Design method of high-strength low-deformation vacuum brazing process for aluminum alloy

Abstract

The invention relates to the technical field of aluminum alloy precision welding, in particular to an aluminum alloy high-strength low-deformation vacuum brazing process design method, which comprises the following steps of: constructing a relation formula of welding seam strength sigma and welding parameters such as temperature, time, pressure and the like and a brazing creep constitutive equation under an aluminum alloy low-pressure loading vacuum brazing condition; the welding strength and thickness deformation results under the welding process parameters can be obtained, optimal design of the high-strength low-deformation vacuum brazing process parameters of the thin-wall aluminum alloy structure is achieved according to the design welding strength and thickness deformation requirements of the aluminum alloy structure, and the problems that time and labor are wasted and optimization is difficult when the welding parameters are obtained through a test method are solved; and the product development efficiency and the manufacturing yield are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of precision welding of aluminum alloys, and particularly to a method for designing a high-strength and low-deformation vacuum brazing process for aluminum alloys. Background Art

[0002] Aluminum alloy thin-walled structures such as microchannel liquid-cooling components and waveguide antennas are key structures for realizing the heat dissipation performance and electrical performance of a new generation of radar equipment. They have extremely high requirements for manufacturing accuracy and quality, and the strain deformation generally does not exceed 0.15%. Such structures are complex, and the vacuum brazing process is mainly used in the manufacturing process. Since the weld strength and deformation of vacuum brazing are both related to welding parameters, and aluminum alloy microchannel liquid-cooling components and millimeter-wave waveguide antennas have the characteristics of thin walls and low rigidity, the application of pressure during the high-temperature brazing process is extremely likely to cause welding deformation. Therefore, high-quality and low-deformation welding needs to be achieved under low-pressure loading conditions.

[0003] According to the research experience of welding performance and welding deformation under low-pressure loading conditions, the pressure during the welding process is generally much smaller than the material yield strength during welding. Therefore, the vacuum brazing deformation mainly comes from high-temperature creep deformation. According to the creep deformation principle, the main influencing factors of welding creep deformation are welding time, welding temperature, and welding pressure. At the same time, these three welding factors are also the main factors affecting the brazing strength. In order to realize the design of the vacuum brazing process for complex structures such as aluminum alloy microchannel liquid-cooling components and millimeter-wave waveguide antennas, multi-factor coupling design needs to be achieved, which is difficult.

[0004] In the actual welding process design, it is generally necessary to go through multiple rounds of physical iterations to determine the welding parameters that can simultaneously meet the strength and precision indicators, which is time-consuming and laborious and difficult to meet the rapid development needs of a new generation of radar equipment. Therefore, there is an urgent need to propose a new welding process design method to improve the design efficiency of the high-strength and low-deformation brazing process of aluminum alloys and support the development of a new generation of radar equipment.

[0005] In view of the above defects, the creators of the present invention have finally obtained the present invention through long-term research and practice. Summary of the Invention

[0006] The purpose of the present invention is to solve the problem that in the actual welding process design, it is generally necessary to go through multiple rounds of physical iterations to determine the welding parameters that can simultaneously meet the strength and precision indicators, which is time-consuming and laborious and difficult to meet the rapid development needs of a new generation of radar equipment, and provide a method for designing a high-strength and low-deformation vacuum brazing process for aluminum alloys.

[0007] To achieve the above purpose, the present invention discloses a method for designing a high-strength and low-deformation vacuum brazing process for aluminum alloys, including the following steps:

[0008] S1, determining the weld strength index σ0 and the thickness allowable deformation index ε0 of the aluminum alloy structure according to the design requirements;

[0009] S2. Conduct an orthogonal test on the vacuum brazing of aluminum alloy and solder to obtain the test data of welding strength σ and welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relational formula between the joint weld strength σ and welding parameters: σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solder solidus temperature;

[0010] S3. Conduct a creep test under the condition of aluminum alloy brazing to obtain the test data of creep deformation ε and welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation perform data fitting to obtain relevant constants, where is the creep deformation rate, α is a material constant, s is a stress exponent constant, Q is the creep activation energy, and R is the molar gas constant;

[0011] S4. Select a welding temperature T1 and time t1, and substitute them together with σ0 into the formula σ = At l (T - T0) m (B + P n ) for the first calculation to obtain the brazing pressure P1 required to achieve the strength index σ0;

[0012] S5. Substitute T1 and P1 into the creep constitutive equation to obtain the creep deformation rate of the aluminum alloy under welding conditions and according to ×t1 = ε1, calculate the thickness deformation ε1;

[0013] S6. When ε1 ≤ ε0, the complete welding process parameters are obtained: temperature T1, time t1, and pressure P1; when ε1 ≥ ε0, the parameters that meet the deformation conditions and strength requirements cannot be obtained under the current temperature T1, time t1, and pressure P1. Another set of temperature Tn and time tn need to be selected, and step 4 is repeated to calculate the pressure Pn, and then step 5 is performed until εn ≤ ε0, so as to obtain the complete welding process parameters: temperature Tn, time tn, and pressure Pn.

[0014] In the above step S2, the aluminum alloy material grades include 3A21, 6063, 6061, 5A06, and AlSi10Mg.

[0015] The solders corresponding to the aluminum alloys 3A21 and 6063 are AlSi10Mg1.5, and the solders corresponding to the aluminum alloys 6061, 5A06, and AlSi10Mg are AlCuSiNi.

[0016] The solidus temperature of the solder AlSi10Mg1.5 is taken as 560°C, and the solidus temperature of the solder AlCuSiNi is taken as 510°C.

[0017] In the said step S2, the welding temperature T is the peak holding temperature on the welding temperature curve, and the welding time t is the total time during which the temperature on the aluminum alloy part exceeds the solidus temperature T0 of the solder.

[0018] When the solder is AlSi10Mg1.5, the welding temperature curve program is as follows:

[0019] A1, uniformly heat to 280°C within 60 min and hold for 30 min;

[0020] A2, heat to 500°C within 60 min and hold for 200 min;

[0021] A3, heat to 550°C within 60 min and hold for 200 min;

[0022] A4, heat to the welding temperature T within 30 min and hold for 40 - 80 min;

[0023] A5, cool down to 500°C within 30 min and hold for 40 min;

[0024] A6, cool down to 200°C within 60 min and hold for 200 min;

[0025] A7, cool down to 70°C within 120 min.

[0026] When the solder is AlCuSiNi, the welding temperature curve program is as follows:

[0027] B1, uniformly heat to 280°C within 60 min and hold for 30 min;

[0028] B2, heat to 400°C within 60 min and hold for 200 min;

[0029] B3, heat to 480°C within 60 min and hold for 200 min;

[0030] B4, heat to the welding temperature T within 30 min and hold for 40 - 100 min;

[0031] B5, cool down to 450°C within 30 min and hold for 40 min;

[0032] B6, cool down to 200°C within 60 min and hold for 200 min;

[0033] B7, cool down to 70°C within 120 min.

[0034] In the step S2, the application time of the brazing pressure P is within the entire welding time t, that is, the pressure is loaded when the actual temperature of the welding structure rises to the solidus temperature of the solder, and the pressure is unloaded when the actual temperature of the welding structure drops to the solidus temperature of the solder, and no pressure is applied in other temperature intervals to avoid increasing part deformation.

[0035] In the step S3, the brazing creep constitutive equation is obtained through a hot compression test. The temperature T ranges from T0 to T0 + 50 °C, the time t ranges from 40 - 150 min, and the pressure P ranges from 0 - 1 MPa.

[0036] The beneficial effects of the present invention compared with the prior art are as follows:

[0037] 1. Aiming at the dual-index requirements of welding strength and deformation control for the thin-walled aluminum alloy structure, the present invention changes the time-consuming and laborious method of determining process parameters through a large number of experimental studies. By constructing a quantitative relationship model of "welding parameters - weld strength" and a creep constitutive equation for low-pressure loading vacuum brazing, a coupled optimization design method is proposed, realizing the high-strength and low-deformation vacuum brazing process design for thin-walled aluminum alloy structures and improving the design efficiency.

[0038] 2. Through a large number of experimental and theoretical studies, the present invention has established a quantitative relationship model between welding parameters and weld strength for aluminum alloys such as 3A21, 6063, 6061, 5A06, and AlSi10Mg under low-pressure loading vacuum brazing conditions (0.05 - 1 MPa), filling the industry gap. It can not only be applied to the brazing performance process design of thin-walled structures but also be equally applicable to the brazing process design of other aluminum alloy structures, providing design support for the brazing industry.

[0039] 3. The present invention provides the welding temperature design curves for AlSi10Mg1.5 solder and AlCuSiNi solder. Compared with the traditional welding process, the pressure is applied during the period when the welding temperature exceeds the solidus temperature of the solder, and basically no pressure is applied during other periods, thus significantly reducing the thickness deformation and achieving high-precision control of welding deformation. Description of the Drawings

[0040] Figure 1 It is a process design flow chart for high-strength and low-deformation vacuum brazing of aluminum alloys;

[0041] Figure 2 It is the vacuum brazing process parameters corresponding to AlSi10Mg1.5 solder;

[0042] Figure 3 It is the vacuum brazing process parameters corresponding to AlCuSiNi solder;

[0043] Figure 4 It is a schematic diagram of a thin-walled aluminum alloy structure. Detailed implementation mode

[0044] The following further elaborates on the above and additional technical features and advantages of the present invention with reference to the accompanying drawings.

[0045] Embodiment 1

[0046] Combined with Figures 1-4 To illustrate this embodiment, the specific process of this embodiment is as follows:

[0047] (1) Determine the weld strength index σ0 = 60 MPa and the thickness allowable deformation index ε0 = 0.15% of the 6063 aluminum alloy microchannel liquid cooling component according to the design requirements;

[0048] (2) Conduct an orthogonal test on the vacuum brazing of 6063 aluminum alloy and AlSi10Mg1.5 solder to obtain the test data of welding strength σ, welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relational formula between the joint weld strength σ and welding parameters σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solidus temperature of AlSi10Mg1.5 solder, 560 °C. Through fitting calculation, A = 8.217, B = 1.014, l = 0.152, m = 0.208, n = 0.496 are obtained;

[0049] (3) Conduct a creep test under the brazing conditions of 6063 aluminum alloy to obtain the test data of creep deformation ε, welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is a material constant, s is a stress index constant, Q is the creep activation energy, and R is the molar gas constant 8.31 J / (mol·K). Through fitting calculation, α = 2.13×10 3 , s = 2.08, Q = 139746 J / mol are obtained;

[0050] (4) Select a welding temperature T1 = 580 °C and time t1 = 70 min, and substitute them together with σ0 = 60 MPa into the formula σ = At l (T - T0) m (B + P n ) for the first calculation to obtain the brazing pressure P1 = 0.364 Mpa required to achieve the strength index σ0;

[0051] (5) Substitute T1 and P1 into the creep constitutive equation to obtain the creep deformation rate of the aluminum alloy under welding conditions And according to Calculate the thickness deformation ε1 = 0.299%;

[0052] (6) At this time, when ε1≥ε0 = 0.15%, that is, it is impossible to obtain parameters that meet the deformation conditions and strength requirements under the current temperature T1, time t1, and pressure P1. It is necessary to select another set of temperature T2 = 590°C, time t2 = 60 min, repeat step 4 to calculate the pressure P2 = 0.235 MPa, and then perform step 5 to obtain ε2 = 0.130% ≤ ε0, so as to obtain the complete welding process parameters: temperature T = 590°C, time t = 60 min, pressure P = 0.235 MPa.

[0053] In step 2, the welding temperature T is the peak holding temperature on the set welding temperature curve, and the welding time t is the total time when the temperature on the aluminum alloy part exceeds the solder solidus temperature.

[0054] In step 2, the application time of the brazing pressure P is within the entire welding time t, that is, the pressure is loaded when the actual temperature of the welding structure rises to the solder solidus temperature, and the pressure is unloaded when the actual temperature of the welding structure drops to the solder solidus temperature, and no pressure is applied in other temperature intervals to avoid increasing part deformation.

[0055] In step 3, the brazing creep constitutive equation is obtained through a hot compression test. The temperature T range is from T0 to T0 + 50°C, the time t range is 40 - 150 min, and the pressure P range is 0 - 1 MPa.

[0056] For the set welding temperature curve, for the solder AlSi10Mg1.5, its program is as follows:

[0057] A1, uniformly heat to 280°C within 60 min and hold for 30 min;

[0058] A2, heat to 500°C within 60 min and hold for 200 min;

[0059] A3, heat to 550°C within 60 min and hold for 200 min;

[0060] A4, heat to the welding temperature of 590°C within 30 min and hold for 60 min;

[0061] A5, cool down to 500°C within 30 min and hold for 40 min;

[0062] A6, cool down to 200°C within 60 min and hold for 200 min;

[0063] A7, cool down to 70°C within 120 min.

[0064] Example 2

[0065] Combined with Figures 1-4To illustrate this embodiment, the specific process of this embodiment is as follows:

[0066] (1) Determine the weld strength index σ0 = 50 MPa and the allowable thickness deformation index ε0 = 0.13% of the AlSi10Mg aluminum alloy waveguide antenna according to the design requirements.

[0067] (2) Conduct an orthogonal experiment on the vacuum brazing of AlSi10Mg aluminum alloy and AlCuSiNi solder to obtain the experimental data of welding strength σ, welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relationship formula between the joint weld strength σ and welding parameters: σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solidus temperature of AlCuSiNi solder, 510 °C. Through fitting calculation, obtain A = 7.842, B = 1.138, l = 0.161, m = 0.215, n = 0.483;

[0068] (3) Conduct a creep experiment under the brazing conditions of AlSi10Mg aluminum alloy to obtain the experimental data of creep deformation ε, welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is the material constant, s is the stress exponent constant, Q is the creep activation energy, and R is the molar gas constant, 8.31 J / (mol·K). Through fitting calculation, obtain α = 4.27×10 3 , s = 3.62, Q = 115482 J / mol;

[0069] (4) Select a welding temperature T1 = 540 °C and time t1 = 50 min, and substitute them together with σ0 = 50 MPa into the formula σ = At l (T - T0) m (B + P n ) for the first calculation to obtain the brazing pressure P1 = 0.235 MPa required to achieve the strength index σ0.

[0070] (5) Substitute T1 and P1 into the creep constitutive equation to obtain the creep deformation rate of the aluminum alloy under welding conditions And according to Calculate the thickness deformation ε1 = 0.196%;

[0071] (6) When ε1≥ε0 = 0.13% at this time, that is, it is impossible to obtain parameters that meet the deformation conditions and strength requirements under the current temperature T1, time t1, and pressure P1. It is necessary to select another set of temperature T2 = 540°C, time t2 = 60 min, repeat step 4 to calculate the pressure P2 = 0.191 MPa, and then perform step 5 to obtain ε2 = 0.11% ≤ ε0, so as to obtain the complete welding process parameters: temperature T = 540°C, time t = 60 min, pressure P = 0.191 MPa.

[0072] In step (2), the welding temperature T is the peak holding temperature on the set welding temperature curve, and the welding time t is the total time when the temperature on the aluminum alloy part exceeds the solder solidus temperature.

[0073] In step (2), the application time of the brazing pressure P is within the entire welding time t, that is, the pressure is loaded when the actual temperature of the welding structure rises to the solder solidus temperature, and the pressure is unloaded when the actual temperature of the welding structure drops to the solder solidus temperature, and no pressure is applied in other temperature intervals to avoid increasing part deformation.

[0074] In step (3), the brazing creep constitutive equation is obtained through a hot compression test. The temperature T range is from T0 to T0 + 50°C, the time t range is 40 - 150 min, and the pressure P range is 0 - 1 MPa.

[0075] For the set welding temperature curve, for the solder AlCuSiNi, its welding temperature curve program is:

[0076] B1, uniformly heat to 280°C within 60 min and hold for 30 min;

[0077] B2, heat to 400°C within 60 min and hold for 200 min;

[0078] B3, heat to 480°C within 60 min and hold for 200 min;

[0079] B4, heat to the welding temperature of 540°C within 30 min and hold for 60 min;

[0080] B5, cool down to 450°C within 30 min and hold for 40 min;

[0081] B6, cool down to 200°C within 60 min and hold for 200 min;

[0082] B7, cool down to 70°C within 120 min.

[0083] Example 3

[0084] Combined with Figures 1-4For this embodiment, the first three steps are the same as those of Embodiment 1, and the fourth step is different from that of Embodiment 1. The specific process is as follows:

[0085] (1) Determine the weld strength index σ0 = 60 MPa and the allowable thickness deformation index ε0 = 0.15% for the 6063 aluminum alloy microchannel liquid cooling component according to the design requirements;

[0086] (2) Conduct an orthogonal test on the vacuum brazing of 6063 aluminum alloy and AlSi10Mg1.5 solder to obtain the test data of welding strength σ, welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relationship formula between the joint weld strength σ and welding parameters: σ = At l (T - T0) m (B + P n ), where A, B, l, m, and n are constants, and T0 is the solidus temperature of AlSi10Mg1.5 solder, 560 °C. Through fitting calculation, A = 8.217, B = 1.014, l = 0.152, m = 0.208, and n = 0.496 are obtained;

[0087] (3) Conduct a creep test under the brazing conditions of 6063 aluminum alloy to obtain the test data of creep deformation ε, welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is the material constant, s is the stress exponent constant, Q is the creep activation energy, and R is the molar gas constant, 8.31 J / (mol·K). Through fitting calculation, α = 2.13×10 3 , s = 2.08, and Q = 139746 J / mol are obtained;

[0088] (4) Compare with Embodiment 1 to obtain the complete welding process parameters: temperature T = 590 °C, time t = 60 min, and pressure P = 0.235 MPa. This embodiment uses a lower welding pressure: temperature T = 590 °C, time t = 60 min, and pressure P = 0.1 MPa. Substitute into the same formula as in Embodiment 1: σ = At l (T - T0) m (B + P n ), and the joint weld strength σ is obtained as 53.9 MPa, which does not meet the design index.

[0089] Embodiment 4

[0090] Combined with Figures 1-4 For this embodiment, the first three steps are the same as those of Embodiment 3, and the fourth step is different from that of Embodiment 3. The specific process is as follows:

[0091] (1) Determine the weld strength index σ0 = 60 MPa and the thickness allowable deformation index ε0 = 0.15% of the 6063 aluminum alloy microchannel liquid cooling component according to the design requirements;

[0092] (2) Conduct an orthogonal test on the vacuum brazing of 6063 aluminum alloy and AlSi10Mg1.5 solder to obtain the test data of welding strength σ, welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relationship formula between the joint weld strength σ and welding parameters σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solidus temperature of AlSi10Mg1.5 solder, 560 °C. Through fitting calculation, A = 8.217, B = 1.014, l = 0.152, m = 0.208, n = 0.496 are obtained;

[0093] (3) Conduct a creep test under the brazing conditions of 6063 aluminum alloy to obtain the test data of creep deformation ε, welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is a material constant, s is a stress index constant, Q is the creep activation energy, and R is the molar gas constant 8.31 J / (mol·K). Through fitting calculation, α = 2.13×10 3 , s = 2.08, Q = 139746 J / mol are obtained;

[0094] (4) Compare the welding process parameters of Example 3: temperature T = 590 °C, time t = 60 min, pressure P = 0.1 MPa. In this example, a longer welding time is used to improve the weld strength: temperature T = 590 °C, time t = 120 min, pressure P = 0.1 MPa. Substitute into the same formula as in Example 3, σ = At l (T - T0) m (B + P n ), and the joint weld strength σ is obtained as 60 MPa, meeting the design index. However, compared with Example 1, although both meet the design index, the welding time in this example has increased by 100%, significantly increasing the energy consumption.

[0095] Example 5

[0096] Combined Figures 1-4 Describe this example. The first three steps of this example are the same as those of Example 1, and the fourth and fifth steps are different from those of Example 1. The specific process is as follows:

[0097] (1) Determine the weld strength index σ0 = 60 MPa and the thickness allowable deformation index ε0 = 0.15% of the 6063 aluminum alloy microchannel liquid cooling component according to the design requirements;

[0098] (2) Conduct an orthogonal experiment on the vacuum brazing of 6063 aluminum alloy and AlSi10Mg1.5 solder to obtain the experimental data of welding strength σ, welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relational formula between the joint weld strength σ and welding parameters: σ = At l (T - T0) m (B + P n ), where A, B, l, m, and n are constants, and T0 is the solidus temperature of AlSi10Mg1.5 solder, 560 °C. Through fitting calculation, A = 8.217, B = 1.014, l = 0.152, m = 0.208, and n = 0.496 are obtained;

[0099] (3) Conduct a creep experiment under the brazing conditions of 6063 aluminum alloy to obtain the experimental data of creep deformation ε, welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is a material constant, s is a stress exponent constant, Q is the creep activation energy, and R is the molar gas constant, 8.31 J / (mol·K). Through fitting calculation, α = 2.13×10 3 , s = 2.08, and Q = 139746 J / mol are obtained;

[0100] (4) Compare with Example 1 to obtain the complete welding process parameters: temperature T = 590 °C, time t = 60 min, pressure P = 0.235 MPa. In this example, a relatively large welding pressure is adopted: temperature T = 590 °C, time t = 60 min, pressure P = 2 MPa. Using these parameters for product welding, the joint weld strength σ is 90 MPa, meeting the design index, while the thickness deformation ε = 0.5%, not meeting the design index.

[0101] Example 6

[0102] Combined with Figures 1-4 Explain this example. The first three steps of this example are the same as those of Example 1, and the fourth and fifth steps are different from those of Example 5. The specific process is as follows:

[0103] (1) Determine the weld strength index σ0 = 60 MPa and the thickness allowable deformation index ε0 = 0.15% of the 6063 aluminum alloy microchannel liquid cooling component according to the design requirements;

[0104] (2) Conduct an orthogonal experiment on the vacuum brazing of 6063 aluminum alloy and AlSi10Mg1.5 solder to obtain the experimental data of welding strength σ, welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relational formula between the joint weld strength σ and welding parameters: σ = At l (T - T0)m (B + P n ) where A, B, l, m, n are constants, and T0 is the solidus temperature of AlSi10Mg1.5 solder, which is 560 °C. Through fitting calculation, A = 8.217, B = 1.014, l = 0.152, m = 0.208, n = 0.496 are obtained;

[0105] (3) Conduct a creep test under the brazing conditions of 6063 aluminum alloy to obtain the test data of creep deformation ε and welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is a material constant, s is a stress exponent constant, Q is the creep activation energy, and R is the molar gas constant 8.31 J / (mol·K). Through fitting calculation, α = 2.13×10 3 , s = 2.08, Q = 139746 J / mol;

[0106] (4) Compare with Example 5 to obtain the complete welding process parameters: temperature T = 590 °C, time t = 60 min, pressure P = 0.235 MPa. In this example, a shorter welding time is used to make the weld strength reach the accurate design value: temperature T = 590 °C, time t = 5 min, pressure P = 2 MPa. Using these parameters for product welding, the joint weld strength σ is 60 MPa, meeting the design index, while the thickness deformation ε = 0.22%, still not meeting the design index. Further reducing the welding time will cause the weld strength to be lower than the design value. Therefore, under the condition of pressure P = 2 MPa, the process parameters that meet the design index cannot be obtained.

[0107] Example 7

[0108] Combined with Figures 1-4 Describe this example. The first three steps of this example are the same as those of Example 2, and the fourth step is different from that of Example 2. The specific process is as follows:

[0109] (1) Determine the weld strength index σ0 = 50 MPa and the thickness allowable deformation index ε0 = 0.13% of the AlSi10Mg aluminum alloy waveguide antenna according to the design requirements.

[0110] (2) Conduct an orthogonal test on the vacuum brazing of AlSi10Mg aluminum alloy and AlCuSiNi solder to obtain the test data of welding strength σ and welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relationship formula between the joint weld strength σ and welding parameters: σ = At l (T - T0) m (B + P n), where A, B, l, m, n are constants, and T0 is the solidus temperature of the AlCuSiNi solder, which is 510 °C. Through fitting calculations, A = 7.842, B = 1.138, l = 0.161, m = 0.215, and n = 0.483 are obtained;

[0111] (3) Conduct a creep test under the brazing conditions of AlSi10Mg aluminum alloy to obtain the test data of creep deformation ε, welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is a material constant, s is a stress exponent constant, Q is the creep activation energy, and R is the molar gas constant, which is 8.31 J / (mol·K). Through fitting calculations, α = 4.27×10 3 , s = 3.62, and Q = 115482 J / mol are obtained;

[0112] (4) Compare with Example 2 to obtain the complete welding process parameters: temperature T = 540 °C, time t = 60 min, and pressure P = 0.191 MPa. In this example, a lower welding pressure is used: temperature T = 540 °C, time t = 60 min, and pressure P = 0.1 MPa. Substitute into the same formula as in Example 2, σ = At l (T - T0) m (B + P n ), and the joint weld strength σ is obtained as 46.2 MPa, which does not meet the design requirements.

[0113] Example 8

[0114] Combined with Figures 1-4 To illustrate this example, the first three steps of this example are the same as those of Example 7, and the fourth step is different from that of Example 7. The specific process is as follows:

[0115] (1) Determine the weld strength index σ0 = 50 MPa and the allowable thickness deformation index ε0 = 0.13% of the AlSi10Mg aluminum alloy waveguide antenna according to the design requirements.

[0116] (2) Conduct an orthogonal test on the vacuum brazing of AlSi10Mg aluminum alloy and AlCuSiNi solder to obtain the test data of welding strength σ, welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relationship formula between the joint weld strength σ and the welding parameters, σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solidus temperature of the AlCuSiNi solder, which is 510 °C. Through fitting calculations, A = 7.842, B = 1.138, l = 0.161, m = 0.215, and n = 0.483 are obtained;

[0117] (3) Conduct a creep test under the brazing conditions of AlSi10Mg aluminum alloy to obtain the test data of creep deformation ε and welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is a material constant, s is a stress exponent constant, Q is the creep activation energy, and R is the molar gas constant 8.31 J / (mol·K). Through fitting calculation, α = 4.27×10 3 , s = 3.62, Q = 115482 J / mol;

[0118] (4) Compare with the welding process parameters of Example 6: temperature T = 540 °C, time t = 60 min, pressure P = 0.1 MPa. In this example, a longer welding time is used to improve the weld strength: temperature T = 540 °C, time t = 100 min, pressure P = 0.1 MPa. Substitute into the same formula as in Example 7, σ = At l (T - T0) m (B + P n ), and the joint weld strength σ is obtained as 50.1 MPa, meeting the design requirements. However, compared with Example 2, although both meet the design requirements, the welding time in this example is increased by 60%, significantly increasing the energy consumption.

[0119] Example 9

[0120] Combined with Figures 1-4 Explain this example. The first three steps of this example are the same as those of Example 2, and the fourth and fifth steps are different from those of Example 2. The specific process is as follows:

[0121] (1) Determine the weld strength index σ0 = 50 MPa and the thickness allowable deformation index ε0 = 0.13% of the AlSi10Mg aluminum alloy waveguide antenna according to the design requirements.

[0122] (2) Conduct an orthogonal test on the vacuum brazing of AlSi10Mg aluminum alloy and AlCuSiNi solder to obtain the test data of welding strength σ and welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relationship formula between the joint weld strength σ and welding parameters, σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solidus temperature of AlCuSiNi solder, 510 °C. Through fitting calculation, A = 7.842, B = 1.138, l = 0.161, m = 0.215, n = 0.483;

[0123] (3) Conduct a creep test under the brazing conditions of AlSi10Mg aluminum alloy to obtain the test data of creep deformation ε and welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Perform data fitting to obtain relevant constants, where α is the material constant, s is the stress exponent constant, Q is the creep activation energy, and R is the molar gas constant 8.31 J / (mol·K). Through fitting calculation, α = 4.27×10 3 , s = 3.62, Q = 115482 J / mol;

[0124] (4) Compare with Example 2 to obtain the complete welding process parameters: temperature T = 540 °C, time t = 60 min, pressure P = 0.191 MPa. In this example, a higher welding pressure is adopted: temperature T = 540 °C, time t = 60 min, pressure P = 2 MPa. Using these parameters for product welding, the joint weld strength σ is 79 MPa, meeting the design index, while the thickness deformation ε = 0.35%, not meeting the design index.

[0125] Example 10

[0126] Combined with Figures 1-4 Describe this example. The first three steps of this example are the same as those of Example 9, and the fourth and fifth steps are different from those of Example 9. The specific process is as follows:

[0127] (1) Determine the weld strength index σ0 = 50 MPa and the allowable thickness deformation index ε0 = 0.13% of the AlSi10Mg aluminum alloy waveguide antenna according to the design requirements.

[0128] (2) Conduct an orthogonal test on the vacuum brazing of AlSi10Mg aluminum alloy and AlCuSiNi solder to obtain the test data of welding strength σ and welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relationship formula between the joint weld strength σ and welding parameters σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solidus temperature of AlCuSiNi solder, 510 °C. Through fitting calculation, A = 7.842, B = 1.138, l = 0.161, m = 0.215, n = 0.483;

[0129] (3) Conduct a creep test under the brazing conditions of AlSi10Mg aluminum alloy to obtain the test data of creep deformation ε and welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Data fitting is carried out to obtain relevant constants, where α is a material constant, s is a stress exponent constant, Q is the creep activation energy, and R is the molar gas constant 8.31 J / (mol·K). Through fitting calculation, α = 4.27×10 3 , s = 3.62, Q = 115482 J / mol;

[0130] (4) Comparing with Example 9 to obtain the complete welding process parameters: temperature T = 540 °C, time t = 60 min, pressure P = 0.191 MPa. In this example, a shorter welding time is adopted to make the weld strength reach the accurate design value: temperature T = 540 °C, time t = 3 min, pressure P = 2 MPa. Using these parameters for product welding, the joint weld strength σ is 50 MPa, meeting the design index, while the thickness deformation ε = 0.18%, still not meeting the design index. Further reducing the welding time will cause the weld strength to be lower than the design value. Therefore, under the condition of pressure P = 2 MPa, process parameters that meet the design index cannot be obtained.

[0131] Example 11

[0132] Combined with Figures 1-4 To illustrate this example, the first three steps of this example are the same as those of Example 1, the welding process parameters are the same as those of Example 1, and the fourth and fifth steps are different from those of Example 1. The specific process is as follows:

[0133] (1) Determine the weld strength index σ0 = 60 MPa and the thickness allowable deformation index ε0 = 0.15% of the 6063 aluminum alloy microchannel liquid cooling component according to the design requirements;

[0134] (2) Conduct an orthogonal experiment on the vacuum brazing of 6063 aluminum alloy and AlSi10Mg1.5 solder to obtain the experimental data of welding strength σ and welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relationship formula between the joint weld strength σ and welding parameters σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solidus temperature of AlSi10Mg1.5 solder, which is 560 °C. Through fitting calculation, A = 8.217, B = 1.014, l = 0.152, m = 0.208, n = 0.496;

[0135] (3) Conduct a creep experiment under the brazing condition of 6063 aluminum alloy to obtain the experimental data of creep deformation ε and welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Data fitting is carried out to obtain relevant constants, where α is a material constant, s is a stress exponent constant, Q is the creep activation energy, and R is the molar gas constant 8.31 J / (mol·K). Through fitting calculation, α = 2.13×10 3 , s = 2.08, Q = 139746 J / mol;

[0136] (4) The set welding process parameters are as follows: temperature T = 590 °C, time t = 60 min, pressure P = 0.235 MPa.

[0137] (5) The application time of the brazing pressure P is within the whole process of the welding temperature rising and falling, that is, the welding structure is loaded with pressure at room temperature, the pressure is maintained during the temperature rising and falling process, and the pressure is unloaded when the actual temperature of the welding structure drops to room temperature.

[0138] The weld strength finally obtained in this embodiment is σ = 60 MPa, meeting the design index. The thickness deformation ε is 0.25%, not meeting the design index.

[0139] Example 12

[0140] Combined Figures 1-4 To illustrate this embodiment, the first three steps of this embodiment are the same as those of Example 2, the welding process parameters are the same as those of Example 2, and the fourth and fifth steps are different from those of Example 2. The specific process is as follows:

[0141] (1) According to the design requirements, determine the weld strength index σ0 = 50 MPa and the thickness allowable deformation index ε0 = 0.13% of the AlSi10Mg aluminum alloy waveguide antenna.

[0142] (2) Conduct an orthogonal test on the vacuum brazing of AlSi10Mg aluminum alloy and AlCuSiNi solder to obtain the test data of the welding strength σ and the welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relational formula between the joint weld strength σ and the welding parameters σ = At l (T - T0) m (B + P n ), where A, B, l, m, n are constants, and T0 is the solidus temperature of AlCuSiNi solder, 510 °C. Through fitting calculation, A = 7.842, B = 1.138, l = 0.161, m = 0.215, n = 0.483;

[0143] (3) Conduct a creep test under the brazing conditions of AlSi10Mg aluminum alloy to obtain the test data of the creep deformation ε and the welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation, the creep deformation rate Data fitting is carried out to obtain relevant constants, where α is a material constant, s is a stress exponent constant, Q is the creep activation energy, and R is the molar gas constant 8.31 J / (mol·K). Through fitting calculation, α = 4.27×10 3 , s = 3.62, Q = 115482 J / mol;

[0144] (4) The set welding process parameters are as follows: temperature T = 540 °C, time t = 60 min, pressure P = 0.191 MPa.

[0145] (5) The application time of the brazing pressure P is within the whole process of the welding temperature rising and falling, that is, the pressure is loaded when the welding structure is at room temperature, the pressure is maintained during the temperature rising and falling process, and the pressure is unloaded when the actual temperature of the welding structure drops to room temperature.

[0146] The weld strength finally obtained in this embodiment is σ = 50 MPa, meeting the design index. The thickness deformation ε is 0.19%, not meeting the design index.

[0147] The above are only the preferred embodiments of the present invention, which are illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all will fall within the protection scope of the present invention.

Claims

1. A design method for a high-strength and low-deformation vacuum brazing process of aluminum alloy, characterized in that, It includes the following steps: S1. Determine the weld strength index σ0 and the allowable thickness deformation index ε0 of the aluminum alloy structure according to the design requirements; S2. Conduct an orthogonal test on the vacuum brazing of aluminum alloy and solder to obtain the test data of welding strength σ and welding temperature T, welding time t, and welding pressure P. Through data fitting, obtain the relational formula between the joint weld strength σ and welding parameters: σ = At l (T - T0) m (B + P n ), where A, B, l, m, and n are constants, and T0 is the solder solidus temperature; S3. Conduct a creep test under the conditions of aluminum alloy brazing to obtain the test data of creep deformation ε, welding temperature T, welding time t, and welding pressure P. According to the creep constitutive equation perform data fitting to obtain relevant constants, where is the creep deformation rate, α is the material constant, s is the stress exponent constant, Q is the creep activation energy, and R is the molar gas constant; S4. Select a soldering temperature T1 and time t1, and substitute them together with σ0 into the formula σ = At l (T - T0) m (B + P n ), perform the first calculation to obtain the brazing pressure P1 required to achieve the desired strength index σ0; S5. Substitute T1 and P1 into the creep constitutive equation to obtain the creep deformation rate of the aluminum alloy under welding conditions and according to calculate the thickness deformation ε1; S6. When ε1 ≤ ε0, the complete welding process parameters are obtained: temperature T1, time t1, and pressure P1; when ε1 ≥ ε0, it means that parameters satisfying the deformation conditions and strength requirements cannot be obtained under the current temperature T1, time t1, and pressure P1 conditions. Another set of temperature Tn and time tn need to be selected, and step 4 is repeated to calculate the pressure Pn, and then step 5 is carried out until εn ≤ ε0, so as to obtain the complete welding process parameters: temperature Tn, time tn, and pressure Pn.

2. The design method of a vacuum brazing process for high-strength and low-deformation aluminum alloy as claimed in claim 1, characterized in that In the said step S2, the aluminum alloy material grades include 3A21, 6063, 6061, 5A06, and AlSi10Mg.

3. A method for designing a vacuum brazing process for high-strength and low-deformation aluminum alloy, as described in claim 2, wherein, The solders corresponding to the aluminum alloys 3A21 and 6063 are AlSi10Mg1.5, and the solders corresponding to the aluminum alloys 6061, 5A06, and AlSi10Mg are AlCuSiNi.

4. A method for designing an aluminum alloy high-strength and low-deformation vacuum brazing process as described in claim 3, characterized in that, The solidus temperature of the solder AlSi10Mg1.5 is taken as 560 °C, and the solidus temperature of the solder AlCuSiNi is taken as 510 °C.

5. A method for designing a vacuum brazing process for high-strength and low-deformation aluminum alloy, as described in claim 1, characterized in that, In the said step S2, the welding temperature T is the peak holding temperature on the welding temperature curve, and the welding time t is the total time when the temperature on the aluminum alloy part exceeds the solidus temperature T0 of the solder.

6. A method for designing an aluminum alloy high-strength and low-deformation vacuum brazing process according to claim 5, characterized in that, When the solder is AlSi10Mg1.5, the welding temperature curve program is as follows: A1. Uniformly heat to 280 °C within 60 min and hold for 30 min; A2. Heat to 500 °C within 60 min and hold for 200 min; A3. Heat to 550 °C within 60 min and hold for 200 min; A4. Heat to the welding temperature T within 30 min and hold for 40 - 80 min; A5. Cool down to 500 °C within 30 min and hold for 40 min; A6. Cool down to 200 °C within 60 min and hold for 200 min; A7. Cool down to 70 °C within 120 min.

7. A method for designing an aluminum alloy high-strength and low-deformation vacuum brazing process according to claim 5, characterized in that, When the solder is AlCuSiNi, the welding temperature curve program is as follows: B1. Uniformly heat to 280 °C within 60 min and hold for 30 min; B2. Heat to 400 °C within 60 min and hold for 200 min; B3. Heat to 480 °C within 60 min and hold for 200 min; B4. Heat to the welding temperature T within 30 min and hold for 40 - 100 min; B5. Cool down to 450 °C within 30 min and hold for 40 min; B6. Cool down to 200 °C within 60 min and hold for 200 min; B7. Cool down to 70 °C within 120 min.

8. A design method for a high-strength and low-deformation vacuum brazing process of aluminum alloy as described in claim 1, characterized in that, In the said step S2, the application time of the brazing pressure P is within the entire welding time t, that is, the pressure is loaded when the actual temperature of the welding structure rises to the solidus temperature of the solder, and the pressure is unloaded when the actual temperature of the welding structure drops to the solidus temperature of the solder, and no pressure is applied in other temperature intervals to avoid increasing part deformation.

9. A method for designing a vacuum brazing process for high-strength and low-deformation aluminum alloy, as described in claim 1, characterized in that In the step S3, the brazing creep constitutive equation is obtained through a hot compression test. The temperature T ranges from T0 to T0 + 50 °C, the time t ranges from 40 to 150 min, and the pressure P ranges from 0 to 1 MPa.

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