A method and apparatus for two-stage aging of aluminum alloys

Abstract

The application belongs to the technical field of inorganic material preparation, and particularly relates to a two-stage aging heat treatment method and device for aluminum alloy. The two-stage aging heat treatment method for aluminum alloy provided by the application comprises sequentially performing first-stage aging treatment and second-stage aging treatment on a supersaturated aluminum alloy solid solution in a magnetic field. During the first-stage aging and the second-stage aging, the pulse current of the magnetic field is independently 1-100 A, the pulse frequency of the magnetic field is independently 1-100 Hz, and the duty cycle of the magnetic field is independently 1-100%. The two-stage aging heat treatment method provided by the application can significantly improve the tensile strength and tensile properties of the aluminum alloy material. Meanwhile, compared with the two-stage aging heat treatment without the magnetic field, the two-stage aging heat treatment method provided by the application in the magnetic field reduces the holding temperature and holding time of the aging heat treatment, and improves the production efficiency of the aluminum alloy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal material preparation, and particularly relates to a double-stage aging heat treatment method and device for aluminum alloy. BACKGROUND

[0002] Aluminum alloy material has become a metal material with extremely light weight, and occupies an increasingly important position in the industrial field. The ultra-high strength aluminum alloy mainly refers to the alloy containing elements Al-Zn-Mg-Cu in the 7XXX series, and the 7A04 aluminum alloy is one of the Al-Zn-Mg-Cu series ultra-high strength deformed aluminum alloys. The reason why it is called ultra-high strength aluminum alloy is that the tensile strength is above 500 Mpa. The 7A04 has high specific strength and specific stiffness, good toughness and corrosion resistance, and because its cost is relatively low, the titanium alloy is replaced by it in many fields, thereby becoming an indispensable light structure material in the aerospace industry and military industry.

[0003] In the aging heat treatment process of the aluminum alloy, aging refers to the process that the supersaturated solid solution obtained after solution quenching is decomposed to form a precipitation strengthening phase. Aging treatment is usually divided into two types, one is artificial aging, and the other is natural aging. At present, artificial aging is mainly divided into four types, which are single-stage aging, double-stage aging, regression re-aging (RRA) and multi-stage aging. The traditional double-stage aging heat treatment is to perform pre-aging treatment on the supersaturated aluminum alloy solid solution after solution treatment at a high temperature, and then heat to a higher temperature for aging treatment. Although the 7A04 aluminum alloy meeting the national use standard can be obtained, the performance requirements can be basically met, but the heat treatment time is not shortened, and the process is complex and the power consumption is large. SUMMARY

[0004] Therefore, the application provides an aluminum alloy double-stage aging heat treatment method and device, and the double-stage aging heat treatment method provided by the application can significantly improve the mechanical properties of the aluminum alloy.

[0005] In order to solve the above technical problems, the application provides an aluminum alloy double-stage aging heat treatment method, which comprises the following steps:

[0006] The aluminum alloy supersaturated solid solution is sequentially subjected to first-stage aging treatment and second-stage aging treatment in a magnetic field. The pulse current of the magnetic field is independently 1-100 A, the pulse frequency of the magnetic field is independently 1-100 Hz, and the duty cycle of the magnetic field is independently 1-100%.

[0007] Preferably, the pulse current of the magnetic field is independently 10-50 A, the pulse frequency of the magnetic field is independently 10-50 Hz, and the duty cycle of the magnetic field is independently 10-50%.

[0008] Preferably, the holding temperature of the primary aging treatment is 100-120 DEG C, and the temperature time of the primary aging treatment is 25-40 min.

[0009] Preferably, the holding temperature of the secondary aging treatment is 120-160 DEG C, and the temperature time of the secondary aging treatment is 55-80 min.

[0010] Preferably, the method for preparing the supersaturated solid solution of aluminum alloy comprises the following steps:

[0011] The aluminum alloy ingot is solution treated, the holding temperature of the solution treatment is 470-480 DEG C, and the holding time of the solution treatment is 1-3 h.

[0012] Preferably, after the secondary aging treatment, the aluminum alloy after the secondary aging treatment is air cooled.

[0013] Preferably, after the solution treatment, the aluminum alloy after the solution treatment is quenched to obtain the supersaturated solid solution of aluminum alloy.

[0014] The application provides a device used in the double-stage aging heat treatment method, comprising a sample container 3, wherein the sample container 3 is not provided with a gas inlet and a gas outlet.

[0015] A temperature control component 2 is sleeved outside the sample container 3, and a plurality of layers of magnetic induction coils 1 are wound outside the temperature control component 2, and the magnetic induction coils 1 are electrically connected with a power supply cabinet.

[0016] Preferably, the magnetic induction coils 1 are 6 layers, the winding directions of the first layer of magnetic induction coils, the second layer of magnetic induction coils and the third layer of magnetic induction coils are the same, the winding directions of the fourth layer of magnetic induction coils, the fifth layer of magnetic induction coils and the sixth layer of magnetic induction coils are the same, the first layer of magnetic induction coils and the fourth layer of magnetic induction coils are connected in series, the second layer of magnetic induction coils and the fifth layer of magnetic induction coils are connected in series, the third layer of magnetic induction coils and the sixth layer of magnetic induction coils are connected in series, and the magnetic field directions generated by each layer of magnetic induction coils are the same.

[0017] Preferably, the first layer of magnetic induction coils, the second layer of magnetic induction coils and the third layer of magnetic induction coils are connected in parallel.

[0018] The application provides a double-stage aging heat treatment method of an aluminum alloy, comprising the following steps: sequentially performing first-stage aging treatment and second-stage aging treatment on a supersaturated aluminum alloy solid solution in a magnetic field, wherein the pulse current of the magnetic field is 1-100 A independently, the pulse frequency of the magnetic field is 1-100 Hz independently, and the duty cycle of the magnetic field is 1-100% independently. The double-stage aging heat treatment method provided by the application can make the aluminum alloy quickly form fine and highly dispersed strengthening precipitates during the double-stage aging treatment, and the strengthening precipitates are uniformly dispersed in the aluminum matrix, so that the double-stage aging heat treatment method provided by the application can significantly improve the tensile strength and tensile properties of the aluminum alloy material. Meanwhile, compared with the double-stage aging heat treatment without the magnetic field, the double-stage aging heat treatment method provided by the application reduces the holding temperature and holding time of the aging heat treatment, and improves the production efficiency of the aluminum alloy. The results of the examples show that the tensile strength of the 7A04 aluminum alloy treated by the double-stage aging heat treatment provided by the application is up to 624 MPa, and the elongation is up to 9.5%.

[0019] The double-stage aging heat treatment method of the aluminum alloy provided by the application is to perform double-stage aging heat treatment on the aluminum alloy in a magnetic field, which is the same as the conventional aging operation, and only the magnetic field is added during the first-stage aging heat treatment and the second-stage aging heat treatment, so that the operation is simple, and the temperature of the first-stage aging heat treatment and the second-stage aging heat treatment is reduced by 20 DEG C. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is an electron microscope photo of the 7A04 aluminum alloy treated by the double-stage aging heat treatment according to Example 1 of the application;

[0021] Figure 2 is an electron microscope photo of the 7A04 aluminum alloy treated by the double-stage aging heat treatment according to Example 2 of the application;

[0022] Figure 3 is an electron microscope photo of the 7A04 aluminum alloy treated by the double-stage aging heat treatment according to Example 3 of the application;

[0023] Figure 4 is a tensile strength and elongation change graph of the 7A04 aluminum alloy treated by the double-stage aging heat treatment according to Examples 1-3 of the application;

[0024] Figure 5 is a schematic diagram of the device used in the application;

[0025] Figure 6A cross-sectional view of a magnetic induction coil used in the device of the embodiment of the present application;

[0026] Figure 7 A circuit connection diagram of a magnetic induction coil used in the device of the embodiment of the present application;

[0027] 1 - magnetic induction coil, 2 - temperature control component, 3 - sample container. DETAILED DESCRIPTION

[0028] The present application provides a two-stage aging heat treatment method of aluminum alloy, comprising the following steps:

[0029] The supersaturated aluminum alloy solid solution is sequentially subjected to first-stage aging treatment and second-stage aging treatment in a magnetic field, and the pulse current of the magnetic field is independently 1-100 A, the pulse frequency of the magnetic field is independently 1-100 Hz, and the duty cycle of the magnetic field is independently 1-100%.

[0030] In the present application, the preparation method of the supersaturated aluminum alloy solid solution preferably comprises the following steps:

[0031] The aluminum alloy ingot is subjected to solid solution treatment, and the holding temperature of the solid solution treatment is 470-480℃, and the holding time of the solid solution treatment is 1-3h.

[0032] In the present application, the aluminum alloy ingot is preferably 7XXX series aluminum alloy.

[0033] In the specific embodiment of the present application, the aluminum alloy ingot is particularly preferably 7A04 aluminum alloy.

[0034] In the present application, when the aluminum alloy is 7A04 aluminum alloy, the precipitated strengthening phase after the two-stage aging is preferably MgZn2.

[0035] In the present application, the holding temperature of the solid solution treatment is preferably 470-480℃, and more preferably 470℃.

[0036] In the present application, the holding time of the solid solution treatment is preferably 1-3h, and more preferably 2h.

[0037] In the present application, the heating rate from room temperature to the holding temperature of the solid solution treatment is preferably 5-8℃ / min, and more preferably 7℃ / min.

[0038] In the present application, after the solid solution treatment, the present application preferably further comprises quenching the aluminum alloy ingot subjected to the solid solution treatment to obtain the supersaturated aluminum alloy solid solution.

[0039] In the present application, the quenching is preferably performed immediately after the end of the holding of the solution treatment, and the interval between the solution treatment and the quenching is preferably as short as possible.

[0040] After the quenching, the aluminum alloy after the quenching is subjected to the primary aging treatment in a magnetic field in the present application.

[0041] In the present application, the holding temperature of the primary aging treatment is preferably 100 to 120°C, and more preferably 110°C.

[0042] In the present application, the temperature time of the primary aging treatment is preferably 25 to 40 minutes, and more preferably 30 minutes.

[0043] In the present application, the pulse current of the magnetic field during the primary aging treatment is 1 to 100 A, preferably 10 to 50 A, and more preferably 18 A.

[0044] In the present application, the pulse frequency of the magnetic field during the primary aging treatment is 1 to 100 Hz, preferably 10 to 60 Hz, and more preferably 20 Hz.

[0045] In the present application, the duty ratio of the magnetic field during the primary aging treatment is 1 to 100%, preferably 10 to 50%, and more preferably 20%.

[0046] In the present application, after the primary aging treatment, the holding temperature of the primary aging treatment is increased to the holding temperature of the secondary aging treatment, and the secondary aging treatment is performed.

[0047] In the present application, the holding temperature of the secondary aging treatment is preferably 120 to 160°C, and in the specific embodiments of the present application, the holding temperature of the secondary aging treatment is specifically preferably 120°C, 140°C, and 160°C.

[0048] In the present application, the temperature time of the secondary aging treatment is preferably 55 to 80 minutes, and more preferably 60 minutes.

[0049] In the present application, the pulse current of the magnetic field during the secondary aging treatment is 1 to 100 A, preferably 10 to 50 A, and more preferably 18 A.

[0050] In the present application, the pulse frequency of the magnetic field during the secondary aging treatment is 1 to 100 Hz, preferably 10 to 60 Hz, and more preferably 20 Hz.

[0051] In the present application, the duty ratio of the magnetic field during the secondary aging treatment is 1 to 100%, preferably 10 to 50%, and more preferably 20%.

[0052] In the present application, after the secondary aging treatment, the present application preferably further comprises air cooling the aluminum alloy after the secondary aging treatment.

[0053] The present application provides a device used in the two-stage aging heat treatment method, comprising: a sample container 3, wherein the sample container is not provided with a gas inlet and a gas outlet;

[0054] A temperature control component 2 is sleeved outside the sample container 3, and a plurality of layers of magnetic induction coils 1 are wound outside the temperature control component 2, wherein the magnetic induction coils 1 are electrically connected with a power supply cabinet.

[0055] The device provided by the present application comprises a sample container 3, wherein the sample container is not provided with a gas inlet and a gas outlet.

[0056] As a specific embodiment of the present application, the material of the sample container 3 is corundum.

[0057] As a specific embodiment of the present application, the sample container 3 is a corundum tube.

[0058] The device provided by the present application comprises a temperature control component 2 sleeved outside the sample container 3, wherein the temperature control component 2 is used for heating and temperature control of the sample in the sample container 3.

[0059] As a specific embodiment of the present application, the temperature control component 2 comprises a heating component and a temperature measuring component.

[0060] As a specific embodiment of the present application, the adding component is a heating coil.

[0061] As a specific embodiment of the present application, the heating component is a hollow heating coil, wherein when the heating component is working, and the temperature of the heating component is higher than 100℃ after working, cooling water is introduced into the hollow heating coil, and the temperature of the cooling water is preferably room temperature.

[0062] The device provided by the present application comprises a plurality of layers of magnetic induction coils 1 wound outside the temperature control component 2, wherein the plurality of layers of magnetic induction coils form a magnetic field, so that the aluminum alloy sample in the sample container 3 is located in the magnetic field formed by the plurality of layers of magnetic induction coils.

[0063] As a specific embodiment of the present application, the magnetic induction coil 1 is 6 layers, the winding directions of the first layer magnetic induction coil, the second layer magnetic induction coil and the third layer magnetic induction coil are the same, the winding directions of the fourth layer magnetic induction coil, the fifth layer magnetic induction coil and the sixth layer magnetic induction coil are the same, the first layer magnetic induction coil and the fourth layer magnetic induction coil are connected in series, the second layer magnetic induction coil and the fifth layer magnetic induction coil are connected in series, the third layer magnetic induction coil and the sixth layer magnetic induction coil are connected in series, and the magnetic fields generated by each layer of the magnetic induction coil are in the same direction.

[0064] As a specific embodiment of the present application, the first layer magnetic induction coil, the second layer magnetic induction coil and the third layer magnetic induction coil are connected in parallel with each other.

[0065] As a specific embodiment of the present application, the magnetic induction coil is a hollow magnetic induction coil, and when the magnetic induction coil is working and the temperature of the magnetic induction coil is higher than 100℃ after working, cooling water is introduced into the hollow magnetic induction coil, and the temperature of the cooling water is preferably room temperature.

[0066] In the present application, the magnetic induction coil 1 is electrically connected with a power cabinet. In the present application, the power cabinet is used to supply power to the magnetic induction coil 1 to form a magnetic field.

[0067] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in combination with embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0068] Embodiment 1

[0069] Use Figure 5 The device shown, wherein the corundum tube 3 is used to hold the aluminum alloy sample, the corundum tube 3 is sleeved with the temperature control component 2, the temperature control component 2 includes a hollow heating coil, when the temperature of the heating coil is higher than 100℃, water is introduced into the hollow heating coil. The outer periphery of the temperature control component 2 is wound with 6 layers of magnetic induction coils 1, the winding directions of the first layer magnetic induction coil, the second layer magnetic induction coil and the third layer magnetic induction coil are the same, the winding directions of the fourth layer magnetic induction coil, the fifth layer magnetic induction coil and the sixth layer magnetic induction coil are the same, the first layer magnetic induction coil and the fourth layer magnetic induction coil are connected in series, the second layer magnetic induction coil and the fifth layer magnetic induction coil are connected in series, the third layer magnetic induction coil and the sixth layer magnetic induction coil are connected in series, the magnetic fields generated by each layer of the magnetic induction coil are in the same direction, and the first layer magnetic induction coil, the second layer magnetic induction coil and the third layer magnetic induction coil are connected in parallel with each other; the magnetic induction coil 1 is a hollow coil, and when the temperature of the magnetic induction coil is higher than 100℃, water is introduced into the magnetic induction coil.

[0070] The corundum tube 3 was heated to 470℃ at a rate of 7℃ / min using temperature control component 2. A 7A04 aluminum alloy ingot was then placed inside the corundum tube 3 and subjected to heat treatment for 2 hours. Immediately after heat treatment, the ingot was quenched. The quenched 7A04 aluminum alloy was then placed back into the corundum tube 3. A magnetic field was generated using magnetic induction coil 1 controlled by the power supply cabinet, placing the quenched 7A04 aluminum alloy within the magnetic field. The pulse current of the magnetic field was 18A, the pulse frequency was 20Hz, and the duty cycle was 20%. The corundum tube 3 was then heated to 110℃ at a rate of 7℃ / min using temperature control component 2, held for 30 minutes, then heated to 120℃ and held for 60 minutes. The power supply to the temperature control device and the power supply cabinet were then turned off. The double-stage aging treated aluminum alloy was then air-cooled to room temperature. The aluminum alloy sample was then removed and tested. Figure 1 The image shown is an electron microscope image of the 7A04 aluminum alloy after two-stage aging heat treatment prepared in this embodiment. Figure 1 It can be concluded that fine, highly dispersed strengthening phase precipitates were formed in the 7A04 aluminum alloy after the double-stage aging heat treatment, and the strengthening precipitates were uniformly dispersed in the aluminum matrix.

[0071] Example 2

[0072] use Figure 5 The apparatus shown includes an alumina tube 3 for holding an aluminum alloy sample. A temperature control component 2 is fitted around the outer periphery of the alumina tube 3. The temperature control component 2 includes a hollow heating coil. When the temperature of the heating coil exceeds 100°C, water is introduced into the hollow heating coil. Six layers of magnetic induction coils 1 are wound around the outer periphery of the temperature control component 2. The first, second, and third layers of magnetic induction coils are wound in the same direction, as are the fourth, fifth, and sixth layers. The first and fourth layers of magnetic induction coils are connected in series, as are the second and fifth layers, and the third and sixth layers. The magnetic fields generated by each layer of magnetic induction coils are in the same direction. The first, second, and third layers of magnetic induction coils are connected in parallel with each other. The magnetic induction coils 1 are hollow coils, and water is introduced into them when the temperature exceeds 100°C.

[0073] The corundum tube 3 was heated to 470℃ at a rate of 7℃ / min using temperature control component 2. 7A04 aluminum alloy was then placed inside the corundum tube 3 and subjected to heat treatment for 2 hours. Immediately after heat treatment, the alloy was quenched. The quenched 7A04 aluminum alloy was then placed back into the corundum tube 3. A magnetic field was generated using magnetic induction coil 1 controlled by the power supply cabinet, placing the quenched 7A04 aluminum alloy ingot within the magnetic field. The pulse current of the magnetic field was 18A, the pulse frequency was 20Hz, and the duty cycle was 20%. The corundum tube 3 was then heated to 110℃ at a rate of 7℃ / min using temperature control component 2 and held for 30 minutes. The temperature was then increased to 140℃ and held for 60 minutes. The power supply to the temperature control device and the power supply cabinet were then turned off. The double-stage aging treated aluminum alloy was then air-cooled to room temperature. The aluminum alloy sample was then removed and tested. Figure 2 The image shown is an electron microscope image of the 7A04 aluminum alloy after two-stage aging heat treatment prepared in this embodiment. Figure 2 It can be concluded that fine, highly dispersed strengthening phase precipitates were formed in the 7A04 aluminum alloy after the double-stage aging heat treatment, and the strengthening precipitates were uniformly dispersed in the aluminum matrix.

[0074] Example 3

[0075] use Figure 5 The apparatus shown includes an alumina tube 3 for holding an aluminum alloy sample. A temperature control component 2 is fitted around the outer periphery of the alumina tube 3. The temperature control component 2 includes a hollow heating coil. When the temperature of the heating coil exceeds 100°C, water is introduced into the hollow heating coil. Six layers of magnetic induction coils 1 are wound around the outer periphery of the temperature control component 2. The first, second, and third layers of magnetic induction coils are wound in the same direction, as are the fourth, fifth, and sixth layers. The first and fourth layers of magnetic induction coils are connected in series, as are the second and fifth layers, and the third and sixth layers. The magnetic fields generated by each layer of magnetic induction coils are in the same direction. The first, second, and third layers of magnetic induction coils are connected in parallel with each other. The magnetic induction coils 1 are hollow coils, and water is introduced into them when the temperature exceeds 100°C.

[0076] The corundum tube 3 was heated to 470℃ at a rate of 7℃ / min using temperature control component 2. A 7A04 aluminum alloy ingot was then placed inside the corundum tube 3 and subjected to heat treatment for 2 hours. Immediately after heat treatment, the ingot was quenched. The quenched 7A04 aluminum alloy was then placed back into the corundum tube 3. A magnetic field was generated using magnetic induction coil 1 controlled by the power supply cabinet, placing the quenched 7A04 aluminum alloy within the magnetic field. The pulse current of the magnetic field was 18A, the pulse frequency was 20Hz, and the duty cycle was 20%. The corundum tube 3 was then heated to 110℃ at a rate of 7℃ / min using temperature control component 2 and held for 30 minutes. The temperature was then increased to 160℃ and held for 60 minutes. The power supply to the temperature control device and the power supply cabinet were then turned off. The double-stage aging treated aluminum alloy was then air-cooled to room temperature. The aluminum alloy sample was then removed and tested. Figure 3 The image shown is an electron microscope image of the 7A04 aluminum alloy after two-stage aging heat treatment prepared in this embodiment. Figure 3 It can be concluded that fine, highly dispersed strengthening phase precipitates were formed in the 7A04 aluminum alloy after the double-stage aging heat treatment, and the strengthening precipitates were uniformly dispersed in the aluminum matrix.

[0077] Comparative Example 1

[0078] use Figure 5 The apparatus shown includes an alumina tube 3 for holding an aluminum alloy sample. A temperature control component 2 is fitted around the outer periphery of the alumina tube 3. The temperature control component 2 includes a hollow heating coil. When the temperature of the heating coil exceeds 100°C, water is introduced into the hollow heating coil. Six layers of magnetic induction coils 1 are wound around the outer periphery of the temperature control component 2. The first, second, and third layers of magnetic induction coils are wound in the same direction, as are the fourth, fifth, and sixth layers. The first and fourth layers of magnetic induction coils are connected in series, as are the second and fifth layers, and the third and sixth layers. The magnetic fields generated by each layer of magnetic induction coils are in the same direction. The first, second, and third layers of magnetic induction coils are connected in parallel with each other. The magnetic induction coils 1 are hollow coils, and water is introduced into them when the temperature exceeds 100°C.

[0079] After heating the corundum tube 3 to 470°C at a rate of 7°C / min using the temperature control component 2, the 7A04 aluminum alloy ingot was placed into the corundum tube 3. After heat treatment and solution treatment for 3 hours, it was immediately quenched. The quenched 7A04 aluminum alloy was placed back into the corundum tube 3, and the corundum tube 3 was heated to 110°C at a rate of 7°C / min using the temperature control component 2. After holding at this temperature for 120 minutes, the temperature was raised to 160°C and held for 360 minutes. Then, the power supply of the temperature control device and the power cabinet were turned off, and the aluminum alloy after the double-stage aging treatment was air-cooled to room temperature. The aluminum alloy sample was then taken out for testing.

[0080] Comparative Example 2

[0081] Using Figure 5 The device shown in the figure, wherein the corundum tube 3 is used to hold the aluminum alloy sample, the corundum tube 3 is sleeved with the temperature control component 2, the temperature control component 2 includes a hollow heating coil, when the temperature of the heating coil is higher than 100℃, water is introduced into the hollow heating coil. The outer periphery of the temperature control component 2 is wound with 6 layers of magnetic induction coils 1, the winding directions of the first layer of magnetic induction coils, the second layer of magnetic induction coils and the third layer of magnetic induction coils are the same, the winding directions of the fourth layer of magnetic induction coils, the fifth layer of magnetic induction coils and the sixth layer of magnetic induction coils are the same, the first layer of magnetic induction coils and the fourth layer of magnetic induction coils are connected in series, the second layer of magnetic induction coils and the fifth layer of magnetic induction coils are connected in series, the third layer of magnetic induction coils and the sixth layer of magnetic induction coils are connected in series, the magnetic field directions generated by each layer of magnetic induction coils are the same, the first layer of magnetic induction coils, the second layer of magnetic induction coils and the third layer of magnetic induction coils are connected in parallel with each other; the magnetic induction coils 1 are hollow coils, when the temperature of the magnetic induction coils is higher than 100℃, water is introduced into the magnetic induction coils.

[0082] After the corundum tube 3 is heated to 470℃ at a speed of 7℃ / min by using the temperature control component 2, the 7A04 aluminum alloy is put into the corundum tube 3, and then the solution treatment is carried out for 2h, and immediately after that, quenching is carried out. The 7A04 aluminum alloy ingot after quenching is put back into the corundum tube 3, the magnetic field is formed by the magnetic induction coils 1 controlled by the power cabinet, so that the 7A04 aluminum alloy after quenching is in the magnetic field, the pulse current of the magnetic field is 18A, the pulse frequency of the magnetic field is 20Hz, and the duty cycle of the magnetic field is 20%. After the corundum tube 3 is heated to 130℃ at a speed of 7℃ / min by using the temperature control component 2, the temperature is kept for 60min, and then the power supply of the temperature control device and the power cabinet are turned off. The aluminum alloy after aging treatment is air-cooled to room temperature, and then the aluminum alloy sample is taken out for testing.

[0083] Test Example 1

[0084] The 7A04 aluminum alloy after the double-stage aging heat treatment prepared in Examples 1-3 and Comparative Example 1 is tested for mechanical properties, wherein the tensile strength and elongation are tested according to the national standard GB / T 4437.1-2000, wherein the tensile strength of the 7A04 aluminum alloy is required to be greater than 530MPa, and the elongation is required to be greater than 5%. The test results are shown in Table 1 and Figure 4 Table 2. Figure 4 It can be concluded from Table 1 and

[0085] Table 1 Mechanical property test results of 7A04 aluminum alloy after double-stage aging heat treatment of Examples 1-3 and Comparative Example 1

[0086] Serial number Tensile strength / MPa Elongation / % Example 1 624 8.9 Example 2 622.5 9.5 Example 3 599.7 8.9 Comparative Example 1 562 5.5 Comparative Example 2 506 17

[0087] Although the above-mentioned embodiments have been described in detail, they are only some embodiments of the present application, but not all embodiments. Other embodiments can be obtained by those skilled in the art without creativity on the basis of the above-mentioned embodiments, and these embodiments also belong to the protection scope of the present application.

Claims

1. A method of two-stage ageing heat treatment of an aluminium alloy characterised in that, The method comprises the following steps: 7A04 aluminum alloy is solution treated at a holding temperature of 470 DEG C for 2 hours, and quenched to obtain a supersaturated aluminum alloy solid solution; the supersaturated aluminum alloy solid solution is subjected to primary aging treatment and secondary aging treatment in a magnetic field, the primary aging treatment is performed at a holding temperature of 110 DEG C for 30 minutes, the secondary aging treatment is performed at a holding temperature of 120-140 DEG C for 60 minutes, the pulse current of the magnetic field is independently 18 A, the pulse frequency of the magnetic field is independently 20 Hz, and the duty cycle of the magnetic field is independently 20%.

2. The two-step aging heat treatment method according to claim 1, characterized by, After the secondary aging treatment, the aluminum alloy is air-cooled.

3. The two-step aging heat treatment method according to claim 1, characterized by, The device used in the two-stage aging heat treatment method comprises a sample container (3) without a gas inlet and a gas outlet; A temperature control component (2) is sleeved outside the sample container (3), and a plurality of layers of magnetic induction coils (1) are wound outside the temperature control component (2), and the magnetic induction coils (1) are electrically connected with a power supply cabinet.

4. The two-step aging heat treatment method according to claim 3, characterized by The magnetic induction coils (1) are 6 layers, the winding directions of the first layer of magnetic induction coils, the second layer of magnetic induction coils and the third layer of magnetic induction coils are the same, the winding directions of the fourth layer of magnetic induction coils, the fifth layer of magnetic induction coils and the sixth layer of magnetic induction coils are the same, the first layer of magnetic induction coils and the fourth layer of magnetic induction coils are connected in series, the second layer of magnetic induction coils and the fifth layer of magnetic induction coils are connected in series, the third layer of magnetic induction coils and the sixth layer of magnetic induction coils are connected in series, and the magnetic fields generated by each layer of magnetic induction coils are in the same direction.

5. The two-step aging heat treatment method according to claim 4, characterized by The first layer of magnetic induction coils, the second layer of magnetic induction coils and the third layer of magnetic induction coils are connected in parallel with each other.

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