Aluminum alloy welding material and high-toughness welding seam preparation method

Abstract

The invention relates to an aluminum alloy welding material and a high-toughness welding seam preparation method, and belongs to the technical field of welding. According to the aluminum alloy welding material, cold metal transition, pulse hybrid welding, laser welding and other welding technologies are combined for rapid cooling, so that Mg, Cu, Zn and other elements in a weld joint are subjected to complete solid solution and are in a supersaturated state, and the joint strength mainly comes from solid solution strengthening contribution of Mg, Cu, Zn and other alloy elements and precipitation strengthening contribution of a corresponding strengthening phase; and then a solute-vacancy coupling diffusion mechanism can be achieved through short-time natural aging, a high-density strengthening phase is rapidly separated out from the welding seam, and therefore the welding seam is strengthened and toughened, and the welding seam strength and the welding coefficient are remarkably improved. Therefore, manual aging intervention is avoided, the welding cost is reduced, and the welding efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of welding, and particularly relates to an aluminum alloy welding material and a method for preparing a high-strength and tough weld seam. Background Art

[0002] Aluminum alloys have the advantages of low density, high specific strength, good weldability, and low cost, and are increasingly widely used in the fields of automobiles, rail transit, ships, aerospace, etc., and have also become the key materials for lightweight development. In actual production and manufacturing, it is inevitable to weld aluminum alloy parts. However, when using traditional commercial welding wires, such as ER4043 (Al-5Si), ER4047 (Al-12Si), etc., the strength of the welded joint seriously depends on the composition dilution of the base material, and the welding coefficient of the joint is generally only 50%-70%, which is difficult to meet the requirements of high-performance welded joints in actual production and manufacturing, and greatly limits the industrial application of aluminum alloys.

[0003] After welding with traditional commercial welding wires, only atomic clusters and GP zones are formed, resulting in serious softening of the weld seam. Post-weld heat treatment is required to strengthen the joint, which increases the welding cost, is not conducive to energy conservation and emission reduction, and in most cases, it is not feasible to heat-treat and strengthen the welded parts. Therefore, the composition regulation of welding materials and the development of welding processes are effective means to enhance the performance of aluminum alloy welded joints.

[0004] At present, alloying of welding materials is a common way to improve the performance of welded joints. Patent CN118875569A discloses an aluminum-magnesium alloy welding wire and its preparation method, in which a mixture of Mg, Al, Al-Mn alloy, and Al-Cr alloy is melted to prepare the welding wire to improve the mechanical properties of the weld seam. Patent CN116005047A discloses an aluminum alloy wire for welding and additive manufacturing and its preparation method, in which elements such as Si, Mn, Sc, and Zr are added to the Al-Mg welding wire for alloying to improve the strength of the weld seam. Patent CN118875568A discloses an aluminum alloy welding wire for fusion welding of 6-series aluminum alloys and its preparation method, by adding rare earth elements such as La and Ce during the preparation of the aluminum alloy welding wire to reduce the thermal crack sensitivity during welding and optimize and regulate the comprehensive performance of the material. However, at present, welding materials need to add rare earth elements and other expensive alloy elements, which increases the cost, and the improvement of the performance of welded joints is still limited, and it is not suitable for preparing high-strength and tough weld seams and cannot meet the requirements of industrial production and manufacturing.

[0005] Based on this, the present invention is proposed. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides an aluminum alloy welding material and a method for preparing a high-strength and high-toughness weld, realizing the strengthening and toughening of the weld, improving the strength of the welded joint (greater than 280 Mpa) and the welding coefficient (reaching 74.3%) to meet the requirements for high performance of aluminum alloy welded joints in actual production and manufacturing.

[0007] The first object of the present invention is to provide an aluminum alloy welding material. The elemental composition and mass percentage of the aluminum alloy welding material are as follows: Si 6.0% - 12.0%, Mg 0.6% - 0.9%, Cu 0.5% - 1.9%, Zn 0.1% - 0.9%, Cr 0.1% - 0.5%, Mn 0.1% - 1.0%, Fe 0 - 0.15%, and the balance is Al and other inevitable impurities, with a total impurity of 0 - 0.15%; the aluminum alloy welding material diluted into the weld satisfies the following points: The mass ratio of Mg to Si is (0.16 - 0.83):1; The mass fraction of Cu is at least 1.00%, and the mass ratio of Cu to Mg is (1.20 - 1.65):1; The mass fraction of Zn is 0.05% - 0.50%, and the mass ratio of (Zn + Cu) to Mg is (1.50 - 2.50):1.

[0008] In an embodiment of the present invention, the form of the aluminum alloy welding material is selected from one or more of powder, thin sheet, and wire.

[0009] In an embodiment of the present invention, the particle size of the powder is 10 μm - 250 μm, the thickness of the thin sheet is 50 μm - 1000 μm, and the diameter of the wire is 0.5 mm - 3.2 mm.

[0010] The second object of the present invention is to provide a method for preparing a high-strength and high-toughness aluminum alloy weld, including the following steps: welding an aluminum alloy base material with a welding material, and combining with a cooling treatment to completely dissolve elements such as Mg, Cu, and Zn in the weld, and then subjecting the welded joint to natural aging treatment to precipitate strengthening phases; the welding material is the above-mentioned aluminum alloy welding material; the strengthening phases are selected from one or more of θ'-Al2Cu, β''-Mg5Si6, Q'-AlCuMgSi, S-Al2CuMg, and η'-Mg2Zn5.

[0011] In an embodiment of the present invention, the aluminum alloy base material is selected from one or more of Al-Cu series alloys, Al-Si series alloys, Al-Mg series alloys, Al-Mg-Si series alloys, and Al-Zn series alloys.

[0012] In one embodiment of the present invention, the initial form of the aluminum alloy base material is in the T0 state - T10 state.

[0013] In one embodiment of the present invention, the welding method is selected from cold metal transfer and pulse composite welding and / or laser welding.

[0014] In one embodiment of the present invention, the process parameters of the cold metal transfer and pulse composite welding are as follows: the synchronous pulse frequency is 2 Hz - 10 Hz, the welding speed is 6 mm / s - 12 mm / s, and the wire feeding speed is 3.8 m / min - 5.2 m / min; The process parameters of the laser welding are as follows: the oscillation frequency is 80 Hz - 250 Hz, the oscillation amplitude is 1.0 mm - 3.0 mm, the welding speed is 20 mm / s - 33 mm / s, and the wire feeding speed is 3 m / min - 6 m / min.

[0015] In one embodiment of the present invention, the laser in the laser welding is a swinging laser and / or a galvanometer laser, and the laser type is one or more of infrared light, blue light, and green light.

[0016] In one embodiment of the present invention, the cooling treatment method is selected from one or more of high - thermal - conductivity metal substrate cooling, liquid cooling, forced air cooling, and cryogenic fluid cooling; the cooling treatment is cooling during welding, aiming to increase the cooling rate of the molten pool during the welding process to increase the solid solubility of alloying elements and promote the response of the precipitated phase in the natural aging behavior; The rate of the cooling treatment is at least 2.94×10 3 K / s.

[0017] In one embodiment of the present invention, the temperature of the natural aging treatment is 15°C - 35°C, and the time is 3 days - 15 days.

[0018] The technical solution of the present invention has the following advantages compared with the prior art: (1) The aluminum alloy welding material of the present invention combines welding techniques such as cold metal transfer and pulsed composite welding, laser welding, etc. with rapid cooling, so that the mass ratio of Mg and Si in the weld is (0.16 - 0.83):1. The Mg / Si ratio within this range is beneficial to reducing the energy barrier and critical nucleation size for the precipitation of strengthening phases, enabling the β''-Mg5Si6 phase to precipitate in the form of small size and high density; the mass fraction of Cu is at least 1.00%, and at the same time, the mass ratio of Cu and Mg is (1.20 - 1.65):1, which enables a large amount of θ'-Al2Cu phase to precipitate in the weld, and also precipitates Q'-AlCuMgSi phase and S-Al2CuMg and other Cu-containing precipitation phases; the mass fraction of Zn is 0.05% - 0.50%, and the mass ratio of (Zn + Cu) and Mg is (1.50 - 2.50):1. Within this range, η'-Mg2Zn5 can be formed, and the presence of Cu and Zn can promote the precipitation of the β''-Mg5Si6 phase.

[0019] (2) The preparation method of the present invention combines welding techniques such as cold metal transfer and pulsed composite welding, laser welding, etc. with rapid cooling, so that elements such as Mg, Cu, and Zn in the weld are completely solid-solved and in a supersaturated state. The joint strength mainly comes from the solid-solution strengthening contribution of alloying elements such as Mg, Cu, and Zn and the precipitation strengthening contribution of the corresponding strengthening phases; then, through short-term natural aging, the solute-vacancy coupling diffusion mechanism can be realized, promoting the rapid precipitation of high-density strengthening phases in the weld, thereby achieving the strengthening and toughening of the weld, and significantly improving the weld strength (>280 MPa) and the welding coefficient (reaching 74.3%). Thus, the intervention of artificial aging is avoided, the welding cost is reduced, and the welding efficiency is improved.

[0020] (3) The preparation method of the present invention through rapid cooling (the cooling rate is at least 2.94×10 3 K / s) makes the cellular substructure of the weld significantly refined, the cellular substructure spacing is less than 10 μm, and the denser eutectic Si network provides more nucleation sites for the precipitation of strengthening phases; and the solid solubility of alloying elements such as Mg, Cu, and Zn in the weld is increased, enhancing the precipitation response of natural aging. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention and in combination with the drawings, where: Figure 1 is a high-resolution image of the precipitation phase of the welded joint in Embodiment 1 of the present invention; Figure 2 is a high-resolution image of the precipitation phase of the welded joint in Embodiment 2 of the present invention; Figure 3High-resolution image of the precipitated phase of the welded joint of Comparative Example 1 of the present invention; Figure 4 High-resolution image of the precipitated phase of the welded joint of Comparative Example 2 of the present invention; Figure 5 Metallographic image of the cellular substructure of the welded joint of Example 2 of the present invention; Figure 6 Metallographic image of the cellular substructure of the welded joint of Comparative Example 3 of the present invention; Figure 7 Tensile curve diagrams of the welded joints of Examples 1-3 and Comparative Examples 1-4 of the present invention; Figure 8 Bar graph of the tensile strength and welding coefficient of the welded joints of Examples 1-3 and Comparative Examples 1-4 of the present invention. Detailed implementation manners

[0022] The present invention will be further described below in conjunction with specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. It should be understood that the specific embodiments are only used to explain the present invention, but the exemplified embodiments do not limit the present invention.

[0023] In the present invention, unless otherwise specified, the technical and scientific terms used in the present invention have the same meanings as those generally understood by those skilled in the technical field to which the present invention belongs.

[0024] In the present invention, unless otherwise specified, the term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0025] In the present invention, unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods without special instructions, and the materials, reagents, etc. used can be obtained from commercial channels without special instructions.

[0026] In the present invention, unless otherwise specified, the preparation of the solid wire used in the embodiments of the present invention specifically includes the following steps: melting, DC casting, extrusion and drawing.

[0027] In the present invention, unless otherwise specified, the elemental composition and its mass percentage of the Al-Mg-Si-Cu alloy used in the embodiments of the present invention are: Mg 0.81%, Si 0.97%, Cu 0.43%, Mn 0.50%, Cr 0.23%, Ti 0.03%, and the balance is Al and other inevitable impurities.

[0028] Example 1

[0029] The elemental composition and its mass percentage of the aluminum alloy welding material in this embodiment are as follows: Si 9.0%, Mg 0.8%, Cu 1.9%, Zn 0.9%, Cr 0.1%, Mn 0.1%, Fe 0 - 0.15%, the balance being Al and other inevitable impurities, the total impurities < 0.15%, and it is a solid wire with a diameter of 1.2 mm.

[0030] The method for preparing the high-strength and high-toughness aluminum alloy weld specifically includes the following steps: filling the aluminum alloy welding material between the welds formed by two aluminum alloy base materials, and using the cold metal transfer and pulse composite welding technology for welding, the synchronous pulse frequency is 4 Hz, the welding speed is 8 mm / s, and the wire feeding speed is 4.3 m / min; then using the high-thermal-conductivity metal substrate cooling method for rapid cooling (the cooling rate is at least 2.94×10 3 K / s), so that elements such as Mg, Cu, and Zn in the weld are completely solid-solved and in a supersaturated state; finally, standing at room temperature for 15 days, so that strengthening phases precipitate at the weld joint, thereby realizing the strengthening and toughening of the weld; the aluminum alloy base material is an Al-Mg-Si-Cu series alloy with a size of 60 mm × 100 mm, and the initial state is T5 state; The mass ratio of Mg and Si in the weld is 0.22:1; The mass fraction of Cu is 1.03%, and the mass ratio of Cu and Mg is 1.24:1; The mass fraction of Zn is 0.34%, and the mass ratio of (Zn + Cu) and Mg is 1.65:1.

[0031] Example 2

[0032] The elemental composition and its mass percentage of the aluminum alloy welding material in this embodiment are as follows: Si 9.0%, Mg 0.8%, Cu 1.9%, Zn 0.9%, Cr 0.1%, Mn 0.1%, Fe 0 - 0.15%, the balance being Al and other inevitable impurities, the total impurities < 0.15%, and it is a solid wire with a diameter of 1.2 mm.

[0033] The method for preparing the high-strength and high-toughness aluminum alloy weld specifically includes the following steps: filling the aluminum alloy welding material between the welds formed by two aluminum alloy base materials, and using the laser welding technology for welding, the swing frequency of the infrared laser is 250 Hz, the swing amplitude is 3.0 mm, the welding speed is 20 mm / s, and the wire feeding speed is 6 m / min; then using the composite method of high-thermal-conductivity metal substrate cooling and forced air cooling for rapid cooling (the cooling rate is at least 2.94×10 3(K / s), so that elements such as Mg, Cu, and Zn in the weld are completely solid-soluted and in a supersaturated state; finally, it is left standing at room temperature for 7 days, so that strengthening phases precipitate at the weld joint, thereby achieving the strengthening and toughening of the weld; the aluminum alloy base material is an Al-Mg-Si-Cu series alloy with dimensions of 60mm×100mm, and the initial state is T5 state; The mass ratio of Mg and Si in the weld is 0.17:1; The mass fraction of Cu is 1.23%, and the mass ratio of Cu and Mg is 1.50:1; The mass fraction of Zn is 0.46%, and the mass ratio of (Zn + Cu) and Mg is 2.06:1.

[0034] Example 3

[0035] The elemental composition and its mass percentage of the aluminum alloy welding material in this example are: Si 9.0%, Mg 0.8%, Cu 1.9%, Zn 0.1%, Cr 0.1%, Mn 0.1%, Fe 0 - 0.15%, and the balance is Al and other inevitable impurities, with the total impurities < 0.15%, and it is a solid wire with a diameter of 1.2mm.

[0036] The method for preparing the high-strength and high-toughness weld of aluminum alloy specifically includes the following steps: filling the aluminum alloy welding material between the welds formed by two aluminum alloy base materials, and using laser welding technology for welding. The swing frequency of the infrared laser is 250Hz, the swing amplitude is 3.0mm, the welding speed is 20mm / s, and the wire feeding speed is 6m / min; then, a composite method of cooling with a high-thermal-conductivity metal substrate and forced air cooling is used for rapid cooling (the cooling rate is at least 2.94×10 3 K / s), so that elements such as Mg, Cu, and Zn in the weld are completely solid-soluted and in a supersaturated state; finally, it is left standing at room temperature for 7 days, so that strengthening phases precipitate at the weld joint, thereby achieving the strengthening and toughening of the weld; the aluminum alloy base material is an Al-Mg-Si-Cu series alloy with dimensions of 60mm×100mm, and the initial state is T5 state; The mass ratio of Mg and Si in the weld is 0.17:1; The mass fraction of Cu is 1.23%, and the mass ratio of Cu and Mg is 1.50:1; The mass fraction of Zn is 0.08%, and the mass ratio of (Zn + Cu) and Mg is 1.60:1.

[0037] Comparative Example 1

[0038] Basically the same as Example 1, except that: the aluminum alloy welding material is ER4047 welding wire, purchased from Beckhoff (China), and its elemental composition and mass percentage are: Si 11.6%, Mg 0.01%, Mn 0.02%, Fe 0.20%, the balance is Al and other inevitable impurities, and the total impurities < 0.15%; The mass ratio of Mg and Si in the weld is 0.12:1; The mass fraction of Cu is 0.40%, and the mass ratio of Cu and Mg is 0.68:1; The mass fraction of Zn is 0.10%, and the mass ratio of (Zn + Cu) and Mg is 0.85:1.

[0039] Comparative Example 2

[0040] Basically the same as Example 2, except that: the aluminum alloy welding material is ER4047 welding wire; The mass ratio of Mg and Si in the weld is 0.08:1; The mass fraction of Cu is 0.36%, and the mass ratio of Cu and Mg is 0.73:1; The mass fraction of Zn is 0.11%, and the mass ratio of (Zn + Cu) and Mg is 0.96:1.

[0041] Comparative Example 3

[0042] Basically the same as Example 1, except that: the welding method is gas metal arc welding, the synchronous pulse frequency is 4 Hz, the welding speed is 8 mm / s, and the wire feeding speed is 4.5 m / min.

[0043] Comparative Example 4

[0044] Basically the same as Example 2, except that: it is left standing at room temperature for 2 days.

[0045] Test Example 1

[0046] The welded joints obtained from Examples 1-2 and Comparative Examples 1-2 were characterized by TEM, and the results are as Figures 1-4 shown. It can be seen from Figures 1-2 that the welded joints of the examples precipitate high-density θ'-Al2Cu, β''-Mg5Si6 and Q'-AlCuMgSi strengthening phases, thus realizing the strengthening and toughening of the weld. It can be seen from Figures 3-4 that the welded joints of Comparative Example 1 can only precipitate atomic clusters, and the strengthening effect on the weld is insufficient; the welded joints of Comparative Example 2 can only precipitate GP zones and partial β'' precursor phases, and the strengthening effect on the weld is insufficient.

[0047] Test Example 2

[0048] The cellular substructure of the welded joints in Example 2 and Comparative Example 3 was characterized by a metallurgical microscope, and the results are as follows. Figures 5-6 As shown. From Figures 5-6 it can be seen that the average distance of the cellular substructure in Example 2 is 6.72 μm, and the average distance of the cellular substructure in Comparative Example 3 is 14.53 μm. This shows that a welding method with a higher cooling rate can obtain a fine cellular structure. The fine cellular structure makes the eutectic Si network denser, enhances the strengthening effect of the eutectic Si phase, and at the same time provides more nucleation sites for the precipitation of the strengthening phase, promoting the precipitation of the strengthening phase, thereby promoting the strengthening and toughening of the weld.

[0049] Test Example 3

[0050] Tensile tests were carried out on the welded joints and Al-Mg-Si-Cu series alloys (base metals) obtained in Examples 1-3 and Comparative Examples 1-4, and the results are as follows. Figure 7 As shown. From Figure 7 it can be seen that the aluminum alloy welding materials and welding processes in the examples can prepare welds with higher strength and toughness, and improve the strength of the welded joints (greater than 280 Mpa). This is because the welding process with a higher cooling rate can greatly increase the solid solubility of alloying elements such as diluted Mg, Cu, and Zn in the welding materials in the weld, enhance the precipitation response of natural aging, and precipitate strengthening phases such as θ'-Al2Cu, β''-Mg5Si6, and Q'-AlCuMgSi in the weld, thereby realizing the strengthening and toughening of the weld. In Comparative Examples 1-2, ER4047 welding wire was used, and the tensile properties of the joints were only 250 MPa - 260 MPa, and the strengthening effect on the weld was insufficient. This is because the weld prepared with ER4047 welding wire lacks alloying elements such as Cu, Mg, and Zn, and only part of the GP zone, atomic clusters, and some precursor phases can be precipitated, and it is difficult to precipitate strengthening phases only through natural aging. In Comparative Example 3, MIG welding was used, and the tensile properties of the joints were seriously insufficient. This is because the heat input during MIG welding is too large, the cooling rate of the molten pool is too small, and the solid solubility of alloying elements such as Cu, Mg, and Zn is insufficient, resulting in serious softening of the joint. The natural aging time in Comparative Example 4 was only 2 days, and the strengthening effect of the joint was average. This is because 2 days of natural aging is not enough to completely precipitate the strengthening phase.

[0051] Tensile strength and welding coefficient tests were carried out on the welded joints and Al-Mg-Si-Cu series alloys (base metals) obtained in Examples 1-3 and Comparative Examples 1-4, and the results are as follows. Figure 8 As shown. From Figure 8 it can be seen that the aluminum alloy welding materials and welding processes in the examples can prepare welds with a higher welding coefficient, and the welding coefficient reaches 74.3%.

[0052] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An aluminum alloy welding material, characterized in that, The elemental composition and its mass percentage of the aluminum alloy welding material are as follows: Si 6.0% - 12.0%, Mg 0.6% - 0.9%, Cu 0.5% - 1.9%, Zn 0.1% - 0.9%, Cr 0.1% - 0.5%, Mn 0.1% - 1.0%, Fe 0 - 0.15%, and the balance is Al and other inevitable impurities, with the total impurities being 0 - 0.15%; when the aluminum alloy welding material is diluted into the weld, the following points are met: The mass ratio of Mg to Si is (0.16 - 0.83):1; The mass fraction of Cu is at least 1.00%, and the mass ratio of Cu to Mg is (1.20 - 1.65):1; The mass fraction of Zn is 0.05% - 0.50%, and the mass ratio of (Zn + Cu) to Mg is (1.50 - 2.50):

1.

2. The aluminum alloy welding material according to claim 1, wherein The form of the aluminum alloy welding material is selected from one or more of powder, sheet, and wire.

3. The aluminum alloy welding material according to claim 2, wherein The particle size of the powder is 10μm - 250μm, the thickness of the sheet is 50μm - 1000μm, and the diameter of the wire is 0.5mm - 3.2mm.

4. A method for preparing a high-strength and high-toughness weld of aluminum alloy, characterized in that, It includes the following steps: Weld the aluminum alloy base material with the welding material, and combine with cooling treatment to make the Mg, Cu, and Zn elements in the weld completely solid-solved, and then through natural aging treatment to precipitate strengthening phases at the weld joint; the welding material is the aluminum alloy welding material according to any one of claims 1 - 3; the strengthening phase is selected from one or more of θ'-Al2Cu, β''-Mg5Si6, Q'-AlCuMgSi, S-Al2CuMg, and η'-Mg2Zn5.

5. The preparation method of the high-strength and tough aluminum alloy weld according to claim 4, characterized in that, The aluminum alloy base material is selected from one or more of Al-Cu series alloys, Al-Si series alloys, Al-Mg series alloys, Al-Mg-Si series alloys, and Al-Zn series alloys.

6. The preparation method of the high-strength and high-toughness aluminum alloy weld according to claim 4, wherein, The initial form of the aluminum alloy base material is in the T0 state - T10 state.

7. The method for preparing a high-strength and tough weld of aluminum alloy according to claim 4, characterized in that The welding method is selected from cold metal transfer and pulse composite welding and / or laser welding.

8. The method for preparing a high-strength and high-toughness weld of aluminum alloy according to claim 7, wherein The process parameters of the cold metal transfer and pulse composite welding are: the synchronous pulse frequency is 2Hz - 10Hz, the welding speed is 6mm / s - 12mm / s, and the wire feeding speed is 3.8m / min - 5.2m / min; The process parameters of the laser welding are: the oscillation frequency is 80Hz - 250Hz, the oscillation amplitude is 1.0mm - 3.0mm, the welding speed is 20mm / s - 33mm / s, and the wire feeding speed is 3m / min - 6m / min.

9. The method for preparing a high-strength and tough weld seam of aluminum alloy according to claim 4, characterized in that, The cooling treatment method is selected from one or more of high thermal conductivity metal substrate cooling, liquid cooling, forced air cooling, and cryogenic fluid cooling; The rate of the cooling treatment is at least 2.94×10 3 K / s.

10. The method for preparing a high-strength and tough aluminum alloy weld according to claim 4, characterized in that, The temperature of the natural aging treatment is 15°C - 35°C, and the time is 3 days - 15 days.

Images