Method and system for repairing defects in friction stir welding seams of high-strength aluminum alloy

Abstract

The present invention provides a method and system for repairing defects in friction stir welds of high-strength aluminum alloys, including: delineating the area to be repaired; calculating the filling passes and layers, planning a multi-layer and multi-pass filling path for the cross-sectional interface effect, and saving it in a three-dimensional model readable by the device; determining the repair manufacturing process parameters; importing a data model containing the contour of the area to be repaired, the filling layers, and the filling passes of each layer into model processing software in a file format, processing the repair model according to the repair manufacturing process parameters to obtain the filling repair path of the part to be repaired; and preparing a repaired high-strength aluminum alloy component by cooperating with the tool of the additive repair device according to the repair manufacturing process parameters and the planned path. On the one hand, the present invention solves the problems of excessive heat input of the filler for repairing material shortage in high-strength aluminum alloys, great influence on the properties of the base material, and limited performance improvement. On the other hand, it effectively weakens the anisotropy between the properties of the filling area and the matrix.

Description

Technical Field

[0001] The present invention relates to the technical field of additive defect repair, and specifically, to a method and system for repairing defects in friction stir welds of high-strength aluminum alloys. In particular, it relates to a design of a filler path for repairing friction stir welding defects that has low heat input and combines transverse and longitudinal connection strengthening and toughening to form a mechanical interlocking interface. Background Art

[0002] Friction Stir Welding (FSW) is an advanced solid-state material joining method invented by The Welding Institute (TWI) in the UK in 1991. This technology has the advantages of low heat input, high quality of welded joints, small welding deformation, insensitivity to temperature and humidity, and environmental friendliness, and is particularly suitable for welding aluminum alloy materials. Therefore, since the advent of the FSW technology, it has received extensive attention from experts and scholars. Due to the significant technical and economic benefits of this technology, up to now, the FSW technology has been widely used in aviation, aerospace, shipbuilding, automotive manufacturing, and rail vehicle processing and manufacturing.

[0003] The characteristics of new aluminum alloys such as 2195 aluminum-lithium alloy being lightweight and high-strength provide more possibilities for the manufacture of large lightweight storage tanks. Due to the high sensitivity to hot cracking, the fusion welding quality of aluminum-lithium alloy is poor. Due to the extremely high heat input, fatal defects such as pores and cracks are likely to appear, and it is often difficult to completely avoid them only by relying on parameter optimization. Therefore, the development of friction stir additive technology is crucial for the engineering application of aluminum-lithium alloy. However, defects such as weld thinning or sinking often occur during the friction stir welding process. Currently, such defects are often improved by the method of first performing fusion welding with filler wire and then friction stir welding to improve the microstructure, but there are many problems:

[0004] ① During the fusion welding process, the introduction of melting heat has a great impact on the microstructure and properties of the aluminum-lithium alloy matrix.

[0005] ② At present, there is a lack of mature filler wires for aluminum-lithium alloy that have been verified by engineering applications.

[0006] ③ The fusion welding filling has poor tissue compactness, and defects still exist after the repaired part is friction stir welded.

[0007] Therefore, it is urgent to develop a new method for additive repair of aluminum-lithium alloy, especially the design of a friction stir welding defect repair tool and repair technology that form a mechanical interlocking effect and metallurgical bonding with low heat input.

[0008] Patent document CN209648007U discloses a device for repairing surface defects of aluminum alloy welds, including a base and a connecting block. A bottom chute is provided on the upper surface of the bottom of the base. The connecting blocks are symmetrically welded on both outer sides of the base. Threaded holes are reserved inside both sides of the base, and the inner side of the base is connected to a clamping plate through a spring. The upper part of the base is connected to a side rod through an upper rotating shaft, and side chutes are provided on both outer sides of the side rod. Side sliders are installed on the sides of the positioning blocks. Fixed columns are installed inside both the welding torch and the positioning blocks, and the fixed columns are connected to the side rod through fixing holes.

[0009] However, the patent document CN209648007U cannot repair the defects of friction stir welding that forms a mechanical interlocking effect and metallurgical bonding with low heat input.

[0010] In addition, common solid-phase repair technologies, such as friction stir additive manufacturing, rolling, powder metallurgy, etc., all have disadvantages such as limited repair shape and complex post-treatment to varying degrees. Moreover, there are obvious anisotropies in the formed parts. The bonding mechanism and the interlayer bonding force between multiple passes and multiple layers are still problems to be solved, especially the problem of poor bonding interface strength between the repair area and the matrix. Summary of the Invention

[0011] Aiming at the defects in the prior art, the purpose of the present invention is to provide a method and system for repairing defects of friction stir welds of high-strength aluminum alloys.

[0012] According to a method for repairing defects of friction stir welds of high-strength aluminum alloys provided by the present invention, it includes:

[0013] Step S1: Mark the area to be repaired and extract the contour of the area to be repaired;

[0014] Step S2: Calculate the filling passes and layers according to the distribution of the area to be repaired, plan the multi-layer and multi-pass filling path with cross-interface effect, and save it in a three-dimensional model that can be read by the device;

[0015] Step S3: Determine the parameters of the repair manufacturing process;

[0016] Step S4: Data model processing. Import the data model containing the contour of the area to be repaired, the filling layers, and the filling passes of each layer into the model processing software in a file format. According to the parameters of the repair manufacturing process, complete the repair model processing to obtain the filling repair path of the part to be repaired;

[0017] Step S5: Prepare the repaired high-strength aluminum alloy component according to the parameters of the repair manufacturing process and the path planned in Step S4 in cooperation with the tools of the additive repair equipment.

[0018] Preferably, in step S1, according to the path of the repair tool and the filling requirements, a three-dimensional model entity is established using computer-aided software, and the three-dimensional model entity is saved in a file format recognizable by the model processing software;

[0019] The file format includes stl format and stp format.

[0020] Preferably, step S2 includes extracting three-dimensional information of the area to be repaired, and calculating the filling passes and layers according to the three-dimensional information;

[0021] The three-dimensional information includes the size of the area to be repaired, the single-pass width, and the single-layer thickness;

[0022] The calculation formulas for the filling layers and the filling passes of each layer are as follows:

[0023] N=(h + 5) / t

[0024] M = l or M = w / d

[0025] Wherein, N represents the filling layers, M represents the filling passes of each layer, l, w, and h respectively represent the length, width, and height of the area to be repaired, d represents the single-layer width, and t represents the single-layer thickness.

[0026] Preferably, step S3 includes a first process and a second process;

[0027] In the first process, material is supplemented with low heat input. At this time, there is no metallurgical and mechanical bonding between the filling material layers, between the passes, and between the filled area and the base material. The adjacent layers in the filling area are rotated clockwise by 63°, and a non-linear close-packed filling method is used for the single layer to introduce a multi-interface effect;

[0028] In the second process, a repair tool with a serrated feature on the side is used for homogenization treatment of the grain refiner, increasing the metallurgical bonding and mechanical locking effects between the layers, between the passes in the repair area, and between the repair area and the base material.

[0029] Preferably, the heat input in the first process is less than that in the second process, and the heat input in the second process is less than the heat introduced by the melting welding filler method.

[0030] Preferably, in step S4, a non-linear dense arrangement method is adopted for the single-layer passes in the filling area, while a wide-profile filling method is adopted for the interface area between the prepared filling area and the base material to cover all interface areas.

[0031] Preferably, the step S4 includes importing the three-dimensional format file generated in step S2 into the additive manufacturing slicing and layering model processing software, and according to the repair manufacturing parameters determined in step S3, where t is the single-layer thickness and d is the single-pass laying spacing, and then planning the manufacturing path according to the contour of the area to be repaired to generate a defect repair command file for the substrate filling path.

[0032] Preferably, in the step S5, non-linear laying of continuous passes is performed in the area to be repaired, so that the continuous passes cross the non-planar cross-section distribution, and a repair tool with a serrated structure in the circumferential direction is used to modify the material while filling the repair area, and a weakly anisotropic area to be repaired with multiple cross-interfaces is prepared.

[0033] Preferably, a low-heat filler method including friction stir additive manufacturing is adopted, and the additive material is filled in the area to be repaired in a poor distribution manner, so that multiple contacts are formed between the continuously filled area and the filler material, and finally a weakly anisotropic high-strength aluminum alloy repair area with low heat input is obtained.

[0034] A friction stir welding defect repair system for high-strength aluminum alloy according to the present invention includes:

[0035] Module M1: Mark the area to be repaired and extract the contour of the area to be repaired;

[0036] Module M2: Calculate the filling passes and layers according to the distribution of the area to be repaired, plan the multi-layer and multi-pass filling path with cross-interface effect, and save it in the three-dimensional model that can be read by the device;

[0037] Module M3: Determine the repair manufacturing process parameters;

[0038] Module M4: Data model processing, importing the data model including the contour of the area to be repaired, the number of filling layers and the number of filling passes per layer into the model processing software in a file format, and completing the repair model processing according to the repair manufacturing process parameters to obtain the filling repair path of the part to be repaired;

[0039] Module M5: According to the repair manufacturing process parameters and the path planned by Module M4, cooperate with the tool of the additive repair device to prepare the repaired high-strength aluminum alloy component.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention uses low-heat additive methods such as friction stir additive manufacturing to replace the original high-heat input melting welding filling method. The filling part adopts an irregular wavy close-packed distribution method, which can effectively increase the multi-interface effect, alleviate the abnormal growth of the microstructure and the anisotropy of properties caused by a single heat input, effectively improve the comprehensive properties of the material, reduce the influence of heat input on the substrate, reduce the risk of hot cracking, and at the same time break the limitation that high-strength aluminum alloy welds cannot be repaired multiple times.

[0042] Compared with the traditional solid-phase repair method, the present invention uses a repair tool with serrated structures on both sides, which can realize the mass and heat exchange between the substrate and the filling area, and between the filling area passes and layers, forming a transverse and longitudinal interface distribution with both metallurgical bonding and mechanical locking effects, improving the bonding strength between the repair area and the substrate, improving the interlayer bonding strength of the repair area, and weakening the anisotropy of the component.

[0043] Through the optimization of the stirring tool, the present invention invents a new filling method to avoid the high-energy heat input filling method such as fusion welding and melt transition, thereby avoiding the grain coarsening and even cracking of the high-strength aluminum alloy substrate due to excessive heat input; in addition, by designing the structure of the repair tool to increase the mass conversion efficiency between the repair area and the substrate and weaken the single interface effect, the problems of poor interface performance between the repair layer and the substrate and anisotropy of the performance of the multi-layer and multi-pass repair area are effectively weakened. Especially, the serrated design on the side of the repair tool realizes the interpenetrating distribution of the repair area and the substrate structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other features, objects, and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0045] Figure 1 is a schematic flow chart of the working method of the present invention;

[0046] Figure 2 is a three-dimensional schematic diagram of the repair principle of the filler for high-strength and highly anisotropic high-strength aluminum alloy welds;

[0047] Figure 3 is the bonding between layers and passes after repair. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0049] The present invention adopts a defect repair technology for optimizing and improving the properties and tissue uniformity of high-strength aluminum alloy by means of non-linear close-packed laying with low energy input and tissue modification methods for increasing interlayer and inter-pass material transformation, thereby enhancing the strength of the repaired area of the high-strength aluminum alloy obtained by preparation and weakening the anisotropy of the properties between the filling area and the matrix. By using a non-linear filling material laying method with low heat input and a tissue modification method with a high material exchange rate between the repaired area and the matrix, a high-strength aluminum alloy component with high strength and weak anisotropy is obtained. The repair objects of the present invention include welding defects of high-strength aluminum alloy or defects caused by damage during long-term service and the like.

[0050] A method for repairing defects in friction stir welds of high-strength aluminum alloy provided by the present invention, as Figure 1 shown, includes:

[0051] Step S1: Mark the area to be repaired (filled) and extract the contour of the area to be repaired. According to the path of the repair tool and the filling requirements, use computer-aided software to establish a three-dimensional model entity and save it in a file format recognizable by the model processing software, such as stl or stp format. For example: Use computer-aided drawing software creo 2.0 or UG to draw and extract the contour of the area to be repaired, including three directions of X, Y, and Z. The drawn contour is expanded 5 mm outward compared with the physical contour, and the three-dimensional model is exported as stl or stp format.

[0052] Step S2: Calculate the filling passes and layers according to the distribution of the area to be repaired, and plan a multi-layer and multi-pass filling path for cross-sectional interface effect, and save it in a three-dimensional model readable by the device. According to the three-dimensional information of the area to be repaired extracted, the three-dimensional information includes: the size of the area to be repaired, the single-pass width, and the single-layer thickness. The calculation formulas for the filling layers and the number of filling passes per layer are as follows:

[0053] N = (h + 5) / t

[0054] M = l or M = w / d

[0055] Wherein, N represents the filling layers, M represents the number of filling passes per layer, l, w, and h respectively represent the length, width, and height of the area to be repaired, d represents the single-layer width, and t represents the single-layer thickness.

[0056] The filling method is as Figure 2As shown in the figure. The single layers are arranged in an interspersed manner, and adjacent layers are rotated by 63° to form a multiple interface effect with non-single heat transfer paths. The distribution passes of the nth layer are along the x direction, and the pass distributions are n(1), n(2), n(3), n(4), n(5); the (n + 1)th layer is rotated clockwise by 63° compared to the nth layer, and the pass distributions are n+1(1), n+1(2), n+1(3), n+1(4), n+1(5). Among them, the laying direction of the filling material in the nth layer is rotated clockwise by 63° with respect to the laying axis between the (n + 1)th layer. In the single-layer passes of the filling area, a non-linear dense arrangement is adopted, and the prepared filling area and the substrate interface area adopt a wide-profile filling method to cover all interface areas. For example: the heating temperature of the substrate is 250°C, the heating temperature of the fiber head is 250°C, the single-layer thickness t is 2.5 mm, the single-pass laying spacing d is 5 mm, the rotation speed is 700 rpm, and the forward speed is 150 mm / min.

[0057] In addition, referring to Figure 2 It can be seen that adjacent layers are rotated by a certain angle, and the edges of the specimens adopt a wide-profile filling method, with the profile width being A, and A needs to completely cover all interface areas. Finally, the model is exported to a file format recognizable by the device. Among them, referring to Figure 3 , in the filling path, the substrate adopts a non-linear dense arrangement, and a close arrangement is adopted between passes; the edges of the repair area ( Figure 2 the position shown by A in the figure) adopt a wide-profile filling method. The filling angle between adjacent layers changes. In this embodiment, a preferred method of increasing by 63° is adopted. Referring to Figure 2 , the nth layer and the (n + 1)th layer are rotated by 63° in sequence. Finally, a file format containing parameters and path planning that can be recognized by the device is generated.

[0058] Step S3: Determine the repair manufacturing process parameters; the formability of the repair of the friction stir welding seam defect of high-strength aluminum alloy with low heat input and weak anisotropy mainly depends on the high-strength fusion between the structure of the filler area with low energy input and the matrix. First, low heat input is used for material supplementation. During this process 1, no metallurgical or mechanical bonding occurs between the filling material layers, between passes, and between the filling area and the substrate. In process 1, in order to break through the directional heat transfer and single interface effect, the adjacent layers in the filler area are rotated clockwise by 63°, and a non-linear dense filling method is adopted between single layers to introduce a multi-interface effect. Immediately afterwards, in process 2, a repair tool with serrated features on the side is used for homogenization treatment of the structure modifier to increase the metallurgical bonding and mechanical locking effects between the layers, between passes, and between the repair area and the substrate. The heat input in process 1 is less than that in process 2, but the heat input in process 2 is less than the heat introduced by filling methods such as fusion welding. And, the repair process parameters are determined according to the above material system and manufacturing requirements.

[0059] For example: When selecting an appropriate material system, 2195 high-strength aluminum-lithium alloy is chosen as the base material, and serious thinning defects occur in the friction stir welding seam. In Process 1, continuous water cooling is adopted to keep the filler temperature at 150 - 250°C. Only surface adhesion is generated in this process, without metallurgical bonding or mechanical locking. In Process 2, an optimized combination of repair tools, rotational speed, and feed rate is selected, making the tissue optimization temperature range from 400 - 450°C. Obvious metallurgical bonding and mechanical locking effects occur between layers, between passes, and between the filling area and the base material during this process.

[0060] The repair manufacturing process parameters include: the filler process temperature ranges from 150 - 250°C, the tissue modification process temperature range is from 400 - 450°C, continuous water cooling is used for the base material, the filler process temperature ranges from 150 - 250°C, the tissue modification process temperature range is from 400 - 450°C, the single-layer thickness t of the material filling is 2.5 mm, the movement spacing h between adjacent passes of the machine head is 5 mm, the clockwise rotation angle between adjacent layers is 63°, the rotational speed of the repair tool is 700 rpm, and the feed rate is 200 mm / min.

[0061] Step S4: Data model processing. Import the data model containing the contour of the area to be repaired, the number of filling layers, and the number of filling passes per layer into the model processing software in file format. According to the repair manufacturing process parameters, complete the repair model processing to obtain the processed repair model. Specifically, import the three-dimensional format file generated in Step S2 into the additive manufacturing slicing and layer model processing software. According to the repair manufacturing parameters determined in Step S3, where t is the single-layer thickness and d is the single-pass laying spacing, then plan the manufacturing path based on the contour of the area to be repaired to generate a defect repair command file for the base material filling path with a non-linear close-packed distribution in a single layer.

[0062] Step S5: According to the repaired manufacturing process parameters and the path planned in step S4, cooperate with the tools of the additive repair equipment to prepare the repaired high-strength aluminum alloy component. Conduct non-linear laying in continuous passes in the area to be repaired, so that the continuous passes have a cross-non-planar truncated interface distribution. Use a repair tool with a serrated structure in the circumferential direction to modify the material while filling the repair area. The repair tool with a serrated structure at the edge improves the heat generation uniformity and mass exchange efficiency between layers and passes, increases the bonding strength between layers and passes, eliminates anisotropy, and prepares a repaired area with multiple cross-interfaces and weak anisotropy. Import the file format generated in step S3 into the equipment. Through the movement coordination between the multi-axis linkage equipment head and the turntable, use a repair tool with a serrated structure in the circumferential direction to modify the material while filling the repair area. The repair tool with a serrated structure at the edge improves the heat generation uniformity and mass exchange efficiency between layers and passes, increases the bonding strength between layers and passes, eliminates anisotropy. Finally, prepare a high-strength aluminum alloy repair part with low heat input and weak anisotropy. Set the equipment parameters, import the file generated in step S4 into the equipment, make the direction of the first-layer filling material parallel to the +X direction of the equipment, and the second layer is +X biased +Y 63°. Finally, prepare the repaired high-strength aluminum alloy component with low heat input and weak anisotropy.

[0063] The present invention adopts a low-heat-input filling method to increase the repair area and a method of realizing tissue modification by thermal mass exchange. Among them, the filling material presents a non-linear close-packed distribution form, so that the filling area has a multi-interface effect to replace the original single-interface form, forming multiple contacts between passes in the filling area, and finally obtaining a repaired high-strength aluminum alloy component with weak anisotropy in performance between the repair area and the substrate. High-strength aluminum alloys include 2195, 7075, etc. with high hot cracking sensitivity. Among them, the additive material is filled in the area to be repaired in a poor distribution manner, avoiding obvious anisotropy caused by a single interface formed by a layered or single-linear distribution, forming multiple contacts between the continuously filled area and the filling material, and finally obtaining an additive repair area with low heat input and weak anisotropy. The tensile strength of the repaired high-strength aluminum alloy component in the X-Y direction is 410 Mpa, and the tensile strength in the Z direction is 365 Mpa, and the anisotropy strength difference is reduced to 10.97%. The matrix material includes one or more of 2195 aluminum-lithium alloy, 6061 aluminum alloy, 7075 aluminum alloy, 2219 aluminum alloy, and 2050 aluminum alloy. The matrix material is the body of the repaired component.

[0064] In this embodiment, for the 2195 aluminum-lithium alloy parts repaired by the traditional fusion welding filler method + traditional friction stir structure modification technology, the tensile strength in the X-Y direction is 310 Mpa, and the tensile strength in the Z direction is 220 Mpa; for the specimen prepared by the present invention, the tensile strength in the X-Y direction is 410 Mpa after testing, and the tensile strength in the Z direction is 365 Mpa. The anisotropy strength difference is reduced from the original 29.03% to 10.97%.

[0065] In the present invention, the substrate adopts a non-linear filler method with low energy input, which can effectively reduce the heat input while weakening the directional heat transfer, reduce the single interface effect, and effectively weaken the anisotropy of the material. A tool with a serrated structure is used for tissue modification to increase the mass and heat transfer between single passes and single layers, and form a high-strength interface with both mechanical locking and metallurgical bonding. At the same time, the non-linear material filling method can achieve multi-point stable contact between adjacent passes and between the filling area and the substrate, form a good bonding interface, and improve the anisotropy between the X-Y direction and the Z direction of the filling area and between the filling area and the matrix. By combining the angle rotation of 63° between adjacent layers to improve the formation of a single texture, the anisotropy of the parts can be effectively improved.

[0066] The present invention aims to achieve synchronous filling and repair of material-deficient weld defects such as thinning and gouging of high-strength aluminum alloys, and relates to a low heat input filling method for friction stir weld defects of high-strength aluminum alloys and an organizational optimization method for reducing anisotropy. On the one hand, it solves the problem that the heat input during the filling of material-deficient repairs of high-strength aluminum alloys is too high, which has a greater impact on the performance of the substrate and the performance improvement is limited. On the other hand, it effectively weakens the anisotropy between the performance of the filling area and the matrix.

[0067] During the forming process of the parts of the present invention, the processes such as the assembly and parameter setting of the parts can be the same as those of the traditional friction stir welding method. Only by replacing the repair tool can the transformation from friction stir welding to low-heat weld quality repair be realized. Therefore, it can be repaired based on the existing additive manufacturing equipment, tooling and production systems. However, different from the prior art, in this case, through the non-linear close-packed filling method in the repair area, a multi-interface effect is generated in the filling area, overcoming the problems of weak interlayer bonding and obvious anisotropy caused by the single interface effect. In addition, through the processing of the serrated steps around the repair tool, more mass exchange is generated between layers, between passes, and between the repair area and the matrix. On the basis of forming the traditional welding metallurgical bond, an obvious mechanical locking effect is formed. Therefore, the performance is further improved, thereby weakening the anisotropy of the performance of the repaired weld and components, and finally obtaining a high-strength aluminum alloy weld repair method with low heat input and a friction stir weld that meets the standard requirements after repair.

[0068] A friction stir weld defect repair system for high-strength aluminum alloys provided by the present invention includes:

[0069] Module M1: Delimit the area to be repaired and extract the contour of the area to be repaired; in the module M1, according to the path of the repair tool and the filling requirements, a three-dimensional model entity is established using computer-aided software, and the three-dimensional model entity is saved in a file format recognizable by the model processing software; the file formats include stl format and stp format.

[0070] Module M2: Calculate the filling passes and layers according to the distribution of the area to be repaired, plan the multi-layer and multi-pass filling path for the cross-interface effect, and save it in the three-dimensional model readable by the device; the module M2 includes the three-dimensional information of the area to be repaired extracted, and calculates the filling passes and layers according to the three-dimensional information; the three-dimensional information includes the size of the area to be repaired, the single-pass width and the single-layer thickness; the calculation formulas for the filling layers and the filling passes per layer are as follows:

[0071] N=(h + 5) / t

[0072] M = l or M = w / d

[0073] Wherein, N represents the filling layers, M represents the filling passes per layer, l, w, and h respectively represent the length, width, and height of the area to be repaired, d represents the single-layer width, and t represents the single-layer thickness.

[0074] Module M3: Determine the repair manufacturing process parameters; the module M3 includes a first process and a second process; in the first process, low heat input is first used for material replenishment. At this time, there is no metallurgical and mechanical bonding between the filling material layers, between the passes, and between the replenished area and the substrate. The adjacent layers in the filling area are rotated clockwise by 63°, and a non-linear close-packed filling method is used for the single layer to introduce the multi-interface effect; in the second process, a repair tool with a serrated feature on the side is used for homogenization treatment of the grain refiner to increase the metallurgical bonding and mechanical locking effect between the layers, between the passes in the repair area, and between the repair area and the substrate. The heat input in the first process is less than that in the second process, and the heat input in the second process is less than the heat introduced by the method of melting and welding the filler.

[0075] Module M4: Data model processing. Import the data model containing the contour of the area to be repaired, the number of filling layers, and the number of filling passes per layer into the model processing software in file format. According to the repair manufacturing process parameters, complete the repair model processing to obtain the filling repair path of the part to be repaired. In the single-layer passes of the filling area in Module M4, a non-linear dense arrangement is adopted, and a wide-profile filling method is used in the interface area between the prepared filling area and the substrate to cover all interface areas. Module M4 includes importing the three-dimensional format file generated by Module M2 into the additive manufacturing slicing and layer model processing software. According to the repair manufacturing parameters determined by Module M3, where t is the single-layer thickness and d is the single-pass laying spacing, and then plan the manufacturing path according to the contour of the area to be repaired to generate a defect repair command file for the substrate filling path.

[0076] Module M5: According to the repair manufacturing process parameters and the path planned by Module M4, cooperate with the tools of the additive repair equipment to prepare the repaired high-strength aluminum alloy component. In Module M5, non-linear laying of continuous passes is carried out in the area to be repaired, so that the continuous passes cross the non-planar cross-section interface distribution. A repair tool with a serrated structure in the circumferential direction is used to modify the repaired area while filling the material, and a multi-cross interface and weakly anisotropic area to be repaired is prepared. A low-heat filler method including friction stir additive manufacturing is adopted, and the added material is filled in the area to be repaired in a poorly distributed manner, so that multiple contacts are formed between the continuously filled area and the filling material, and finally a low-heat input and weakly anisotropic high-strength aluminum alloy repair area is obtained.

[0077] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, 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. Without conflict, the embodiments of the present application and the features in the embodiments can be combined arbitrarily with each other.

Claims

1. A method for repairing defects in high-strength aluminum alloy friction stir welds, characterized in that: include: Step S1: Mark the area to be repaired and extract the outline of the area to be repaired; Step S2: Calculate the filling pass and number of filling layers for each layer according to the distribution of the area to be repaired, plan a multi-layer and multi-pass filling path of the cross-interface effect, and save it in a three-dimensional model that can be read by the device; Step S3: Determine repair manufacturing process parameters; Step S4: data model processing, importing the data model including the outline of the area to be repaired, the number of filling layers and the filling passes of each layer into the model processing software in a file format, completing the repair model processing according to the repair manufacturing process parameters, and obtaining the filling repair path of the part to be repaired; Step S5: preparing a repaired high-strength aluminum alloy component according to the repair manufacturing process parameters and the filling repair path planned in step S4 in coordination with the tool of the additive repair equipment; The step S3 includes a first process and a second process; The first process is to first use low heat input to supplement the material. At this time, no metallurgical and mechanical bonding is generated between the filling material layers, between the channels, and between the filling and supplementing areas and the substrate. The adjacent layers in the filling area are rotated 63° clockwise, and a non-linear close-packed filling method is used between the single layers to introduce a multi-interface effect. The second process is to use a repair tool with sawtooth features on the side to perform a homogenization treatment of the tissue modifier, thereby increasing the metallurgical bonding and mechanical locking effect between layers and paths in the repair area, and between the repair area and the substrate; The filling area prepared in step S4 and the interface area of ​​the substrate are filled in a wide contour manner to cover all interface areas.

2. The high-strength aluminum alloy friction stir weld defect repair method according to claim 1, characterized in that: In the step S1, a three-dimensional model entity is established using computer-aided software according to the path and filling requirements of the repair tool, and the three-dimensional model entity is saved in a file format recognizable by the model processing software; The file formats include stl format and stp format.

3. The high-strength aluminum alloy friction stir weld defect repair method according to claim 1, characterized in that: The step S2 includes extracting three-dimensional information of the area to be repaired, and calculating the filling passes and the number of layers according to the three-dimensional information; The three-dimensional information includes the size of the area to be repaired, the width of a single pass, and the thickness of a single layer; The calculation formula for the number of filling layers and the number of filling passes per layer is as follows: N=(h+5) / t M=l or M=w / d Wherein, N represents the number of filling layers, M represents the number of filling passes in each layer, l, w, h represent the length, width, and height of the area to be repaired, respectively, d represents the width of a single layer, and t represents the thickness of a single layer.

4. The high-strength aluminum alloy friction stir weld defect repair method according to claim 1, characterized in that: The heat input in the first process is less than that in the second process, and the heat input in the second process is less than the heat introduced by means of melting the welding filler.

5. The high-strength aluminum alloy friction stir weld defect repair method according to claim 1, characterized in that: The step S4 includes importing the three-dimensional format file generated in step S2 into the additive manufacturing slice layer model processing software, planning the manufacturing path according to the contour of the area to be repaired according to the repair manufacturing parameters determined in step S3, and generating a defect repair command file for the substrate filling path.

6. The high-strength aluminum alloy friction stir weld defect repair method according to claim 1, characterized in that: In step S5, continuous non-linear paving is performed in the area to be repaired, so that the continuous non-linear interfaces are distributed, and a repair tool with a circumferential sawtooth structure is used to fill and modify the repair area to prepare a weakly anisotropic area to be repaired with multiple cross interfaces.

7. A high-strength aluminum alloy friction stir weld defect repair system, characterized in that: include: Module M1: Mark the area to be repaired and extract the contour of the area to be repaired; Module M2: Calculate the filling pass and number of filling layers for each layer according to the distribution of the area to be repaired, plan the multi-layer and multi-pass filling path of the cross-interface effect, and save it in a three-dimensional model that can be read by the device; Module M3: Determine the repair manufacturing process parameters; Module M4: data model processing, importing the data model containing the outline of the area to be repaired, the number of filling layers and the filling passes of each layer into the model processing software in a file format, completing the repair model processing according to the repair manufacturing process parameters, and obtaining the filling repair path of the part to be repaired; Module M5: preparing a repaired high-strength aluminum alloy component according to the repair manufacturing process parameters and the filling repair path planned in module M4 in coordination with the tool of the additive repair equipment; The module M3 includes a first process and a second process; The first process is to first use low heat input to supplement the material. At this time, no metallurgical and mechanical bonding is generated between the filling material layers, between the channels, and between the filling and supplementing areas and the substrate. The adjacent layers in the filling area are rotated 63° clockwise, and a non-linear close-packed filling method is used between the single layers to introduce a multi-interface effect. The second process is to use a repair tool with sawtooth features on the side to perform a homogenization treatment of the tissue modifier, thereby increasing the metallurgical bonding and mechanical locking effect between layers and paths in the repair area, and between the repair area and the substrate; The filling area prepared in the module M4 and the interface area of ​​the substrate are filled in a wide profile manner to cover all interface areas.

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