An arc wire feeding additive manufacturing method for a heat-resistant aluminum alloy component of low porosity Al-Cu-Mg-Ag

Abstract

The present invention provides an arc wire feeding additive manufacturing method for a low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component, which relates to the technical field of additive manufacturing of heat-resistant alloys. The present invention uses a low-frequency pulse arc of 2-10 Hz and a hot wire current of 60-140 A to assist in additive manufacturing, effectively removing the contaminants on the surface of the wire, improving the quality of the wire. The escape speed of the gas is greater than the cooling speed of the metal, and the gas is more likely to overflow, greatly reducing the number of pores and improving the porosity of the Al-Cu-Mg-Ag heat-resistant aluminum alloy component. Further, the present invention adopts a T6 heat treatment process. After solution treatment, a large number of Ω strengthening phases precipitate in the Al-Cu-Mg-Ag heat-resistant aluminum alloy, and some of the strengthening phases redissolve into the Al matrix under the effect of solution to form a supersaturated solid solution, greatly improving the strength of the Al-Cu-Mg-Ag heat-resistant aluminum alloy structural component.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing of heat-resistant alloys, and particularly to an arc wire feeding additive manufacturing method for an Al-Cu-Mg-Ag heat-resistant aluminum alloy component with low porosity. Background Art

[0002] Aluminum alloys have the characteristics of low density, high specific strength, and high specific stiffness, and are widely used in fields such as aerospace, shipbuilding, and rail transit. They are the preferred materials for realizing the lightweight of large structures. With the continuous increase in the speed of aircraft such as missiles, the surface aerodynamic heat effect intensifies, which poses a huge challenge to the heat resistance of their key structural components. It is urgent to develop new heat-resistant aluminum alloys and their advanced forming technologies to meet the design and manufacturing requirements of new models of aircraft such as missiles.

[0003] The addition of Ag element makes a new phase, Ω phase, precipitate in the Al-Cu series heat-resistant alloy, which has better thermal stability and can improve the high-temperature performance of the aluminum alloy. The Al-Cu-Mg-Ag alloy has excellent thermal stability and heat resistance, and has become a very promising high-strength material in the current aerospace field, with broad application prospects.

[0004] As a typical additive manufacturing technology, wire arc additive manufacturing (WAAM) is a manufacturing process that uses arc heat to melt metal wire and continuously cools and stacks it layer by layer, greatly shortening the process flow and enabling the rapid near-net shaping of metal components. Wire arc additive manufacturing has the characteristics of high material energy absorption rate, safe wire forming, and high forming rate, and is very suitable for the high-efficiency manufacturing of large components of aluminum alloys and other high laser reflectivity metals. However, in the process of additive manufacturing of aluminum alloys, the problem of pore defects often occurs, seriously affecting the performance of the alloy.

[0005] Therefore, how to prepare an Al-Cu-Mg-Ag heat-resistant aluminum alloy component with low porosity by the method of arc wire feeding additive manufacturing is a technical problem to be solved in this field. Summary of the Invention

[0006] The purpose of the present invention is to provide an arc wire feeding additive manufacturing method for an Al-Cu-Mg-Ag heat-resistant aluminum alloy component with low porosity. The Al-Cu-Mg-Ag heat-resistant aluminum alloy component prepared by the method of the present invention has low porosity.

[0007] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0008] The present invention provides an arc wire feeding additive manufacturing method for an Al-Cu-Mg-Ag heat-resistant aluminum alloy component with low porosity, comprising the following steps:

[0009] Preheat the aluminum alloy substrate. After the preheating is completed, start the wire feeding system to perform arc wire - feeding additive manufacturing of Al - Cu - Mg - Ag alloy wire on the preheated aluminum alloy substrate. The welding torch scanning speed is 220 - 260 mm / min, the wire feeding speed is 260 - 300 cm / min, the pulse frequency is 2 - 10 Hz, the hot - wire current is 60 - 140 A, the peak current is 125 - 220 A, the peak - time ratio is 25 - 35%, the base - current ratio is 10 - 30%, the shielding gas is argon, and the argon flow rate is 18 - 22 L / min. After the arc wire - feeding additive manufacturing is completed, a low - porosity Al - Cu - Mg - Ag heat - resistant aluminum alloy component is obtained.

[0010] Preferably, after the arc wire - feeding additive manufacturing is completed, it further includes performing T6 heat treatment on the obtained component; the T6 heat treatment includes successively performing first - stage solution treatment, second - stage solution treatment, and aging treatment. The temperature of the first - stage solution treatment is 490 - 510 °C, and the holding time is 3 - 5 h; the temperature of the second - stage solution treatment is 510 - 530 °C, and the holding time is 5 - 7 h; the temperature of the aging treatment is 150 - 180 °C, and the holding time is 16 - 24 h.

[0011] Preferably, the number of preheating passes of the aluminum alloy substrate is 2 passes.

[0012] Preferably, the preheating conditions include: the welding torch scanning speed is 220 - 260 mm / min, the peak current is 200 - 240 A, the peak - time ratio is 28 - 32%, the base - current is 22 - 26%, and the pulse frequency is 1.2 - 3 Hz.

[0013] Preferably, the single - layer deposition height of the arc wire - feeding additive manufacturing is 1.5 - 2.0 mm.

[0014] Preferably, the diameter of the Al - Cu - Mg - Ag alloy wire is 1.0 - 1.5 mm.

[0015] Preferably, before the arc wire - feeding additive manufacturing, adjust the tungsten - electrode tip of the welding torch to be 5 - 10 mm above the aluminum alloy substrate, adjust the position of the wire - feeding tube in the wire - feeding system so that the angle between the wire - feeding tube and the welding torch is 30 - 50°, and make the wire - feeding tube and the welding torch in the same vertical plane.

[0016] Preferably, the front end of the Al - Cu - Mg - Ag alloy wire is 3 - 7 mm directly below the tungsten - electrode tip and is spaced 0.2 - 0.5 mm from the aluminum alloy substrate.

[0017] Preferably, as the number of deposition layers increases, the peak current of arc wire additive manufacturing is adjusted to 125 - 145 A, the peak time ratio is 27 - 28%, and the base current ratio is 13 - 24%.

[0018] Preferably, the porosity of the low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component is lower than 2%.

[0019] The present invention provides an arc wire additive manufacturing method for a low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component, comprising the following steps: preheating an aluminum alloy substrate, and after the preheating is completed, starting a wire feeding system to perform arc wire additive manufacturing of an Al-Cu-Mg-Ag alloy wire on the preheated aluminum alloy substrate, with a welding torch scanning speed of 220 - 260 mm / min, a wire feeding speed of 260 - 300 cm / min, a pulse frequency of 2 - 10 Hz, a hot wire current of 60 - 140 A, a peak current of 125 - 220 A, a peak time ratio of 25 - 35%, a base current ratio of 10 - 30%, a shielding gas of argon, and an argon flow rate of 18 - 22 L / min. After the arc wire additive manufacturing is completed, a low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component is obtained.

[0020] The present invention uses a low-frequency pulse arc of 2 - 10 Hz and a hot wire current of 60 - 140 A to assist in additive manufacturing, effectively removing surface contaminants of the wire, improving the wire quality, with the gas escape speed being greater than the metal cooling speed, making it easier for the gas to overflow, greatly reducing the number of pores, and improving the porosity of the Al-Cu-Mg-Ag heat-resistant aluminum alloy component. Especially when the pulse frequency is 2 - 3 Hz, the obtained Al-Cu-Mg-Ag heat-resistant aluminum alloy structural component not only has a low porosity but also has good mechanical properties, manifested as high tensile strength, yield strength, and elongation.

[0021] Furthermore, the present invention adopts a T6 heat treatment process. After solution treatment, a large number of Ω strengthening phases precipitate in the Al-Cu-Mg-Ag heat-resistant aluminum alloy, and some of the strengthening phases redissolve into the Al matrix under the action of solution to form a supersaturated solid solution, greatly enhancing the strength of the Al-Cu-Mg-Ag heat-resistant aluminum alloy structural component.

[0022] The present invention adopts arc wire additive manufacturing technology, which can shorten the preparation cycle of aluminum alloy parts, improve the material utilization rate, and thus save time and material costs. Description of the Drawings

[0023] Figure 1 Macromorphology diagram of the Al-Cu-Mg-Ag heat-resistant aluminum alloy thin-walled part manufactured in Example 1;

[0024] Figure 2 Porosity map of the thin-walled part of Al-Cu-Mg-Ag heat-resistant aluminum alloy manufactured in Example 1;

[0025] Figure 3 Mechanical properties of the thin-walled part of Al-Cu-Mg-Ag heat-resistant aluminum alloy before and after heat treatment at room temperature in Example 1. Detailed implementation manners

[0026] The present invention provides an arc wire feeding additive manufacturing method for a low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component, comprising the following steps:

[0027] Preheat the aluminum alloy substrate. After the preheating is completed, start the wire feeding system to perform arc wire feeding additive manufacturing of the Al-Cu-Mg-Ag alloy wire on the preheated aluminum alloy substrate. The welding torch scanning speed is 220-260 mm / min, the wire feeding speed is 260-300 cm / min, the pulse frequency is 2-10 Hz, the hot wire current is 60-140 A, the peak current is 125-220 A, the peak time ratio is 25-35%, the base current ratio is 10-30%, the shielding gas is argon, and the argon gas flow rate is 18-22 L / min. After the arc wire feeding additive manufacturing is completed, a low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component is obtained.

[0028] Before preheating the aluminum alloy substrate in the present invention, preferably set the arc additive processing path according to the shape of the Al-Cu-Mg-Ag heat-resistant aluminum alloy component, then set the single-layer deposition height of the arc wire feeding additive manufacturing and the preheating passes of the aluminum alloy substrate, write a processing program according to the above processing path, deposition height and preheating passes and import it into the computer control system; then fix the aluminum alloy substrate to the processing machine tool, adjust the positions of the welding torch and the wire feeding tube in the wire feeding system to facilitate the subsequent arc wire feeding additive manufacturing steps; then set the condition parameters of the arc wire feeding additive manufacturing (including the welding torch scanning speed, wire feeding speed, pulse frequency, hot wire current, peak current, peak time ratio, base current ratio and argon gas flow rate).

[0029] In the present invention, the preheating passes of the aluminum alloy substrate are preferably 2 passes, and the preheating conditions preferably include: the welding torch scanning speed is 220-260 mm / min, the peak current is 200-240 A, the peak time ratio is 28-32%, the base current is 22-26%, and the pulse frequency is 1.2-3 Hz; more preferably, the welding torch scanning speed is 240 mm / min, the peak current is 220 A, the peak time ratio is 30%, the base current is 25%, and the pulse frequency is 2.4 Hz.

[0030] The present invention has no special requirements for the composition of the aluminum alloy substrate, and any aluminum alloy substrate well-known in the art can be used, such as 2-series aluminum alloy or 7-series aluminum alloy specifically.

[0031] After the preheating is completed, the present invention starts the wire feeding system to perform arc wire feeding additive manufacturing of Al-Cu-Mg-Ag alloy wire on the preheated aluminum alloy substrate.

[0032] In the present invention, the single-layer deposition height of the arc wire feeding additive manufacturing is preferably 1.5 - 2.0 mm, more preferably 1.7 - 1.8 mm. The diameter of the Al-Cu-Mg-Ag alloy wire is preferably 1.0 - 1.5 mm, more preferably 1.2 - 1.4 mm.

[0033] In the present invention, before the arc wire feeding additive manufacturing, it is preferred to adjust the tungsten electrode tip of the welding torch to be 5 - 10 mm above the aluminum alloy substrate, adjust the position of the wire feeding tube in the wire feeding system so that the included angle between the wire feeding tube and the welding torch is 30 - 50°, and make the wire feeding tube and the welding torch be in the same vertical plane. In the present invention, the front end of the Al-Cu-Mg-Ag alloy wire is located 3 - 7 mm directly below the tungsten electrode tip and is spaced 0.2 - 0.5 mm from the aluminum alloy substrate.

[0034] In the present invention, the conditions of the arc wire feeding additive manufacturing include: the welding torch scanning speed is 220 - 260 mm / min, preferably 230 - 250 mm / min; the wire feeding speed is 260 - 300 cm / min, preferably 270 - 290 cm / min; the pulse frequency is 2 - 10 Hz, preferably 2 - 3 Hz, more preferably 2.4 Hz; the hot wire current is 60 - 140 A, preferably 80 - 100 A; the peak current is 125 - 220 A, preferably 125 - 200 A; the peak time ratio is 25 - 35%, preferably 28 - 32%; the base current ratio is 10 - 30%, preferably 15 - 25%; the shielding gas is argon, and the argon flow rate is 18 - 22 L / min, preferably 19 - 21 L / min.

[0035] As the number of deposition layers increases, the present invention preferably adjusts the peak current of the arc wire feeding additive manufacturing to be 125 - 145 A, the peak time ratio to be 27 - 28%, and the base current ratio to be 13 - 24%; after the deposition is stable, the present invention preferably adjusts the scanning speed percentage to be 60 - 120% according to the deposition conditions at different positions.

[0036] The present invention preferably regulates the peak current, peak time, base current ratio, and scanning speed percentage according to the size of the molten pool and the arc length during the arc wire feeding additive manufacturing process, which is common general knowledge in the art.

[0037] The present invention uses a low-frequency pulsed arc of 2-10 Hz and a hot wire current of 60-140 A to assist in additive manufacturing, effectively removing the surface contaminants of the wire, improving the quality of the wire. The escape velocity of the gas is greater than the cooling rate of the metal, making it easier for the gas to overflow, greatly reducing the number of pores, and improving the porosity of the Al-Cu-Mg-Ag heat-resistant aluminum alloy component. Especially when the pulse frequency is 2-3 Hz, the obtained Al-Cu-Mg-Ag heat-resistant aluminum alloy structural component not only has a low porosity, but also has good mechanical properties, manifested as high tensile strength, yield strength and high elongation rate.

[0038] After the arc wire feeding additive manufacturing is completed, the present invention preferably performs T6 heat treatment on the obtained component; the T6 heat treatment preferably includes a first-stage solution treatment, a second-stage solution treatment and an aging treatment in sequence. The temperature of the first-stage solution treatment is preferably 490-510 °C, more preferably 495-505 °C, and the holding time is preferably 3-5 h, more preferably 4 h; the temperature of the second-stage solution treatment is preferably 510-530 °C, more preferably 515-525 °C, and the holding time is preferably 5-7 h, more preferably 6 h; the temperature of the aging treatment is preferably 150-180 °C, more preferably 160-170 °C, and the holding time is preferably 16-24 h, more preferably 18-20 h.

[0039] In the present invention, the cooling method for solution treatment is preferably water cooling (i.e., water cooling is carried out after the completion of the first-stage solution treatment and the second-stage solution treatment); the cooling method for the aging treatment is preferably air cooling.

[0040] The present invention adopts the T6 heat treatment process. After solution treatment, a large number of Ω strengthening phases precipitate in the Al-Cu-Mg-Ag heat-resistant aluminum alloy, and some of the strengthening phases redissolve into the Al matrix under the action of solution to form a supersaturated solid solution, greatly improving the strength of the Al-Cu-Mg-Ag heat-resistant aluminum alloy structural component.

[0041] The porosity of the low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component manufactured by the method of the present invention is less than 2%, the pore diameter is all below 180 μm, and the fine pores are mostly distributed around the large pores.

[0042] The following combines examples to detail the arc wire feeding additive manufacturing method of the low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component provided by the present invention, but they cannot be understood as limiting the protection scope of the present invention.

[0043] Example 1

[0044] Arc wire - feeding additive manufacturing method for thin - wall parts of Al - Cu - Mg - Ag heat - resistant aluminum alloy, with the specific chemical composition: 92.23% Al - 6.05% Cu - 0.16% Mg - 0.71% Ag - 0.54% Mn - 0.17% Ti - 0.14% Zr. The manufacturing method is as follows:

[0045] Step 1: Use computer software to construct a 3D model of the Al - Cu - Mg - Ag heat - resistant aluminum alloy thin - wall part to be deposited, with a length of 50 mm, a width of 25 mm, and a height of 46.8 mm, to determine the processing path of the deposited part. Set the layer height of single - layer deposition to 1.8 mm and the number of layers to 26 layers. Set the pre - heating passes of the CNC locomotive control system to two passes. Write the processing program according to the processing path, single - layer deposition layer height, and pre - heating passes, and import the above - mentioned processing program into the computer control system of the CNC machine tool;

[0046] Step 2: After wiping the aluminum alloy substrate with a length of 200 mm, a width of 200 mm, and a thickness of 6 mm with anhydrous ethanol, fix it in the CNC numerical control processing locomotive. Adjust the position of the welding torch so that the tip of the tungsten electrode of the welding torch is 6.5 mm above the aluminum substrate. Adjust the wire - feeding system so that the included angle between the wire - feeding tube in the wire - feeding system and the welding torch is 45°, and the two are in the same plane. Send out the Al - Cu - Mg - Ag alloy wire with a diameter of 1.2 mm from the wire - feeding tube, with the front end of the wire located directly below the tip of the tungsten electrode at 6 mm, and the front end of the wire spaced 0.5 mm from the substrate;

[0047] Step 3: Set the parameters of the Al - Cu - Mg - Ag heat - resistant aluminum alloy arc wire - feeding additive manufacturing: the scanning speed of the welding torch is 240 mm / min, the wire - feeding speed of the wire - feeding system is 280 cm / min, the pulse frequency is 2.4 Hz, the hot - wire current is 100 A, the peak current is 200 A, the peak - time ratio is 30%, the base - current ratio is 25%, the shielding gas is argon, and the argon flow rate is 20 L / min;

[0048] Step 4: Do not start the wire - feeding system and pre - heat the aluminum alloy substrate. Set the pre - heating process parameters of the aluminum substrate: the scanning speed of the welding torch is 240 mm / min, the peak current is 220 A, the peak - time ratio is 30%, the base - current ratio is 25%, and the pulse frequency is 2.4 Hz. After pre - heating, start the wire - feeding system and carry out the arc additive manufacturing of the Al - Cu - Mg - Ag heat - resistant aluminum alloy. As the number of deposited layers increases, adjust some parameters of the arc additive manufacturing: the peak current is 145 A, the peak - time ratio is 28%, and the base - current ratio is 24%. After the deposition is stable, adjust the scanning - speed percentage according to the deposition situation at different positions for manufacturing, and the adjusted scanning - speed percentage is: 60 - 120%;

[0049] Step 5: After the arc additive manufacturing is completed, cool it to room temperature to obtain an Al-Cu-Mg-Ag heat-resistant aluminum alloy thin-walled part with a wall thickness of 7 mm;

[0050] Step 6: Perform T6 heat treatment on the obtained Al-Cu-Mg-Ag heat-resistant aluminum alloy. The parameters of the heat treatment process are as follows: the first-stage solution temperature is 500 °C, the solution time is 4 h, the second-stage solution temperature is 520 °C, the solution time is 6 h, the aging temperature is 165 °C, and the aging time is 21 h. After the solution treatment, the alloy is water-cooled, and after the aging treatment, the alloy is air-cooled.

[0051] The macroscopic morphology diagram of the Al-Cu-Mg-Ag heat-resistant aluminum alloy thin-walled part fabricated by TIG arc additive manufacturing is as Figure 1 shown. It can be seen from Figure 1 that the Al-Cu-Mg-Ag heat-resistant aluminum alloy thin-walled part obtained by using the method provided by the present invention has a dense layer deposition morphology and good structure formability.

[0052] Cut a sample with a length of 10 mm, a width of 8 mm, and a height of 6 mm from the Al-Cu-Mg-Ag heat-resistant aluminum alloy thin-walled part prepared in this example. Grind, polish, and clean it, and then observe it under an optical microscope. The overall pore diagram is as Figure 2 shown. It can be seen from Figure 2 that the pores are all regular spheres and are mainly distributed at the remelting positions between layers. Measure the pore size and porosity through Image-J software. The pore diameter is all below 180 μm, and small pores are mostly distributed around large pores. The porosity is 1.77%. Using a 2.4 Hz low-frequency pulse and a 100 A hot-wire assisted arc additive manufacturing process can effectively remove the hydrogen pollutants carried on the surface of the wire, reduce the formation conditions of pores, and lower the porosity of the Al-Cu-Mg-Ag heat-resistant aluminum alloy.

[0053] Use an Instron 5966 universal testing machine to test the mechanical properties of the Al-Cu-Mg-Ag heat-resistant aluminum alloy thin-walled part prepared in Example 1 before and after heat treatment at room temperature. The test results are as Figure 3 shown. It can be seen from Figure 3It can be seen that the tensile strength of the thin-walled parts of Al-Cu-Mg-Ag heat-resistant aluminum alloy before heat treatment at room temperature is 305.7 MPa, the yield strength is 192.4 MPa, and the elongation is 6.4%; the tensile strength of the thin-walled parts of Al-Cu-Mg-Ag heat-resistant aluminum alloy after heat treatment at room temperature is 429.5 MPa, the yield strength is 403.5 MPa, and the elongation is 2.0%. After using the heat treatment process, the strength of the thin-walled parts of Al-Cu-Mg-Ag heat-resistant aluminum alloy is further improved, the tensile strength is increased by 40.5%, and the yield strength is increased by 109.7%. After using the low-frequency pulsed hot wire assisted arc additive manufacturing process, the porosity is reduced, the influence on the load-bearing area of the Al-Cu-Mg-Ag heat-resistant aluminum alloy is reduced, and the mechanical properties of the alloy are improved. After using the heat treatment process, a large number of Ω strengthening phases will precipitate in the Al-Cu-Mg-Ag heat-resistant aluminum alloy, and some of the strengthening phases will re-dissolve into the Al matrix under the solution effect to form a supersaturated solid solution, which can greatly improve the strength of the structural parts of the Al-Cu-Mg-Ag heat-resistant aluminum alloy and improve the mechanical properties.

[0054] Example 2

[0055] Step 1 and Step 2 are the same as those in Example 1;

[0056] In Step 3, the pulse frequency is 10 Hz, and the others are the same as those in Example 1;

[0057] In Step 4, some parameters of the arc additive manufacturing are adjusted: the peak current is 138 A, the peak time ratio is 30%, and the base current ratio is 28%, and the others are the same as those in Example 1;

[0058] In Step 5, the wall thickness is 7.5 mm;

[0059] Step 6 is the same as that in Example 1.

[0060] The porosity is 1.80%, the tensile strength before heat treatment at room temperature is 275.9 MPa, the yield strength is 199.5 MPa, and the elongation is 3.6%. The tensile strength of the thin-walled parts of Al-Cu-Mg-Ag heat-resistant aluminum alloy after heat treatment at room temperature is 362.4 MPa, the yield strength is 346.4 MPa, and the elongation is 1.5%.

[0061] Comparative Example 1

[0062] Step 1 and Step 2 are the same as those in Example 1;

[0063] In Step 3, the hot wire current is 0 A, and the others are the same as those in Example 1;

[0064] In Step 4, some parameters of the arc additive manufacturing are adjusted: the peak current is 165 A, the peak time ratio is 24%, and the base current ratio is 15%, and the others are the same as those in Example 1;

[0065] In Step 5, the wall thickness is 8 mm;

[0066] Step 6 is the same as that in Example 1.

[0067] The porosity is 3.13%, the tensile strength before heat treatment at room temperature is 272.9 MPa, the yield strength is 225.6 MPa, and the elongation is 1.9%. The tensile strength of the Al-Cu-Mg-Ag heat-resistant aluminum alloy thin-walled part after heat treatment at room temperature is 400.7 MPa, the yield strength is 376.4 MPa, and the elongation is 1.6%.

[0068] Comparative Example 2

[0069] Steps 1 and 2 are the same as those in Example 1;

[0070] In Step 3, the hot wire current is 150 A, and the rest is the same as that in Example 1;

[0071] In Step 4, some parameters of the arc additive manufacturing are adjusted: the peak current is 126 A, the peak time ratio is 30%, and the base current ratio is 13%, and the rest is the same as that in Example 1;

[0072] In Step 5, the wall thickness is 8.2 mm;

[0073] Step 6 is the same as that in Example 1.

[0074] The porosity is 2.01%, the tensile strength before heat treatment at room temperature is 257.4 MPa, the yield strength is 212.3 MPa, and the elongation is 2.1%.

[0075] Comparative Example 3

[0076] Steps 1 and 2 are the same as those in Example 1;

[0077] In Step 3, the pulse frequency is 50 Hz, and the rest is the same as that in Example 1;

[0078] In Step 4, some parameters of the arc additive manufacturing are adjusted: the peak current is 140 A, the peak time ratio is 30%, and the base current ratio is 25%, and the rest is the same as that in Example 1;

[0079] In Step 5, the wall thickness is 7.6 mm;

[0080] Step 6 is the same as that in Example 1.

[0081] The porosity is 2.01%, the tensile strength before heat treatment at room temperature is 242.0 MPa, the yield strength is 185.2 MPa, and the elongation is 2.12%.

[0082] As can be seen from the above examples and comparative examples, when the pulse frequency is too high (Comparative Example 3), or the hot wire current is too high (Comparative Example 2), or no hot wire current is applied (Comparative Example 1), the porosity of the obtained Al-Cu-Mg-Ag heat-resistant aluminum alloy component is relatively high, > 2%. In addition, from the results of Example 1 and Example 2, it can be known that when the pulse frequency is 2 - 3 Hz, the obtained Al-Cu-Mg-Ag heat-resistant aluminum alloy structural component not only has a lower porosity, but also has more excellent mechanical properties.

[0083] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An arc wire and arc additive manufacturing method for a low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component, characterized in that, It includes the following steps: Preheat the aluminum alloy substrate. After the preheating is completed, start the wire feeding system to perform arc wire feeding additive manufacturing of Al-Cu-Mg-Ag alloy wire on the preheated aluminum alloy substrate. The welding torch scanning speed is 220 - 260 mm / min, the wire feeding speed is 260 - 300 cm / min, the pulse frequency is 2 - 10 Hz, the hot wire current is 60 - 140 A, the peak current is 125 - 220 A, the peak time ratio is 25 - 35%, the base current ratio is 10 - 30%, the shielding gas is argon, and the argon flow rate is 18 - 22 L / min. After the arc wire feeding additive manufacturing is completed, a low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component is obtained.

2. The arc wire feeding additive manufacturing method according to claim 1, wherein After the arc wire feeding additive manufacturing is completed, it also includes performing T6 heat treatment on the obtained component; the T6 heat treatment includes performing primary solution treatment, secondary solution treatment, and aging treatment in sequence. The temperature of the primary solution treatment is 490 - 510 °C, and the holding time is 3 - 5 h; the temperature of the secondary solution treatment is 510 - 530 °C, and the holding time is 5 - 7 h; the temperature of the aging treatment is 150 - 180 °C, and the holding time is 16 - 24 h.

3. The wire arc additive manufacturing method according to claim 1, characterized in that, The number of preheating passes of the aluminum alloy substrate is 2 passes.

4. The wire arc additive manufacturing method according to claim 1 or 3, characterized in that, The preheating conditions include: the welding torch scanning speed is 220 - 260 mm / min, the peak current is 200 - 240 A, the peak time ratio is 28 - 32%, the base current is 22 - 26%, and the pulse frequency is 1.2 - 3 Hz.

5. The method for arc wire additive manufacturing according to claim 1 or 2, characterized in that The single-layer deposition height of the arc wire feeding additive manufacturing is 1.5 - 2.0 mm.

6. The wire arc additive manufacturing method according to claim 1 or 2, characterized in that The diameter of the Al-Cu-Mg-Ag alloy wire is 1.0 - 1.5 mm.

7. The wire arc additive manufacturing method according to claim 1 or 2, characterized in that, Before the arc wire feeding additive manufacturing, adjust the tungsten electrode tip of the welding torch to be 5 - 10 mm above the aluminum alloy substrate, adjust the position of the wire feeding tube in the wire feeding system so that the angle between the wire feeding tube and the welding torch is 30 - 50°, and make the wire feeding tube and the welding torch in the same vertical plane.

8. The wire arc additive manufacturing method according to claim 7, wherein The front end of the Al-Cu-Mg-Ag alloy wire is 3 - 7 mm directly below the tungsten electrode tip and is spaced 0.2 - 0.5 mm from the aluminum alloy substrate.

9. The wire arc additive manufacturing method according to claim 1 or 2, characterized in that As the number of deposition layers increases, adjust the peak current of the arc wire feeding additive manufacturing to 125 - 145 A, the peak time ratio to 27 - 28%, and the base current ratio to 13 - 24%.

10. The wire arc additive manufacturing method according to claim 1, 2, 3 or 8, characterized in that, The porosity of the low-porosity Al-Cu-Mg-Ag heat-resistant aluminum alloy component is less than 2%.

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