Heat treatment method for improving strength-plasticity synergistic performance of Al-Mg series alloy through combination of non-isothermal pre-aging and pre-deformation

Abstract

The invention belongs to the technical field of aluminum alloy heat treatment, and particularly relates to a heat treatment method for improving the strength-plasticity synergistic performance of Al-Mg series alloy through combination of non-isothermal pre-aging and pre-deformation. The method comprises the steps of solution treatment, quenching, non-isothermal pre-aging, pre-deformation, isothermal aging treatment and the like. The non-isothermal pre-deformation heating rate after quenching ranges from 1 DEG C / h to 30 DEG C / h, the temperature interval ranges from 20 DEG C to 260 DEG C, the selected deformation range of the cold rolling pre-deformation amount after cooling to the room temperature ranges from 5% to 80%, and finally isothermal aging is conducted. The method is suitable for the aluminum alloy containing Mg, Zn, Mn, Cu, Ag and other elements, through the specific heat treatment technology, uniform distribution of alloy precipitation strengthening phases is effectively promoted, meanwhile, formation of harmful phases is restrained, the comprehensive performance of the material is improved, and the method is suitable for being applied to aluminum alloy materials in the fields of aviation, automobiles and high-end manufacturing.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloy heat treatment, and specifically relates to a heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation. Background Art

[0002] Aluminum alloys have been widely used in aerospace, automotive, and high-end manufacturing due to their excellent specific strength, corrosion resistance, and machinability. Among them, the mechanical properties of deformed aluminum alloys, represented by Al-Mg and Al-Mg-Zn alloys, rely heavily on reasonable heat treatment processes. The core of heat treatment lies in optimizing the alloy's microstructure by controlling the phase transformation process to achieve high strength, high plasticity and toughness, and good service stability. However, traditional heat treatment methods, which mainly use solution treatment + isothermal aging, have certain limitations in regulating the precipitation of strengthening phases, making it difficult to further improve the alloy's overall performance.

[0003] In the traditional isothermal aging process, the strengthening of the alloy mainly depends on the diffusion of solute atoms in the matrix and the precipitation of metastable phases. However, since the nucleation rate is limited by the temperature field and solute concentration, the initial precipitate nucleation kinetics are slow, resulting in insufficient dispersion of the precipitation strengthening phase, affecting the strengthening effect of the alloy. In addition, if the precipitate grows too fast or is unevenly distributed during the isothermal aging process, the plasticity and toughness of the alloy will decrease, and even affect the service stability. In addition, for some aluminum alloys containing strengthening elements such as Zn and Cu, since the nucleation and growth of the precipitate phase are affected by more complex thermodynamic and kinetic factors, a single isothermal aging process is difficult to achieve the best balance between strengthening and toughness. Therefore, how to optimize the heat treatment process to achieve precise control of the precipitation strengthening phase is one of the key issues in improving the performance of aluminum alloys.

[0004] In recent years, researchers have proposed methods such as pre-aging, pre-deformation and non-isothermal treatment to optimize the precipitation behavior of the strengthening phase in response to the shortcomings of traditional heat treatment processes. Among them, pre-aging treatment can promote the short-range diffusion of solute atoms at low temperatures to form GP zones, providing nucleation sites for subsequent precipitation phases, thereby improving the aging response rate. However, the traditional isothermal pre-aging method has limited control over the precipitation kinetics, and it is difficult to optimize the formation rate and distribution uniformity of the GP zone. Pre-deformation treatment can provide additional nucleation sites by introducing high-density dislocations, reduce the nucleation energy barrier, and promote the precipitation of the strengthening phase. However, if there is a lack of reasonable aging control, the morphology and distribution of the precipitated phase will still be difficult to reach the optimal state.

[0005] Patents CN117702017A, CN114438428A, CN105112826A, and CN105441837A all use a pre-deformation treatment followed by pre-aging heat treatment during the heat treatment process, aiming to improve the mechanical properties and corrosion resistance of 7xxx series aluminum alloys and optimize process parameters for materials serving in aviation environments. Although this method can introduce dislocations through deformation to promote precipitation, it also has obvious defects. Pre-deformation causes solute atoms to segregate at dislocations, and the strengthening phase is mainly precipitated in the high dislocation area, which easily causes uneven distribution of the precipitated phase, unstable structure, and reduces the overall strengthening effect of the material. At the same time, the high dislocation density limits the uniform formation of the GP zone during the pre-aging process, weakening the promoting effect of pre-aging on subsequent aging. In addition, the residual stress and work hardening effect introduced by pre-deformation are not easy to be completely released during the subsequent treatment process, which may affect the plasticity and toughness of the material, thereby limiting the further improvement of the overall performance.

[0006] Patent CN105441837A discloses a method for improving the forming performance and strength of 7xxx series aluminum alloy thin plates. Its process adopts a method of cold deformation followed by pre-aging treatment, which is intended to improve the precipitation strengthening effect by introducing dislocations. Although this method has certain results in improving strength, the process path may cause the strengthening phase to precipitate in high dislocation areas, resulting in structural heterogeneity, thereby affecting the plasticity and mechanical properties of the material. In addition, the pre-aging effect after pre-deformation is limited, the difficulty of controlling the precipitation of the strengthening phase is increased, and work hardening residual stress is easily generated, which reduces the flexibility of subsequent aging control and is not conducive to the optimization of the comprehensive performance of the material.

[0007] Patent CN116695032A discloses a method for the retrogradation and re-aging heat treatment of aluminum alloys for aerospace applications. This patent utilizes a complex process flow consisting of three stages of solution treatment and two stages of aging heat treatment. While this method aims to improve the strength of aluminum alloys, its complex heat treatment steps can lead to extended production cycles, increased energy consumption, and higher production costs. Furthermore, the excessive number of heat treatment stages can introduce additional process variables, complicating quality control.

[0008] Patent CN116214082A adopts a process that combines traditional solution treatment and aging treatment. Although it improves the mechanical properties of aluminum alloy to a certain extent, it has limitations in controlling the precipitation of strengthening phases and regulating dislocation density, which may lead to less than ideal strengthening effects and limit further improvement of material properties.

[0009] Therefore, there is an urgent need for an optimized heat treatment method to coordinate the formation, distribution and evolution of the precipitated phase, improve the strength, plasticity-toughness matching and service stability of aluminum alloys, and meet the demand for lightweight and high-strength materials in the high-end manufacturing field. Summary of the Invention

[0010] In response to the above-mentioned problems existing in the prior art, the present invention provides a novel heat treatment process combining non-isothermal pre-aging and pre-deformation. By controlling the aging temperature and heating rate of non-isothermal pre-aging, as well as the pre-deformation process parameters, the overall improvement of mechanical properties is ultimately achieved. The material exhibits an excellent strength-plasticity synergistic effect, taking into account the balance between high strength and good plasticity, thereby meeting the application requirements of the new Al-Mg alloy in the field of high-end manufacturing, and at the same time providing new ideas for the study of plastic deformation mechanism.

[0011] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0012] The present invention provides a heat treatment method for improving the strength-plasticity synergy of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation. The heat treatment method comprises the following steps:

[0013] (1) Melting and casting;

[0014] (2) Homogenization treatment;

[0015] (3) hot rolling;

[0016] (4) Cold rolling;

[0017] (5) Solution treatment;

[0018] (6) Quenching;

[0019] (7) After non-isothermal pre-aging treatment, cold rolling pre-deformation is performed;

[0020] (8) Isothermal aging treatment;

[0021] In the step (7), the non-isothermal pre-aging treatment is: heating at a constant heating rate, the heating rate range is 1 to 30°C / h, and the temperature range is 20 to 260°C; the deformation range of the cold rolling pre-deformation treatment is 5% to 80%.

[0022] In the above technical solution, further, the composition requirements of the Al-Mg alloy are specifically as follows: Mg content 1wt%~10wt%, Zn content 0.15wt%~4wt%, Mn content 0.4wt%, Cu content 0.15wt%~0.5wt%, Ag content 0.15wt%~0.6wt%, and the balance is Al.

[0023] In the above technical solution, further, in the step (1), the smelting and casting are: the materials are prepared according to the alloy composition requirements and then smelted and cast, the smelting temperature is 720-750°C, and the casting temperature is 700-720°C.

[0024] In the above technical solution, further, in the step (2), the homogenization treatment is: homogenization temperature 450° C., insulation time 10 h.

[0025] In the above technical solution, further, in the step (3), the hot rolling is: hot rolling temperature is 450° C., and rolling is performed to a thickness of 5 mm.

[0026] In the above technical solution, further, in the step (4), the cold rolling is: the cold rolling temperature is room temperature, and the thickness is rolled to 2 mm.

[0027] In the above technical solution, further, in step (5), the solution treatment is as follows: the sample is heated in the furnace from 20°C to 500°C at a heating rate of 24°C / min, and kept warm for 30 minutes.

[0028] In the above technical solution, further, in the step (6), the quenching is: cooling to room temperature by water quenching, and the quenching transfer time does not exceed 5s.

[0029] In the above technical solution, further, in step (7), the non-isothermal pre-aging treatment is: from room temperature to 120-220°C, and the heating rate range is 15-25°C / h; the deformation range of the cold rolling pre-deformation treatment is 20%-40%.

[0030] In the above technical solution, further, in step (7), the non-isothermal pre-aging treatment is: from room temperature to 180°C, and the heating rate is 20°C / h; the deformation amount of the cold rolling pre-deformation treatment is 40%.

[0031] In the above technical solution, further, in step (8), the isothermal aging treatment is as follows: the sample is heated with the furnace, the heating time is 15 minutes, from 20°C to 180°C, and kept warm for 30 minutes.

[0032] The principle of the present invention is: the unidirectional supersaturated solid solution formed after solution treatment continuously undergoes atomic cluster aggregation during the non-isothermal pre-aging process, which promotes the formation of GP zones. These metastable atomic clusters serve as early precipitation phases, which can effectively reduce the nucleation barrier of the metastable phase during the subsequent aging process and regulate the morphology, size and distribution characteristics of the precipitation phase. In the subsequent pre-deformation process, due to the generation of high-density dislocations inside the alloy, the nucleation sites are increased and the nucleation driving force is improved. In addition, pre-deformation can also significantly affect the preferred orientation and interface characteristics of the precipitation phase, making the strengthening phase and the matrix more tightly combined. Finally, in the isothermal aging stage, through appropriate temperature and time control, the GP zone and the metastable precipitation phase are gradually transformed into a more stable nanoscale precipitation strengthening phase, further improving the strength and thermal stability of the alloy.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention adopts a heat treatment method that combines non-isothermal pre-aging with pre-deformation to improve the strength-plasticity synergistic properties of Al-Mg alloys. By introducing non-isothermal pre-aging after solution treatment, the formation of GP zones is effectively promoted, so that the solute atoms are more evenly aggregated in the matrix; at the same time, the introduction of pre-deformation treatment induces high-density dislocations inside the alloy, increases the nucleation density of the precipitate phase, reduces the nucleation energy barrier, and further promotes the uniform precipitation of fine precipitates, thereby greatly improving the yield strength and tensile strength of the alloy.

[0035] In traditional heat treatment processes, aging treatment takes a long time and the precipitation kinetics of strengthening phases are limited, making it difficult to strike a balance between performance and efficiency. The present invention uses non-isothermal pre-aging to optimize the precipitation process, allowing the GP zone to form rapidly, shortening the overall aging time and improving production efficiency. Pre-deformation promotes precipitation and enhances the strengthening effect of the alloy, allowing the alloy to achieve excellent performance in a shorter aging time and reducing industrial production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Example 3 precipitation phase organization diagram;

[0037] Figure 2 Example 3 dislocation substructure diagram;

[0038] Figure 3 Example 8 precipitation phase organization diagram;

[0039] Figure 4 Dislocation substructure diagram of Example 8. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to specific examples, but the present invention is not limited in any way. To avoid redundancy, the raw materials in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0041] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0042] (1) Melting and casting: The materials are prepared according to the alloy composition requirements; the alloy composition requirements are as follows: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After the materials are prepared, they are melted and cast. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0043] (2) Homogenization treatment: homogenization temperature 450°C, holding time 10h;

[0044] (3) Hot rolling: hot rolling temperature 450℃, rolled to 5mm thickness;

[0045] (4) Cold rolling: The cold rolling temperature is room temperature and the thickness is 2 mm.

[0046] (5) Solution treatment: The sample was heated in a furnace from 20°C to 500°C at a heating rate of 24°C / min and kept at this temperature for 30 min.

[0047] (6) Quenching: Water quenching to room temperature, the quenching transfer time does not exceed 5s;

[0048] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: heating at a constant heating rate, the heating rate range is 1 to 30°C / h, the temperature range is 20 to 260°C; the deformation range of the cold rolling pre-deformation treatment is 5% to 80%;

[0049] (8) Isothermal aging treatment: The sample is heated in a furnace from 20°C to 180°C for 15 minutes and kept at this temperature for 30 minutes.

[0050] In the following examples, Al, Mg, Zn, Cu, and Ag are added in the form of pure metals, and other elements are added in the form of master alloys. Any matters not described in the following examples are the same as those described in the above specific embodiments.

[0051] Example 1

[0052] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0053] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0054] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0055] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0056] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0057] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0058] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0059] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: the non-isothermal pre-aging heating rate is 1 ° C / h, rising to 20 ° C, and the pre-deformation treatment is performed after the non-isothermal pre-aging, and the cold rolling deformation amount is 80%;

[0060] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0061] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 1 are 280.56 MPa, 397.58 MPa and 20.64%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 1 and the mechanical properties of the alloy are shown in Table 1.

[0062] Example 2

[0063] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0064] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0065] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0066] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0067] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0068] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0069] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0070] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 5°C / h, from room temperature to 40°C, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 60%;

[0071] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0072] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 2 are 305.63 MPa, 421.63 MPa and 30.42%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 2 and the mechanical properties of the alloy are shown in Table 1.

[0073] Example 3

[0074] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0075] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0076] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0077] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0078] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0079] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0080] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0081] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 10 ° C / h, from room temperature to 140 ° C, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 5%;

[0082] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0083] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 3 are 362.28 MPa, 481.07 MPa and 26.57%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 3 and the mechanical properties of the alloy are shown in Table 1.

[0084] Example 4

[0085] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0086] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0087] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0088] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0089] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0090] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0091] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0092] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 10 ° C / h, from room temperature to 180 ° C, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 20%;

[0093] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0094] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 4 are 390.05 MPa, 501.57 MPa and 25.6%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 4 and the mechanical properties of the alloy are shown in Table 1.

[0095] Example 5

[0096] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0097] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0098] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0099] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0100] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0101] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0102] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0103] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 15℃ / h, from room temperature to 180℃, and the pre-deformation treatment is carried out after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 20%; the tenth step is isothermal aging treatment, the isothermal aging heating time is 15min, from 20℃ to 180℃, and the temperature is kept for 30min.

[0104] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 5 are 400.5 MPa, 517.12 MPa and 24.8%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 5 and the mechanical properties of the alloy are shown in Table 1.

[0105] Example 6

[0106] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0107] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0108] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0109] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0110] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0111] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0112] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0113] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 15 ° C / h, from room temperature to 200 ° C, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 80%;

[0114] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0115] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 6 are 419.74 MPa, 529.34 MPa and 23.35%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 6 and the mechanical properties of the alloy are shown in Table 1.

[0116] Example 7

[0117] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0118] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0119] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0120] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0121] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0122] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0123] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0124] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 20 ° C / h, from room temperature to 180 ° C, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 20%;

[0125] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0126] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 7 are 409.64 MPa, 518.12 MPa and 24.72%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 7 and the mechanical properties of the alloy are shown in Table 1.

[0127] Example 8

[0128] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0129] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0130] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0131] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0132] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0133] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0134] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0135] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 20 ° C / h, from room temperature to 180 ° C, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 40%;

[0136] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0137] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 8 are 442.58 MPa, 542.53 MPa and 23.91%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 8 and the mechanical properties of the alloy are shown in Table 1.

[0138] Example 9

[0139] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0140] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0141] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0142] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0143] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0144] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0145] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0146] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 20℃ / h, from room temperature to 180℃, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 60%;

[0147] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0148] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 9 are 427.66 MPa, 530.15 MPa and 22.1%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 9 and the mechanical properties of the alloy are shown in Table 1.

[0149] Example 10

[0150] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0151] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0152] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0153] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0154] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0155] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0156] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0157] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 20℃ / h, from room temperature to 220℃, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 80%;

[0158] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0159] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 10 are 415.23 MPa, 526.7 MPa and 24.58%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 10 and the mechanical properties of the alloy are shown in Table 1.

[0160] Example 11

[0161] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0162] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0163] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0164] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0165] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0166] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0167] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0168] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 25 ° C / h, from room temperature to 120 ° C, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 20%;

[0169] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0170] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 11 are 352.42 MPa, 471.25 MPa and 28.72%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 11 and the mechanical properties of the alloy are shown in Table 1.

[0171] Example 12

[0172] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0173] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0174] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0175] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0176] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0177] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0178] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0179] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 25 ° C / h, from room temperature to 180 ° C, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 20%;

[0180] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0181] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 12 are 411.25 MPa, 512.32 MPa and 24.2%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 12 and the mechanical properties of the alloy are shown in Table 1.

[0182] Example 13

[0183] A heat treatment method for improving the strength-plasticity synergistic properties of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, comprising the following steps:

[0184] (1) Melting and casting: The following alloy composition is prepared: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al. After preparing the ingredients, melting and casting are performed. The melting temperature is 720 to 750°C and the casting temperature is 700 to 720°C.

[0185] (2) Homogenization treatment: homogenization temperature 450°C, time 10 h;

[0186] (3) Hot rolling: rolled to 5 mm thick, hot rolling temperature is 450 ° C;

[0187] (4) Cold rolling: rolled to 2 mm thick, the cold rolling temperature is room temperature;

[0188] (5) Solution treatment: heating from 20°C to 500°C at a rate of 24°C / min and holding for 30 min;

[0189] (6) Quenching: After solutionizing, the aluminum alloy is water-quenched and cooled to room temperature. The quenching transfer time does not exceed 5s.

[0190] (7) Non-isothermal pre-aging treatment + cold rolling pre-deformation treatment: The non-isothermal pre-aging heating rate is 30℃ / h, from room temperature to 260℃, and the pre-deformation treatment is performed after the non-isothermal pre-aging treatment, and the cold rolling deformation amount is 5%;

[0191] (8) Isothermal aging treatment: The isothermal aging heating time is 15 minutes, from 20℃ to 180℃, and the temperature is kept for 30 minutes.

[0192] The yield strength, tensile strength and elongation of the Al-Mg alloy obtained in Example 13 are 321.76 MPa, 456.26 MPa and 29.57%, respectively. The parameters of the non-isothermal pre-aging treatment and pre-deformation treatment in Example 13 and the mechanical properties of the alloy are shown in Table 1.

[0193] Table 1 Parameters of non-isothermal pre-aging treatment, pre-deformation treatment and mechanical properties of alloys in various embodiments

[0194]

[0195]

[0196] Figures 1 to 4 The precipitated phase structures and dislocation substructure diagrams of Example 3 and Example 8 are given. Figure 1 and Figure 2 After the sample is treated with a lower heating rate and a smaller pre-deformation, the precipitated phase has a coarse morphology, low density, and uneven distribution, which makes it difficult to effectively pin dislocations, and the precipitation strengthening effect is limited; at the same time, the dislocation structure is relatively loose, mainly distributed in a forest-like manner, and the cellular or sub-grained structure is not obvious, indicating that the strain energy introduced by plastic deformation is low, making it difficult to provide sufficient nucleation sites for precipitation, and the overall organizational strengthening effect is weak. In contrast, Figure 3 and Figure 4 The samples shown, under high heating rates and significant pre-deformation, exhibit fine, dense, and uniformly distributed precipitates, synergizing well with the dislocation network. Dislocation cells and subgrain boundaries significantly increase, demonstrating the facilitation of precipitation by the high-density dislocation structure. These differences in microstructural evolution directly lead to significant differences in the mechanical properties of the materials, demonstrating the effectiveness of the proposed heat treatment pathway in enhancing strength-ductility synergy.

[0197] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the scope defined in the claims. Other variations or modifications may be made based on the above description. Obvious variations or modifications derived therefrom shall remain within the scope of protection of the present invention.

Claims

1. A heat treatment method for improving the strength-plasticity synergy of Al-Mg alloys by combining non-isothermal pre-aging with pre-deformation, characterized in that: The heat treatment method comprises the following steps: (1) Melting and casting; (2) Homogenization treatment; (3) hot rolling; (4) Cold rolling; (5) Solution treatment; (6) Quenching; (7) After non-isothermal pre-aging treatment, cold rolling pre-deformation is performed; (8) Isothermal aging treatment; In the step (7), the non-isothermal pre-aging treatment is: heating at a constant heating rate, the heating rate range is 1 to 30°C / h, and the temperature range is 20 to 260°C; the deformation range of the cold rolling pre-deformation treatment is 5% to 80%.

2. The heat treatment method according to claim 1, characterized in that The composition requirements of the Al-Mg alloy are specifically as follows: Mg content 1wt% to 10wt%, Zn content 0.15wt% to 4wt%, Mn content 0.4wt%, Cu content 0.15wt% to 0.5wt%, Ag content 0.15wt% to 0.6wt%, and the balance is Al.

3. The heat treatment method according to claim 1, characterized in that In the step (1), the smelting and casting are as follows: the materials are prepared according to the alloy composition requirements and then smelted and cast, the smelting temperature is 720-750°C, and the casting temperature is 700-720°C.

4. The heat treatment method according to claim 1, characterized in that In the step (2), the homogenization treatment is as follows: homogenization temperature 450° C., holding time 10 h.

5. The heat treatment method according to claim 1, wherein In the step (3), the hot rolling is as follows: the hot rolling temperature is 450° C. and the thickness is rolled to 5 mm.

6. The heat treatment method according to claim 1, characterized in that In the step (4), the cold rolling is performed at room temperature and the thickness is 2 mm.

7. The heat treatment method according to claim 1, characterized in that In the step (5), the solution treatment is as follows: the sample is heated in a furnace from 20°C to 500°C at a heating rate of 24°C / min, and kept warm for 30 minutes.

8. The heat treatment method according to claim 1, wherein In the step (6), the quenching is: cooling to room temperature by water quenching, and the quenching transfer time does not exceed 5s.

9. The heat treatment method according to claim 1, characterized in that In the step (7), the non-isothermal pre-aging treatment is: from room temperature to 120-220°C, preferably 180°C, and the heating rate range is 15-25°C / h, preferably 20°C / h; the deformation range of the cold rolling pre-deformation treatment is 20%-40%, preferably 40%.

10. The heat treatment method according to claim 1, characterized in that In the step (8), the isothermal aging treatment is as follows: the sample is heated in a furnace for 15 minutes from 20°C to 180°C, and kept warm for 30 minutes.

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