Arc additive forming improvement and defect suppression method

Abstract

The invention relates to the technical field of metal electric arc additive manufacturing, and provides an electric arc additive forming improvement and defect suppression method which comprises the following steps: step 1, pretreating the surface of a workpiece substrate; 2, the nano-particle reinforced aluminum alloy wire is conveyed to the position below a welding gun, and a workpiece base plate is preheated; 3, single-channel multi-layer electric arc additive manufacturing is conducted through a cold metal transition welding heat source, additive manufacturing is conducted through a two-way reciprocating machining path under the protective atmosphere, a welding gun conducts arc starting from the starting position of the left side for deposition, arc quenching is conducted after the welding gun reaches the end position of the right side, the welding gun is raised by a preset layer height, and then the temperature of the upper surface of a deposition layer is measured; and the additive manufacturing process of the second layer is conducted from right to left. According to the method, the forming precision and the internal quality are remarkably improved, and the nano-particle reinforced aluminum alloy electric arc additive large-size component which is high in surface comprehensive performance and good in formability can be obtained.

Description

Technical Field

[0001] This invention relates to the field of metal arc additive manufacturing technology, specifically to a method for improving arc additive forming and suppressing defects, and more particularly to a method for improving arc additive forming and suppressing defects in nanoparticle-reinforced aluminum alloy components. Background Technology

[0002] Particle-reinforced aluminum alloys possess excellent comprehensive properties such as high specific strength, high specific stiffness, low coefficient of thermal expansion, and high temperature resistance, making them promising for lightweight applications in aerospace structures such as next-generation launch vehicles and space stations. However, the introduction of hard reinforcing particles deteriorates the liquid phase fluidity and plastic forming ability of the aluminum alloy matrix to varying degrees. When using traditional processing techniques (e.g., powder metallurgy, stir casting, plastic forming) to fabricate large-sized, complex-shaped aerospace components, bottlenecks such as high processing stress, poor material ductility, high tendency for particle clustering, easy debonding of the particle / matrix interface, and high incidence of voids and cracks are easily encountered.

[0003] Arc-fed additive manufacturing technology uses an electric arc to melt metal wire to achieve layer-by-layer deposition, offering advantages such as large formable dimensions, high deposition efficiency, and high raw material utilization. It effectively meets the rapid response manufacturing needs of large, complex-shaped components. Due to the low melting point of aluminum alloys, the temperature of the cladding layer affects the spreadability of the molten pool during the arc-fed process. As the temperature increases, the intermolecular forces in the liquid phase increase, surface tension decreases, wettability increases, and the contact angle becomes larger. Therefore, at higher interlayer temperatures, the aluminum alloy molten pool spreads well in arc-fed additive manufacturing, resulting in an uneven surface on the formed part and increased filament elongation, affecting the stability of the deposition process. At lower interlayer temperatures, the molten pool spreads poorly, the cladding layer contact angle is small, and deep grooves will exist on the sides of the formed part, affecting the effective wall thickness ratio. Simultaneously, poor molten pool spread leads to a faster growth rate of the cladding layer at the deposition height, resulting in shorter filament elongation, affecting process stability, and ultimately leading to poor forming quality.

[0004] To address the bottlenecks in arc additive manufacturing of particle-reinforced aluminum alloys, such as poor surface forming, the high melting point of the introduced nano-ceramic particles making them prone to hydrogen evolution sites within the molten pool, leading to micropores, and difficulty in controlling internal pores and cracks, there is an urgent need to develop an arc additive manufacturing method that can reliably produce nano-particle-reinforced aluminum alloy components with high forming quality, dense structure with few pores, and excellent mechanical properties. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for improving and suppressing defects in arc additive manufacturing.

[0006] A method for improving and suppressing defects in arc additive manufacturing according to the present invention includes the following steps: Step 1: Pre-treat the surface of the workpiece substrate; Step 2: Feed the nanoparticle-reinforced aluminum alloy wire to the bottom of the welding torch through the wire feeding mechanism to preheat the workpiece substrate; Step 3: Single-pass multi-layer arc additive manufacturing is performed using a cold metal transition welding heat source. The deposition direction is perpendicular to the surface of the workpiece substrate, and the travel direction is along the length of the workpiece substrate. Under a protective atmosphere, additive manufacturing is performed using a bidirectional reciprocating processing path. The welding torch starts the deposition process from the left starting position and ends at the right ending position. The welding torch is raised by one preset layer height, and the welding torch extension is checked. Then, the surface temperature of the deposited layer is measured. After heating or cooling for a period of time, the preset temperature is reached, and the arc is restarted. The second layer of additive manufacturing is performed from right to left. This process is repeated to deposit several layers, and finally, a nano-reinforced aluminum alloy straight-wall component manufactured by arc additive manufacturing is obtained.

[0007] Preferably, the workpiece substrate is an aluminum alloy substrate, and the pretreatment involves polishing with a sander, cleaning the surface of the substrate with alcohol, and fixing the workpiece substrate on the worktable with a clamping fixture.

[0008] Preferably, in step 2, a nanoparticle-reinforced aluminum alloy wire with a diameter of 0.8 to 1.6 mm is fed to the bottom of the welding torch through a wire feeding mechanism, with a dry extension of 11 to 14 mm and a wire feeding angle of 0 to 10°. The wire feeding angle is the angle between the aluminum alloy wire and the normal of the workpiece substrate. The workpiece substrate is preheated at a temperature of 100-200°C. Preferably, in step 2, the nanoparticle-reinforced aluminum alloy component is an in-situ synthesized TiC-reinforced 2219 aluminum alloy wire, wherein the content of nano-TiC ceramic particles is 0-1 vol.%.

[0009] Preferably, in step 3, the protective gas flow rate is 18-30 L / min.

[0010] Preferably, the welding torch travels in step 3 in an oscillating welding manner, wherein the oscillation manner is triangular oscillation, sinusoidal oscillation, or semi-circular oscillation.

[0011] Preferably, in step 3, the swing width of the welding torch is 2-12 mm, and the welding torch deposition speed is 5-20 mm / s; at the same time, the ratio of the swing length to the welding torch deposition speed is 1:2.

[0012] Preferably, the preset layer height at which the welding torch is raised in step 3 is 0.5 to 5.0 mm.

[0013] Preferably, in step 3, the method for calibrating the welding torch extension is to use a laser displacement sensor for automated measurement and calibration to ensure that the extension is always between 11 and 14 mm.

[0014] Preferably, in step 3, the method for measuring the surface temperature of the deposition layer is to use an infrared thermometer for automated measurement to ensure that the interlayer temperature is stable at 80-120℃. The straight-walled component obtained in step 3 has a length of 50–300 mm, a width of 5–40 mm, and a height of 30–200 mm.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention significantly improves forming accuracy and internal quality by combining the relevant process tests of wire arc additive manufacturing with an intelligent distance control and temperature measurement automated monitoring system. By adopting specific oscillation parameters, it improves the interlayer bonding area and strength, reduces incomplete fusion defects, and fully stirs the molten pool to promote bubble merging and floating. On the other hand, it extends the existence time of the molten pool during printing, slows down the solidification rate, and provides a longer time window for gas escape. At the same time, the introduction of an intelligent control device (dry extension / interlayer temperature) optimizes the dry extension in real time to stabilize arc stability, reduce fluctuations during droplet transition, and avoid the risk of introducing gas due to insufficient protective gas coverage caused by excessive dry extension. Interlayer temperature control can effectively prevent the expansion of heat accumulation due to excessively high temperature (>150℃), which aggravates molten pool boiling and hydrogen evolution. It can obtain large-size components of nanoparticle-reinforced aluminum alloy arc additive manufacturing with high surface comprehensive performance and good formability.

[0016] 2. This invention reduces hydrogen evolution during the printing process by controlling the dry extension to ensure the protective gas prevents the introduction of pores and by controlling the interlayer temperature within a reasonable range. Furthermore, the use of cathode cleaning combined with an oscillating mode allows for thorough stirring of the molten pool, promoting bubble merging and escaping, reducing pores remaining internally, and effectively improving forming quality. Ultimately, this enhances the internal quality and mechanical properties of the printed component, solving the problems of poor forming quality and pore defects that are common in the arc additive manufacturing process of nanoparticle TiC-reinforced aluminum alloy components. This results in large-size nanoparticle-reinforced aluminum alloy components with excellent internal quality and comprehensive mechanical properties. Attached Figure Description

[0017] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 A schematic diagram and physical image of a laser ranging + infrared temperature measurement sensor device provided in an embodiment of the present invention; Figure 2This is a macroscopic comparison diagram of the 1 vol.% TiC particle-reinforced 2219 aluminum alloy arc additive straight-walled component provided in Example 1 and Comparative Example 1 of the present invention; Figure 3 Comparison of internal porosity defects in 1 vol.% TiC particle-reinforced 2219 aluminum alloy arc additive straight-walled components provided in Embodiment 1 of the present invention with those in Comparative Examples 1 and 2; Figure 4 The diagram shows the room temperature vertical and horizontal tensile strength and elongation properties of 1.0 wt.% TiC particle-reinforced 2219 aluminum alloy arc additive components provided in Embodiments 1 and 2 of the present invention in the deposited state and T6 heat-treated state. Detailed Implementation

[0018] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0019] This invention provides a method for improving and suppressing defects in arc additive manufacturing, comprising the following steps: Step 1: Pre-treat the surface of the workpiece substrate. The workpiece substrate is an aluminum alloy substrate, preferably a 2219 aluminum alloy substrate. The pre-treatment involves grinding the surface of the workpiece substrate with a sander, cleaning the surface of the workpiece substrate with alcohol, and fixing the workpiece substrate on the worktable with a clamping fixture. Step 2: Feed nanoparticle-reinforced aluminum alloy wire with a diameter of 0.8-1.6 mm to the bottom of the welding torch through a wire feeding mechanism. The wire extension is 11-14 mm and the wire feeding angle is 0-10°. The wire feeding angle is the angle between the aluminum alloy wire and the normal of the workpiece substrate. Preheat the workpiece substrate to a temperature of 100-200°C. The nano-reinforced aluminum alloy component is an in-situ synthesized TiC-reinforced 2219 aluminum alloy wire, wherein the content of nano-TiC ceramic particles is 0-1 vol.%.

[0020] Step 3: Single-pass multi-layer arc additive manufacturing is performed using a cold metal transfer welding (CMT) heat source. The deposition direction is perpendicular to the workpiece substrate surface, and the travel direction is along the length of the workpiece substrate. Additive manufacturing is carried out under a protective atmosphere using a bidirectional reciprocating machining path. The shielding gas flow rate is 18-30 L / min. The welding torch starts deposition from the left-hand starting position and extinguishes the arc after reaching the right-hand ending position. The welding torch travels using an oscillating welding method, which can be triangular, sinusoidal, or semi-circular oscillation. The oscillation width is 2-12 mm, and the oscillation length is related to the welding torch's weld penetration. The ratio of deposition speed is 1:2; the deposition speed of the welding torch is 5-20 mm / s. The welding torch is raised by one preset layer height, which is 0.5-5.0 mm. The welding torch extension is calibrated, and then the surface temperature of the deposited layer is measured. After heating or cooling for a period of time, the preset temperature is reached before the arc is ignited again. The additive manufacturing process of the second layer is carried out from right to left. Several layers are deposited in this way to finally obtain a nano-reinforced aluminum alloy straight wall component manufactured by arc additive manufacturing. The method for calibrating the welding torch extension is to use a laser displacement sensor for automated measurement and calibration to ensure that the extension is always within 11-14 mm.

[0021] Specifically, in step 3, the method for measuring the surface temperature of the deposition layer is to use an infrared thermometer for automated measurement to ensure that the interlayer temperature is stable at 80-120℃; the length of the obtained straight-walled component is 50-300mm, the width is 5-40mm, and the height is 30-200mm.

[0022] Example 1 This embodiment provides a method for improving and suppressing defects in arc additive manufacturing, specifically a method for arc additive manufacturing of straight-walled components from 1 vol.% TiC nanoparticle-reinforced aluminum alloy components with a wire diameter of 1.2 mm, comprising the following steps: Step 1: Before performing wire arc additive manufacturing, the oxide film on the surface of the workpiece substrate needs to be pretreated. The workpiece substrate is a 2219 aluminum alloy substrate with dimensions of 500mm×320mm×35mm. The pretreatment involves grinding with a sander, cleaning the substrate surface with alcohol, and fixing the substrate on the worktable with a clamping fixture. Step 2: Feed the 1.2mm nanoparticle-reinforced aluminum alloy wire directly to the bottom of the welding gun through the wire feeding mechanism. Adjust the wire extension to 12mm and the wire feeding angle to 5°. The wire feeding angle is the angle between the aluminum alloy wire and the normal of the substrate. Preheat the substrate to 150°C. Step 3: Single-pass multilayer arc additive manufacturing is performed using a cold metal transfer (CMT) heat source. The deposition direction is perpendicular to the substrate surface, and the travel direction is along the substrate width. Under a shielding gas atmosphere of 22 L / min, a bidirectional reciprocating printing path is used for additive manufacturing. The welding torch starts deposition from the left side and extinguishes after reaching the right side. The torch is first raised 1.25 mm, and then a laser displacement sensor is used to calibrate and compensate for the torch extension, ensuring it remains at 12 mm. Finally, infrared temperature measurement is used... The sensor measures the surface temperature of the deposited layer to see if the average temperature meets the preset temperature range (80-100℃). If the temperature is below 80℃, a ceramic heating element is used to heat the substrate and component until the temperature exceeds 80℃. If the temperature exceeds 100℃, air cooling is used to cool the component surface and wait. After a fixed interval (20s), the temperature is measured again until it falls below 100℃. Once the surface temperature of the component meets the preset interlayer temperature, the arc is initiated, and the additive manufacturing process for the second layer begins from right to left. This process is repeated 90 times to obtain the desired result. Figure 2 (a) shows a nano-reinforced aluminum alloy straight-wall component manufactured by arc additive manufacturing, with a final component size of 180mm × 12mm × 100mm. In addition to measuring and controlling the interlayer temperature of the upper surface, the preset layer height of the next layer should be calibrated against the actual measured dry extension to ensure consistency of the dry extension.

[0023] Furthermore, the arc additive printing process is as follows: wire feed speed 7.8 m / min, preset layer height 1.25 mm, re-temperature measurement waiting time 20 s, welding torch deposition speed 10 mm / s, welding torch uses a triangular oscillating motion with a swing width of 9 mm and a swing length of 5 mm. After each layer is printed, point laser displacement measurement is performed to measure the welding torch extension and workpiece surface height, and the height is automatically adjusted to ensure the extension. Subsequently, an infrared thermometer is used to measure the temperature of the upper surface of the component. The next layer is printed when the average temperature reaches the preset interlayer temperature (80-100℃). In addition, X-ray inspection is performed on the interior of the printed straight-wall component, and the inspection results are as follows. Figure 3 As shown in (a).

[0024] The straight-walled component obtained in this embodiment has good forming on both sides, and its height is basically consistent with that of the middle forming section. At the same time, X-ray detection results show that no pores or cracks were found inside, indicating that the component has good formability and internal quality.

[0025] Comparative Example 1: This comparative example provides a method for arc additive manufacturing of a straight-walled component from a 1 vol.% nanoparticle TiC-reinforced aluminum alloy component with a wire diameter of 1.2 mm, comprising the following steps: Step 1: Before performing wire arc additive manufacturing, the oxide film on the surface of the workpiece substrate needs to be pretreated. The workpiece substrate is a 2219 aluminum alloy substrate with dimensions of 500mm×320mm×35mm. The pretreatment involves grinding with a sander, cleaning the substrate surface with alcohol, and fixing the substrate on the worktable with a clamping fixture. Step 2: Feed the 1.2mm nanoparticle-reinforced aluminum alloy wire directly to the bottom of the welding gun through the wire feeding mechanism. Adjust the wire extension to 12mm and the wire feeding angle to 5°. The wire feeding angle is the angle between the aluminum alloy wire and the normal of the substrate. Preheat the substrate to 150°C. Step 3: Single-pass multilayer arc additive manufacturing is performed using a cold metal transfer soldering (CMT) heat source. The deposition direction is perpendicular to the substrate surface, and the travel direction is along the substrate width. Under a shielding gas atmosphere of 22 L / min, a bidirectional reciprocating printing path is used for additive manufacturing. The soldering torch starts deposition from the left side and extinguishes after reaching the right side. The torch is then raised 1.5 mm, and the gas cooling is turned on. After a fixed interlayer waiting time of 90 seconds, the gas cooling is turned off, and the second layer is deposited from right to left. This process is repeated 25 times to obtain the desired result. Figure 2 (b) shows a nano-reinforced aluminum alloy straight-wall component manufactured by arc additive manufacturing, with a final component size of 120mm × 12mm × 30mm. The arc additive manufacturing process is as follows: wire feed speed 7.8m / min, preset layer height 1.5mm, interlayer waiting time 90s, welding torch deposition speed 10mm / s, welding torch does not use an oscillating travel method, and no point laser displacement ranging + infrared temperature measurement device (e.g., after each layer is printed) is used. Figure 1 (As shown in the image) After the waiting time is complete, the next layer is printed directly. In addition, X-ray inspection is performed on the interior of the printed straight-walled component, and the inspection results are as follows. Figure 3 As shown in (b).

[0026] The metal straight-walled component obtained in this comparative example has low forming accuracy on both sides and obvious pores inside the component, especially at the arc initiation and arc extinguishing points of each layer, resulting in continuous pores and poor formability, making it impossible to deposit high-quality samples.

[0027] Comparative Example 2: This comparative example provides a method for arc additive manufacturing of a straight-walled component from a 1 vol.% nanoparticle TiC-reinforced aluminum alloy component with a wire diameter of 1.2 mm, comprising the following steps: Step 1: Before performing wire arc additive manufacturing, the oxide film on the surface of the workpiece substrate needs to be pretreated. The workpiece substrate is a 2219 aluminum alloy substrate with dimensions of 500mm×320mm×35mm. The pretreatment involves grinding with a sander, cleaning the substrate surface with alcohol, and fixing the substrate on the worktable with a clamping fixture. Step 2: Feed the 1.2mm nanoparticle-reinforced aluminum alloy wire directly to the bottom of the welding gun through the wire feeding mechanism. Adjust the wire extension to 12mm and the wire feeding angle to 4°. The wire feeding angle is the angle between the aluminum alloy wire and the normal of the substrate. Preheat the substrate to 150°C. Step 3: Single-pass multilayer arc additive manufacturing is performed using a cold metal transfer welding (CMT) heat source. The deposition direction is perpendicular to the substrate surface, and the travel direction is along the substrate width. Under a shielding gas atmosphere of 22L / min, a bidirectional reciprocating printing path is used for additive manufacturing. The welding torch starts the deposition process from the left side and extinguishes the arc after reaching the right side. The welding torch is raised by 1.25mm, the gas cooling is turned on, and then the interlayer waiting time is fixed for 90s before the gas cooling is turned off. The second layer of additive manufacturing is then performed from right to left. This process is repeated for 35 layers to obtain a nano-reinforced aluminum alloy straight-wall component manufactured by arc additive manufacturing. The final component size is 120mm×12mm×39mm. The arc additive manufacturing process is as follows: wire feed speed 7.8 m / min, preset layer height 1.25 mm, interlayer waiting time 90 s, welding torch deposition speed 10 mm / s, welding torch uses a triangular oscillating motion with a swing width of 9 mm and a swing length of 5 mm. No point laser displacement ranging + infrared temperature measurement is performed after each layer is printed; the next layer is printed directly after the interlayer waiting time is completed. Furthermore, the internal structure of the final formed component is inspected using X-rays, and the results are as follows... Figure 3 As shown in (c).

[0028] Compared with Comparative Example 1, the metal straight-walled component obtained in this comparative example has improved forming accuracy on both sides, significantly reduced internal pores, no obvious pores at the arc initiation and extinguishing points of each layer, and only a small number of pores in the middle of the interior.

[0029] Example 2: This embodiment provides a method for arc additive manufacturing of straight-walled components from 1 vol.% TiC nanoparticle-reinforced aluminum alloy components with a wire diameter of 1.2 mm, comprising the following steps: Step 1: Before performing wire arc additive manufacturing, the oxide film on the surface of the workpiece substrate needs to be pretreated. The workpiece substrate is a 2219 aluminum alloy substrate with dimensions of 500mm×320mm×35mm. The pretreatment involves grinding with a sander, cleaning the substrate surface with alcohol, and fixing the substrate on the worktable with a clamping fixture. Step 2: Feed the 1.2mm nanoparticle-reinforced aluminum alloy component directly to the bottom of the welding torch through the wire feeding mechanism. Adjust the wire extension to 12mm and the wire feeding angle to 6°. The wire feeding angle is the angle between the aluminum alloy component and the normal of the substrate. Preheat the substrate to 150°C. Step 3: Single-pass multilayer arc additive manufacturing is performed using a cold metal transfer (CMT) heat source. The deposition direction is perpendicular to the substrate surface, and the travel direction is along the substrate width. Under a shielding gas atmosphere of 22 L / min, a bidirectional reciprocating printing path is used for additive manufacturing. The welding torch starts deposition from the left side and extinguishes after reaching the right side. The torch is first raised 1.25 mm, and then a laser displacement sensor is used to calibrate and compensate for the torch extension, ensuring it remains at 12 mm. Next, an infrared temperature sensor is used to measure the surface temperature of the deposited layer and observe the average temperature. If the temperature is within the preset temperature range (80-95℃), and the temperature is below 80℃, a ceramic heating belt is used to heat the substrate and component until the temperature is above 80℃. If the temperature is above 95℃, the surface of the component is cooled by air cooling and waiting. After a fixed interval (20s), the temperature is measured again until it is below 95℃. When the surface temperature of the component meets the preset interlayer temperature, the arc is started again, and the additive manufacturing process of the second layer is carried out from right to left. This process is repeated to deposit 140 layers to obtain a nano-reinforced aluminum alloy straight-wall component manufactured by arc additive manufacturing. The final component size is 185mm×13.5mm×160mm. The arc additive manufacturing process is as follows: wire feed speed 8m / min, preset layer height 1.25mm, waiting time for temperature measurement again 20s, welding torch deposition speed 9mm / s, welding torch uses a semi-circular oscillating motion with an oscillation width of 10mm and an oscillation length of 4.5mm. After each layer is printed, point laser displacement measurement is performed to measure the welding torch extension and workpiece surface height, and the height is automatically adjusted to ensure the extension. Subsequently, an infrared thermometer is used to measure the temperature of the upper surface of the component. The next layer is printed when the average temperature is at the preset interlayer temperature (80-95℃). In addition, the straight-walled component printed in this embodiment is subjected to a T6 heat treatment regime of solution treatment + artificial aging. The solution treatment temperature is 535℃, held for 2 hours, then transferred for quenching within 60 seconds, followed by artificial aging at 175℃ for 10 hours. Wire-cut pull rods were used to sample the deposited straight-walled component in Example 1 and the T6 straight-walled component in this example. The sampling directions were the deposition direction (vertical) and the travel direction (horizontal). The tensile strength and elongation of the pull rods were tested according to the method disclosed in national standard GB / T228-2002. The results are as follows. Figure 4 As shown.

[0030] Comparing Example 1 with Comparative Examples 1 and 2, it can be seen that the welding torch oscillation ensures the full spread of the weld layer, improves formability, promotes the escape of pores, and reduces porosity. The synergistic monitoring of laser distance control and infrared thermometry ensures consistent heat extension and interlayer temperature for each layer, effectively improving the stability between the welding torch and the molten pool, and further improving the surface forming and internal defects of the printed components. Furthermore, the mechanical property results of Examples 1 and 2 also indirectly demonstrate that the synergistic effect of the process and parameters of this invention has a significant effect on improving the tensile strength and plasticity of the material.

[0031] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0032] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for improving and suppressing defects in electric arc additive manufacturing, characterized in that, Includes the following steps: Step 1: Pre-treat the surface of the workpiece substrate; Step 2: Feed the nanoparticle-reinforced aluminum alloy wire to the bottom of the welding torch through the wire feeding mechanism to preheat the workpiece substrate; Step 3: Single-pass multi-layer arc additive manufacturing is performed using a cold metal transition welding heat source. The deposition direction is perpendicular to the surface of the workpiece substrate, and the travel direction is along the length of the workpiece substrate. Under a protective atmosphere, additive manufacturing is performed using a bidirectional reciprocating processing path. The welding torch starts the deposition process from the left starting position and ends at the right ending position. The welding torch is raised by one preset layer height, and the welding torch extension is checked. Then, the surface temperature of the deposited layer is measured. After heating or cooling for a period of time, the preset temperature is reached, and the arc is restarted. The second layer of additive manufacturing is performed from right to left. This process is repeated to deposit several layers, and finally, a nano-reinforced aluminum alloy straight-wall component manufactured by arc additive manufacturing is obtained.

2. The method for improving and suppressing defects in arc additive manufacturing according to claim 1, characterized in that, The workpiece substrate is an aluminum alloy substrate. The pretreatment involves polishing with a sander, cleaning the surface of the substrate with alcohol, and fixing the workpiece substrate on the worktable with a clamping fixture.

3. The method for improving and suppressing defects in arc additive manufacturing according to claim 1, characterized in that, In step 2, a nanoparticle-reinforced aluminum alloy wire with a diameter of 0.8 to 1.6 mm is fed to the bottom of the welding torch through a wire feeding mechanism. The wire extension is 11 to 14 mm and the wire feeding angle is 0 to 10°. The wire feeding angle is the angle between the aluminum alloy wire and the normal of the workpiece substrate. The workpiece substrate is preheated at a temperature of 100-200°C.

4. The method for improving and suppressing defects in arc additive manufacturing according to claim 1, characterized in that, In step 2, the nanoparticle-reinforced aluminum alloy component is an in-situ synthesized TiC-reinforced 2219 aluminum alloy wire, wherein the content of nano-TiC ceramic particles is 0-1 vol.%.

5. The method for improving and suppressing defects in arc additive manufacturing according to claim 1, characterized in that, In step 3, the protective gas flow rate is 18-30 L / min.

6. The method for improving and suppressing defects in arc additive manufacturing according to claim 1, characterized in that, In step 3, the welding torch travels in an oscillating welding manner, which can be triangular oscillation, sinusoidal oscillation, or semi-circular oscillation.

7. The method for improving and suppressing defects in arc additive manufacturing according to claim 6, characterized in that, In step 3, the swing width of the welding torch is 2-12 mm, and the welding torch deposition speed is 5-20 mm / s; at the same time, the ratio of the swing length to the welding torch deposition speed is 1:

2.

8. The method for improving and suppressing defects in arc additive manufacturing according to claim 1, characterized in that, In step 3, the preset height of the welding torch being raised is 0.5 to 5.0 mm.

9. The method for improving and suppressing defects in arc additive manufacturing according to claim 1, characterized in that, In step 3, the method for calibrating the welding torch extension is to use a laser displacement sensor for automated measurement and calibration to ensure that the extension is always between 11 and 14 mm.

10. The method for improving and suppressing defects in arc additive manufacturing according to claim 1, characterized in that, In step 3, the method for measuring the surface temperature of the deposition layer is to use an infrared thermometer for automated measurement to ensure that the interlayer temperature is stable at 80-120℃. The straight-walled component obtained in step 3 has a length of 50–300 mm, a width of 5–40 mm, and a height of 30–200 mm.

Images