A method for preparing microalloyed high-temperature resistant aluminum alloy

Abstract

The present invention discloses a method for preparing a microalloyed high-temperature resistant aluminum alloy, wherein the high-temperature resistant aluminum alloy is composed of the following components by mass percentage: Cu: 4.7% to 5.04%, Fe: 0.98% to 1.08%, Ni: 1.45% to 1.6%, Mn: 0.51% to 0.56%, Mg: 0.45% to 0.55%, Ti: 0.18% to 0.2%, Ce: 0.2% to 0.32%, Zr: 0.05% to 0.3%, impurities, and the balance Al. The present invention can form an Al alloy with high thermal stability by adding Mn. 20 Cu3Mn2 precipitates and Mn gathers around the θ' phase to inhibit its coarsening, thereby improving the high-temperature strength and alloy properties of the aluminum alloy. Adding Fe and Ni to form a stable iron-rich phase Al9FeNi also helps to improve the thermal stability and high-temperature strength of the alloy. Ti adheres to the θ' precipitated phase and hinders its coarsening and refines the grains, synergistically improving the high-temperature strength of the aluminum alloy. Ce can form Al‑Ce‑M (M=Fe,Ti) intermetallic compounds, which can also synergistically improve the thermal stability of the aluminum alloy. In addition, the addition of a compound refining agent helps to improve the efficiency of degassing and impurity removal, and after deep purification, it promotes the high-temperature strength of the aluminum alloy. The overall effect of improving the high-temperature strength of the alloy is achieved.

Description

Technical Field

[0001] The present invention relates to the field of aluminum alloy preparation, and in particular to a method for preparing a micro-alloyed high-temperature resistant aluminum alloy. Background Art

[0002] Aluminum alloys, due to their low density and excellent thermal conductivity, are widely used in applications such as automobiles, ships, weapons, aerospace, and aviation. However, their poor mechanical properties at high temperatures limit further expansion of their application. Therefore, improving the high-temperature mechanical properties of aluminum alloys not only has important practical applications but also profound theoretical significance. Commonly used alloy systems in cast heat-resistant aluminum alloys include Al-Si and Al-Cu. The advantage of the Al-Si system lies in its excellent casting properties, enabling the formation of a variety of complex components. However, its relatively low strength at room temperature and high temperatures makes it unsuitable for the manufacture of parts requiring higher operating temperatures and strength requirements. In contrast, Al-Cu cast aluminum alloys offer superior heat resistance to Al-Si. For example, the applicable temperature for cast Al-Si-Mg alloys generally does not exceed 185°C, while the operating temperature for Al-Si-Cu-Mg alloys can be raised to 200°C to 225°C. This is primarily due to the presence of the W (Al4Mg5Si4Cu4) phase within the alloy, which maintains high thermal stability even at 225°C. Therefore, Al-Cu cast aluminum alloys have superior high-temperature mechanical properties and can be used in operating environments between 300°C and 400°C. However, when the operating temperature approaches 350°C, the main strengthening phase coarsens and loses its strengthening effect. Therefore, it is necessary to improve the high-temperature strength of Al-Cu alloys at 350°C and above.

[0003] Chinese Patent Publication No. CN 114807693A discloses a method for preparing a combined microalloyed, high-heat-resistant aluminum alloy and its application. The alloy comprises 0.01-0.05 wt.% Sb and 0.1-0.3 wt.% Mn, with the remainder being an aluminum alloy matrix. By combining the addition of Sb and Mn elements and performing a solution-assisted aging heat treatment, a heat-resistant alloy with a tensile strength of 150 MPa or greater at 300°C is obtained. Another example is Chinese Patent Publication No. CN109402441A, which discloses a method for preparing an aluminum-based composite material reinforced with AlN and Al2O3 particles using ultrafine aluminum powder and air as raw materials. This composite material exhibits a tensile strength of up to 130 MPa at 375°C. All of these patents achieve relatively good high-temperature performance through optimized composition design and preparation methods. However, the alloy disclosed in CN 114807693 A is close to pure aluminum, has poor casting properties, and its high-temperature resistance needs to be further improved. The method of CN 109402441 A has a complex preparation process, high cost, and is difficult to control, making it unsuitable for industrial application and production. Summary of the Invention

[0004] Based on this, in order to solve the technical problem of poor high-temperature mechanical properties of aluminum alloys prepared by the prior art, the present invention provides a method for preparing a micro-alloyed high-temperature resistant aluminum alloy. The specific technical solution is as follows:

[0005] A method for preparing a microalloyed high-temperature resistant aluminum alloy, comprising the following steps:

[0006] The pure aluminum ingot is then added to the melting furnace, and Al-Fe alloy, Al-Mn alloy, Al-Ni alloy and Al-Cu alloy are added in sequence, heated for melting, and after being completely melted, raw materials containing Ti, Mg, Zr and Ce elements are added, and electromagnetic stirring is used to promote melt flow to obtain a highly uniform melt;

[0007] Using an inert gas as a carrier, a refining agent with a mass fraction of 0.05% to 0.15% is introduced for the first refining, and the first refining is carried out at a temperature of 720° C. to 750° C. for 10 to 30 minutes, sampling and testing the composition, and adjusting the alloy composition;

[0008] The scum on the surface of the melt is removed, and a refining agent with a mass fraction of 0.03% to 0.13% is introduced with an inert gas as a carrier to perform a second refining, and the second refining is carried out at a temperature of 720°C to 750°C for 10 minutes to 30 minutes;

[0009] After the second refining is completed, the scum on the surface of the melt is removed again, and then the melt is introduced into the degassing and filtration device for online degassing and online filtration, and flows through the launder into the holding furnace and directly supplied to the casting molding machine for casting processing to obtain ingots;

[0010] The ingot is subjected to T6 heat treatment, and the conditions of the T6 heat treatment are: raising the furnace temperature to 500°C to 550°C and maintaining it for 10h to 15h, then quickly taking it out and quenching it to room temperature, then raising the temperature to 150°C to 200°C, keeping it for 6h to 10h, air cooling, completing aging treatment, and obtaining a high-temperature resistant aluminum alloy.

[0011] Furthermore, the high-temperature resistant aluminum alloy is composed of the following components in mass percentage: Cu: 4.7% to 5.04%, Fe: 0.98% to 1.08%, Ni: 1.45% to 1.6%, Mn: 0.51% to 0.56%, Mg: 0.45% to 0.55%, Ti: 0.18% to 0.2%, Ce: 0.2% to 0.32%, Zr: 0.05% to 0.3%, the total amount of unavoidable impurity elements does not exceed 0.3%, and the balance is Al.

[0012] Furthermore, the temperature of the smelting treatment is 750-800°C.

[0013] Furthermore, the average particle size of the refining agent is 0.5 mm to 3 mm.

[0014] Furthermore, the refining agent consists of KCl, MnCl2 and K2CO3 in a mass ratio of (1-3): (1-5): (1-2).

[0015] Furthermore, the preparation method of the refining agent is: KCl, MnCl2 and K2CO3 are mixed, dried at 100℃~120℃, calcined at 500℃~800℃ for 20min~30min, and pulverized after cooling.

[0016] Furthermore, during the first refining and the second refining, the flow rate of the inert gas is controlled to be 45 L / min to 60 L / min.

[0017] Furthermore, the online degassing time is 10 min to 40 min, and the online degassing uses N2 as the covering gas, the pressure is 0.15 MPa to 0.35 MPa, and the flow rate is 50 L / min to 120 L / min.

[0018] Furthermore, the online filtration is performed using a two-stage foam ceramic filter plate with a front mesh size of 40 to 60 and a rear mesh size of 60 to 80.

[0019] Furthermore, the casting process speed is 15mm / min to 30mm / min, the temperature is 720℃ to 750℃, and the flow rate of cooling water is 25m 3 / h~30m 3 / h.

[0020] Compared with the prior art, this application has the following beneficial effects:

[0021] The present invention improves the high-temperature mechanical properties of aluminum alloys by optimizing the alloy composition ratio and heat treatment process. The invention has the following significant advantages: (1) By adding trace alloying elements to traditional aluminum alloys, the high-temperature mechanical properties of aluminum alloys can be significantly improved; (2) The preparation method of the present invention significantly enhances the thermal stability of aluminum alloys during long-term high-temperature exposure; (3) The aluminum alloy of the present invention has excellent heat resistance, with the tensile strength, yield strength and elongation at 300°C reaching 270MPa, 195MPa and more than 4.0% respectively, the tensile strength, yield strength and elongation at 350°C reaching 225MPa, 155MPa and more than 4.5% respectively, and the tensile strength at 400°C still reaching 145MPa, 13MPa and more than 7.0%, which can meet the requirements of aluminum alloy parts with different heat resistance requirements; (4) The preparation process is simple, no special treatment is required, and mass production can be achieved. Therefore, the present invention is based on Al-Cu alloys and significantly improves the heat resistance of the alloy through composition design, microalloying and heat treatment, making it suitable for manufacturing structural components of aircraft such as aircraft, rockets, missiles, and automobile engine parts.

[0022] Specifically, by adding a small amount of Mn element, Al 20 Cu3Mn2 precipitates, with Mn clustering around the θ' phase, inhibiting its coarsening and improving the high-temperature strength of the aluminum alloy. Furthermore, the formation of flaky iron-rich phases is suppressed, resulting in a spatially interconnected network of iron-rich phases, Al6(FeMn), thereby improving the alloy's performance. Simultaneously, appropriate amounts of Fe and Ni are added to form a stable iron-rich phase, Al9FeNi, enhancing the alloy's thermal stability and high-temperature strength. Ti, with its slow diffusion rate in the aluminum matrix, adheres to the θ' precipitates and inhibits their coarsening, further improving the alloy's high-temperature strength. Furthermore, Ti, as a refining element, refines the grain size, synergistically enhancing the alloy's room-temperature strength. Ce forms an Al-Ce-M (M=Fe,Ti) intermetallic compound, further enhancing the alloy's thermal stability. Furthermore, the addition of a compounded refining agent not only improves degassing and impurity removal efficiency but also, after deep purification, positively impacts the alloy's heat-resistant strength. Overall, the present invention achieves improved high-temperature strength through optimized component ratios. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] In one embodiment of the present invention, a method for preparing a microalloyed high-temperature resistant aluminum alloy comprises the following steps:

[0026] The pure aluminum ingot is then added to the melting furnace, and Al-Fe alloy, Al-Mn alloy, Al-Ni alloy and Al-Cu alloy are added in sequence, heated for melting, and after being completely melted, raw materials containing Ti, Mg, Zr and Ce elements are added, and electromagnetic stirring is used to promote melt flow to obtain a highly uniform melt;

[0027] Using an inert gas as a carrier, a refining agent with a mass fraction of 0.05% to 0.15% is introduced for the first refining, and the first refining is carried out at a temperature of 720° C. to 750° C. for 10 to 30 minutes, sampling and testing the composition, and adjusting the alloy composition;

[0028] The scum on the surface of the melt is removed, and a refining agent with a mass fraction of 0.03% to 0.13% is introduced with an inert gas as a carrier to perform a second refining, and the second refining is carried out at a temperature of 720°C to 750°C for 10 minutes to 30 minutes;

[0029] After the second refining is completed, the scum on the surface of the melt is removed again, and then the melt is introduced into the degassing and filtration device for online degassing and online filtration, and flows through the launder into the holding furnace and directly supplied to the casting molding machine for casting processing to obtain ingots;

[0030] The ingot is subjected to T6 heat treatment, and the conditions of the T6 heat treatment are: raising the furnace temperature to 500°C to 550°C and maintaining it for 10h to 15h, then quickly taking it out and quenching it to room temperature, then raising the temperature to 150°C to 200°C, keeping it for 6h to 10h, air cooling, completing aging treatment, and obtaining a high-temperature resistant aluminum alloy.

[0031] In one embodiment, the high temperature resistant aluminum alloy is composed of the following components in mass percentage: Cu: 4.7% to 5.04%, Fe: 0.98% to 1.08%, Ni: 1.45% to 1.6%, Mn: 0.51% to 0.56%, Mg: 0.45% to 0.55%, Ti: 0.18% to 0.2%, Ce: 0.2% to 0.32%, Zr: 0.05% to 0.3%, the total amount of unavoidable impurity elements does not exceed 0.3%, and the balance is Al.

[0032] In one embodiment, the smelting temperature is 750-800°C.

[0033] In one embodiment, the average particle size of the refining agent is 0.5 mm to 3 mm.

[0034] In one embodiment, the refining agent consists of KCl, MnCl2 and K2CO3 in a mass ratio of (1-3): (1-5): (1-2).

[0035] In one embodiment, the refining agent is prepared by mixing KCl, MnCl2 and K2CO3, drying them at 100°C to 120°C, calcining them at 500°C to 800°C for 20min to 30min, and then cooling and crushing them.

[0036] In one embodiment, during the first refining and the second refining, the flow rate of the inert gas is controlled to be 45 L / min to 60 L / min.

[0037] In one embodiment, the online degassing time is 10 min to 40 min, and the online degassing uses N2 as the covering gas with a pressure of 0.15 MPa to 0.35 MPa and a flow rate of 50 L / min to 120 L / min.

[0038] In one embodiment, the online filtration is performed using a two-stage foam ceramic filter plate with a front mesh of 40 to 60 mesh and a rear mesh of 60 to 80 mesh.

[0039] In one embodiment, the casting process speed is 15mm / min to 30mm / min, the temperature is 720℃ to 750℃, and the flow rate of cooling water is 25m 3 / h~30m 3 / h.

[0040] The above scheme can obtain an aluminum alloy with excellent high-temperature resistance and strength by optimizing the composition and component ratio.

[0041] The embodiments of the present invention will be described in detail below with reference to specific examples.

[0042] Example 1:

[0043] A microalloyed high-temperature resistant aluminum alloy consists of the following components in percentage by mass: Cu: 4.7%, Fe: 0.98%, Ni: 1.45%, Mn: 0.51%, Mg: 0.45%, Ti: 0.18%, Ce: 0.32%, Zr: 0.1%, the total amount of unavoidable impurity elements does not exceed 0.3%, and the balance is Al.

[0044] A method for preparing a microalloyed high-temperature resistant aluminum alloy comprises the following steps:

[0045] Mix KCl, MnCl2 and K2CO3 in a mass ratio of 3:1:1, dry them at 120℃, calcine them at 650℃ for 25min, cool them down and grind them to obtain a refining agent with an average particle size of 1mm for later use;

[0046] The pure aluminum ingot is then added to the melting furnace, and Al-Fe alloy, Al-Mn alloy, Al-Ni alloy and Al-Cu alloy are added in sequence. The alloy is smelted at 750°C. After the alloy is completely melted, raw materials containing Ti, Mg, Zr and Ce are added. Electromagnetic stirring is used to promote melt flow to obtain a highly uniform melt.

[0047] The inert gas flow rate was controlled to 45 L / min and a refining agent with a mass fraction of 0.15% was introduced using the inert gas as a carrier for the first refining. The first refining was kept at 750° C. for 30 minutes, and samples were taken for composition testing and the alloy composition was adjusted.

[0048] The scum on the surface of the melt was removed, and the flow rate of the inert gas was controlled to 45 L / min. A refining agent with a mass fraction of 0.12% was introduced using the inert gas as a carrier to perform a second refining. The second refining was kept at 750°C for 30 minutes.

[0049] After the second refining is completed, the scum on the surface of the melt is removed again, and then the melt is introduced into the degassing and filtration device for online degassing and online filtration. The online degassing time is 20 minutes. The online degassing uses N2 as the cover gas with a pressure of 0.15 MPa and a flow rate of 80 L / min. The online filtration uses a two-stage foam ceramic filter plate with a front mesh of 40 mesh and a rear mesh of 60 mesh for filtration.

[0050] The liquid flows into the holding furnace through the flow channel and is directly supplied to the casting molding machine for casting processing. The casting processing speed is 25mm / min, the temperature is 720℃, and the cooling water flow rate is 30m 3 / h, to obtain an ingot;

[0051] The ingot is subjected to T6 heat treatment. The conditions of the T6 heat treatment are: raising the furnace temperature to 538°C and maintaining it for 12 hours, then quickly taking it out and quenching it to room temperature, then raising the temperature to 160°C, maintaining it for 8 hours, and air cooling to complete aging treatment to obtain a high-temperature resistant aluminum alloy.

[0052] Example 2:

[0053] A microalloyed high-temperature resistant aluminum alloy consists of the following components in percentage by mass: Cu: 4.85%, Fe: 1.02%, Ni: 1.52%, Mn: 0.53%, Mg: 0.48%, Ti: 0.19%, Ce: 0.24%, Zr: 0.21%, the total amount of unavoidable impurity elements does not exceed 0.3%, and the balance is Al.

[0054] A method for preparing a microalloyed high-temperature resistant aluminum alloy comprises the following steps:

[0055] Mix KCl, MnCl2 and K2CO3 in a mass ratio of 2:2:1, dry them at 120℃, calcine them at 700℃ for 20min, cool them down and grind them to obtain a refining agent with an average particle size of 1mm for later use;

[0056] The pure aluminum ingot is then added to the melting furnace, and Al-Fe alloy, Al-Mn alloy, Al-Ni alloy and Al-Cu alloy are added in sequence. The alloy is smelted at 750°C. After the alloy is completely melted, raw materials containing Ti, Mg, Zr and Ce are added. Electromagnetic stirring is used to promote melt flow to obtain a highly uniform melt.

[0057] The inert gas flow rate was controlled to 45 L / min and a refining agent with a mass fraction of 0.15% was introduced using the inert gas as a carrier for the first refining. The first refining was kept at 720° C. for 20 minutes. Samples were taken for composition testing and the alloy composition was adjusted.

[0058] The scum on the surface of the melt was removed, and the flow rate of the inert gas was controlled to 45 L / min. A refining agent with a mass fraction of 0.1% was introduced using the inert gas as a carrier to perform a second refining, and the second refining was kept at 720°C for 20 minutes;

[0059] After the second refining is completed, the scum on the surface of the melt is removed again, and then the melt is introduced into the degassing and filtration device for online degassing and online filtration. The online degassing time is 20 minutes. The online degassing uses N2 as the cover gas with a pressure of 0.15 MPa and a flow rate of 80 L / min. The online filtration uses a two-stage foam ceramic filter plate with a front mesh of 50 mesh and a rear mesh of 70 mesh for filtration.

[0060] The liquid flows into the holding furnace through the flow channel and is directly supplied to the casting molding machine for casting processing. The casting processing speed is 25mm / min, the temperature is 720℃, and the flow rate of cooling water is 25m 3 / h, to obtain an ingot;

[0061] The ingot is subjected to T6 heat treatment. The conditions of the T6 heat treatment are: raising the furnace temperature to 520°C and maintaining it for 11 hours, then quickly taking it out and quenching it to room temperature, then raising the temperature to 170°C, maintaining it for 8 hours, and air cooling to complete aging treatment to obtain a high-temperature resistant aluminum alloy.

[0062] Example 3:

[0063] A microalloyed high-temperature resistant aluminum alloy consists of the following components in percentage by mass: Cu: 4.96%, Fe: 1.05%, Ni: 1.57%, Mn: 0.55%, Mg: 0.51%, Ti: 0.2%, Ce: 0.28%, Zr: 0.27%, the total amount of unavoidable impurity elements does not exceed 0.3%, and the balance is Al.

[0064] A method for preparing a microalloyed high-temperature resistant aluminum alloy comprises the following steps:

[0065] Mix KCl, MnCl2 and K2CO3 in a mass ratio of 1:3:1, dry them at 120℃, calcine them at 700℃ for 20min, cool them down and grind them to obtain a refining agent with an average particle size of 1mm for later use;

[0066] The pure aluminum ingot is then added to the melting furnace, and Al-Fe alloy, Al-Mn alloy, Al-Ni alloy and Al-Cu alloy are added in sequence. The alloy is smelted at 750°C. After the alloy is completely melted, raw materials containing Ti, Mg, Zr and Ce are added. Electromagnetic stirring is used to promote melt flow to obtain a highly uniform melt.

[0067] The inert gas flow rate was controlled to 45 L / min and a refining agent with a mass fraction of 0.1% was introduced using the inert gas as a carrier for the first refining. The first refining was kept at 720° C. for 15 minutes, and samples were taken for composition testing and the alloy composition was adjusted.

[0068] The scum on the surface of the melt was removed, and the flow rate of the inert gas was controlled to 45 L / min. A refining agent with a mass fraction of 0.05% was introduced using the inert gas as a carrier to perform a second refining, and the second refining was kept at 720°C for 15 minutes;

[0069] After the second refining is completed, the scum on the surface of the melt is removed again, and then the melt is introduced into the degassing and filtration device for online degassing and online filtration. The online degassing time is 20 minutes. The online degassing uses N2 as the cover gas with a pressure of 0.15 MPa and a flow rate of 80 L / min. The online filtration uses a two-stage foam ceramic filter plate with a front mesh of 60 mesh and a rear mesh of 80 mesh for filtration.

[0070] The liquid flows through the launder into the holding furnace and is directly supplied to the casting molding machine for casting. The casting speed is 25 mm / min, the temperature is 730°C, and the cooling water flow rate is 30 m 3 / h, to obtain an ingot;

[0071] The ingot is subjected to T6 heat treatment. The conditions of the T6 heat treatment are: raising the furnace temperature to 540°C and maintaining it for 14 hours, then quickly taking it out and quenching it to room temperature, then raising the temperature to 180°C, maintaining it for 6 hours, and air cooling to complete aging treatment to obtain a high-temperature resistant aluminum alloy.

[0072] Example 4:

[0073] A microalloyed high-temperature resistant aluminum alloy consists of the following components in percentage by mass: Cu: 5.04%, Fe: 1.08%, Ni: 1.6%, Mn: 0.56%, Mg: 0.55%, Ti: 0.2%, Ce: 0.2%, Zr: 0.3%, the total amount of unavoidable impurity elements does not exceed 0.3%, and the balance is Al.

[0074] A method for preparing a microalloyed high-temperature resistant aluminum alloy comprises the following steps:

[0075] Mix KCl, MnCl2 and K2CO3 in a mass ratio of 2:1:2, dry them at 120°C, calcine them at 650°C for 20 minutes, cool them down and grind them to obtain a refining agent with an average particle size of 1 mm for later use;

[0076] The pure aluminum ingot is then added to the melting furnace, and Al-Fe alloy, Al-Mn alloy, Al-Ni alloy and Al-Cu alloy are added in sequence. The alloy is smelted at 750°C. After the alloy is completely melted, raw materials containing Ti, Mg, Zr and Ce are added. Electromagnetic stirring is used to promote melt flow to obtain a highly uniform melt.

[0077] The inert gas flow rate was controlled to 45 L / min and a refining agent with a mass fraction of 0.13% was introduced using the inert gas as a carrier for the first refining. The first refining was kept at 720° C. for 20 minutes, and samples were taken for composition testing and the alloy composition was adjusted.

[0078] The scum on the surface of the melt was removed, and the flow rate of the inert gas was controlled to 45 L / min. A refining agent with a mass fraction of 0.06% was introduced using the inert gas as a carrier to perform a second refining, and the second refining was kept at 720°C for 20 minutes;

[0079] After the second refining is completed, the scum on the surface of the melt is removed again, and then the melt is introduced into the degassing and filtration device for online degassing and online filtration. The online degassing time is 20 minutes. The online degassing uses N2 as the cover gas with a pressure of 0.15 MPa and a flow rate of 80 L / min. The online filtration uses a two-stage foam ceramic filter plate with a front mesh of 40 mesh and a rear mesh of 80 mesh for filtration.

[0080] The liquid flows through the launder into the holding furnace and is directly supplied to the casting molding machine for casting. The casting speed is 25 mm / min, the temperature is 730°C, and the cooling water flow rate is 30 m 3 / h, to obtain an ingot;

[0081] The ingot is subjected to T6 heat treatment. The conditions of the T6 heat treatment are: raising the furnace temperature to 520°C and maintaining it for 10 hours, then quickly taking it out and quenching it to room temperature, then raising the temperature to 150°C, maintaining it for 7 hours, and air cooling to complete aging treatment to obtain a high-temperature resistant aluminum alloy.

[0082] Comparative Example 1:

[0083] Compared with Example 1, Comparative Example 1 does not add Ce, and the other parts are the same as Example 1.

[0084] Comparative Example 2:

[0085] Compared with Example 2, Comparative Example 2 has the following characteristics: the addition amount of Mn in Comparative Example 2 is 0.2%, the addition amount of Mg is 0.25%, and the others are the same as Example 2.

[0086] Comparative Example 3:

[0087] Compared with Example 3, Comparative Example 3 does not add Mn, and the other parts are the same as Example 3.

[0088] Comparative Example 4:

[0089] Compared with Example 4, Comparative Example 4 has the following characteristics: the amount of Fe added in Comparative Example 4 is 0.5%, the amount of Ni added in Comparative Example 4 is 1.6%, and the others are the same as Example 4.

[0090] Standard tensile specimens were prepared from the aluminum alloys of Examples 1-4 and Comparative Examples 1-4 and subjected to high-temperature tensile testing at 300°C, 350°C, and 400°C on a microcomputer-controlled electronic universal testing machine. The loading rate was 1 mm / min, and at least three sets of tests were performed for each alloy group. The test results are shown in Tables 1-3.

[0091] Table 1: Mechanical properties at 300℃

[0092]

[0093]

[0094] Table 2: Mechanical properties at 350℃

[0095]

[0096] Table 3: Mechanical properties at 400℃

[0097]

[0098] Analysis of the data in Tables 1 to 3 demonstrates that, under identical conditions, the aluminum alloy material designed in this invention exhibits superior mechanical properties after casting and T6 heat treatment, with significantly superior high-temperature strength compared to existing materials. The tensile strength of the alloy prepared in Example 1 at 300°C, 350°C, and 400°C increased by 23.5%, 16.2%, and 19.2%, respectively, compared to Comparative Example 1, which lacks Ce. It can be seen from Example 2 and Comparative Example 2 that when the Mn and Mg contents are increased from 0.25% and 0.2% to 0.53% and 0.48%, the high-temperature strength of the alloy at 300°C, 350°C and 400°C is increased by 17.2%, 20.0% and 21.4%, respectively, indicating that appropriately increasing the Mn and Mg contents is helpful to improve the alloy performance; from the high-temperature performance of Example 3 and Comparative Example 3, it can be seen that adding Mn is beneficial to improving the high-temperature performance of the alloy. Compared with the alloy without adding Mn, the tensile strength of the alloy in Example 3 at 300°C, 350°C and 400°C is increased by 15.5%, 24.9% and 18.1%, respectively, and the high-temperature strength is significantly improved. Comparative Example 4 and Comparative Example 4 demonstrate that increasing the Fe content improves the alloy's high-temperature performance. When the Fe content is increased from 0.4% to 1.08%, the alloy's tensile strength at 300°C, 350°C, and 400°C increases by 30.3%, 21.6%, and 26.3%, respectively. Therefore, high-temperature-resistant aluminum alloys prepared by multi-component microalloying fully meet the high-strength and high-toughness requirements of the aerospace and automotive industries, and can be used in the manufacture of aircraft structural components and automotive engine blocks.

[0099] In addition, in order to study the effect of the refining agent on the high-temperature strength of the aluminum alloy, comparative examples 5 to 8 were prepared. Compared with Example 4, comparative examples 5 to 8 differed only in the composition and ratio of the refining agent, and were the same as Example 4 in other respects. The composition and ratio of the refining agent of comparative examples 5 to 8 are shown in Table 4, and the mechanical property test results at 400°C are shown in Table 4.

[0100] Table 4: Refining agent and mechanical properties test results

[0101]

[0102] From the data analysis in Table 4, it can be seen that optimizing the composition and ratio of the refining agent in this application helps to improve the high-temperature mechanical properties of the aluminum alloy.

[0103] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing a microalloyed high temperature resistant aluminum alloy, characterized in that: The preparation method The following steps are involved: The pure aluminum ingot is then added to the melting furnace, and Al-Fe alloy, Al-Mn alloy, Al-Ni alloy and Al-Cu alloy are added in sequence, heated for melting, and after being completely melted, raw materials containing Ti, Mg, Zr and Ce elements are added, and electromagnetic stirring is used to promote melt flow to obtain a highly uniform melt; Using an inert gas as a carrier, a refining agent with a mass fraction of 0.05% to 0.15% is introduced for the first refining, and the first refining is carried out at a temperature of 720° C. to 750° C. for 10 to 30 minutes, sampling and testing the composition, and adjusting the alloy composition; The scum on the surface of the melt is removed, and a refining agent with a mass fraction of 0.03% to 0.13% is introduced with an inert gas as a carrier to perform a second refining, and the second refining is carried out at a temperature of 720°C to 750°C for 10 minutes to 30 minutes; After the second refining is completed, the scum on the surface of the melt is removed again, and then the melt is introduced into the degassing and filtration device for online degassing and online filtration, and flows through the launder into the holding furnace and directly supplied to the casting molding machine for casting processing to obtain ingots; The ingot is subjected to T6 heat treatment, wherein the conditions of the T6 heat treatment are as follows: the furnace temperature is raised to 500° C. to 550° C. and maintained for 10 h to 15 h, then quickly taken out and quenched to room temperature, then the temperature is raised to 150° C. to 200° C., maintained for 6 h to 10 h, and air-cooled to complete aging treatment to obtain a high-temperature resistant aluminum alloy; Wherein, the high temperature resistant aluminum alloy is composed of the following components in percentage by mass: Composition: Cu: 4.7% ~ 5.04%, Fe: 0.98% ~ 1.08%, Ni: 1.45% ~ 1.6%, Mn: 0.51% ~ 0.56%, Mg: 0.45% ~ 0.55%, Ti: 0.18% ~ 0.2%, Ce: 0.2% ~ 0.32%, Zr: 0.05% ~ 0.3%, the total amount of unavoidable impurity elements does not exceed 0.3%, the balance is Al; The refining agent is composed of KCl, MnCl2 and K2CO3 in a mass ratio of (1-3): (1-5): (1-2). The preparation method of the refining agent is: KCl, MnCl2 and K2CO3 are mixed, dried at 100°C to 120°C, calcined at 500°C to 800°C for 20min to 30min, and pulverized after cooling.

2. The preparation method according to claim 1, characterized in that The temperature of the smelting treatment is 750-800°C.

3. The preparation method according to claim 1, characterized in that The average particle size of the refining agent is 0.5 mm to 3 mm.

4. The preparation method according to claim 1, characterized in that During the first refining and the second refining, the flow rate of the inert gas is controlled to be 45 L / min to 60 L / min.

5. The preparation method according to claim 1, characterized in that The online degassing time is 10 min to 40 min, and the online degassing uses N2 as the covering gas, with a pressure of 0.15 MPa to 0.35 MPa and a flow rate of 50 L / min to 120 L / min.

6. The preparation method according to claim 5, characterized in that The online filtration adopts a two-stage foam ceramic filter plate with a front mesh of 40 to 60 meshes and a rear mesh of 60 to 80 meshes for filtration.

7. The preparation method according to claim 1, characterized in that The casting process speed is 15mm / min to 30mm / min, the temperature is 720℃ to 750℃, and the flow rate of cooling water is 25m 3 / h~30m 3 / h.

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