a smelting furnace to melt, and maintain the melt temperature at 760°C after it is completely melted.
[0045] S3. Put the dried Al-50Cu master alloy, Al-Mn master alloy and Al-10Ca master alloy into the molten aluminum liquid, and stir and remove slag after the master alloy is melted.
[0046] S4. Adjust the solution temperature to 730°C, add a refining agent to the melt, stir and remove the slag.
[0047] S5. Adjust the solution temperature to 700°C, use a degassing device to purify the alloy melt, and then let it stand for 20 minutes.
[0048] S7. Cast into a steel mold preheated to 200°C.
[0049] S8. Perform solution aging treatment on the alloy taken out from the mold. The solution temperature is 580℃, the time is 12 hours, and the aging temperature is 250℃, the time is 30 hours.
[0050] The heat-resistant cast aluminum alloy prepared in Example 2 has a tensile strength of 404 MPa and a yield strength of 306 MPa at room temperature; a tensile strength of 247 MPa and a yield strength of 184 MPa at a high temperature of 250°C; an elongation of more than 6% at room temperature and more than 10% at a high temperature of 250°C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0051] Only the single-stage aging treatment after the solution treatment in step S8 in the preparation method of the heat-resistant cast aluminum alloy described in Example 2 is replaced by a regression aging treatment: aging at 220°C for 18 hours, aging at 480°C for 150 minutes, and then aging at 250°C for 6 hours. The room temperature strength of the prepared heat-resistant cast aluminum alloy is similar to that of Example 2, but the high temperature strength is enhanced.
[0052] Example 3
[0053] The raw materials of the heat-resistant cast aluminum alloy include, by mass percentage, Cu: 9%, Ca: 1.2%, Ti: 0.21%, and the balance is Al.
[0054] A method for preparing a heat-resistant cast aluminum alloy comprises the following steps:
[0055] S1. Dry the calculated weight of pure Al, Al-50Cu master alloy, Al-Ti and Al-10Ca master alloy.
[0056] S2. Put pure Al into a smelting furnace to melt, and maintain the melt temperature at 740°C after it is completely melted.
[0057] S3. Put the dried Al-50Cu master alloy, Al-Ti master alloy and Al-10Ca master alloy into the molten aluminum liquid, and stir and remove slag after the master alloy is melted.
[0058] S4. Adjust the solution temperature to 780°C, add a refining agent to the melt, stir and remove the slag.
[0059] S5. Adjust the solution temperature to 720°C, use a degassing device to purify the alloy melt, and then let it stand for 20 minutes.
[0060] S7. Cast into a steel mold preheated to 200°C.
[0061] S8. Perform solution aging treatment on the alloy taken out from the mold. The solution temperature is 520℃, the time is 30 hours, and the aging temperature is 165℃, the time is 5h.
[0062] The heat-resistant cast aluminum alloy prepared in Example 3 has a tensile strength of 395 MPa and a yield strength of 295 MPa at room temperature; a tensile strength of 245 MPa and a yield strength of 182 MPa at a high temperature of 250°C; an elongation of more than 6% at room temperature and more than 10% at a high temperature of 250°C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0063] Only the single-stage aging treatment after the solution treatment in step S8 in the preparation method of the heat-resistant cast aluminum alloy described in Example 3 is replaced by a regression aging treatment: aging at 220°C for 18 hours, aging at 480°C for 150 minutes, and then aging at 250°C for 6 hours. The room temperature strength of the prepared heat-resistant cast aluminum alloy is similar to that of Example 3, but the high temperature strength is enhanced.
[0064] Example 4
[0065] The difference between this example and Example 1 is that the raw materials thereof, calculated by mass percentage, include: Cu: 9%, Ca: 1.2%, Ti: 0.18%, Sc: 0.05%, and the balance is Al.
[0066] The heat-resistant cast aluminum alloy prepared in Example 4 has a tensile strength of 429 MPa and a yield strength of 310 MPa at room temperature; a tensile strength of 254 MPa and a yield strength of 191 MPa at a high temperature of 250°C; an elongation of more than 6% at room temperature and more than 10% at a high temperature of 250°C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0067] Only the single-stage aging treatment after the solution treatment in step S8 in the preparation method of the heat-resistant cast aluminum alloy described in Example 4 is replaced by a regression aging treatment: aging at 220°C for 18 hours, aging at 480°C for 150 minutes, and then aging at 250°C for 6 hours. The room temperature strength of the prepared heat-resistant cast aluminum alloy is similar to that of Example 4, but the high temperature strength is enhanced.
[0068] Example 5
[0069] The raw materials of the heat-resistant cast aluminum alloy include, by mass percentage, Cu: 9%, Ca: 1.0%, Mn: 0.27%, Ce: 0.15%, Sc: 0.13%, Ti: 0.23%, and the balance is Al.
[0070] A method for preparing a heat-resistant cast aluminum alloy comprises the following steps:
[0071] S1. Dry the calculated weight of pure Al, Al-Cu, Al-Ca, Al-Ce, Al-Sc, Al-Mn and Al-Ti master alloys.
[0072] S2. Put pure Al into a smelting furnace to melt, and maintain the melt temperature at 750°C after it is completely melted.
[0073] S3. Put the dried Al-Cu, Al-Ca, Al-Ce, Al-Sc, Al-Mn and Al-Ti master alloys into the molten aluminum liquid, and stir and remove slag after the master alloys are melted.
[0074] S4. Adjust the solution temperature to 740°C, add a refining agent to the melt, stir and remove the slag.
[0075] S5. Adjust the solution temperature to 720°C, use a degassing device to purify the alloy melt, and then let it stand for 20 minutes.
[0076] S7. Cast into a steel mold preheated to 200°C.
[0077] S8. Perform solution aging treatment on the alloy taken out from the mold, specifically: solution treatment at 535°C for 18 hours, aging at 220°C for 18 hours, aging at 480°C for 150 minutes, and then aging at 250°C for 6 hours.
[0078] The heat-resistant cast aluminum alloy prepared in Example 5 has a tensile strength of 441 MPa and a yield strength of 323 MPa at room temperature; a tensile strength of 263 MPa and a yield strength of 194 MPa at a high temperature of 250°C; an elongation of more than 6% at room temperature and more than 10% at a high temperature of 250°C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0079] Example 6
[0080] The raw materials of the heat-resistant cast aluminum alloy include, by weight percentage, 10.3% Cu, 1.1% Ca, 0.18% Mn, 0.18% La, 0.24% Er, and the balance Al.
[0081] A method for preparing a heat-resistant cast aluminum alloy comprises the following steps:
[0082] S1. Dry the calculated weight of pure Al, Al-Cu, Al-Ca, Al-La, Al-Mn and Al-Er master alloys.
[0083] S2. Put pure Al into a smelting furnace to melt, and maintain the melt temperature at 750°C after it is completely melted.
[0084] S3. Put the dried Al-Cu, Al-Ca, Al-Ce, Al-Sc, Al-Mn and Al-Ti master alloys into the molten aluminum liquid, and stir and remove slag after the master alloys are melted.
[0085] S4. Adjust the solution temperature to 740°C, add a refining agent to the melt, stir and remove the slag.
[0086] S5. Adjust the solution temperature to 720°C, use a degassing device to purify the alloy melt, and then let it stand for 20 minutes.
[0087] S7. Cast into a steel mold preheated to 200°C.
[0088] S8. Perform solution aging treatment on the alloy taken out from the mold, specifically: solution treatment at 535°C for 18 hours, aging at 350°C for 5 hours, aging at 550°C for 10 minutes, and then aging at 150°C for 25 hours.
[0089] The DSC curve and microstructure of the cast alloy of Example 5 are as follows: Figure 1 As shown, the second phase in the organization is mainly discontinuous strip-shaped Al 8 Cu 4 Ca eutectic phase and skeletal Al 2 Cu eutectic phase.
[0090] The heat-resistant cast aluminum alloy prepared in Example 6 has a tensile strength of 452 MPa and a yield strength of 334 MPa at room temperature; a tensile strength of 287 MPa and a yield strength of 202 MPa at a high temperature of 250°C; an elongation of more than 6% at room temperature and more than 10% at a high temperature of 250°C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0091] Example 7
[0092] The raw materials of the heat-resistant cast aluminum alloy are calculated by mass percentage and include: Cu: 12%, Ca: 0.5%, Mn: 0.27%, Ti: 0.23%, and the balance is Al.
[0093] A method for preparing a heat-resistant cast aluminum alloy comprises the following steps:
[0094] S1. Dry the calculated weight of pure Al, Al-Cu, Al-Ca, Al-Mn and Al-Ti master alloys.
[0095] S2. Put pure Al into a smelting furnace to melt, and maintain the melt temperature at 750°C after it is completely melted.
[0096] S3. Put the dried Al-Cu, Al-Ca, Al-Mn and Al-Ti master alloys into the molten aluminum liquid, and stir and remove slag after the master alloys are melted.
[0097] S4. Adjust the solution temperature to 740°C, add a refining agent to the melt, stir and remove the slag.
[0098] S5. Adjust the solution temperature to 720°C, purify the alloy melt using a degassing device, and then let it stand for 20 minutes.
[0099] S7. Cast into a steel mold preheated to 200°C.
[0100] S8. Perform solution aging treatment on the alloy taken out from the mold, specifically: solution treatment at 535°C for 18 hours, aging at 220°C for 18 hours, aging at 480°C for 150 minutes, and then aging at 250°C for 6 hours.
[0101] The heat-resistant cast aluminum alloy prepared in Example 7 has a tensile strength of 423 MPa and a yield strength of 306 MPa at room temperature; a tensile strength of 262 MPa and a yield strength of 187 MPa at a high temperature of 250°C; an elongation of more than 6% at room temperature and more than 10% at a high temperature of 250°C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0102] Comparative Example 1
[0103] The raw materials of the heat-resistant cast aluminum alloy include, by weight percentage, Cu: 5%, Ca: 1.2%, Mn: 0.3%, Ce: 0.5%, Sc: 0.3%, Ti: 0.5%, and the balance is Al.
[0104] The preparation method of a heat-resistant cast aluminum alloy is the same as that in Example 5.
[0105] The DSC curve and microstructure of the as-cast alloy of Comparative Example 1 are shown in Figure 2 As shown in the figure, the second phase in the organization is mainly a network eutectic phase continuously distributed at the grain boundary. The eutectic phase is mainly Al with a high melting point. 8 Cu 4 Ca ternary eutectic phase.
[0106] The heat-resistant cast aluminum alloy prepared in Comparative Example 1 has a tensile strength of 307 MPa and a yield strength of 143 MPa at room temperature; a tensile strength of 131 MPa and a yield strength of 97 MPa at a high temperature of 250°C; an elongation of more than 6% at room temperature and more than 10% at a high temperature of 250°C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0107] according to Figure 1 and Figure 2 The cast Al-Cu-Ca alloy was analyzed by differential scanning calorimetry and scanning electron microscopy. In Comparative Example 1, since the Cu / Ca mass ratio is less than 7:1, the main eutectic phase at the grain boundary in the alloy is Al 8 Cu 4 Ca ternary eutectic phase, binary eutectic phase Al 2 Cu is less or even non-existent, and the main strengthening phase θ'-Al is precipitated during the subsequent heat treatment. 2 The amount of Cu phase is small, so the room temperature and high temperature tensile strength and yield strength of the alloy of Comparative Example 1 are smaller than those of the alloys of Examples 1-7.
[0108] Comparative Example 2
[0109] The raw materials of the heat-resistant cast aluminum alloy are calculated by mass percentage and include: Cu: 4%, Ca: 0.5%, Mn: 0.27%, Ce: 0.15%, Sc: 0.13%, Ti: 0.23%, and the balance is Al.
[0110] The preparation method of a heat-resistant cast aluminum alloy is the same as that in Example 5.
[0111] The heat-resistant cast aluminum alloy prepared in Comparative Example 2 has a tensile strength of 367 MPa and a yield strength of 220 MPa at room temperature; a tensile strength of 215 MPa and a yield strength of 131 MPa at a high temperature of 250°C, an elongation of more than 6% at room temperature, and an elongation of more than 10% at a high temperature of 250°C. The present invention enhances the strength at room temperature and high temperature while ensuring the elongation.
[0112] Comparative Example 2 Compared with Examples 1-7, the Cu content is reduced and Al is generated in the alloy. 4 Ca phase, the strength of the alloy is weakened at room temperature and high temperature.
[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.
Claims
1. A heat-resistant cast aluminum alloy, It is characterized in that Containing the following elements in percentage by weight: Cu: 5-12wt.%, Ca: 0.5-2.0wt.%, RE≤0.8wt.%, Mn≤0.3wt.%, Ti≤0.5wt.%, the remainder being Al and unavoidable impurities; RE is Ce, La, Sc or Er; The preparation method of the heat-resistant cast aluminum alloy comprises the following steps: (1) preparing pure Al, Al-Cu, Al-Ca, Al-RE, Al-Mn and Al-Ti master alloys, melting pure Al, then adding Al-Cu, Al-Ca, Al-RE, Al-Mn and Al-Ti master alloys and stirring to obtain a uniform melt; (2) adding a refining agent to the melt, then purifying and standing the melt to obtain an alloy liquid; (3) cooling the alloy liquid and then casting it to obtain an ingot; (4) The ingot is subjected to solution treatment and aging treatment to obtain a heat-resistant cast aluminum alloy.
2. The heat-resistant cast aluminum alloy according to claim 1, It is characterized in that The mass ratio of Cu / Ca in the heat-resistant cast aluminum alloy is ≥7:
1.
3. The heat-resistant cast aluminum alloy according to claim 2, It is characterized in that The element comprises the following mass percentages: Cu: 9-10.5wt.%, Ca: 1.0-1.1wt.%, Mn: 0.18-0.27wt.%, 0.28≤RE≤0.45wt.%, Ti≤0.25wt.%, and the remainder is Al and unavoidable impurities.
4. The heat-resistant cast aluminum alloy according to claim 1, It is characterized in that The melting temperature is 740-760°C.
5. The heat-resistant cast aluminum alloy according to claim 1, It is characterized in that The melt temperature is adjusted to 730-780°C and then the refining agent is added.
6. The heat-resistant cast aluminum alloy according to claim 1, It is characterized in that The alloy melt is purified using a degassing device and then allowed to stand for 10-30 minutes.
7. The heat-resistant cast aluminum alloy according to claim 1, It is characterized in that The alloy liquid is cooled to 700-720°C for casting.
8. The heat-resistant cast aluminum alloy according to claim 1, It is characterized in that The solution temperature is 520-580° C., the heat preservation time is 12-30 hours, and the solution is quenched in hot water at 60-80° C.
9. The heat-resistant cast aluminum alloy according to claim 1, It is characterized in that The aging treatment is a single-stage aging treatment or a regression aging treatment; The temperature of the single-stage aging treatment is 165-250°C and the time is 5-48h; The regression aging treatment specifically includes: aging at a temperature of 200-350° C. for 5-25 hours, then aging at a temperature of 450-550° C. for 10-300 minutes, and then aging at 150-300° C. for 5-25 hours.