7075Al structure and method based on ultrasonic energy field assisted laser direct energy deposition

Abstract

The invention discloses a 7075Al structure and method based on ultrasonic energy field assisted laser direct energy deposition, and belongs to the technical field of metal additive manufacturing. The method disclosed by the invention comprises the following steps: respectively pretreating 7075Al spherical powder and a substrate for later use; an ultrasonic energy controller is connected with the bottom face of the base plate through an ultrasonic amplitude-change pole, then the ultrasonic energy controller is started, and the base plate is made to vibrate through emitted ultrasound; then, it is ensured that laser and ultrasound are focused on the same focus on the surface of the substrate, powder conveying is started, laser energy deposition is started for deposition according to specific forming requirements, and after deposition is finished, a 7075Al structure is obtained; and during deposition, stopping light for 10s every time when a layer is printed, and stopping light for 3min every time when a layer is printed. According to the method, the metallurgical behavior of the molten pool is regulated and controlled through the cavitation effect and the acoustic streaming effect generated by ultrasound in the molten pool, and the 7075Al part with the fine equiaxed crystal structure can be prepared.

Description

Technical Field

[0001] This invention belongs to the field of metal additive manufacturing technology, specifically relating to a 7075Al microstructure and method based on ultrasonic energy field-assisted laser direct energy deposition. Background Technology

[0002] 7075 aluminum alloy, as a representative of Al-Zn-Mg-Cu series ultra-hard aluminum alloys, has been a core material in the aerospace industry since the 1940s. Its density is only 2.80-2.85 g / cm³. 3 With a specific strength far exceeding that of most metals, 7075 aluminum alloy achieves a perfect combination of high strength and lightweight. In the aerospace field, 7075 aluminum alloy is widely used in aircraft wing spars, bulkheads, missile components, and high-stress structures, supporting scenarios with extremely high material performance requirements. To meet the market demand for integrated manufacturing of highly complex structures, lightweight structures, and near-fully dense workpiece production, the use of LDED technology to manufacture 7075Al alloy parts is a very important development direction. LDED forms three-dimensional parts by melting and depositing powder materials layer by layer, offering unique advantages in the integrated forming of complex structures. However, due to the process characteristics of LDED, which involves repeated layer-by-layer reheating cycles, the prepared 7075Al alloy is prone to epitaxial growth of grains, forming coarse columnar crystal structures with anisotropic microstructure characteristics. Existing research indicates that during the LDED preparation of 7-series Al alloys, the sample microstructure is composed of coarse columnar crystals, and the equiaxed crystal structure obtained by researchers through periodic adjustment of scanning speed and laser power is still relatively coarse. Other methods, such as adding alloying elements or ceramic particles, can effectively improve the mechanical properties of parts, but they inevitably lead to changes in the composition of alloying elements. Therefore, how to solve the anisotropy of the part structure and thus improve the part's forming performance remains a huge challenge for LDED forming of 7-series aluminum alloys.

[0003] Therefore, providing a method that is simple to prepare and can improve the solidification structure and mechanical properties of 7075Al during LDED molding has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing 7075Al microstructure based on ultrasonic energy field assisted laser direct energy deposition, in order to solve the technical problem of coarse microstructure in the existing LDED preparation method for 7075 aluminum alloy.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue, comprising the following steps: The 7075Al spherical powder and the substrate were pretreated separately and set aside for later use. The ultrasonic energy controller is connected to the bottom surface of the substrate via an ultrasonic amplitude transformer. Then the ultrasonic energy controller is turned on, causing the emitted ultrasonic waves to vibrate the substrate. Subsequently, ensuring that the laser and ultrasound are focused on the same focal point on the substrate surface, powder delivery is activated, and laser energy deposition is initiated according to specific forming requirements. After deposition, a 7075Al microstructure is obtained. During deposition, the light was stopped for 10 seconds after each layer was printed, and for 3 minutes after every 4 layers were printed.

[0006] Furthermore, the pretreatment of 7075Al spherical powder includes the following steps: 7075Al spherical powder was vacuum dried; The vacuum drying temperature is 120~150℃, and the time is 2~3 hours; The particle size range of the 7075Al spherical powder is 53~150μm.

[0007] Furthermore, the pretreatment of the substrate includes the following steps: First, the substrate surface is polished, followed by cleaning.

[0008] Furthermore, the amplitude range of vibration generated by the substrate is 1~9μm.

[0009] Furthermore, the powder feeding rate is 4.6~9 g / min.

[0010] Furthermore, in the laser energy deposition process, argon is used as both the powder carrier gas and the protective gas; and in the laser energy deposition process, the oxygen content of the forming atmosphere is below 200 ppm.

[0011] Furthermore, the process parameters for laser energy deposition are as follows: Laser power 1500~1800W, scanning speed 10~20mm / s, spot diameter 3mm, laser cladding head lifting amount 0.1~0.2mm per layer printed.

[0012] Furthermore, the number of deposition layers for laser energy deposition, which is initiated according to specific forming requirements, can be a single layer or multiple layers.

[0013] Furthermore, after the deposition is completed, the laser energy deposition, ultrasonic energy controller and powder delivery are turned off in sequence to obtain 7075Al tissue.

[0014] The present invention also discloses a 7075Al microstructure prepared by the above preparation method, wherein the 7075Al microstructure is an equiaxed crystal microstructure.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for 7075Al microstructure based on ultrasonic energy field-assisted laser direct energy deposition. By leveraging the synergistic effect of cavitation and acoustic flow generated by ultrasound within the molten pool—that is, utilizing the cavitation and acoustic flow effects—the metallurgical behavior of the molten pool can be controlled, thereby refining and controlling the grain structure. Optimization of the grain structure is achieved through controlling the metallurgical behavior of the molten pool. Furthermore, by pausing the laser for 10 seconds after each layer is printed, and then pausing for 3 minutes after every four layers, heat accumulation is eliminated, molten pool collapse is avoided, excess heat is effectively released, heat accumulation is reduced, and molding quality is guaranteed. This method can prepare 7075Al parts with fine equiaxed grain structures.

[0016] Furthermore, the method disclosed in this invention is highly operable and applicable. In practical applications, different laser and ultrasonic process matching parameters can be selected according to the specific forming requirements of different metal parts. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the equipment structure for laser energy deposition according to the present invention; Wherein: 1-Deposited multilayer metal; 2-Molten pool; 3-Laser; 4-Powder feeding nozzle; 5-Substrate; 6-Ultrasonic amplitude transformer; 7-Ultrasonic transmitter; 8-Ultrasonic energy controller; 9-Ammeter; 10-Frequency adjustment knob; 11-Power adjustment knob; Figure 2 The microstructure of 7075Al grains with and without ultrasonic energy field-assisted laser direct energy deposition; Where: a - ultrasound present; b - ultrasound absent Detailed Implementation To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0018] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0019] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0020] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0021] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0022] This invention provides a method for ultrasonic-assisted laser direct energy deposition (EDD) of 7075Al microstructure. By pausing the laser at certain intervals after each layer to eliminate heat accumulation and prevent molten pool collapse, the metallurgical behavior of the molten pool is controlled through the cavitation and acoustic flow effects generated by ultrasound, thereby achieving grain refinement and control. This method can be used to prepare 7075Al parts with fine equiaxed grain structures. The method specifically includes the following steps: Step 1: Dry the 7075 aluminum alloy spherical powder in a vacuum drying oven at 120°C for 2-3 hours to remove the absorbed moisture. After drying, cool it to room temperature in the oven and then take it out for use. The particle size range of the 7075Al spherical powder is 53-150 μm. Step 2: Use 500-grit sandpaper to sand the surface of the substrate to remove the oxide layer, then clean it with alcohol and blow it dry to remove any residual oil. Step 3: Based on Figure 1 The principle of the equipment preparation is as follows: turn on the ultrasonic energy controller 8. At this time, the ultrasonic wave is output by the transmitter 7 and transmitted to the substrate 5 through the ultrasonic amplitude transformer 6. Adjust the frequency adjustment knob 10 and the power adjustment knob 11. Adjust the output frequency until the reading of the ammeter 9 is greater than 1A. At this time, the substrate 5 reaches the resonance state and undergoes cyclic elastic deformation. The surface of the substrate 5 generates uniform vibration. Adjust the output frequency to change the amplitude of the substrate 5 surface. Use a dial indicator to measure the amplitude of the substrate 5 surface to ensure that the ultrasonic intensity meets the experimental requirements. In this equipment, the frequency adjustment knob 10 can be adjusted to reach the resonance state, and then the power adjustment knob 11 can be adjusted to control the amplitude of the substrate 5 surface, which can be freely adjusted within the range of 0~9μm. Step 4: High-purity argon gas is selected as both the powder carrier gas and the protective gas. The protective gas is activated to prevent oxidation and inclusion contamination of the alloy during the forming process; during the experiment, the oxygen content of the forming atmosphere is controlled below 200 ppm. Step 5: Ensure that the powder controlled by the laser 3, ultrasound and powder feeding nozzle 4 converges at the same focal point (molten pool 2) on the substrate 5, start the powder delivery, and set the powder feeding rate to 4.6g / min; start the laser to form a stable molten pool on the substrate 5. The laser energy deposition parameters include: laser power 1500W, scanning speed 20mm / s, spot diameter 3mm, 10s pause after each layer is printed, 3min pause after every 4 layers are printed, and laser cladding head lift 0.1~0.2mm. Step 6: By controlling the movement of the laser cladding head within the surface area of ​​substrate 5, single-pass, multi-pass, and multi-layer deposition are carried out according to specific forming requirements until the part is formed; Step 7: After deposition, sequentially shut down the laser, ultrasound, powder delivery, and protective gas. Figure 1 The image shows the deposited multilayer metal 1.

[0023] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0024] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0025] Example 1 A method for ultrasound-assisted laser direct energy deposition of 7075Al tissue includes the following steps: Step 1: 7075Al spherical powder was prepared by plasma rotating electrode method, with a particle size range of 53~150 μm. It was dried in a vacuum drying oven at 120℃ for 2 hours to remove absorbed moisture. After drying, it was cooled to room temperature in the oven and then removed for use. Step 2: Use 500-grit sandpaper to sand the surface of the substrate to remove the oxide layer, then clean it with alcohol and blow it dry to remove any residual oil on the surface; Step 3: Based on Figure 1Prepare the equipment according to the principle shown; turn on the ultrasonic energy controller 8, and the ultrasonic transmitter 7 outputs ultrasound, which is transmitted to the substrate 5 through the ultrasonic amplitude transformer 6; adjust the output frequency by the frequency adjustment knob 10 until the current reading of the ammeter 9 is 1.5A. At this time, the substrate 5 reaches the resonance state and undergoes cyclic elastic deformation, and the surface of the substrate 5 generates uniform vibration; adjust the output power by the power adjustment knob 11 to change the amplitude of the substrate 5 surface. Use a dial indicator to measure the amplitude of the substrate 5 surface, which is 9μm, to ensure that the ultrasonic intensity meets the experimental requirements. Step 4: Select high-purity argon as the powder carrier gas and protective gas; start the protective gas to prevent oxidation and inclusion contamination of the alloy during the forming process; during the experiment, the oxygen content of the forming atmosphere is controlled below 200 ppm; Step 5: Ensure that the laser 3, ultrasound, and powder converge at the same focal point on the substrate (molten pool 2); turn on the powder delivery and set the powder feed rate to 4.6 g / min; start the laser to form a stable molten pool 2 on the substrate. The laser energy deposition parameters include: laser power 1500W, scanning speed 10mm / s, spot diameter 3mm, 10s pause after each layer is printed, 3min pause after every 4 layers are printed, and laser cladding head lift 0.1mm. Step 7: By controlling the movement of the laser cladding head within the substrate surface area, single-pass, multi-pass, and multi-layer deposition are carried out according to specific forming requirements until the part is formed.

[0026] Step 8: After deposition is complete, turn off the laser, ultrasound, powder delivery, and protective gas in sequence.

[0027] Example 2 A method for ultrasound-assisted laser direct energy deposition of 7075Al tissue includes the following steps: Step 1: 7075Al spherical powder was prepared by plasma rotating electrode method, with a particle size range of 53~150μm. It was dried in a vacuum drying oven at 140℃ for 2h to remove the absorbed moisture. After drying, it was cooled to room temperature in the oven and then taken out for use. Step 2: Use 500-grit sandpaper to sand the surface of the substrate to remove the oxide layer, then clean it with alcohol and blow it dry to remove any residual oil on the surface; Step 3: Based on Figure 1 Prepare the equipment according to the principle shown; turn on the ultrasonic energy controller 8, and the ultrasonic transmitter 7 outputs ultrasound, which is transmitted to the substrate 5 through the ultrasonic amplitude transformer 6. Adjust the output frequency by the frequency adjustment knob 10 until the current reading of the ammeter 9 is 1.5A. At this time, the substrate 5 reaches the resonance state and undergoes cyclic elastic deformation, and the surface of the substrate 5 produces uniform vibration; adjust the output power by the power adjustment knob 11 to change the amplitude of the substrate 5 surface. Use a dial indicator to measure the amplitude of the substrate 5 surface, which is 5μm, to ensure that the ultrasonic intensity meets the experimental requirements. Step 4: High-purity argon gas is selected as both the powder carrier gas and the protective gas. The protective gas is activated to prevent oxidation and inclusion contamination of the alloy during the forming process. During the experiment, the oxygen content of the forming atmosphere is controlled below 200 ppm. Step 5: Ensure that the laser 3, ultrasound, and powder converge at the same focal point on the substrate (molten pool 2). Turn on the powder delivery and set the powder feed rate to 6g / min; start the laser to form a stable molten pool 2 on the substrate. The laser energy deposition parameters include: laser power 1800W, scanning speed 15mm / s, spot diameter 3mm, 10s pause after each layer is printed, 3min pause after every 4 layers are printed, and laser cladding head lift 0.15mm. Step 7: By controlling the movement of the laser cladding head in the substrate surface area, single-pass, multi-pass, and multi-layer deposition are carried out according to specific forming requirements until the part is formed; Step 8: After deposition is complete, turn off the laser, ultrasound, powder delivery, and protective gas in sequence.

[0028] Example 3 A method for ultrasound-assisted laser direct energy deposition of 7075Al tissue includes the following steps: Step 1: 7075Al spherical powder was prepared by plasma rotating electrode method, with a particle size range of 53~150μm. It was dried in a vacuum drying oven at 120℃ for 2h to remove the absorbed moisture. After drying, it was cooled to room temperature in the oven and then removed.

[0029] Step 2: Use 500-grit sandpaper to sand the surface of the substrate to remove the oxide layer, then clean it with alcohol and blow it dry to remove any residual oil on the surface; Step 3: Based on Figure 1 Prepare the equipment according to the principle shown. Turn on the ultrasonic energy controller 8, and the ultrasonic transmitter 7 outputs ultrasound, which is transmitted to the substrate 5 through the ultrasonic amplitude transformer 6. Adjust the output frequency by adjusting the frequency knob 10 until the current reading of the ammeter 9 is 1.5A. At this time, the substrate 5 reaches the resonant state and undergoes cyclic elastic deformation, and the surface of the substrate 5 generates uniform vibration. Adjust the output power by adjusting the power knob 11 to change the amplitude of the substrate 5 surface. Use a dial indicator to measure the amplitude of the substrate 5 surface, which is 3μm, to ensure that the ultrasonic intensity meets the experimental requirements. Step 4: High-purity argon gas is selected as both the powder carrier gas and the protective gas. The protective gas is activated to prevent oxidation and inclusion contamination of the alloy during the forming process. During the experiment, the oxygen content of the forming atmosphere is controlled below 200 ppm. Step 5: Ensure that the laser 3, ultrasound, and powder converge at the same focal point on the substrate (molten pool 2). Turn on the powder delivery and set the powder feed rate to 6g / min. Start the laser to form a stable molten pool 2 on the substrate. The laser energy deposition parameters include: laser power 1500W, scanning speed 20mm / s, spot diameter 3mm, 10s pause after each layer is printed, 3min pause after every 4 layers are printed, and laser cladding head lift 0.2mm. Step 7: By controlling the movement of the laser cladding head within the substrate surface area, single-pass, multi-pass, and multi-layer deposition are carried out according to specific forming requirements until the part is formed.

[0030] Step 8: After deposition is complete, turn off the laser, ultrasound, powder delivery, and protective gas in sequence.

[0031] Example 4 A method for ultrasound-assisted laser direct energy deposition of 7075Al tissue includes the following steps: Step 1: 7075Al spherical powder was prepared by plasma rotating electrode method, with a particle size range of 53~150μm. It was dried in a vacuum drying oven at 140℃ for 2h to remove absorbed moisture. After drying, it was cooled to room temperature in the oven and then removed. Step 2: Use 500-grit sandpaper to sand the surface of the substrate to remove the oxide layer, then clean it with alcohol and blow it dry to remove any residual oil on the surface; Step 3: Based on Figure 1 Prepare the equipment according to the principle shown. Turn on the ultrasonic energy controller 8, and the ultrasonic transmitter 7 outputs ultrasound, which is transmitted to the substrate 5 through the ultrasonic amplitude transformer 6. Adjust the output frequency by adjusting the frequency knob 10 until the current reading of the ammeter 9 is 1.5A. At this time, the substrate 5 reaches the resonant state and undergoes cyclic elastic deformation, and the surface of the substrate 5 produces uniform vibration. Adjust the output power by adjusting the power knob 11 to change the amplitude of the substrate 5 surface. Use a dial indicator to measure the amplitude of the substrate 5 surface, which is 5μm, to ensure that the ultrasonic intensity meets the experimental requirements. Step 4: High-purity argon gas was selected as both the powder carrier gas and the protective gas; the protective gas was activated to prevent oxidation and inclusion contamination of the alloy during the forming process. During the experiment, the oxygen content of the forming atmosphere was controlled below 200 ppm. Step 5: Ensure that the laser 3, ultrasound, and powder converge at the same focal point on the substrate (molten pool 2). Turn on the powder delivery and set the powder feed rate to 4.6 g / min; start the laser to form a stable molten pool 2 on the substrate. The laser energy deposition parameters include: laser power 1800 W, scanning speed 20 mm / s, spot diameter 3 mm, 10 s pause after each layer is printed, 3 min pause after every 4 layers are printed, and laser cladding head lift 0.2 mm. Step 7: By controlling the movement of the laser cladding head in the substrate surface area, single-pass, multi-pass, and multi-layer deposition are carried out according to specific forming requirements until the part is formed; Step 8: After deposition is complete, turn off the laser, ultrasound, powder delivery, and protective gas in sequence.

[0032] Comparative Example A method for ultrasound-assisted laser direct energy deposition of 7075Al tissue includes the following steps: Step 1: 7075Al spherical powder was prepared by plasma rotating electrode method, with a particle size range of 53~150 μm. It was dried in a vacuum drying oven at 120℃ for 2 hours to remove absorbed moisture. After drying, it was cooled to room temperature in the oven and then removed. Step 2: Use 500-grit sandpaper to sand the surface of the substrate to remove the oxide layer, then clean it with alcohol and blow it dry to remove any residual oil on the surface; Step 3: Select high-purity argon as the powder carrier gas and protective gas; start the protective gas to prevent oxidation and inclusion contamination of the alloy during the forming process; during the experiment, the oxygen content of the forming atmosphere is controlled below 200 ppm; Step 4: Ensure that the laser 3, ultrasound, and powder converge at the same focal point on the substrate (molten pool 2); turn on the powder delivery and set the powder feed rate to 4.6 g / min; start the laser to form a stable molten pool 2 on the substrate. The laser energy deposition parameters include: laser power 1500W, scanning speed 10mm / s, spot diameter 3mm, 10s pause after each layer is printed, 3min pause after every 4 layers are printed, and laser cladding head lift 0.1mm. Step 5: By controlling the movement of the laser cladding head within the substrate surface area, single-pass, multi-pass, and multi-layer deposition are carried out according to specific forming requirements until the part is formed.

[0033] Step 6: After deposition is complete, turn off the laser, powder delivery, and protective gas in sequence.

[0034] Figure 2 The image shows a comparison between the 7075Al microstructure prepared in step 1 and the 7075Al microstructure prepared in the comparative example. It can be seen from the image that the microstructure of 7075Al prepared by ultrasound-assisted laser direct energy deposition is significantly refined compared to the coarse columnar grain structure obtained by ultrasound-assisted laser direct energy deposition of 7075Al.

[0035] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue, characterized in that, Includes the following steps: The 7075Al spherical powder and the substrate were pretreated separately and set aside for later use. The ultrasonic energy controller is connected to the bottom surface of the substrate via an ultrasonic amplitude transformer. Then the ultrasonic energy controller is turned on, causing the emitted ultrasonic waves to vibrate the substrate. Subsequently, ensuring that the laser and ultrasound are focused on the same focal point on the substrate surface, powder delivery is activated, and laser energy deposition is initiated according to specific forming requirements. After deposition, a 7075Al microstructure is obtained. During deposition, the light was stopped for 10 seconds after each layer was printed, and for 3 minutes after every 4 layers were printed.

2. The method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue according to claim 1, characterized in that, The pretreatment of 7075Al spherical powder includes the following steps: 7075Al spherical powder was vacuum dried; The vacuum drying temperature is 120~150℃, and the time is 2~3 hours; The particle size range of the 7075Al spherical powder is 53~150μm.

3. The method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue according to claim 1, characterized in that, The pretreatment of the substrate includes the following steps: First, the substrate surface is polished, followed by cleaning.

4. The method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue according to claim 1, characterized in that, The amplitude range of vibration generated by the substrate is 1~9μm.

5. The method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue according to claim 1, characterized in that, The powder feeding rate is 4.6~9 g / min.

6. The method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue according to claim 1, characterized in that, In the laser energy deposition process, argon is used as both the powder carrier gas and the protective gas; and the oxygen content of the forming atmosphere is below 200 ppm during the laser energy deposition process.

7. The method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue according to claim 1, characterized in that, The process parameters for laser energy deposition are as follows: Laser power 1500~1800W, scanning speed 10~20mm / s, spot diameter 3mm, laser cladding head lifting amount 0.1~0.2mm per layer printed.

8. The method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue according to claim 1, characterized in that, The number of deposition layers for laser energy deposition, which is initiated according to specific forming requirements, can be a single layer or multiple layers.

9. The method for ultrasonic energy field-assisted laser direct energy deposition of 7075Al tissue according to claim 1, characterized in that, After the deposition was completed, the laser energy deposition, ultrasonic energy controller and powder delivery were turned off in sequence to obtain 7075Al tissue.

10. A 7075Al tissue prepared by the method of ultrasonic energy field assisted laser direct energy deposition of 7075Al tissue according to any one of claims 1 to 9, characterized in that, The 7075Al structure is an equiaxed crystal structure.

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