A multi-step solution heat treatment method for improving high-temperature tensile and endurance properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys

Abstract

The present application relates to a kind of multi-step solid solution heat treatment methods for improving the high temperature tensile and endurance performance of Al-Cu-Mg-Ag-Mn-Zr deformation alloy, belong to aluminum alloy technical field, to solve at least one of the problems such as the high temperature tensile and endurance performance of Al-Cu-Mg-Ag-Mn-Zr deformation alloy prepared by existing method is not good, application range is limited etc..The method of the present application obtains smaller size excess phase and coarser matrix grain after three-step solid solution heat treatment process, ensures that the alloy has excellent high temperature tensile and endurance performance.Meanwhile, the alloy element of back solution increases the effect of subsequent aging precipitation, so that the alloy also has higher room temperature tensile performance.The alloy treated by the present application can be used under high temperature and high stress conditions for a short time and under high temperature and low stress conditions for a long time.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, and in particular to a multi-step solution heat treatment method for improving the high-temperature tensile and creep properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys. Background Technology

[0002] In recent years, with the continuous development of the aviation industry, higher requirements have been placed on heat-resistant aluminum alloys as lightweight aerospace structural materials. Aerospace structural components are subjected to temperature and loads while flying at high speeds, requiring heat-resistant aluminum alloys to withstand high stresses at high temperatures, and to be able to serve for hundreds of hours at low stresses at high temperatures without fracture.

[0003] Al-Cu-Mg-Ag-Mn-Zr alloys represent an important research direction in heat-resistant wrought aluminum alloys. These alloys are primarily strengthened by nanoscale precipitates of the Ω phase. The Ω phase can pin dislocations and exhibits good high-temperature stability, providing stable strengthening at both room temperature and high temperatures. To obtain more Ω phase, a significant amount of alloying elements such as Cu, Mg, and Ag are incorporated into these alloys.

[0004] However, due to the high degree of alloying in this series, a large number of coarse excess phases are easily formed during industrial semi-continuous casting, which seriously affects the high-temperature tensile and creep rupture properties of the alloy. Simultaneously, the alloy exhibits fine grains after deformation processing, which is also detrimental to its high-temperature tensile and creep rupture properties. These problems limit the application of Al-Cu-Mg-Ag-Mn-Zr heat-resistant wrought aluminum alloys. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a multi-step solution heat treatment method to improve the high-temperature tensile and creep properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys, in order to solve at least one of the problems of poor high-temperature tensile and creep properties and limited application range of Al-Cu-Mg-Ag-Mn-Zr wrought alloys prepared by existing methods.

[0006] In a first aspect, the present invention provides a multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys, comprising the following steps:

[0007] (1) Heat the Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts from room temperature to 360-400℃ and perform a first heat preservation treatment.

[0008] (2) Heat the deformed part after the heat preservation treatment in step (1) to 510-530℃ and perform a second heat preservation treatment;

[0009] (3) Heat the deformed part after the heat preservation treatment in step (2) to 540-560℃, perform a third heat preservation treatment, and cool it to room temperature to obtain aluminum alloy billet.

[0010] Furthermore, in step (1), the heating rate is 100-200℃ / h.

[0011] Furthermore, in step (1), the heat preservation time is 4 to 12 hours.

[0012] Furthermore, in step (2), the heating rate is 30–60 °C / h.

[0013] Furthermore, in step (2), the heat preservation time is 2 to 4 hours.

[0014] Furthermore, in step (3), the heating rate is 1 to 10 °C / h.

[0015] Furthermore, in step (3), the heat preservation time is 4 to 8 hours.

[0016] Furthermore, the method also includes step (4), which involves aging the aluminum alloy billet to obtain an Al-Cu-Mg-Ag-Mn-Zr wrought alloy.

[0017] Furthermore, the heating temperature during the aging treatment is 160–190℃, and the holding time is 4–24 hours.

[0018] Secondly, the present invention provides an Al-Cu-Mg-Ag-Mn-Zr deformable alloy prepared by the above method.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] (1) The method of the present invention uses a three-step solution heat treatment process. The first step of the solution heat treatment is at a low temperature, which can consume the stored energy of the transformed alloy. With a reasonable heating rate, the driving force for recrystallization nucleation can be reduced, thereby avoiding grain refinement of the alloy. The second step of the solution heat treatment is at the same temperature as the traditional single-step solution heat treatment, which can eliminate the low melting point phase and increase the initial melting point of the alloy. With a reasonable heating rate, the heating temperature can be further increased. The third step of the solution heat treatment uses the highest possible solution temperature without overheating, which can increase the phase transformation driving force of the excess phase and the diffusion ability of alloying elements, thereby increasing the degree of excess phase re-dissolution into the matrix. At the same time, the increase in temperature can further coarsen the matrix grains, so that the alloy obtains better high-temperature tensile and creep properties than the traditional single-step solution heat treatment method.

[0021] (2) The method of the present invention obtains an Al-Cu-Mg-Ag-Mn-Zr wrought alloy with no loss of room temperature tensile properties by artificial aging treatment after multi-step solution heat treatment. This heat treatment process is easy to implement and can be effectively applied to the industrial production of Al-Cu-Mg-Ag-Mn-Zr system products. This is because after the solution heat treatment of the present invention, the dissolved alloying elements precipitate again in the form of nano-strengthening phases in the subsequent aging process, which can offset the adverse effect of grain coarsening on the room temperature strength of the alloy, so that the alloy also has high room temperature tensile properties. The alloy treated by the present invention can be used for a short time under high temperature and high stress conditions and for a long time under high temperature and low stress conditions.

[0022] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0023] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0024] Figure 1 Metallographic image of the alloy grain structure prepared in Example 1;

[0025] Figure 2 SEM image of the excess phase microstructure of the alloy prepared in Example 1;

[0026] Figure 3 Metallographic image of the grain structure of the alloy prepared in Comparative Example 1;

[0027] Figure 4 SEM image of the excess phase microstructure of the alloy prepared in Comparative Example 1;

[0028] Figure 5 Metallographic image of the alloy grain structure prepared in Example 3;

[0029] Figure 6 SEM image of the excess phase microstructure of the alloy prepared in Example 3;

[0030] Figure 7 Metallographic image of the alloy grain structure prepared in Comparative Example 3;

[0031] Figure 8 SEM image of the excess phase microstructure of the alloy prepared in Comparative Example 3

[0032] Figure 9The diagram shows the remelting eutectic phase that appears in the excess phase of the alloy prepared in Example 4. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0034] A specific embodiment of the present invention discloses a multi-step solution heat treatment method for improving the high-temperature tensile and creep properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys, comprising the following steps:

[0035] (1) Heat the Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts from room temperature to 360-400℃ (e.g., 360℃, 365℃, 370℃, 375℃, 380℃, 385℃, 390℃, 395℃, 400℃) and hold them for the first time.

[0036] (2) Heat the deformed part after the heat preservation treatment in step (1) to 510-530℃ (e.g., 510℃, 515℃, 520℃, 525℃, 530℃) and perform a second heat preservation treatment;

[0037] (3) Heat the deformed part after the heat preservation treatment in step (2) to 540-560℃ (e.g., 540℃, 545℃, 550℃, 555℃, 560℃), perform a third heat preservation treatment, and cool to room temperature to obtain aluminum alloy billet.

[0038] Compared with existing technologies, the method of this invention, through a three-step solution heat treatment process, obtains smaller-sized excess phases and coarser matrix grains, ensuring that the alloy possesses excellent high-temperature tensile and creep properties. Simultaneously, the re-dissolved alloying elements enhance the effect of subsequent aging precipitation, giving the alloy high room-temperature tensile properties as well. Alloys treated by this invention can be used for short periods under high-temperature, high-stress conditions and for extended periods under high-temperature, low-stress conditions.

[0039] It should be noted that the method of the present invention employs a three-step solution heat treatment process. The first step involves a relatively low temperature solution heat treatment, which consumes the stored energy of the transformed alloy. Combined with a reasonable heating rate, this reduces the driving force for recrystallization nucleation, thereby preventing grain refinement in the alloy. The second step involves a solution heat treatment at the same temperature as the traditional single-step solution heat treatment, which eliminates low-melting-point phases and increases the initial melting point of the alloy. Combined with a reasonable heating rate, the heating temperature can be further increased. The third step involves a solution heat treatment using the highest possible solution temperature without overheating, which increases the driving force for phase transformation of excess phases and the diffusion capacity of alloying elements, thereby increasing the degree of resolution of excess phases back into the matrix. At the same time, the increased temperature can further coarsen the matrix grains, enabling the alloy to obtain excellent high-temperature tensile and creep properties.

[0040] In one specific implementation, in step (1), the heating rate is 100 to 200°C / h, for example, 100°C / h, 110°C / h, 120°C / h, 130°C / h, 140°C / h, 150°C / h, 160°C / h, 170°C / h, 180°C / h, 190°C / h, 200°C / h.

[0041] In one specific implementation, in step (1), the heat preservation time is 4 to 12 hours, for example, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours.

[0042] In step (1), when the temperature is raised to 360-400℃, this temperature range is the recovery temperature of the alloy. Under specific temperature, heating rate and holding time, the stored energy of the alloy can be consumed to avoid grain refinement.

[0043] In one specific implementation, in step (2), the heating rate is 30 to 60°C / h, for example, 30°C / h, 32°C / h, 34°C / h, 36°C / h, 38°C / h, 40°C / h, 42°C / h, 44°C / h, 46°C / h, 48°C / h, 50°C / h, 52°C / h, 54°C / h, 56°C / h, 58°C / h, 60°C / h.

[0044] In one specific implementation, the heat preservation time in step (2) is 2 to 4 hours, for example, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3.0 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, and 4 hours.

[0045] The temperature, heating rate and holding time in step (2) are basically the same as those in conventional one-step solution treatment, which can eliminate low-melting-point phases and increase the initial melting point of the alloy.

[0046] In one specific implementation, in step (3), the heating rate is 1 to 10℃ / h, for example, 1℃ / h, 2℃ / h, 3℃ / h, 4℃ / h, 5℃ / h, 6℃ / h, 7℃ / h, 8℃ / h, 9℃ / h, 10℃ / h.

[0047] In one specific implementation, the heat preservation time in step (3) is 4 to 8 hours, for example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, and 8 hours.

[0048] In step (3), a higher temperature is selected. Within this temperature range, overheating is avoided, and the phase transformation driving force of the excess phase and the diffusion ability of alloying elements are increased, thereby increasing the degree of excess phase re-dissolution in the matrix. At the same time, the increase in temperature can further coarsen the matrix grains, enabling the alloy to obtain excellent high-temperature tensile and creep properties.

[0049] It should be noted that, through experimental research, the inventors determined the temperature, heating rate, and holding time in the three-step solution heat treatment.

[0050] In one specific embodiment, the method further includes step (4), aging the aluminum alloy billet to obtain an Al-Cu-Mg-Ag-Mn-Zr wrought alloy.

[0051] In a specific implementation method, the heating temperature during the aging treatment is 160-190℃, for example, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, and the holding time is 4-24h, for example, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h.

[0052] The method of this invention, through multi-step solution heat treatment followed by artificial aging, yields Al-Cu-Mg-Ag-Mn-Zr wrought alloys with undiminished room-temperature tensile properties. This heat treatment process is easily implemented and effectively applicable to the industrial production of Al-Cu-Mg-Ag-Mn-Zr system products. This is because, after the solution heat treatment of this invention, the dissolved alloying elements precipitate again in the form of nano-reinforcing phases during the subsequent aging process, which can offset the adverse effects of grain coarsening on the room-temperature strength of the alloy, giving the alloy the same high room-temperature performance. The alloy treated by this invention can be used for short periods under high-temperature, high-stress conditions and for long periods under high-temperature, low-stress conditions.

[0053] Specifically, the mass percentages of each element in the Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts of the present invention are as follows: Cu 4~5.5wt%, Mg 0.2~0.8wt%, Ag 0.4~0.9wt%, Mn 0.2~0.6wt%, Zr 0.05~0.2wt%, with the balance being Al.

[0054] Another specific embodiment of the present invention discloses an Al-Cu-Mg-Ag-Mn-Zr wrought alloy prepared by the above method.

[0055] In a preferred embodiment, the Al-Cu-Mg-Ag-Mn-Zr wrought alloy has a yield strength of 438–467 MPa and a tensile strength of 470–510 MPa at room temperature; a yield strength of 353–364 MPa and a tensile strength of 370–387 MPa at 210°C; a creep rupture time of 55–131 h at 210°C / 220 MPa; a creep rupture time of 251–382 h at 210°C / 190 MPa; and a creep rupture time of 458–758 h at 210°C / 170 MPa.

[0056] Most preferably, the Al-Cu-Mg-Ag-Mn-Zr deformable alloy exhibits a maximum creep rupture time of 131 hours, 382 hours, and 758 hours at 210°C and 220 MPa, 190 MPa, and 170 MPa, respectively (Example 1). The maximum yield strength and tensile strength at 210°C are 364 MPa and 387 MPa, respectively (Example 2). Furthermore, the alloy prepared by the method of the present invention does not exhibit a decrease in yield strength and tensile strength at room temperature compared to the comparative example.

[0057] The technical solution of the present invention will be further explained below with reference to specific embodiments.

[0058] In the following embodiments and comparative examples of this invention, the Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts refer to Al-Cu-Mg-Ag-Mn-Zr alloy plates obtained by existing methods, such as semi-continuous casting-homogenization treatment-forging hot deformation.

[0059] Example 1

[0060] In this embodiment, the mass percentages of each component in the Al-Cu-Mg-Ag-Mn-Zr alloy deformed part are as follows: Cu: 5.47%, Mg: 0.33%, Ag: 0.61%, Mn: 0.23%, Zr: 0.16%, with the balance being Al.

[0061] A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to this embodiment includes the following steps:

[0062] (1) The Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts were heated from room temperature to 395℃ at a heating rate of 130℃ / h, and then held for 6h for the first time.

[0063] (2) The deformed part after heat preservation treatment in step (1) is heated to 525°C at a heating rate of 50°C / h, and then heat-preserved for 4 hours for the second time.

[0064] (3) The deformed part after heat preservation treatment in step (2) is heated to 555°C at a heating rate of 6°C / h, and heat preservation treatment is carried out for 8 hours in the third time. Then it is cooled to room temperature to obtain aluminum alloy billet.

[0065] (4) The aluminum alloy billet is aged at 190°C for 4 hours to obtain Al-Cu-Mg-Ag-Mn-Zr wrought alloy.

[0066] Example 2

[0067] In this embodiment, the mass percentages of each component in the Al-Cu-Mg-Ag-Mn-Zr alloy deformed part are as follows: Cu: 4.98%, Mg: 0.46%, Ag: 0.88%, Mn: 0.57%, Zr: 0.07%, with the balance being Al.

[0068] A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to this embodiment includes the following steps:

[0069] (1) The Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts were heated from room temperature to 380℃ at a heating rate of 150℃ / h, and then held for 10h for the first time.

[0070] (2) The deformed part after heat preservation treatment in step (1) is heated to 520°C at a heating rate of 60°C / h, and then heat-preserved for 4 hours for the second time.

[0071] (3) The deformed part after heat preservation treatment in step (2) is heated to 550°C at a heating rate of 8°C / h, heat preservation treatment is performed for a third time for 8h, and then cooled to room temperature to obtain aluminum alloy billet.

[0072] (4) The aluminum alloy billet is aged at 180°C for 8 hours to obtain Al-Cu-Mg-Ag-Mn-Zr wrought alloy.

[0073] Example 3

[0074] In this embodiment, the mass percentages of each component in the Al-Cu-Mg-Ag-Mn-Zr alloy deformed part are as follows: Cu: 4.63%, Mg: 0.22%, Ag: 0.41%, Mn: 0.39%, Zr: 0.15%, with the balance being Al.

[0075] A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to this embodiment includes the following steps:

[0076] (1) The Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts were heated from room temperature to 375℃ at a heating rate of 160℃ / h, and then held for 6h for the first heat treatment.

[0077] (2) The deformed part after heat preservation treatment in step (1) is heated to 530°C at a heating rate of 40°C / h, and then heat-preserved for 2 hours for the second time.

[0078] (3) The deformed part after heat preservation treatment in step (2) is heated to 560°C at a heating rate of 2°C / h, and heat preservation treatment is carried out for 6 hours in the third time. Then it is cooled to room temperature to obtain aluminum alloy billet.

[0079] (4) The aluminum alloy billet is aged at 160°C for 24 hours to obtain Al-Cu-Mg-Ag-Mn-Zr wrought alloy.

[0080] Example 4

[0081] In this embodiment, the mass percentages of each component in the Al-Cu-Mg-Ag-Mn-Zr alloy deformed part are as follows: Cu: 4.03%, Mg: 0.78%, Ag: 0.82%, Mn: 0.32%, Zr: 0.19%, with the balance being Al.

[0082] A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to this embodiment includes the following steps:

[0083] (1) The Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts were heated from room temperature to 365℃ at a heating rate of 180℃ / h, and then held for 10h for the first heat treatment.

[0084] (2) The deformed part after heat preservation treatment in step (1) is heated to 520°C at a heating rate of 40°C / h, and then heat preservation treatment is carried out for 2 hours.

[0085] (3) The deformed part after heat preservation treatment in step (2) is heated to 550°C at a heating rate of 2°C / h, heat preservation treatment for a third time for 4h, and then cooled to room temperature to obtain aluminum alloy billet.

[0086] (4) The aluminum alloy billet is aged at 180°C for 4 hours to obtain Al-Cu-Mg-Ag-Mn-Zr wrought alloy.

[0087] Comparative Example 1

[0088] The preparation method of this comparative synthesis is the same as that of Example 1, except that the three-step solution heat treatment is not used, but only the conventional one-step solution heat treatment is used, that is, holding at 525°C for 8 hours.

[0089] Comparative Example 2

[0090] The preparation method of this comparative synthesis is the same as that of Example 1, except that the three-step solution heat treatment is not used, but only the conventional one-step solution heat treatment is used, that is, holding at 520°C for 8 hours.

[0091] Comparative Example 3

[0092] The preparation method of this comparative synthesis is the same as that of Example 1, except that the three-step solution heat treatment is not used, but only the conventional one-step solution heat treatment is used, that is, holding at 530°C for 6 hours.

[0093] Comparative Example 4

[0094] The preparation method of this comparative synthesis is the same as that of Example 1, except that the three-step solution heat treatment is not used, but only the conventional one-step solution heat treatment is used, that is, holding at 520°C for 4 hours.

[0095] Experimental Example 1

[0096] Rectangular aluminum alloy ingots of 250mm×80mm×40mm were prepared using the methods of Examples 1-4 and Comparative Examples 1-4, respectively. Samples were taken from them to test room temperature tensile, high temperature tensile and creep properties. The room temperature tensile properties are shown in Table 1, the high temperature tensile properties are shown in Table 2, and the creep properties are shown in Table 3.

[0097] Table 1. Room temperature tensile properties of alloys prepared by different methods

[0098]

[0099]

[0100] Table 2 Tensile properties of alloys prepared by different methods at 210℃

[0101] Group Yield strength (MPa) Tensile strength (MPa) Example 1 360 375 Comparative Example 1 320 340 Example 2 364 387 Comparative Example 2 350 372 Example 3 353 370 Comparative Example 3 315 335 Example 4 360 372 Comparative Example 4 345 358

[0102] Table 3 High-temperature creep properties of alloys prepared by different methods

[0103]

[0104]

[0105] According to Tables 1-3, compared with Comparative Examples 1-4, under the same alloy composition, the alloys prepared in the comparative examples have lower yield strength and tensile strength at room temperature and high temperature (210°C) and shorter creep time at high temperature than the alloys prepared in the examples, without losing room temperature tensile properties.

[0106] Experimental Example 2

[0107] Metallographic images of the alloy grain structure and SEM images of the excess phase structure prepared by the method in Example 1 are shown below. Figure 1 and 2 As shown; the metallographic image and SEM image of the excess phase structure of the alloy prepared by the method in Comparative Example 1 are shown in Figure 1, respectively. Figure 3-4 As shown; the metallographic image of the alloy grain structure and the SEM image of the excess phase structure prepared by the method in Example 3 are shown respectively. Figure 5-6 Metallographic images of the alloy grain structure and SEM images of the excess phase structure prepared by the method in Comparative Example 3 are shown below. Figure 7-8 As shown.

[0108] Figure 1 and Figure 3 In comparison, and Figure 5 and Figure 7 In comparison, the alloy obtained by the method of the present invention has a coarser grain structure, while the comparative example has a finer grain structure. Figure 2 and Figure 4 In comparison, and Figure 6 and Figure 8 In contrast, the alloy prepared in the comparative example had more excess phase and larger size, resulting in poorer high-temperature tensile and creep resistance. This is because the three-step solution heat treatment method of this invention increases the phase transformation driving force of the excess phase and the diffusion ability of alloying elements, thereby increasing the degree of excess phase re-dissolution into the matrix. At the same time, the increase in temperature can further coarsen the matrix grains, enabling the alloy to obtain excellent high-temperature tensile and creep resistance.

[0109] The inventors also conducted the above-mentioned experiments on other embodiments, and the results were basically the same. Due to space limitations, they will not be listed one by one.

[0110] Experimental Example 3

[0111] The alloy was prepared by changing only the solution heat treatment temperature in the first step (to 430℃), while the rest of the method was the same as in Example 1 (referred to as Experimental Example 3). The effect on the grain size of the prepared alloy was evaluated, and the results are shown in Table 4.

[0112] Table 4

[0113]

[0114] As shown in Table 4, if the temperature of the first step of solution heat treatment is too high, the alloy will undergo multi-point nucleation of recrystallization, and the grain size of Experimental Example 3 will hardly change compared with Comparative Example 1, which serves as the benchmark, thus the heat treatment process cannot achieve the purpose of grain coarsening.

[0115] The inventors also conducted the above-mentioned experiments on other embodiments, and the results were basically the same. Due to space limitations, they will not be listed one by one.

[0116] Test Example 4

[0117] The solution heat treatment temperature in step three was changed (to 565°C), and the alloy was prepared using the same method as in Example 1 (referred to as Experimental Example 4). The effect on the alloy was evaluated, and the results are shown in Table 5. The remelted eutectic phase appearing in the excess phase of the alloy obtained in this experimental example is as follows: Figure 9 As shown.

[0118] Table 5

[0119]

[0120] Through Table 5 and Figure 9 It is known that if the temperature of the third step of solution heat treatment is too high, the alloy will overheat, resulting in the scrapping of the entire alloy component.

[0121] The inventors also conducted the above-mentioned experiments on other embodiments, and the results were basically the same. Due to space limitations, they will not be listed one by one.

[0122] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys, characterized in that, Includes the following steps: (1) The Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts are heated from room temperature to 360~400℃ at a heating rate of 100~200℃ / h, and then subjected to a first heat preservation treatment. (2) Heat the deformed part after the heat preservation treatment in step (1) to 510~530℃, with a heating rate of 30~60℃ / h, and perform a second heat preservation treatment; (3) Heat the deformed part after the heat preservation treatment in step (2) to 540~560℃, the heating rate is 1~10℃ / h, the third heat preservation treatment is performed, the heat preservation time is 4~8h, and the part is cooled to room temperature to obtain aluminum alloy billet. (4) The aluminum alloy billet is subjected to aging treatment to obtain an Al-Cu-Mg-Ag-Mn-Zr wrought alloy; The mass percentages of each element in the Al-Cu-Mg-Ag-Mn-Zr alloy deformed parts are as follows: Cu 4~5.5wt%, Mg 0.2~0.8wt%, Ag 0.4~0.9wt%, Mn 0.2~0.6wt%, Zr 0.05~0.2wt%, with the balance being Al; The Al-Cu-Mg-Ag-Mn-Zr wrought alloy has a yield strength of 438~467MPa and a tensile strength of 470~510MPa at room temperature; a yield strength of 353~364MPa and a tensile strength of 370~387MPa at 210℃; a creep rupture time of 55~131h at 210℃ / 220MPa; a creep rupture time of 251~382h at 210℃ / 190MPa; and a creep rupture time of 458~758h at 210℃ / 170MPa.

2. The multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to claim 1, characterized in that, In step (1), the heating rate is 110~190℃ / h.

3. The multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to claim 2, characterized in that, In step (1), the heat preservation time is 4~12h.

4. A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to any one of claims 1-3, characterized in that, In step (2), the heating rate is 32~58℃ / h.

5. A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to claim 4, characterized in that, In step (2), the heat preservation time is 2~4 hours.

6. A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to any one of claims 1-3, characterized in that, In step (3), the heating rate is 2~9℃ / h.

7. A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to claim 6, characterized in that, In step (3), the heat preservation time is 4.5~7.5h.

8. A multi-step solution heat treatment method for improving the high-temperature tensile and creep rupture properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloys according to claim 1, characterized in that, The heating temperature during aging treatment is 160~190℃, and the holding time is 4~24h.

9. An Al-Cu-Mg-Ag-Mn-Zr wrought alloy obtained by a multi-step solution heat treatment method for improving the high-temperature tensile and creep properties of Al-Cu-Mg-Ag-Mn-Zr wrought alloy according to claim 1 or 8.

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