Double-wire feeding electric arc additive ultrahigh-strength aluminum alloy in-situ alloying method

Abstract

The invention relates to an in-situ alloying method for an electric arc additive ultrahigh-strength aluminum alloy, in particular to an in-situ alloying method for a double-wire feeding electric arc additive ultrahigh-strength aluminum alloy. The invention aims to solve the problems that the microscopic uniformity of the material is poorer and the ideal mechanical property is difficult to realize due to the fact that the aluminum alloy is easy to form a thick organization structure in a deposition state, and the compactness and the quality stability of the material are seriously influenced due to the fact that solidification shrinkage cavities are easy to appear in the deposition process. By adjusting the wire feeding speed and angle of the two wires, it is ensured that the two wires are molten in the same molten pool, and in-situ alloying of ultrahigh-strength aluminum alloy additive manufacturing is achieved. By optimizing the components and the organization structure, the method effectively improves the component uniformity, the forming stability and the mechanical property of the aluminum alloy, and the high-performance aluminum alloy additive component with high strength, excellent toughness and durability is prepared. The invention belongs to the technical field of additive manufacturing.

Description

Technical Field

[0001] The invention relates to an arc additive ultra-high strength aluminum alloy in-situ alloying method, belonging to the technical field of additive manufacturing. Background Art

[0002] Arc additive manufacturing is an innovative manufacturing method that uses arc welding technology for 3D printing. This technology combines the advantages of traditional welding and additive manufacturing. It uses arc as a heat source to melt metal wire and achieves near-net shaping through layer-by-layer accumulation. It has the characteristics of low cost, high material utilization, and no restrictions on processing shape. In addition, by adding appropriate alloy elements during the melting process, the organizational structure of the component can be effectively improved to meet the requirements of specific composition and function.

[0003] Due to its high alloying degree and wide crystallization range, the 7 series aluminum alloy faces many technical problems that need to be solved in the arc additive manufacturing process. First, the alloy is prone to form a coarse organizational structure in the deposited state, resulting in poor microscopic uniformity of the material and difficulty in achieving ideal mechanical properties. In addition, solidification shrinkage cavities are prone to occur during the deposition process, which seriously affects the density and quality stability of the material. These problems directly lead to the low mechanical properties of the alloy, making it difficult to meet the requirements of high strength and high durability of complex components in actual service.

[0004] In view of the problems existing in the deposited 7-series aluminum alloy, combined with the advantages of additive manufacturing in customized composition control, rare earth elements such as Sc are introduced for microalloying control to achieve grain refinement, thereby improving solidification behavior and reducing defects. However, there are still no commercial products of ultra-high-strength aluminum alloy wires containing rare earth elements. Therefore, the present invention proposes a double-wire synchronous feeding method of Al-Mg-Sc alloy and 7-series aluminum alloy, and realizes the in-situ alloying of aluminum alloy through double-wire GTA (tungsten inert gas protection) arc additive manufacturing technology. This method aims to deeply study and optimize the in-situ alloying process of aluminum alloy, so as to improve the composition uniformity and organizational properties of aluminum alloy in the additive manufacturing process. Through this method, a new type of aluminum alloy material with excellent comprehensive performance can be prepared, which not only significantly improves key mechanical properties such as strength and toughness, but also performs well in forming stability and durability. Summary of the invention

[0005] The present invention aims to solve the problem that aluminum alloys are prone to form a coarse organizational structure in the deposition state, resulting in poor microscopic uniformity of the material and difficulty in achieving ideal mechanical properties. At the same time, solidification shrinkage cavities are prone to occur during the deposition process, which seriously affects the density and quality stability of the material. A method for in-situ alloying of ultra-high-strength aluminum alloys using double-wire feeding arc additive is proposed.

[0006] The technical solution adopted by the present invention to solve the above-mentioned problem is: the steps of the present invention include:

[0007] Step 1: Clean the substrate: Use an angle grinder to grind the substrate to remove surface oxides and oil stains;

[0008] Step 2, preheating the test substrate: place the test substrate in a preheating box, and after the preheating box rises to the set temperature, keep it warm for a certain period of time and then take it out, so that the test substrate as a whole reaches a certain temperature;

[0009] Step 3, adjust the angle of the welding wire: open the first wire feeder, adjust the front angle of the wire feed tube so that the angle between the welding wire and the axis of the TIG welding gun is 15-20°, open the second wire feeder, adjust the front angle of the wire feed tube so that the angle between the welding wire and the substrate is 10-20°, and the two welding wires are placed on the same side of the welding gun;

[0010] Step 4, set process parameters: turn on the welding power supply and adjust the welding current and voltage to the required values, then start the first wire feeder and the second wire feeder and set the wire feeding speed;

[0011] Step 5. Set the additive path: Open the robot control cabinet, adjust the robot control system, accurately control the motion trajectory of the robot arm, make it swing at a suitable angle and position, ensure that the tungsten electrode is vertically aligned with the substrate surface, and set the arc starting position. Then use the straight line path instruction to ensure that the tungsten electrode moves in a straight line along the preset route from the arc starting position to determine the arc extinguishing position;

[0012] Step 6. The additive process begins: First, open the protective gas cylinder and set an appropriate gas flow rate. Then move the welding gun to the predetermined arc starting position and start ventilation for a period of time to remove the impurity air around the position to ensure that the atmosphere in the molten pool area is pure. Then, ignite the arc and start the wire feeder at the same time. Adjust the angle and position of the wire feeder mechanism to feed the Al-Mg-Sc alloy wire and the 7 series aluminum alloy wire into the arc center. The two wires are melted and fused in the same molten pool. According to the preset path, the wire is deposited along the planned trajectory.

[0013] Step 7: Control the interlayer temperature of the additive material: After a layer of additive material is deposited, an infrared thermal imager is used to monitor the cooling of the deposited layer in real time until it cools down to the preset interlayer temperature. At this time, the welding gun will be moved to the starting point of the next pass to prepare for the deposition of the next layer;

[0014] Step 8: Repeat steps 6 and 7 until the size of the additive component reaches a predetermined design requirement, thereby obtaining a Sc-containing 7 series aluminum alloy additive component.

[0015] Furthermore, the substrate used in step 1 is a 5A06 aluminum alloy plate, and the surface is polished to be bright.

[0016] Furthermore, in step 2, the preheating temperature is 200° C. After the preheating box reaches 200° C., it is kept warm for 30 minutes before being taken out.

[0017] Furthermore, in step 3, the first wire feeder is equipped with a built-in wire feeding duct, through which the welding wire is fed to the arc area, and the second wire feeder is equipped with an external wire feeding duct, through which the welding wire is fed into the arc.

[0018] Furthermore, in step 3, the first wire feeder is loaded with Al-Mg-Sc welding wire with a diameter of 1.2 mm, and the second wire feeder is loaded with 7055 grade 7 series aluminum alloy with a diameter of 1.2 mm.

[0019] Furthermore, in step 4, the welding current is 100A-150A, the welding voltage is 8-10V, the wire feeding speed of the first wire feeder is 1000mm / min, and the wire feeding speed of the second wire feeder is 600mm / min.

[0020] Furthermore, in step 5, the vertical height of the tungsten electrode is set to be 3-4 mm from the substrate as the arc starting position, and the travel speed of the welding gun is 100 mm / min.

[0021] Furthermore, in step 6, dry argon gas with a purity of more than 99.99% is used for protection, the gas flow rate of the argon gas is 20 L / min, and the start ventilation time is set to 5 seconds.

[0022] Furthermore, in step 7, the interlayer temperature is controlled to be 100°C.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention uses a double-wire feeding method to simultaneously introduce Sc-containing alloy wire and 7-series aluminum alloy wire in the additive manufacturing process, thereby optimizing the alloy composition. The rare earth element scandium (Sc) in the aluminum-magnesium-scandium alloy (Al-Mg-Sc) can effectively refine the grain structure of the aluminum alloy, thereby improving the mechanical properties of the alloy, especially in terms of high temperature strength and corrosion resistance;

[0025] 2. The 7 series aluminum alloy containing scandium has higher strength and toughness in the deposited state than the traditional 7xxx series aluminum alloy. The addition of scandium promotes solid solution strengthening and precipitation strengthening, thereby improving the tensile strength, yield strength and fatigue resistance of the material;

[0026] 3. The present invention allows precise control of the evolution of alloy composition and microstructure during the deposition process, so that the properties of the aluminum alloy can be adjusted according to demand to meet the requirements of material properties in different application scenarios;

[0027] 4. The present invention can feed two materials of different compositions at the same time, which helps to improve the stability of the molten pool and the deposition efficiency. In addition, the twin-wire arc additive manufacturing can effectively reduce the local overheating or thermal cracking problems that may occur during the deposition of a single material, thereby improving the quality of the deposited parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the processing process of manufacturing Sc-containing 7 series aluminum alloy according to the present invention;

[0029] Figure 2 This is a physical picture of the Sc-containing 7 series aluminum alloy obtained by additive manufacturing;

[0030] Figure 3 This is a microscopic image of the Sc-containing 7 series aluminum alloy obtained by additive manufacturing.

[0031] Figure 4 This is the element distribution diagram of the microstructure of the Sc-containing 7-series aluminum alloy obtained by additive manufacturing;

[0032] Figure 1 Among them, 1-robot control cabinet, 2-infrared thermal imager, 3-robot, 4-first wire feeder, 5-second wire feeder, 6-double-wire TIG welding gun, 7-welding power supply, 8-argon gas bottle, 9-cooling device, 10-base plate. DETAILED DESCRIPTION

[0033] Specific implementation method 1: Figures 1 to 4 As shown, a method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding, the specific steps include:

[0034] Step 1. Clean the substrate: Use an angle grinder to grind the substrate to remove surface oxides and oil stains; the substrate used is 5A06 aluminum alloy plate, and the surface is polished to a bright finish;

[0035] Step 2, preheating the test substrate: place the test substrate in a preheating box, and after the preheating box rises to the set temperature, keep it warm for a certain period of time and then take it out, so that the test substrate as a whole reaches a certain temperature; the preheating temperature is 200°C, and after the preheating box reaches 200°C, keep it warm for 30 minutes before taking it out;

[0036] Step 3, adjust the angle of the welding wire: open the first wire feeder, adjust the front end angle of the wire feed tube so that the angle between the welding wire and the axis of the TIG welding gun is 15-20°, open the second wire feeder, adjust the front end angle of the wire feed tube so that the angle between the welding wire and the substrate is 10-20°, and the two welding wires are placed on the same side of the welding gun; the first wire feeder is equipped with a built-in wire feed tube, through which the welding wire is transported to the arc area, and the second wire feeder is equipped with an external wire feed tube, through which the welding wire is fed into the arc; the first wire feeder is loaded with Al-Mg-Sc welding wire with a diameter of 1.2 mm, and the second wire feeder is loaded with 7055 grade 7 series aluminum alloy with a diameter of 1.2 mm;

[0037] Step 4, set process parameters: turn on the welding power supply and adjust the welding current and voltage to the required values, then start the first wire feeder and the second wire feeder, and set the wire feeding speed; the welding current is 100A-150A, the welding voltage is 8-10V, the wire feeding speed of the first wire feeder is 1000mm / min, and the wire feeding speed of the second wire feeder is 600mm / min;

[0038] Step 5. Set the additive path: Open the robot control cabinet, adjust the robot control system, accurately control the motion trajectory of the robot arm, make it swing at a suitable angle and position, ensure that the tungsten electrode is vertically aligned with the substrate surface, and set the arc starting position. Then use the straight path instruction to ensure that the tungsten electrode moves in a straight line along the preset route from the arc starting position to determine the arc extinguishing position; the vertical height of the tungsten electrode is 3-4mm from the substrate as the arc starting position, and the travel speed of the welding gun is 100mm / min;

[0039] Step 6. The additive process begins: first, open the protective gas bottle and set an appropriate gas flow rate, then move the welding gun to the predetermined arc starting position, and start ventilation for a period of time to remove the impurity air around the position to ensure that the atmosphere in the molten pool area is pure; then, ignite the arc, start the wire feeder at the same time, adjust the angle and position of the wire feeding mechanism, and feed the Al-Mg-Sc alloy wire and the 7 series aluminum alloy wire into the arc center. The two wires are melted and fused in the same molten pool. According to the preset path, the wires are deposited according to the planned trajectory; use dry argon gas with a purity of more than 99.99% for protection, the gas flow rate of argon gas is 20L / min, and the start ventilation time is set to 5 seconds;

[0040] Step 7: Control the interlayer temperature of the additive material: After a layer of additive material is deposited, an infrared thermal imager is used to monitor the cooling of the deposited layer in real time until it cools down to the preset interlayer temperature. At this time, the welding gun will be moved to the starting point of the next pass to prepare for the deposition of the next layer;

[0041] Step 8, repeating steps 6 and 7 until the size of the additive component reaches the predetermined design requirements, and obtaining a Sc-containing 7 series aluminum alloy additive component; the interlayer temperature is controlled to be 100°C.

[0042] like Figure 2 As shown, the wall is well formed as a whole, with tight interlayer bonding and no obvious defects such as cracks and pores. The internal structure of the additive component is analyzed;

[0043] Figure 3 The metallographic structure images of the additive component are shown: Figure (a) is a schematic diagram of the overall structure; Figures (b-c) are the top area, showing a clear equiaxed crystal structure; Figure 3 Figures d to e are the middle area, where columnar crystals and dendrites grow alternately; Figure 3 f to g in the middle are the bottom region, and the grain morphology is similar to that in the middle region; Figure 4 The element distribution of the microstructure is shown, and it is observed that the Sc element precipitates in the form of dots and is not completely dissolved.

[0044] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding, characterized in that: The specific steps include: Step 1: Clean the substrate: Use an angle grinder to grind the substrate to remove surface oxides and oil stains; Step 2, preheating the test substrate: place the test substrate in a preheating box, and after the preheating box rises to the set temperature, keep it warm for a certain period of time and then take it out, so that the test substrate as a whole reaches a certain temperature; Step 3, adjust the angle of the welding wire: open the first wire feeder, adjust the front angle of the wire feed tube so that the angle between the welding wire and the axis of the TIG welding gun is 15-20°, open the second wire feeder, adjust the front angle of the wire feed tube so that the angle between the welding wire and the substrate is 10-20°, and the two welding wires are placed on the same side of the welding gun; Step 4, set process parameters: turn on the welding power supply and adjust the welding current and voltage to the required values, then start the first wire feeder and the second wire feeder and set the wire feeding speed; Step 5. Set the additive path: Open the robot control cabinet, adjust the robot control system, accurately control the motion trajectory of the robot arm, make it swing at a suitable angle and position, ensure that the tungsten electrode is vertically aligned with the substrate surface, and set the arc starting position. Then use the straight line path instruction to ensure that the tungsten electrode moves in a straight line along the preset route from the arc starting position to determine the arc extinguishing position; Step 6: The additive process begins: First, open the protective gas cylinder and set an appropriate gas flow rate. Then, move the welding gun to the predetermined arc starting position and start ventilation for a period of time to remove the impurity air around the position to ensure that the atmosphere in the molten pool area is pure. Next, ignite the arc and start the wire feeder at the same time. Adjust the angle and position of the wire feeder mechanism to feed the Al-Mg-Sc alloy wire and the 7 series aluminum alloy wire into the arc center. The two wires are melted and fused in the same molten pool. According to the preset path, the wires are deposited along the planned trajectory. Step 7: Control the interlayer temperature of the additive material: After a layer of additive material is deposited, an infrared thermal imager is used to monitor the cooling of the deposited layer in real time until it cools down to the preset interlayer temperature. At this time, the welding gun will be moved to the starting point of the next pass to prepare for the deposition of the next layer; Step 8: Repeat steps 6 and 7 until the size of the additive component reaches a predetermined design requirement, thereby obtaining a Sc-containing 7 series aluminum alloy additive component.

2. The method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding according to claim 1, characterized in that: The substrate used in step 1 is a 5A06 aluminum alloy plate, and the surface is polished to a bright finish.

3. The method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding according to claim 1, characterized in that: In step 2, the preheating temperature is 200°C. After the preheating box reaches 200°C, keep it warm for 30 minutes before taking it out.

4. The method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding according to claim 1, characterized in that: In step 3, the first wire feeder is equipped with a built-in wire feed guide tube, through which the welding wire is delivered to the arc area, and the second wire feeder is equipped with an external wire feed guide tube, through which the welding wire is delivered into the arc.

5. The method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding according to claim 1, characterized in that: In step 3, the first wire feeder is loaded with Al-Mg-Sc welding wire with a diameter of 1.2 mm, and the second wire feeder is loaded with 7055 grade 7 series aluminum alloy with a diameter of 1.2 mm.

6. The method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding according to claim 1, characterized in that: In step 4, the welding current is 100A-150A, the welding voltage is 8-10V, the wire feeding speed of the first wire feeder is 1000mm / min, and the wire feeding speed of the second wire feeder is 600mm / min.

7. The method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding according to claim 1, characterized in that: In step 5, the vertical height of the tungsten electrode is set to 3-4 mm from the substrate as the arc starting position, and the travel speed of the welding gun is 100 mm / min.

8. The method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding according to claim 1, characterized in that: In step 6, dry argon gas with a purity of more than 99.99% is used for protection, the gas flow rate of argon gas is 20 L / min, and the start ventilation time is set to 5 seconds.

9. The method for in-situ alloying of ultra-high strength aluminum alloy by arc additive with double wire feeding according to claim 1, characterized in that: In step 7, the interlayer temperature is controlled to be 100°C.

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