Additive manufacturing method for enhancing multi-material interface bonding through transition heterostructure

Abstract

The invention discloses an additive manufacturing method for enhancing multi-material interface bonding through a transition heterostructure, and the method comprises the steps: planning an interface part of the multi-material heterostructure into two forming sub-regions which respectively comprise a plurality of forming lattice points, and the two forming sub-regions correspond to a first forming sub-region and a second forming sub-region; each forming lattice point of the first forming sub-region and each forming lattice point of the second forming sub-region are distributed in a staggered manner to form a checkerboard; when each forming layer of the interface part is manufactured through laser additive manufacturing, the first forming sub-area is formed through laser melting, then the second forming sub-area is formed through laser melting, and meanwhile the laser energy density adopted for forming the first forming sub-area through laser melting is higher than the laser energy density adopted for forming the second forming sub-area through laser melting. Therefore, the problems that interface metallurgical bonding is poor, the number of brittle intermetallic compounds is large, and cracks are generated due to too large stress are solved, and crack-free, high-density and high-bonding-strength titanium alloy-aluminum alloy heterogeneous material laser additive manufacturing forming is achieved.

Description

Technical Field

[0001] The present invention relates to an additive manufacturing method for enhancing the interface bonding of multiple materials through a transitional heterogeneous structure, and belongs to the technical field of multi-material laser additive manufacturing. Background Art

[0002] Multi-material additive manufacturing technology integrates multiple materials into a single part according to structural and functional requirements. It has a higher degree of design freedom in terms of material composition, shape structure and macroscopic performance. It can deposit different materials at any position of the component through precise adjustment, and can specially customize parts according to environmental or structural requirements. It breaks through many limitations of traditional multi-material preparation technology and is suitable for preparing parts with complex functions and structures. It has low production costs and excellent performance, and can form specific materials into specific places to achieve rational utilization of material properties.

[0003] During the laser powder bed forming process of metal multi-materials, changes in laser energy parameters at the interface between dissimilar metals, as well as inconsistencies in their physicochemical properties and crystal structures, inevitably introduce numerous metallurgical defects such as spheroidization, porosity, cracks, and oxide inclusions. Furthermore, alloying element evaporation, intermetallic compound formation, and unmelted particles can further impair interfacial bonding strength. These processes affect the microstructure, grain morphology, element distribution, and mechanical properties. During SLM, high thermal stresses, often higher than those elsewhere, are generated by excessive thermal gradients, rapid cooling rates, and thermophysical mismatches between dissimilar metals. This can lead to stress concentration at the interface, which can lead to cracks due to excessive stress. The surface morphology, roughness, and inter-material arrangement at the interface are important areas of research in materials science, impacting the overall performance of composite materials, coatings, and welding techniques. Summary of the Invention

[0004] The purpose of the present invention is to provide an additive manufacturing method with a transitional heterostructure to enhance the interface bonding of multiple materials, so as to solve the technical problem in the existing SLM process that due to excessive thermal gradients, rapid cooling rates and mismatched thermophysical parameters between dissimilar metal materials, high thermal stress is caused and stress concentration effects are often generated at the interface bonding point that are higher than other parts. The interface transition heterostructure can disperse and reduce the overall energy input, while ensuring good metallurgical bonding of the materials and dispersing the residual stress of the multi-material bonding, thereby improving the interface bonding of multiple materials in additive manufacturing.

[0005] In order to achieve the above technical objectives, the present invention will adopt the following technical solutions: A method for additive manufacturing of a transitional heterostructure-enhanced multi-material interface bonding employs a laser additive manufacturing process to form a target part, wherein the target part is a multi-material heterostructure; the multi-material heterostructure comprises first and second forming portions, and an interface portion between the first and second forming portions; the first and second forming portions employ different forming material systems; the interface portion is divided into two forming sub-regions, each comprising a plurality of forming grid points, corresponding to the first and second forming sub-regions; the forming grid points of the first forming sub-region are staggered with the forming grid points of the second forming sub-region to form a checkerboard pattern; When the interface part is manufactured by laser additive manufacturing, the first forming sub-region is first formed by laser melting, and then the second forming sub-region is formed by laser melting. At the same time, the laser energy density used for laser melting to form the first forming sub-region is higher than the laser energy density used for laser melting to form the second forming sub-region.

[0006] Preferably, the multi-material heterogeneous structure is a titanium alloy-aluminum alloy heterogeneous material component; the titanium alloy-aluminum alloy heterogeneous material component is specifically printed and formed by the following steps: (1) The titanium alloy powder and the aluminum alloy powder are placed in a vacuum drying oven for drying to remove moisture and improve powder fluidity; (2) using modeling software to create a three-dimensional solid STL model of the target part, and then using slicing software to slice the STL model and plan the laser scanning path to obtain three processing data files, corresponding to the first to third processing data files; In the target part, the first formed part is a titanium alloy part, and the second formed part is an aluminum alloy transition heterogeneous transition part; The first processing data file is used for processing and forming the titanium alloy part; the second processing data file is used for processing and forming the first forming sub-region of the interface part; the third processing data file is used for processing and forming the second forming sub-region of the interface part; and the fourth processing data file is used for processing and forming the remaining aluminum alloy part. (3) placing aluminum alloy powder and titanium alloy powder into a powder supply cylinder in sequence, and importing the four processing data files obtained in step (2) into the computer system of the laser powder bed melting equipment; (4) loading a first processing data file to melt and solidify the titanium alloy powder layer by layer on the substrate to form a titanium alloy part; (5) After the titanium alloy part is formed, the excess titanium alloy powder in the powder supply cylinder is pushed away, and the second and third processing data files are loaded; (6) After the powder supply cylinder is moved up by one forming layer thickness, the first forming sub-region of the current forming layer is first processed and formed using the second processing data file, and then the second forming sub-region of the current forming layer is processed and formed using the third processing data file to achieve the staggered connection of the interface molten pool; Repeat step (6) until the set interface portion is melted and solidified layer by layer, and then proceed to step (7); (7) The fourth processing data file is loaded, and the aluminum alloy part is formed layer by layer to obtain a titanium alloy-aluminum alloy heterogeneous material component.

[0007] Preferably, the titanium alloy powder is Ti6Al4V, wherein the Al content is 5.53 wt.%, the V content is 3.57 wt.%, and the balance is Ti; the aluminum alloy powder is AlMgScZr, wherein the Mg content is 4.2 wt.%, the Sc content is 0.55 wt.%, the Zr content is 0.15 wt.%, and the balance is Al.

[0008] Preferably, in the laser additive manufacturing process, the process parameters of the first forming part are: laser power of 170-190 W, laser scanning speed of 900-1000 mm / s, scanning pitch of 50 μm, and powder thickness of 30-50 μm; the process parameters of the second forming part are: laser power of 180-200 W, laser scanning speed of 1000-1200 mm / s, scanning pitch of 60 μm, and powder thickness of 30-50 μm; The laser energy density used in the first forming sub-area is 83.3-111.1 J / mm 3 The laser energy density used in the second forming sub-area is 36.4-44.5 J / mm 3 .

[0009] Preferably, the process parameters of the first forming sub-area are: laser power 180-200 W, laser scanning speed 1000-1200 mm / s, scanning spacing 60 μm, powder thickness 30-50 μm; The process parameters of the second forming sub-area are: laser power 180-200 W, laser scanning speed 2500-2750 mm / s, scanning spacing 60 μm, and powder thickness 30-50 μm.

[0010] Preferably, the number of shaping layers in the interface portion is 3-7 layers.

[0011] Preferably, the substrate is a titanium alloy substrate.

[0012] Preferably, during the forming process, the laser forming chamber is sealed and an inert gas is introduced to control the oxygen content in the forming chamber to be lower than 50 ppm.

[0013] Another technical purpose of the present invention is to provide a multi-material heterostructure, which is manufactured by the above-mentioned method of enhancing the interface bonding of multi-materials in additive manufacturing based on transitional heterostructure.

[0014] Based on the above technical objectives, the present invention has the following advantages over the prior art: 1. The present invention adopts a gradient interface process method to perform transition treatment on the interface of titanium alloy-aluminum alloy heterogeneous materials, which solves the problems of poor metallurgical bonding at the interface of titanium alloy-aluminum alloy heterogeneous materials, a large number of brittle intermetallic compounds, and cracks caused by excessive stress during laser additive manufacturing, thereby realizing laser additive manufacturing of titanium alloy-aluminum alloy heterogeneous materials with no cracks, high density, and high bonding strength.

[0015] 2. This method requires no modification to existing laser powder bed fusion equipment, is simple to operate, and can achieve heterogeneous material forming within standard laser additive manufacturing equipment. During the forming process, there's no need to open the hatch to replace powder; only the laser process parameters need to be changed to achieve transitional heterogeneous structure connection, improving the forming efficiency of laser additive manufacturing of titanium alloy-aluminum alloy heterogeneous materials.

[0016] 3. The method of the present invention for regulating metallurgical reactions and the thermal history of the molten pool by achieving high and low energy density changes at the interface to obtain different molten pools can be further extended and applied to other laser additive manufacturing heterogeneous materials that crack due to excessive interface stress, thereby broadening the process range of laser additive manufacturing heterogeneous materials and promoting the development of heterogeneous multifunctional materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments to more specifically and vividly demonstrate the above advantages.

[0018] Figure 1 It is a two-dimensional schematic diagram of the formed morphology obtained by the present invention.

[0019] Wherein: 1-first forming part; 2-second forming part; 31-forming grid point of the first forming sub-region; 32-forming grid point of the second forming sub-region; Figure 2 Flowchart of the additive manufacturing process of the present invention.

[0020] Figure 3 This is an optical image of the titanium alloy-aluminum alloy interface prepared by the present invention in Example 1.

[0021] Figure 4 This is an optical image of the titanium alloy-aluminum alloy interface prepared by the present invention in Example 2.

[0022] Figure 5 This is an optical image of the titanium alloy-aluminum alloy interface prepared by the present invention in Example 3.

[0023] Figure 6 This is an optical image of the titanium alloy-aluminum alloy interface prepared by the present invention in Example 4.

[0024] Figure 7 This is an optical image of the titanium alloy-aluminum alloy interface prepared by the present invention in Example 5.

[0025] Figure 8 This is an optical image of the titanium alloy-aluminum alloy interface prepared by the present invention in Example 6.

[0026] Figure 9 This is an optical image of the titanium alloy-aluminum alloy interface prepared by the present invention in Example 7.

[0027] Figure 10 This is the optical image of the titanium alloy-aluminum alloy junction interface using a single high energy density for comparative example 1. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way serves as any limitation on the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention. Unless otherwise specified, the relative arrangement of components and steps, expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. Technologies, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods and equipment should be considered part of the specification. In all examples shown and discussed here, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values.

[0029] For multi-material heterogeneous structures, the surface morphology, roughness and mutual arrangement of different materials at the interface structure are important research areas in materials science, affecting the overall performance of composite materials, coatings and welding technologies. Figure 1 、 Figure 2As shown, the present invention constructs a specific forming process for the interface portion (the interface portion is planned to be divided into two forming sub-regions, each including a plurality of forming grid points, corresponding to the first and second forming sub-regions; the forming grid points included in the first forming sub-region and the forming grid points included in the second forming sub-region are staggered to form a checkerboard; when the interface portion is manufactured by laser additive manufacturing, the first forming sub-region is first laser melted to form the first forming sub-region, and then the second forming sub-region is laser melted to form the second forming sub-region, and at the same time, the laser energy density used for laser melting to form the first forming sub-region is higher than the laser energy density used for laser melting to form the second forming sub-region), so that each forming layer of the interface portion and the forming layer adjacent to the interface can achieve mechanical locking through microscopic irregular shapes, thereby increasing the contact area, helping to improve the bonding strength, and promoting better material bonding.

[0030] Furthermore, the present invention achieves adjustment of the laser energy density during the forming of the first and second forming sub-regions by alternating increases in laser energy density. Generally, at high scanning speeds (2500-2750 mm / s), the formation of intermetallic compounds at the interface can be effectively alleviated, but the processing range is relatively limited. At the same time, too low a laser energy density at high scanning speeds can easily lead to problems such as undissolved powder and excessive thermal stress. Dissimilar materials have huge differences in thermal physical parameters, and there is a huge accumulation of thermal stress near the interface. By alternating the energy density in three dimensions, it is possible to reduce energy input while ensuring dense bonding, thereby achieving heterogeneous structural connection in the transition layer.

[0031] In addition, the forming process will destroy the integrity of the molten pool and the thinner intermediate layer in the low-energy-density area due to the large high-energy-density heat-affected zone and the large molten pool disturbance generated. Therefore, the high-energy-density area is formed first, thereby forming a staggered connection of the molten pool, and at the same time providing more cooling time for the high-energy-density area to reduce heat accumulation.

[0032] Therefore, the heterogeneous structure of the transition layer achieved through additive manufacturing process has a significant impact on the bonding performance of the multi-material interface.

[0033] Figure 2 This is a flow chart of the method for enhancing the interface bonding of multiple materials in additive manufacturing based on transitional heterostructures. The process of laser powder bed fusion forming a multi-material heterostructure is as follows: (a) Raw materials preparation: The titanium alloy powder and aluminum alloy powder prepared by gas atomization had a particle size between 15 and 53 μm and good fluidity. They were then dried in a vacuum drying oven at 80 °C for 8 hours to remove moisture and improve powder fluidity.

[0034] The titanium alloy powder selected in the present invention is Ti6Al4V, wherein the Al content is 5.53 wt.%, the V content is 3.57 wt.%, and the balance is Ti; the aluminum alloy powder selected is AlMgScZr, wherein the Mg content is 4.2 wt.%, the Sc content is 0.55 wt.%, the Zr content is 0.15 wt.%, and the balance is Al.

[0035] It should be noted that the raw materials used are based on a multi-material heterogeneous structure. In addition, the formula of the above-mentioned Ti6Al4V powder and AlMgScZr powder may also vary depending on the source.

[0036] (b) Preparation of processing data files: A three-dimensional solid STL model of the target part is established using modeling software, and then the STL model is sliced ​​and layered using slicing software and a laser scanning path is planned to obtain four processing data files, corresponding to the first to fourth processing data files.

[0037] The target part is a multi-material heterogeneous structure, including a first and a second forming part and an interface part between the first and second forming parts. The forming material systems used in the first and second forming parts are different. In the present invention, the first forming part is a titanium alloy part and the second forming part is an aluminum alloy part. Therefore, a first processing data file is planned for the forming of the titanium alloy part. Then, the titanium alloy part can be formed by melting and solidifying the titanium alloy powder layer by layer through the first processing data file. For the interface part, the interface part is first planned into two forming sub-regions, each including a plurality of forming grid points, corresponding to the first and second forming sub-regions. The forming grid points included in the first forming sub-region and the forming grid points included in the second forming sub-region are staggered to form a checkerboard. Then, a second processing data file is constructed for the first forming sub-region and a third processing data file is constructed for the second forming sub-region. By alternately calling the second and third processing data files, the aluminum alloy powder can be melted and solidified layer by layer to form the interface part.

[0038] (c) Preparation before printing: After cleaning the forming chamber, import the processing data file, fill the powder cylinder with aluminum alloy powder and compact it with the powder spreading arm, then spread titanium alloy powder on top. Inert gas is introduced to control the oxygen content in the forming chamber to less than 50 ppm.

[0039] (d) Forming process: 4.1. Place aluminum alloy powder and titanium alloy powder into the powder supply cylinder in sequence, and import the four processing data files obtained into the computer system of the laser powder bed fusion equipment; 4.2. Loading a first processing data file to melt and solidify the titanium alloy powder layer by layer on the substrate to form a titanium alloy part; 4.3. After the titanium alloy printing is completed, use a scraper to scrape off the residual titanium alloy powder on the upper layer of the powder cylinder; since the powder cools during the printing process, the powder is preheated after forming; 4.4. Load the second and third processing data files; 4.5. After the powder supply cylinder is moved up by one forming layer thickness, the first forming sub-area of ​​the current forming layer is first processed and formed using the second processing data file, and then the second forming sub-area of ​​the current forming layer is processed and formed using the third processing data file, to achieve staggered connection of the interface molten pool; Repeat step 4.5 until the layer-by-layer melting and solidification of the set interface is completed, and then proceed to step 4.6; 4.6. Load the fourth processing data file and melt and solidify layer by layer to form the aluminum alloy part.

[0040] After completing the above process, a heterogeneous material having a transition interface and a heterogeneous molten pool interlocking and bonding can be formed. Example 1

[0041] In this embodiment, the inert gas used in step (c) is argon, and the multi-material heterogeneous structure includes different material interface structure samples of heterogeneous molten pools, such as Figure 1 As shown, a titanium alloy-aluminum alloy heterogeneous material component is specifically printed and formed by the following steps: (1) Use 3D modeling software to build a three-dimensional solid geometric model of the target part and export it to an STL file. Then, use 3D slicing software to slice the STL file and set the laser process parameters as follows: (a) For the titanium alloy part, the laser power is 175 W, the laser scanning speed is 950 mm / s, the scanning interval is 50 μm, the powder thickness is 30 μm, and the partitioned island strategy is adopted, with the island size of 5 mm × 5 mm; (b) Aluminum alloy part, laser power 200 W, laser scanning speed 1100 mm / s, scanning pitch 60 μm, powder thickness 30 μm, interlayer rotation 37°, partitioned island strategy, island size 5 mm × 5 mm.

[0042] (c) Heterostructure transition aluminum alloy part: the laser power in the high energy density area is 200 W, the laser scanning speed is 1100 mm / s, the scanning spacing is 60 μm, and the powder thickness is 30 μm; the laser in the low energy density area increases the scanning speed to 2700 mm / s, the scanning spacing is 60 μm, and patternless forming is performed according to the divided sub-areas. The sub-area size is 0.5 mm × 0.5 mm, and the number of formed layers is 5.

[0043] (2) The dried titanium alloy powder and aluminum alloy powder were introduced into the powder cavity, and the slice data file was imported into the computer system of the laser powder bed fusion forming equipment. Then, high-purity Ar gas was introduced into the laser forming chamber as a protective atmosphere to keep the oxygen content below 50 ppm for printing.

[0044] (3) After the forming is completed and cooled, the parts are separated from the substrate using the wire EDM process and ultrasonically cleaned in acetone to remove surface stains.

[0045] (4) The titanium alloy-aluminum alloy heterogeneous material parts were ground and polished according to the standard metallographic preparation method, and the heterogeneous material interface was observed under an optical microscope. Figure 3 shown.

[0046] From the optical microscopy image of Example 1, it can be seen that the titanium alloy-aluminum alloy heterogeneous material interface has good metallurgical bonding, a small amount of brittle intermetallic compounds, and no defects such as cracks and pores. The use of an appropriate heterostructure transition layer can effectively relieve interfacial stress and avoid crack generation and expansion, thereby achieving the purpose of improving the comprehensive mechanical properties. Example 2

[0047] The basic steps of Example 2 are the same as those of Example 1. The only difference is that when forming the aluminum alloy heterogeneous transition layer, the laser power in the high energy density area is 200 W and the scanning speed is 1000 mm / s. The titanium alloy-aluminum alloy heterogeneous material parts are ground and polished according to the standard metallographic preparation method. The heterogeneous material interface is observed under an optical microscope. Figure 4 shown.

[0048] From the optical microscope image of Example 2, it can be seen that due to the increase in laser energy density in the high-energy area of ​​the transition layer, the thickness of the intermetallic compound in the high-energy density area is increased to a certain extent, forming a certain dislocation with the right area of ​​the optical microscope. The use of an appropriate heterostructure transition layer can effectively relieve interface stress and avoid crack generation and expansion. Example 3

[0049] The basic steps of Example 3 are the same as those of Example 1. The only difference is that when forming the aluminum alloy heterogeneous transition layer, the laser power in the high energy density area is 180 W and the scanning speed is 1200 mm / s. The titanium alloy-aluminum alloy heterogeneous material parts are ground and polished according to the standard metallographic preparation method. The heterogeneous material interface is observed under an optical microscope. Figure 5 shown.

[0050] From the optical microscope image of Example 3, it can be seen that due to the reduction of laser energy density in the high-energy region of the transition layer, the molten pool disturbance in the high-energy density region is greatly reduced, which reduces the formation of intermetallic compounds, and on this basis, heterogeneous molten pools are spatially alternatingly distributed, thereby effectively alleviating interlayer thermal stress. Example 4

[0051] The basic steps of Example 4 are the same as those of Example 1. The only difference is that when forming the aluminum alloy heterogeneous transition layer, the laser power in the low energy density zone is 180 W and the scanning speed is 2700 mm / s. The titanium alloy-aluminum alloy heterogeneous material parts are ground and polished according to the standard metallographic preparation method. The heterogeneous material interface is observed under an optical microscope. Figure 6 shown.

[0052] From the optical microscope image of Example 4, it can be seen that due to the reduction of laser energy density in the low energy density area, a small amount of unmelted matter and voids appear in the low energy deposition area, but the metallurgical bonding at the interface of the heterogeneous materials is good, which shows that the modified parameters can effectively alleviate the interface stress. Example 5

[0053] The basic steps of implementation 5 are the same as those of embodiment 1, with the only difference being that the scanning speed in the high energy density region is increased to 1500 mm / s when forming the aluminum alloy heterogeneous transition layer. The titanium alloy-aluminum alloy heterogeneous material parts are ground and polished according to standard metallographic preparation methods, and the heterogeneous material interface is observed under an optical microscope. Figure 7 shown.

[0054] By observing the optical microscope image of Example 5, it can be seen that when the scanning speed increases, as the misalignment between high and low energy densities is insufficient, the mutual interlocking effect of the molten pools is reduced, and cracks occur under the influence of thermal stress and expand along the boundary to form cracks. Example 6

[0055] The basic steps of Example 6 are the same as those of Example 1, with the only difference being that the scanning speed in the high energy density region is reduced to 700 mm / s when forming the aluminum alloy heterogeneous transition layer. The titanium alloy-aluminum alloy heterogeneous material parts are ground and polished according to standard metallographic preparation methods, and the heterogeneous material interface is observed under an optical microscope. Figure 6 shown.

[0056] By comparing the optical microscopy images of Example 6 and Example 1, it can be found that after reducing the scanning speed in the high energy density area, due to the high energy input in the high energy density area, the high energy thermal stress accumulation in the intermetallic compound reaction layer at the interface and the stress concentration produce a cracking tendency, forming a through crack parallel to the interface. Example 7

[0057] The basic steps of Example 7 are the same as those of Example 1, with the only difference being that when forming the aluminum alloy heterogeneous transition layer, the thickness of the transition layer is changed from 5 layers to 15 layers. The titanium alloy-aluminum alloy heterogeneous material parts are ground and polished according to the standard metallographic preparation method, and the heterogeneous material interface is observed under an optical microscope. Figure 9 As shown. (Unmelted) From the optical microscopy image of Example 7, it can be seen that when the number of interlayer transition layers is too many, although good interface bonding can still be obtained at the interface, due to the large difference between the high energy density and low energy density process ranges, the process in the low energy density area is not compatible with the aluminum alloy, resulting in more unfused defects.

[0058] Comparative Example 1 Comparative Example 1 The basic steps are the same as those of Example 1, except that the heterogeneous molten pool intercalation process is not used. After forming the titanium alloy part, the aluminum alloy part is formed using a laser power of 200 W, a laser scanning speed of 2700 mm / s, and a scanning interval of 60 μm. The titanium alloy-aluminum alloy heterogeneous material parts are ground and polished according to the standard metallographic preparation method, and the heterogeneous material interface is observed under an optical microscope. Figure 10 shown.

[0059] By comparing the micrographs of the samples obtained in Example 1 and Comparative Example 1, it can be found that when the aluminum alloy is directly formed on the titanium alloy without adopting the method of dissimilar molten pool intercalation process, the molten pool depth is greatly reduced due to the high scanning speed and the energy is too low, a good metallurgical bond cannot be formed between the two elements, and a large amount of unmelted material appears at the junction. The interfacial metal compound reaction layer and the stress concentration produce a cracking tendency, and a through crack is formed in the direction parallel to the interface.

[0060] The present invention provides an additive manufacturing method for enhancing the interface bonding of multiple materials using transitional heterostructures. The foregoing description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also within the scope of protection of the present invention. Any components not specified in this embodiment may be implemented using existing technologies.

Claims

1. An additive manufacturing method for enhancing multi-material interface bonding through a transitional heterostructure, wherein a target part is formed using a laser additive manufacturing process, wherein the target part is a multi-material heterostructure; the multi-material heterostructure comprises first and second forming portions and an interface portion between the first and second forming portions; the first and second forming portions are formed using different forming material systems; and the method is characterized in that: Planning the interface portion into two forming sub-regions, each including a plurality of forming grid points, corresponding to the first and second forming sub-regions; The forming grid points included in the first forming sub-region and the forming grid points included in the second forming sub-region are staggeredly distributed to form a checkerboard pattern; When laser additive manufacturing each forming layer of the interface part, the first forming sub-region is first laser melt-formed, and then the second forming sub-region is laser melt-formed. At the same time, the laser energy density used for laser melting to form the first forming sub-region is higher than the laser energy density used for laser melting to form the second forming sub-region.

2. The additive manufacturing method for enhancing multi-material interface bonding through transitional heterostructure according to claim 1, characterized in that: The multi-material heterogeneous structure is a titanium alloy-aluminum alloy heterogeneous material component; the titanium alloy-aluminum alloy heterogeneous material component is specifically printed and formed through the following steps: (1) The titanium alloy powder and the aluminum alloy powder are placed in a vacuum drying oven for drying to remove moisture and improve powder fluidity; (2) using modeling software to create a three-dimensional solid STL model of the target part, and then using slicing software to slice the STL model and plan the laser scanning path to obtain four processing data files, corresponding to the first to fourth processing data files; In the target part, the first formed part is a titanium alloy part, and the second formed part is an aluminum alloy part; The first processing data file is used for processing and forming the titanium alloy part; The second processing data file is used for processing the first forming sub-region of the interface portion; the third processing data file is used for processing the second forming sub-region of the interface portion; and the fourth processing data file is used for processing the aluminum alloy portion. (3) placing aluminum alloy powder and titanium alloy powder into a powder supply cylinder in sequence, and importing the four processing data files obtained in step (2) into the computer system of the laser powder bed melting equipment; (4) loading a first processing data file to melt and solidify the titanium alloy powder layer by layer on the substrate to form a titanium alloy part; (5) After the titanium alloy part is formed, the excess titanium alloy powder in the powder supply cylinder is pushed away, and the second and third processing data files are loaded; (6) After the powder supply cylinder is moved up by one forming layer thickness, the first forming sub-region of the current forming layer is first processed and formed using the second processing data file, and then the second forming sub-region of the current forming layer is processed and formed using the third processing data file to achieve the staggered connection of the interface molten pool; Repeat step (6) until the set interface portion is melted and solidified layer by layer, and then proceed to step (7); (7) The fourth processing data file is loaded, and the aluminum alloy part is formed layer by layer to obtain a titanium alloy-aluminum alloy heterogeneous material component.

3. The method for enhancing multi-material interface bonding in additive manufacturing based on transitional heterostructure according to claim 2, characterized in that: The titanium alloy powder is Ti6Al4V, in which the Al content is 5.53 wt.%, the V content is 3.57 wt.%, and the balance is Ti; the aluminum alloy powder is AlMgScZr, in which the Mg content is 4.2 wt.%, the Sc content is 0.55 wt.%, the Zr content is 0.15 wt.%, and the balance is Al.

4. The additive manufacturing method for enhancing multi-material interface bonding through transitional heterostructure according to claim 4, characterized in that: During the laser additive manufacturing process, the process parameters for the first forming part are: laser power 170-190 W, laser scanning speed 900-1000 mm / s, scanning pitch 50 μm, and powder coating thickness 30-50 μm. The process parameters for the fourth forming part are: laser power 180-200 W, laser scanning speed 1000-1200 mm / s, scanning pitch 60 μm, and powder coating thickness 30-50 μm. The laser energy density used in the first forming sub-area is 83.3-111.1 J / mm 3 The laser energy density used in the second forming sub-area is 36.4-44.5 J / mm 3 .

5. The additive manufacturing method based on transitional heterostructure enhanced multi-material interface bonding according to claim 5, characterized in that: The process parameters of the first forming sub-area are: laser power 180-200 W, laser scanning speed 1000-1200 mm / s, scanning spacing 60 μm, and powder thickness 30-50 μm; The process parameters of the second forming sub-area are: laser power 180-200 W, laser scanning speed 2500-2750 mm / s, scanning spacing 60 μm, and powder thickness 30-50 μm.

6. The additive manufacturing method for transitional heterostructure enhanced additive manufacturing of multi-material interface bonding according to claim 6, characterized in that: The number of shaping layers in the interface part is 3-7 layers.

7. The additive manufacturing method for enhancing multi-material interface bonding through transitional heterostructure according to claim 2, characterized in that: The substrate is made of titanium alloy.

8. The additive manufacturing method for enhancing multi-material interface bonding through transitional heterostructure according to claim 2, characterized in that: During the forming process, the laser forming chamber is sealed and an inert gas is introduced to control the oxygen content in the forming chamber to be less than 50 ppm.

9. A multi-material heterostructure, characterized in that: The invention is made by the method for enhancing multi-material interface bonding in additive manufacturing based on transitional heterostructure according to any one of claims 1 to 8.

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