Preparation method of high-strength and high-toughness aluminum-magnesium-silicon alloy material

Abstract

The application discloses a preparation method of high-strength and high-toughness aluminum-magnesium-silicon alloy material and belongs to the technical field of heat treatment of non-ferrous metals. The aluminum-magnesium-silicon alloy material with high-concentration cluster strengthening structure is obtained by high-temperature solid solution and quenching, cyclic rapid heating and quenching, electron beam irradiation, aging strengthening process, optimization of component proportion of the aluminum-magnesium-silicon alloy material and addition of trace rare earth elements to improve the electronic structure of the matrix. Compared with the traditional aluminum-magnesium-silicon alloy, the rapid heating and rapid cooling process retains a higher matrix vacancy concentration, the irradiation of the electron beam makes the generated vacancies and defects more uniform, and finally more cluster strengthening phases are generated in the subsequent aging process. The application reduces the high-temperature homogenization process and prevents the loss of vacancies and defects due to atomic thermal vibration at high temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat treatment processes for nonferrous metals, and in particular relates to a method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material. Background Art

[0002] Aluminum-magnesium-silicon alloys have excellent mechanical properties, corrosion resistance, and weldability. Consequently, they are widely used in aerospace, automotive parts manufacturing, aluminum alloy door and window frames, and other fields where lightweighting, energy reduction, and corrosion resistance are required. However, aluminum-magnesium-silicon alloys currently suffer from high manufacturing costs and low fracture toughness.

[0003] Chinese invention patent application CN105886976A discloses a heat treatment process for aluminum alloys, specifically a thermomechanical treatment process for improving the overall performance of aluminum alloys. The aluminum-magnesium-silicon alloy is subjected to a solution water quenching treatment and then rolled to obtain the rolled aluminum-magnesium-silicon alloy. The material is then subjected to a solution water quenching treatment, a pre-aging treatment, a special deformation treatment, and a secondary aging treatment to obtain a finished product with superior overall performance. The special deformation treatment involves asymmetric rolling. This method is simple, safe, and convenient to operate, resulting in a product with superior performance and amenable to industrial production and application.

[0004] Chinese invention patent application CN109593996A discloses a squeeze-cast, high-strength and toughness aluminum-magnesium-silicon-chromium alloy produced using squeeze casting technology and a T6 heat treatment process. The solution temperature is 560-580°C for 2-3 hours, and the aging temperature is 180-220°C for 2-3 hours. This alloy not only exhibits high strength and toughness, but also exhibits low mold sticking tendency and excellent formability. The raw materials are inexpensive and readily available, making it particularly suitable for manufacturing lightweight parts or components.

[0005] In summary, the traditional heat treatment process for aluminum-magnesium-silicon alloy materials is a combination of solution treatment, aging treatment, and cold deformation processing. However, the ability of traditional solution treatment and aging treatment to improve the performance of the material is limited; the introduction of asymmetric rolling can obtain higher mechanical properties through cold deformation processing, but due to the different rotation speeds of the upper and lower rollers in asynchronous rolling, more stress concentration areas will appear in the material, and stress concentration will occur. Summary of the Invention

[0006] To address the shortcomings of the prior art, the present invention proposes a method for preparing a high-strength, high-toughness aluminum-magnesium-silicon alloy. This method optimizes the traditional heat treatment process by replacing cold deformation with high-energy electron beam irradiation, resulting in an aluminum-magnesium-silicon alloy with uniform structure, excellent strength, and toughness.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material comprises the following steps:

[0008] (1) Solution treatment and quenching: The aluminum-magnesium-silicon alloy is solution treated and then quenched in cold water;

[0009] (2) Induction heating process: Use a high-frequency induction heater to heat the quenched alloy to above 580°C;

[0010] (3) Cyclic heating and cooling: placing the induction-heated alloy into water for quenching, and then cycling the induction heating in step (2) and the quenching in step (3), with the number of cycles being no less than three times;

[0011] (4) Irradiation treatment: After the last quenching, the alloy is irradiated using an electron beam for pretreatment;

[0012] (5) Artificial aging treatment: The alloy is subjected to aging treatment to obtain a high-strength and high-toughness aluminum-magnesium-silicon alloy material.

[0013] As a preferred embodiment of the present invention, the magnesium-silicon alloy includes the following components in atomic percentage: 0.8%-1.6% Mg, 0.8%-1.2% Si, 0.2%-0.3% Cu, 0.1%-0.2% rare earth elements, and the remainder is Al.

[0014] The rare earth element is at least one of La, Sc and Ce.

[0015] As a preferred embodiment of the present invention, the temperature of the solution treatment is 520° C. and the holding time is 1 hour.

[0016] As a preferred embodiment of the present invention, the heating rate of the induction heating is above 120° C. / s to obtain a higher vacancy concentration.

[0017] As a preferred embodiment of the present invention, in the cyclic heating and cooling, multiple quenching treatments are completed in a relatively fast time, and the cooling in water does not exceed 2 minutes. Through the extremely cold and hot methods, a higher vacancy concentration of the matrix is ​​retained.

[0018] As a preferred embodiment of the present invention, the irradiation energy of the electron beam is 2 MeV, the total irradiation dose is 50 Gy to 120 Gy, the irradiation temperature is 150° C. to 180° C., and the irradiation time is 20 min to 35 min.

[0019] The present invention induces more vacancies to be generated by short-term electron beam irradiation treatment with an irradiation temperature selected at 150° C. to 180° C., while ensuring that the irradiation dose is not too high and the structure and performance of the alloy material are not seriously damaged.

[0020] As a preferred embodiment of the present invention, the aging treatment temperature is 160° C. to 180° C., and the time is 4 hours.

[0021] Principle of the present invention:

[0022] The present invention uses a cyclic heating and cooling process to preserve the vacancy concentration in the matrix. Rapid heating increases the thermal vibration rate of atoms, allowing them to fill vacancies more quickly. Rapid cooling rapidly contracts the crystal lattice, slowing the movement of atoms within the lattice and preventing them from rearranging to their normal lattice positions. Through multiple cycles of rapid cooling and heating, vacancies are generated and filled alternately. Rapid temperature changes accelerate the formation and aggregation of vacancies, increasing the number of retained vacancies.

[0023] The present invention uses high-energy electron beam irradiation to change the crystal structure of aluminum-magnesium-silicon alloys. When the high-energy electron beam passes through the aluminum alloy material, atoms and electrons are ionized and excited. The energy of the electron beam is absorbed and converted into ions and lattice defects in the crystal lattice. The energy conversion causes the formation of dislocations, vacancies, holes, and interstitial atoms in the crystal structure. However, the penetration depth of the electron beam is relatively small. The irradiation mainly occurs within a certain depth range of the aluminum alloy. Excessive irradiation can cause severe deformation and damage to the aluminum alloy, seriously affecting the performance of the aluminum alloy. Compared with traditional cold deformation treatment, irradiation can control the density of vacancies by adjusting the irradiation dose and energy. The electron beam can penetrate deep into the material, produce a uniform vacancy distribution, and can produce a high density of vacancies within the material volume. Combined with the mechanism of solute atoms and vacancies forming clusters, electron beam irradiation can uniformly form clusters in the material, ensuring that the mechanical properties of each position in the material have low differences.

[0024] This invention focuses on maintaining the inherent strength of aluminum-magnesium-silicon materials. By utilizing the binding of solute atoms and vacancies, known as the cluster strengthening mechanism, and through the interaction of rare earth elements, this promotes the formation of Mg-Si clusters and improves the toughness of the material. Due to its high corrosion resistance, this invention can broaden the application of aluminum-magnesium-silicon alloy sheet materials in marine floating structural components and shipbuilding.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention obtains an aluminum-magnesium-silicon alloy material with a high-concentration cluster-strengthening structure through high-temperature solid solution and quenching, cyclic rapid heating and quenching, electron beam irradiation, and aging strengthening processes. Compared with traditional aluminum-magnesium-silicon alloys, the rapid heating and cooling process retains a higher matrix vacancy concentration, and the irradiation effect of the electron beam makes the generated vacancies and defects more uniform, and finally produces more cluster-strengthening phases in the subsequent aging process. The present invention reduces the high-temperature homogenization process and prevents the loss of vacancies and defects due to atomic thermal vibration at high temperatures.

[0026] (2) The present invention optimizes the composition ratio of the aluminum-magnesium-silicon alloy material, adds a trace amount of rare earth elements to improve the electronic structure of the matrix, retains the vacancy concentration in the matrix through cyclic rapid heating and quenching treatment, promotes the generation of vacancies in the matrix through electron beam irradiation, forms Mg-Si clusters to improve the strength and toughness of the material, and expands the application range of floating structural components and ships in the ocean. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a flow chart of the preparation method of high-strength and high-toughness aluminum-magnesium-silicon alloy materials.

[0028] Figure 2 Temperature-time diagram for solution treatment and quenching, cyclic heating and cooling, electron beam irradiation, and artificial aging treatment.

[0029] Figure 3 This is a comparison chart of the tensile strength and elongation of the high-strength and high-toughness aluminum-magnesium-silicon alloy materials prepared in Examples 1-3 and Comparative Example 1. DETAILED DESCRIPTION

[0030] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0031] Example 1

[0032] A method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material comprises the following steps:

[0033] (1) According to the composition in Table 1, pure aluminum and intermediate alloys of various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 10 mm × 5 mm and a thickness of 5 mm, because electron beam irradiation mainly occurs within a certain depth of the material.

[0034] (2) Solution treatment: The ingot is subjected to solution treatment, slowly heated to 520°C, and the solution treatment time is 1 hour. After the solution treatment, it is immediately placed in cold water for quenching;

[0035] (3) Induction heating: A high-frequency induction heater is used to rapidly heat the quenched alloy to 580 °C at a heating rate of 120 °C / s;

[0036] (4) Rapid heating and cooling process: the alloy after induction heating is immediately placed in water for quenching treatment, and then the induction heating process in step (2) and the quenching process in step (3) are repeated three times;

[0037] (5) Irradiation pretreatment process: After the last quenching, the sample is placed in an electron beam accelerator and the aluminum alloy is modified by a high-energy electron beam. The irradiation time is 20 min, the irradiation energy of the electron beam is 2 MeV, the total irradiation dose is 50 Gy, and the irradiation temperature is selected to be 180 °C.

[0038] (6) Aging treatment: The alloy is subjected to aging treatment at a temperature of 170°C for 4 hours to obtain a high-strength and high-toughness aluminum-magnesium-silicon alloy material.

[0039] Table 1 Chemical composition of the aluminum-magnesium-silicon alloy of this embodiment (wt%)

[0040]

[0041] Example 2

[0042] A method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material comprises the following steps:

[0043] (1) According to the composition in Table 2, pure aluminum and intermediate alloys of various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 10 mm × 5 mm and a thickness of 5 mm, because electron beam irradiation mainly occurs within a certain depth of the material.

[0044] (2) Strengthening solution treatment: The ingot is subjected to solution strengthening treatment, slowly heated to 520 °C, and the solution time is 1 h. After the solution is completed, it is immediately placed in cold water for quenching;

[0045] (3) Induction heating: Use a high-frequency induction heater to quickly heat the quenched alloy to 600 °C at a heating rate of 150 °C / s;

[0046] (4) Rapid heating and cooling process: the alloy after induction heating is immediately placed in water for quenching treatment, and then the induction heating process in step (2) and the quenching process in step (3) are repeated four times;

[0047] (5) Irradiation pretreatment process: After the last quenching, the sample is placed in an electron beam accelerator and the aluminum alloy is modified by a high-energy electron beam. The irradiation time is 25 min, the irradiation energy of the electron beam is 2 MeV, the total irradiation dose is 80 Gy, and the irradiation temperature is selected to be 180 °C.

[0048] (6) Aging treatment: The alloy is subjected to aging treatment at a temperature of 160°C for 4 hours to obtain a high-strength and high-toughness aluminum-magnesium-silicon alloy material.

[0049] Table 2 Chemical composition of the aluminum-magnesium-silicon alloy of this embodiment (wt%)

[0050]

[0051] Example 3

[0052] A method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material comprises the following steps:

[0053] (1) According to the composition in Table 3, pure aluminum and intermediate alloys of various elements were first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 10 mm × 5 mm and a thickness of 5 mm, because electron beam irradiation mainly occurs within a certain depth of the material.

[0054] (2) Solution treatment: The ingot is subjected to solution treatment, slowly heated to 520°C, and the solution treatment time is 1 hour. After the solution treatment, it is immediately placed in cold water for quenching;

[0055] (3) Induction heating: A high-frequency induction heater is used to rapidly heat the quenched alloy to 600 °C at a heating rate of 180 °C / s;

[0056] (4) Rapid heating and cooling process: the alloy after induction heating is immediately placed in water for quenching treatment, and then the induction heating process in step (2) and the quenching process in step (3) are repeated for 5 times;

[0057] (5) Irradiation pretreatment process: After the last quenching, the sample is placed in an electron beam accelerator and the aluminum alloy is modified by a high-energy electron beam. The irradiation time is 35 minutes, the irradiation energy of the electron beam is 2 MeV, the total irradiation dose is 120 Gy, and the irradiation temperature is selected to be 180 °C.

[0058] (6) Aging treatment: The alloy is subjected to aging treatment at a temperature of 180°C for 4 hours to obtain a high-strength and high-toughness aluminum-magnesium-silicon alloy material.

[0059] Table 3 Chemical composition of the aluminum-magnesium-silicon alloy of this embodiment (wt%)

[0060]

[0061] Example 4

[0062] A method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material comprises the following steps:

[0063] (1) According to the composition in Table 4, pure aluminum and intermediate alloys of various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 10 mm × 5 mm and a thickness of 5 mm, because electron beam irradiation mainly occurs within a certain depth of the material.

[0064] (2) Solution treatment: The ingot is subjected to solution treatment by slowly heating it to 520°C for 1 hour. After the solution treatment, it is immediately placed in cold water for quenching.

[0065] (3) Induction heating: A high-frequency induction heater was used to rapidly heat the quenched alloy to 580 °C at a heating rate of 120 °C / s.

[0066] (4) Rapid heating and cooling process: the alloy after induction heating is immediately placed in water for quenching treatment, and then the induction heating process in step (2) and the quenching process in step (3) are repeated three times.

[0067] (5) Irradiation pretreatment process: After the last quenching, the sample is placed in an electron beam accelerator and the aluminum alloy is modified by a high-energy electron beam. The irradiation time is 20 min, the irradiation energy of the electron beam is 2 MeV, the total irradiation dose is 50 Gy, and the irradiation temperature is selected to be 150 °C.

[0068] (6) Aging treatment: The alloy is subjected to aging treatment at a temperature of 170°C for 4 hours to obtain a high-strength and high-toughness aluminum-magnesium-silicon alloy material.

[0069] Table 4 Chemical composition of the aluminum-magnesium-silicon alloy of this embodiment (wt%)

[0070]

[0071]

[0072] Example 5

[0073] A method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material comprises the following steps:

[0074] (1) According to the composition in Table 5, pure aluminum and intermediate alloys of various elements are first smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 10 mm × 5 mm and a thickness of 5 mm, because electron beam irradiation mainly occurs within a certain depth of the material.

[0075] (2) Solution treatment: The ingot is subjected to solution treatment by slowly heating it to 520°C for 1 hour. After the solution treatment, it is immediately placed in cold water for quenching.

[0076] (3) Induction heating: A high-frequency induction heater was used to rapidly heat the quenched alloy to 580 °C at a heating rate of 120 °C / s.

[0077] (4) Rapid heating and cooling process: the alloy after induction heating is immediately placed in water for quenching treatment, and then the induction heating process in step (2) and the quenching process in step (3) are repeated three times.

[0078] (5) Irradiation pretreatment process: After the last quenching, the sample is placed in an electron beam accelerator and the aluminum alloy is modified by a high-energy electron beam. The irradiation time is 20 min, the irradiation energy of the electron beam is 2 MeV, the total irradiation dose is 50 Gy, and the irradiation temperature is selected to be 180 °C.

[0079] (6) Aging treatment: The alloy is subjected to aging treatment at a temperature of 170°C for 4 hours to obtain a high-strength and high-toughness aluminum-magnesium-silicon alloy material.

[0080] Table 5 Chemical composition of the aluminum-magnesium-silicon alloy of this embodiment (wt%)

[0081]

[0082] Comparative Example 1

[0083] A method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material comprises the following steps:

[0084] (1) According to the composition in Table 6, pure aluminum and intermediate alloys of various elements were smelted and cast to form an aluminum alloy ingot with a size of 50 mm × 10 mm × 5 mm and a thickness of 5 mm.

[0085] (2) Solution treatment: The ingot is subjected to solution treatment, slowly heated to 520°C, and the solution treatment time is 1 hour. After the solution treatment, it is immediately placed in cold water for quenching;

[0086] (3) Induction heating: A high-frequency induction heater is used to rapidly heat the quenched alloy to 580 °C at a heating rate of 120 °C / s;

[0087] (4) Rapid heating and cooling process: the alloy after induction heating is immediately placed in water for quenching treatment, and then the induction heating process in step (2) and the quenching process in step (3) are repeated three times;

[0088] (5) cold rolling process: after the last quenching, the sample is asynchronously cold rolled, the speed ratio of the upper and lower rollers is 1.4, the deformation is 40% to 60%, the rolling temperature is in the range of room temperature to 180℃, and the rolling pass is not limited.

[0089] (6) aging treatment: the alloy is aged at a temperature of 170℃ for 4h to obtain a high-strength high-toughness aluminum-magnesium-silicon alloy material.

[0090] Table 6 Chemical composition table of the aluminum-magnesium-silicon alloy of the comparative example (wt%)

[0091]

[0092] The high-strength high-toughness aluminum-magnesium-silicon alloy materials prepared according to Examples 1-5 and Comparative Example 1 are tested for performance testing, and the results are shown in Table 7.

[0093] Table 7

[0094]

[0095]

[0096] According to the yield strength, tensile strength and elongation of the high-strength high-toughness magnesium-aluminum-silicon alloy materials prepared by different processes in Table 7, in Examples 1-3, the irradiation time is increased, so the absorbed irradiation dose of the material is also increased. As can be seen from Table 7, as the irradiation dose increases, the yield strength also increases, and the tensile strength and elongation are also improved. In Example 3, the decrease in elongation and tensile strength is mainly due to the increase in vacancies and defects in the crystal structure of the material caused by high-energy electron beams. However, due to the limited content of Mg and Si forming cluster structures, vacancies are not completely converted into cluster structures, and there are still a small amount of vacancies, so the mechanical properties decrease slightly. Compared with Comparative Example 1, the strength and elongation of the examples are better than those of Comparative Example 1, which shows that irradiation can well homogenize the vacancies in the material, form a uniform cluster strengthening structure during the subsequent aging process, and increase the number of vacancies to promote the formation of Mg-Si clusters, so that the aluminum-magnesium-silicon alloy has uniform and excellent mechanical properties and elongation.

[0097] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material, characterized in that: The steps include: (1) Solution treatment and quenching: The aluminum-magnesium-silicon alloy is solution treated and then quenched in cold water; (2) Induction heating process: Use a high-frequency induction heater to heat the quenched alloy to above 580°C at a heating rate of more than 120°C / s; (3) Cyclic heating and cooling: the induction-heated alloy is placed in water for quenching, and then the induction heating in step (2) and the quenching in step (3) are repeated for not less than three times; wherein the induction-heated alloy is placed in water for cooling for no more than 2 minutes; (4) Irradiation treatment: After the last quenching, the alloy is irradiated with an electron beam for pretreatment; the irradiation energy of the electron beam is 2 MeV, the total irradiation dose is 50 Gy to 120 Gy, the irradiation temperature is 150 ° C to 180 ° C, and the irradiation time is 20 to 35 min; (5) Artificial aging treatment: The alloy is subjected to aging treatment to obtain a high-strength and high-toughness aluminum-magnesium-silicon alloy material; In step (1), the aluminum-magnesium-silicon alloy includes the following components in percentage: 0.8wt%-1.6wt% Mg, 0.8wt%-1.2wt% Si, 0.2wt%-0.3wt% Cu, 0.1wt%-0.2wt% rare earth elements, and the rest is Al.

2. The method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material according to claim 1, characterized in that: The temperature of the solution treatment is 520° C., and the holding time is 1 hour.

3. The method for preparing a high-strength and high-toughness aluminum-magnesium-silicon alloy material according to claim 1, wherein: The aging treatment is performed at a temperature of 160° C. to 180° C. for 4 hours.

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