High toughness titanium alloy-aluminum alloy dissimilar material interface disordering laser additive manufacturing apparatus and method

Abstract

The application discloses a high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing device and method thereof, which comprises the following steps: step one, overall planning of laser printing strategy of target part, step two, preparation of laser printing powder, step three, laser printing preparation, step four, printing and forming of titanium alloy part, step five, printing and forming of grain boundary disordering interface part, and step six, printing and forming of aluminum alloy part. The grain boundary disordering interface part is printed and formed by using the grain boundary disordering powder which is formed by mixing the metered aluminum alloy powder and metal B powder, therefore, the in-situ segregation phenomenon of B element at the grain boundary in the laser additive manufacturing process forms the disordering grain boundary layer on the interface ordered metal interface compound grain, increases the grain boundary disordering degree of the intermetallic compound, enhances the dislocation migration ability, reduces the critical stress of dislocation transmission, and thus improves the mechanical properties of the titanium alloy-aluminum alloy heterogeneous material.

Description

TECHNICAL FIELD

[0001] The application relates to a high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing device and a method thereof. BACKGROUND

[0002] Light alloy materials are the first choice for realizing the lightweight of modern aerospace equipment, and the development and application level not only reflects the scientific and technological progress of a country, but also embodies its economic strength. The use amount of light alloy materials in a country is often an important indicator for measuring the aerospace and military strength of the country. Titanium alloy is widely favored due to its high specific strength, good corrosion resistance and high-temperature resistance; aluminum alloy is widely used due to its low density, excellent electrical conductivity and thermal conductivity and good processing performance. Both of them have become indispensable key materials in the fields of aerospace, automobile, ship and national defense and military industry. With the increasing demand for lightweight and high performance of metal components in the field of aerospace, titanium alloy / aluminum alloy heterogeneous materials have emerged as the times require. However, there are still many technical problems in the preparation process of titanium-aluminum heterogeneous materials.

[0003] The metallurgical reaction occurring at the interface of aluminum alloy and titanium alloy generates a large amount of brittle intermetallic compounds. The long-range order of atomic arrangement of these intermetallic compounds leads to few slip systems and high energy required for dislocation movement, resulting in poor overall mechanical properties of the components. In order to fully develop the potential of titanium-aluminum heterogeneous materials, it is urgent to develop new preparation methods to overcome this technical problem.

[0004] In recent years, laser powder bed fusion (LPBF) technology has shown significant advantages in manufacturing complex parts. This process melts and solidifies the thin layer of powder deposited by a high-energy laser beam along the pre-set path point by point, line by line and layer by layer, and finally forms a three-dimensional solid part, which has the characteristics of highly free design, high material utilization rate and precise forming. At present, LPBF technology has been successfully applied in high-tech fields such as aerospace and national defense, especially in the preparation of high-performance titanium alloy, aluminum alloy and nickel-based high-temperature alloy. However, due to the inevitable generation of brittle ordered intermetallic compounds in the LPBF manufacturing process of titanium alloy-aluminum alloy heterogeneous materials, the performance is deteriorated, so it is urgent to develop suitable disordering methods for interfacial intermetallic compounds to improve the mechanical properties of titanium alloy-aluminum alloy heterogeneous materials. SUMMARY

[0005] The application aims to provide a high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing method to solve the problem of low mechanical properties caused by interfacial intermetallic compounds in the current LPBF preparation of titanium alloy-aluminum alloy heterogeneous materials.

[0006] To achieve the above technical purposes, the present application will adopt the following technical solutions:

[0007] A high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing method, comprising the following steps:

[0008] Step one, overall planning of the laser printing strategy of the target part:

[0009] The target part is divided into three parts from top to bottom, corresponding to the titanium alloy part at the lower part, the aluminum alloy part at the upper part, and the grain boundary disordering interface part in the middle;

[0010] A three-dimensional entity geometric model of the target part is established using three-dimensional modeling software, and the three-dimensional entity geometric model is sliced and layered using slicing software to obtain a series of layer-by-layer stacked slice layers, and the corresponding laser printing strategy is set for each slice layer;

[0011] Titanium alloy slice data processing files are constructed for each slice layer included in the titanium alloy part; grain boundary disordering interface slice data processing files are constructed for each slice layer included in the grain boundary disordering interface part; aluminum alloy slice data processing files are constructed for each slice layer included in the aluminum alloy part;

[0012] Step two, preparation of laser printing powder:

[0013] The laser printing powder includes three types, corresponding to titanium alloy powder, grain boundary disordering powder and aluminum alloy powder; the grain boundary disordering powder is uniformly mixed from aluminum alloy powder and metal B powder, and the mass of the metal B powder is 0.15-0.25wt.% of the aluminum alloy powder;

[0014] Step three, laser printing preparation:

[0015] The titanium alloy slice data processing files, the grain boundary disordering interface slice data processing files and the aluminum alloy slice data processing files obtained in step one are imported into the control device of the laser powder bed fusion forming equipment;

[0016] The laser printing powder prepared in step two is placed in the three-cylinder powder supply system of the laser powder bed fusion forming equipment;

[0017] Step four, printing and forming the titanium alloy part:

[0018] Load the titanium alloy slice data processing file;

[0019] Start the laser powder bed fusion forming equipment, and under the control of the titanium alloy slice data processing file, melt and solidify the titanium alloy powder layer by layer on the substrate to form the titanium alloy part;

[0020] Step five, printing forming grain boundary disorder interface part:

[0021] Switching the processing file to the grain boundary disorder interface slice data processing file;

[0022] Starting the laser powder bed fusion forming equipment, under the control of the grain boundary disorder interface slice data processing file, the grain boundary disorder powder is layer by layer melted and solidified on the titanium alloy part to form the grain boundary disorder interface part;

[0023] Step six, printing forming aluminum alloy part:

[0024] Switching the processing file to the aluminum alloy slice data processing file;

[0025] Starting the laser powder bed fusion forming equipment, under the control of the aluminum alloy slice data processing file, the aluminum alloy powder is layer by layer melted and solidified on the grain boundary disorder interface part to form the aluminum alloy part.

[0026] Preferably, the process forming parameters in the titanium alloy slice data processing file are: laser power is 170-180W, laser scanning speed is 900-1000mm / s, scanning interval is 50μm, powder laying thickness is 25-35μm.

[0027] Preferably, the process forming parameters in the grain boundary disorder interface slice data processing file are: laser power is 170-190W, laser scanning speed is 2400-2600mm / s, scanning interval is 50μm, powder laying thickness is 25-35μm, forming layer number is 6-9 layers.

[0028] Preferably, the process forming parameters in the aluminum alloy slice data processing file are: laser power is 180-200W, laser scanning speed is 800-1000mm / s, scanning interval is 50μm, powder laying thickness is 25-35μm.

[0029] Preferably, in steps four to six, the scanning strategy adopts a partition island strategy, and the size of the island is 5mm×5mm.

[0030] Preferably, in steps four to six, the oxygen content in the forming cavity is controlled to be less than 50ppm.

[0031] Preferably, in step two, the titanium alloy powder, aluminum alloy powder, and grain boundary disorder powder need to be placed in a vacuum drying oven at 80℃ for 10h to remove moisture and improve powder flowability.

[0032] Another technical purpose of the present application is to provide a high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing device, which is built based on a laser powder bed fusion forming equipment, and comprises a control device, a laser, a galvanometer, a powder supply system, and a forming cavity.

[0033] The control device is integrated with a computer, and a slicing processing file is imported into the computer;

[0034] The slicing processing file is constructed based on a laser fusion strategy of a target component, and comprises a titanium alloy slicing data processing file, a grain boundary disordering slicing data processing file, and an aluminum alloy slicing data processing file.

[0035] The target component is divided into three parts from top to bottom, which are a titanium alloy part at the lower part, an aluminum alloy part at the upper part, and a grain boundary disordering interface part at the middle part.

[0036] The titanium alloy slicing data processing file is used for layer-by-layer laser fusion forming of the titanium alloy part of the target component, and each slicing layer of the titanium alloy part is supplied with powder from the first powder supply cylinder.

[0037] The grain boundary disordering slicing data processing file is used for layer-by-layer laser fusion forming of the grain boundary disordering interface part of the target component, and each slicing layer of the grain boundary disordering interface part is supplied with powder from the second powder supply cylinder.

[0038] The aluminum alloy slicing data processing file is used for layer-by-layer laser fusion forming of the aluminum alloy part of the target component, and each slicing layer of the aluminum alloy part is supplied with powder from the third powder supply cylinder.

[0039] Preferably, the grain boundary disordering powder is uniformly mixed from aluminum alloy powder and metal B powder, and the mass of the metal B powder is 0.15-0.25wt.% of the aluminum alloy powder.

[0040] Based on the above technical purposes, compared with the prior art, the present application has the following advantages:

[0041] 1. The present application uses a grain boundary disordering method to disorder the heterogeneous interface of titanium alloy-aluminum alloy heterogeneous materials, solves the problems of poor interface metallurgical bonding, residual stress concentration leading to cracks, and low mechanical properties of titanium alloy-aluminum alloy heterogeneous materials caused by brittle ordered intermetallic compounds in the process of laser additive manufacturing, and realizes the laser additive manufacturing of titanium alloy-aluminum alloy heterogeneous materials with high density and high mechanical properties.

[0042] 2. The application is distinguished from traditional welding, riveting and other heterogeneous material connection processes, and innovatively uses laser powder bed fusion technology to realize the preparation of integrated heterogeneous material components. This method fully utilizes the advantages of laser additive manufacturing in design freedom and structure optimization, significantly reduces the number of components, simplifies the manufacturing process, shortens the production cycle, and effectively reduces the demand for complex structures such as welding and riveting joints, greatly improving the lightweight and integration characteristics of the formed parts. The process is suitable for aerospace, automotive, marine, medical and other fields with high requirements for complex structures, fine sizes and small batch production, further expanding the application range of titanium alloy-aluminum alloy heterogeneous materials.

[0043] 3. The method of adding grain boundary disordering elements in the Ti-Al system to regulate ordered intermetallic compounds can be further applied to other heterogeneous material systems prone to brittle ordered intermetallic compounds in laser additive manufacturing, widening the range of laser additive manufacturing of heterogeneous materials and improving the mechanical properties of laser additive manufacturing of heterogeneous materials, which is conducive to the development of laser additive manufacturing technology. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The structure of the high-strength and high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing device used in the application is shown in the figure.

[0045] Figure 2 The interface transmission electron microscope image and mechanical properties of the titanium alloy-aluminum alloy heterogeneous material block sample prepared in Example 1 are shown in the figure, wherein (a) is the interface transmission electron microscope image of the block sample, and (b) is the mechanical property curve of the block sample.

[0046] Figure 3 The interface transmission electron microscope image and mechanical properties of the titanium alloy-aluminum alloy heterogeneous material block sample prepared in Comparative Example 1 are shown in the figure, wherein (a) is the interface transmission electron microscope image of the block sample, and (b) is the mechanical property curve of the block sample.

[0047] Figure 4 The interface transmission electron microscope image and mechanical properties of the titanium alloy-aluminum alloy heterogeneous material block sample prepared in Example 2 are shown in the figure, wherein (a) is the interface transmission electron microscope image of the block sample, and (b) is the mechanical property curve of the block sample.

[0048] Figure 5 The interface optical microscope image and mechanical properties of the titanium alloy-aluminum alloy heterogeneous material block sample prepared in Example 3 are shown in the figure, wherein (a) is the interface transmission electron microscope image of the block sample, and (b) is the mechanical property curve of the block sample.

[0049] Figure 6Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 4, wherein (a) is the interface transmission electron microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0050] Figure 7 Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 5, wherein (a) is the interface optical microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0051] Figure 8 Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 6, wherein (a) is the interface optical microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0052] Figure 9 Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 7, wherein (a) is the interface optical microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0053] Figure 10 Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 8, wherein (a) is the interface optical microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0054] Figure 11 Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 9, wherein (a) is the interface optical microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0055] Figure 12 Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 10, wherein (a) is the interface optical microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0056] Figure 13 Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 11, wherein (a) is the interface optical microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0057] Figure 14 Interface optical microscope images and mechanical properties of titanium alloy-aluminum alloy heterogeneous bulk sample prepared in Example 12, wherein (a) is the interface optical microscope image of the bulk sample, (b) is the mechanical property curve of the bulk sample.

[0058] Figure 15 Interface optical microscope images and mechanical properties of the titanium alloy-aluminum alloy heterogeneous material bulk sample prepared in Example 13, wherein (a) is the interface optical microscope image of the bulk sample, and (b) is the mechanical property curve of the bulk sample.

[0059] In the figure: 11, first powder supply cylinder; 12, second powder supply cylinder; 13, third powder supply cylinder; 2, galvanometer; 3, laser; 4, control device; 5, forming cavity; 51, aluminum alloy layer; 52, grain boundary disorder interface layer; 53, titanium alloy layer; 54, titanium alloy substrate; 6, powder recycling cavity. DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. Unless otherwise specified, the relative arrangement, expression and numerical value of the components and steps set forth in these embodiments do not limit the scope of the present application. The technology, method and equipment known to those of ordinary skill in the related art can not be discussed in detail, but should be considered as part of the specification when appropriate. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments can have different values.

[0061] The high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing method described in the present application is based on Figure 1 The high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing method described in the present application is based on

[0062] Specifically, the laser powder bed fusion forming device comprises a control device, a laser, a galvanometer, a powder supply system and a forming cavity. The powder supply system adopts a three-cylinder powder supply system. The three-cylinder powder supply system comprises three powder supply cylinders, which are a first to third powder supply cylinder. The first powder supply cylinder contains titanium alloy powder, the second powder supply cylinder contains grain boundary disordering powder, and the third powder supply cylinder contains aluminum alloy powder. The control device is integrated with a computer, and a slicing processing file can be imported. The powder contained in each powder supply cylinder of the three-cylinder powder supply system can be laid on the titanium alloy substrate by a powder laying arm to form a powder layer required for the current slice layer, and then the laser beam emitted by the laser is controlled to be projected onto the powder layer of the current slice layer by the galvanometer for laser fusion according to the control strategy of the corresponding slicing processing file, so as to obtain the current slice layer. Specifically, the slicing processing file is constructed based on the laser fusion strategy of the target component, and comprises a titanium alloy slicing data processing file, a grain boundary disordering slicing data processing file and an aluminum alloy slicing data processing file. The target component is divided into three parts from top to bottom, which are a titanium alloy part at the lower part, an aluminum alloy part at the upper part and a grain boundary disordering interface part at the middle part. The titanium alloy slicing data processing file is used for laser fusion forming of the titanium alloy part of the target component layer by layer. Each slice layer of the titanium alloy part is supplied by the first powder supply cylinder. The grain boundary disordering slicing data processing file is used for laser fusion forming of the grain boundary disordering interface part of the target component layer by layer. Each slice layer of the grain boundary disordering interface part is supplied by the second powder supply cylinder. The aluminum alloy slicing data processing file is used for laser fusion forming of the aluminum alloy part of the target component layer by layer. Each slice layer of the aluminum alloy part is supplied by the third powder supply cylinder.

[0063] In the present application, the titanium alloy powder used is Ti6Al4V, wherein the content of Al is 5.8 wt.%, the content of V is 4.1 wt.%, and the balance is Ti; the aluminum alloy powder used is AlMgScZr, wherein the content of Mg is 4.2 wt.%, the content of Sc is 0.4 wt.%, the content of Zr is 0.2 wt.%, and the balance is Al. The grain boundary disordering powder used is AlMgScZr powder prepared by ball milling and containing B element.

[0064] The laser powder bed fusion forming process is as follows:

[0065] (a) importing the titanium alloy, grain boundary disordering interface and aluminum alloy three kinds of slicing data processing files into the computer and loading the titanium alloy slicing data processing file;

[0066] (b) the doctor blade (or powder laying arm) lays the metal powder corresponding to the current printing layer on the titanium alloy substrate to form a powder layer;

[0067] (c) the control device controls the laser to generate laser light to selectively scan a partial area of the powder layer, so that the powder is melted and solidified to form a two-dimensional planar entity;

[0068] (d) the forming cavity driving system controls the overall downward movement of the forming cavity by one powder laying thickness, and repeats steps (b) and (c) until the titanium alloy part is completed;

[0069] (e) loading the grain boundary disordering slice data processing file, repeating steps (b) and (c) until the grain boundary disordering interface part is completed;

[0070] (f) loading the aluminum alloy slice data processing file, repeating steps (b) and (c) until the aluminum alloy part is completed;

[0071] (g) using the wire electrical discharge machining process to cut the part from the substrate, and placing it in acetone for ultrasonic cleaning to remove surface stains, thereby obtaining a titanium alloy-aluminum alloy heterogeneous material part.

[0072] The preparation principle of the application is: through in-situ grain boundary segregation of B elements in the molten pool, intermetallic compounds are subjected to grain boundary disordering treatment. On the one hand, the segregation of B elements can form an unordered layer on the grain boundary of the intermetallic compound, and compared with the long-range ordered intermetallic compound, the unordered layer can increase the antiphase domain boundary energy, enhance the dislocation migration ability, and reduce the critical stress of dislocation transmission to below the level required for fracture, thereby improving the plasticity. On the other hand, the unordered B element grain boundary as a buffer zone between the ordered intermetallic compound grains can prevent premature fracture of the ordered intermetallic compound grains, thereby improving the grain boundary damage resistance.

[0073] The high-strength and high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing method described in the application will be described in detail below in combination with several embodiments.

[0074] Embodiment 1

[0075] The high-strength and high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing method described in the application comprises the following steps:

[0076] (1) Preparation of grain boundary disordering powder:

[0077] An appropriate amount of aluminum alloy powder is weighed, and 0.2wt.% of metal B powder is weighed according to the mass of the aluminum alloy powder, and is placed in an argon-protected planetary ball mill to start ball milling to prepare grain boundary disordering powder. The ball milling speed is 250 rpm, and the ball milling time is 4 h. After ball milling, it is stored for use.

[0078] (2) Dry the printing powder:

[0079] Take the appropriate quality of titanium alloy powder, grain boundary disorder powder, aluminum alloy powder, placed in a vacuum drying oven 80 ℃ drying 10 h to remove moisture and improve the flowability of the powder.

[0080] (3) Build slice processing file:

[0081] Using three-dimensional modeling software to establish a three-dimensional entity geometric model of the target part and using slicing software to slice the established three-dimensional entity geometric model to obtain a series of layer-by-layer stacked slice layers, and set the corresponding laser printing strategy for each slice layer.

[0082] The target part is composed of three parts from top to bottom, which are titanium alloy part at the lower part, aluminum alloy part at the upper part, and grain boundary disorder interface part at the middle part.

[0083] For each slice layer included in the titanium alloy part, laser melting titanium alloy powder is used for forming, for each slice layer of the grain boundary disorder interface part, laser melting grain boundary disorder powder is used for forming, and for each slice layer included in the aluminum alloy part, laser melting grain boundary aluminum alloy powder is used for forming.

[0084] The laser printing strategy of the target part is as follows:

[0085] (a) Titanium alloy part, laser power 170 W, laser scanning speed 900 mm / s, scanning interval 50 μm, powder laying thickness 30 μm, layer rotation 67°, using zoned island strategy, island size 5 mm x 5 mm;

[0086] (b) Grain boundary disorder interface part, laser power 180 W, laser scanning speed 2500 mm / s, scanning interval 50 μm, powder laying thickness 30 μm, layer rotation 67°, using zoned island strategy, island size 5 mm x 5 mm, printing 8 layers;

[0087] (c) Aluminum alloy part, laser power 200 W, laser scanning speed 1000 mm / s, scanning interval 50 μm, powder laying thickness 30 μm, layer rotation 67°, using zoned island strategy, island size 5 mm x 5 mm.

[0088] (4) Import the slice data processing file in step (3) into the computer system of the laser powder bed fusion forming equipment, and then load the titanium alloy powder, grain boundary disorder powder and aluminum alloy powder dried in step (2) into the three-cylinder powder supply system for forming. Then, high-purity Ar gas is introduced into the laser forming chamber as a protective atmosphere, and the oxygen content is kept below 50 ppm.

[0089] (5) Load the titanium alloy slice data processing file, turn on the laser, and melt / solidify according to the powder area selected in the path of the slice data processing file. After the titanium alloy part is printed, pause.

[0090] (6) Switch the processing data processing file to the grain boundary disorder interface slice data processing file, turn on the laser, and complete the printing of the grain boundary disorder interface part. After the printing is completed, pause.

[0091] (7) Switch the processing data processing file to the aluminum alloy slice data processing file, turn on the laser, and complete the printing of the aluminum alloy part.

[0092] (8) After the forming is completed and cooled, separate the component from the substrate using the wire electrical discharge machining process, place it in acetone for ultrasonic cleaning to remove surface stains, and grind and polish according to the metallographic sample preparation standard procedure to obtain a titanium alloy-aluminum alloy heterogeneous material component with high density and high mechanical properties.

[0093] (9) Use a focused ion beam to slice the intermetallic compound interface of the titanium alloy-aluminum alloy heterogeneous material component, and observe the heterogeneous material interface under a transmission electron microscope as shown in FIG. 6. Figure 2

[0094] The transmission electron microscope photo of the heterogeneous material interface of Example 1 shows that the titanium alloy-aluminum alloy heterogeneous material interface is well metallurgically bonded, and there is an about 20 nm thick disordered grain boundary layer formed by element B between the brittle intermetallic compound and the matrix. This disordered grain boundary layer can increase the domain wall energy, enhance the dislocation migration ability, and reduce the critical stress of dislocation transmission to below the level required for fracture, thereby improving the mechanical properties. In this case, the tensile strength of the sample is 349 MPa.

[0095] Comparative Example 1

[0096] Comparative Example 1 and Example 1 have basically the same scheme, except that the grain boundary disorder method is not used, i.e., the aluminum alloy part is directly formed after the titanium alloy part is formed. A focused ion beam is used to slice the intermetallic compound interface of the titanium alloy-aluminum alloy heterogeneous material component, and the heterogeneous material interface is observed under a transmission electron microscope as shown in FIG. 6. Figure 3

[0097] Comparing the transmission electron microscope photos and mechanical property data of the samples obtained in Comparative Example 1 and Comparative Example 1, it can be found that without using the grain boundary disorder method, there is no disordered interface between the brittle intermetallic compound and the matrix in the sample, and the highly ordered brittle intermetallic compound makes the mechanical properties of the sample poor, with a tensile strength of only 187 MPa.

[0098] Example 2

[0099] ​​Example 2 is substantially the same as Example 1, the only difference is that the addition amount of B element is increased from 0.2wt.% to 0.3wt.%. The intermetallic compound interface of the titanium alloy-aluminum alloy heterogeneous material component is sliced by focused ion beam, and the heterogeneous material interface is observed under transmission electron microscope as shown in Figure 4 .

[0100] Comparing the transmission electron microscope and mechanical property data of the samples obtained in Example 2 and Example 1, it can be found that increasing the addition amount of B element can increase the thickness of the grain boundary disordered interface layer. However, due to the increase of the thickness of the grain boundary disordered layer with the increase of the addition amount of B element, the dislocation movement and cross slip after the dislocation is activated are not conducive to the improvement of the mechanical properties, and the tensile strength is reduced to 302MPa. However, compared with the laser melting formed component without the grain boundary disordered interface layer, the mechanical properties are still improved.

[0101] Example 3

[0102] Example 3 is substantially the same as Example 1, the only difference is that the addition amount of B element is increased from 0.2wt.% to 0.4wt.%. The intermetallic compound interface of the titanium alloy-aluminum alloy heterogeneous material component is sliced by focused ion beam, and the heterogeneous material interface is observed under transmission electron microscope as shown in Figure 5 .

[0103] Comparing the transmission electron microscope and mechanical property data of the samples obtained in Example 3 and Example 1, it can be found that increasing the addition amount of B element can increase the thickness of the grain boundary disordered interface layer. However, due to the excessive thickness of the grain boundary disordered layer (about 75nm), the dislocation movement and cross slip after the dislocation is activated are not conducive to the improvement of the mechanical properties, and the tensile strength is reduced to 220MPa. However, compared with the laser melting formed component without the grain boundary disordered interface layer, the mechanical properties are still improved.

[0104] Example 4

[0105] Example 4 is substantially the same as Example 1, the only difference is that the addition amount of B element is decreased from 0.2wt.% to 0.1wt.%. The intermetallic compound interface of the titanium alloy-aluminum alloy heterogeneous material component is sliced by focused ion beam, and the heterogeneous material interface is observed under transmission electron microscope as shown in Figure 6 .

[0106] Comparative Example 4 and Example 1, it can be found that reducing the addition amount of element B can reduce the thickness of the grain boundary disordered interface layer. However, due to the too thin thickness of the grain boundary disordered layer, the mechanical property improvement effect is small, and the tensile strength is reduced to 223 MPa. However, compared with the laser melting formed component without the grain boundary disordered interface layer, the mechanical property is still improved.

[0107] Example 5

[0108] Example 5 is basically the same as the scheme of Example 1, and the only difference is that the laser power of the grain boundary disordered interface part is increased to 200 W. The disordered interface is observed by an optical microscope, as shown in Figure 7 .

[0109] Comparing the mechanical property data of the samples obtained in Comparative Example 5 and Example 1, it can be found that the addition of metal B powder significantly changes the laser-powder interaction behavior. The heat accumulation degree of the grain boundary disordered interface part under a larger laser power is increased, and a microcrack along the parallel interface direction is formed. The tensile strength is reduced to 78 MPa.

[0110] Example 6

[0111] Example 6 is basically the same as the scheme of Example 1, and the only difference is that the laser power of the grain boundary disordered interface part is further increased to 220 W. The disordered interface is observed by an optical microscope, as shown in Figure 8 .

[0112] Comparing the mechanical property data of the samples obtained in Comparative Example 6 and Example 1, it can be found that the addition of metal B powder significantly changes the laser-powder interaction behavior. The heat accumulation degree of the grain boundary disordered interface part under a larger laser power is further increased, and a microcrack along the parallel interface direction is formed. The tensile strength is only 18 MPa.

[0113] Example 7

[0114] Example 7 is basically the same as the scheme of Example 1, and the only difference is that the laser power of the grain boundary disordered interface part is reduced to 160 W. The disordered interface is observed by an optical microscope, as shown in Figure 9 .

[0115] Comparing the mechanical property data of the samples obtained in Comparative Example 7 and Example 1, it can be found that reducing the laser energy input can alleviate the cracking problem caused by the different thermal expansion coefficients. However, due to the insufficient energy input, a small amount of unmelted defects appear in the disordered interface layer, and the tensile strength is only 132 MPa.

[0116] Example 8

[0117] Example 8 is basically the same as Example 1, the only difference is that the laser power of the grain boundary disorder interface part is further reduced to 140W, and the grain boundary disorder interface is observed by optical microscope, as shown in Figure 10 .

[0118] Comparing the mechanical property data of the samples obtained in Example 8 and Example 1, it can be found that further reducing the laser energy input causes a large number of unmelted defects in the grain boundary disorder interface layer, which reduces the mechanical property, and the tensile strength is only 56MPa.

[0119] Example 9

[0120] Example 9 is basically the same as Example 1, the only difference is that the laser power of the grain boundary disorder interface part is 170W, and the grain boundary disorder interface is observed by optical microscope, as shown in Figure 11 .

[0121] Comparing the mechanical property data of the samples obtained in Example 9 and Example 1, it can be found that under this process parameter, the multi-material interface is well metallurgically combined, the residual stress is moderate, and the tensile strength reaches 325MPa.

[0122] Example 10

[0123] Example 10 is basically the same as Example 1, the only difference is that the laser power of the grain boundary disorder interface part is 190W, and the grain boundary disorder interface is observed by optical microscope, as shown in Figure 12 .

[0124] Comparing the mechanical property data of the samples obtained in Example 10 and Example 1, it can be found that the multi-material interface is well metallurgically combined, the residual stress is moderate, and the tensile strength reaches 342MPa.

[0125] Example 11

[0126] Example 11 is basically the same as Example 1, the only difference is that the number of layers of the grain boundary disorder interface part is reduced to 5, and the grain boundary disorder interface is observed by optical microscope, as shown in Figure 13 .

[0127] Comparing the mechanical property data of the samples obtained in Example 11 and Example 1, it can be found that after increasing the number of layers of the grain boundary disorder interface part, the thinner grain boundary disorder interface is not enough to offset the thermal stress in the laser additive manufacturing process to relieve residual stress and improve dislocation opening, and a crack is generated in the multi-material sample along the direction parallel to the interface, and the tensile strength is only 110MPa.

[0128] Example 12

[0129] Example 12 is basically the same as the scheme of Example 1, the only difference is that the number of layers of the grain boundary disorder interface part is reduced to 3 layers, and the grain boundary disorder interface is observed by an optical microscope, as shown in Figure 14 .

[0130] Comparing the mechanical property data of the samples obtained in Comparative Example 12 and Example 1, it can be found that, similar to Example 11, further reducing the number of layers of the grain boundary disorder interface part further reduces the effect, and the crack width of the multi-material sample in the direction parallel to the interface is larger, and the tensile strength is only 14 MPa.

[0131] Example 13

[0132] Example 13 is basically the same as the scheme of Example 1, the only difference is that the number of layers of the grain boundary disorder interface part is increased to 10 layers, and the grain boundary disorder interface is observed by an optical microscope, as shown in Figure 15 .

[0133] Comparing the mechanical property data of the samples obtained in Comparative Example 13 and Example 1, it can be found that, after increasing the number of layers of the grain boundary disorder interface part, although the bottom of the part can still achieve metallurgical bonding of the multi-material, the top of the part is far away from the titanium alloy part, the heat conduction speed is accelerated, the part is less heated, the energy is insufficient, and more unmelted defects are generated, and the tensile strength is only 56 MPa.

[0134] By comparing the tensile strength of the titanium alloy-aluminum alloy heterogeneous material components obtained in Examples 1-13 and Comparative Example 1, it can be known that, in order to obtain a laser printing formed component with excellent mechanical properties, we not only need to consider adding a grain boundary disorder interface layer between the titanium alloy slice layer and the aluminum alloy slice layer, but also need to specially consider the process forming parameters (especially the setting of laser power) of the molten grain boundary disorder interface, thereby solving the problems of poor interface metallurgical bonding of titanium alloy-aluminum alloy heterogeneous materials caused by brittle ordered intermetallic compounds, crack caused by residual stress concentration, and low mechanical properties in the process of laser additive manufacturing, and realizing the laser additive manufacturing of titanium alloy-aluminum alloy heterogeneous materials with high density and high mechanical properties.

[0135] The present application provides a high strength and toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing method, and there are many methods and ways to realize the technical scheme, the above description is only the preferred embodiment of the present application, it should be pointed out that for ordinary skilled in the art, without departing from the principle of the present application, can make a number of improvements and decorations, these improvements and decorations should be regarded as the protection scope of the present application. The components not explicitly described in the embodiment can be realized by the existing technology.

Claims

1. A method for disordered laser additive manufacturing of high-strength and high-toughness titanium alloy-aluminum alloy heteromaterial interfaces, characterized in that, Includes the following steps: Step 1: Overall planning of the laser printing strategy for the target part: The target part is divided into three parts from top to bottom: the titanium alloy part at the bottom, the aluminum alloy part at the top, and the grain boundary disordered interface part in the middle. A 3D solid geometric model of the target part is created using 3D modeling software, and a slicing software is used to slice and layer the created 3D solid geometric model to obtain a series of stacked slice layers. A corresponding laser printing strategy is set for each slice layer. For each slice layer included in the titanium alloy section, a titanium alloy slice data processing file is constructed; for each slice layer included in the grain boundary disordered interface section, a grain boundary disordered interface slice data processing file is constructed; for each slice layer included in the aluminum alloy section, an aluminum alloy slice data processing file is constructed. Step 2: Prepare laser printing powder: Laser printing powders fall into three categories: titanium alloy powder, grain boundary disordering powder, and aluminum alloy powder. The grain boundary disordering powder is a uniform mixture of aluminum alloy powder and boron (B) element, with the B element comprising 0.15-0.25 wt.% of the aluminum alloy powder. Step 3: Laser Printing Preparation Import the titanium alloy slice data processing file, the grain boundary disordered interface slice data processing file, and the aluminum alloy slice data processing file obtained in step one into the control device of the laser powder bed melting and forming equipment. The laser printing powder prepared in step two is placed into the three-cylinder powder supply system of the laser powder bed melting and forming equipment; Step 4: Printing and forming the titanium alloy part: Load the titanium alloy slice data processing file; The laser powder bed melting and forming equipment is started, and under the control of the titanium alloy slice data processing file, titanium alloy powder is melted and solidified layer by layer on the substrate to form a titanium alloy part. Step 5: Printing the disordered grain boundary interface: Switch the processing file to a grain boundary disordered interface slice data processing file; The laser powder bed melting and forming equipment is started. Under the control of the grain boundary disorder interface slicing data processing file, the grain boundary disorder powder is melted and solidified layer by layer on the titanium alloy part to form the grain boundary disorder interface part. Step Six: Print the aluminum alloy part: Switch the processing file to an aluminum alloy slice data processing file; The laser powder bed melting and forming equipment is started. Under the control of the aluminum alloy slice data processing file, the aluminum alloy powder is melted and solidified layer by layer on the disordered grain boundary interface to form the aluminum alloy part.

2. The method for disordered laser additive manufacturing of high-strength and high-toughness titanium alloy-aluminum alloy heteromaterial interfaces according to claim 1, characterized in that, The process forming parameters in the titanium alloy slice data processing file are: laser power of 170-180 W, laser scanning speed of 900-1000 mm / s, scanning interval of 50 μm, and powder thickness of 25-35 μm.

3. The method for disordered laser additive manufacturing of high-strength and high-toughness titanium alloy-aluminum alloy heteromaterial interfaces according to claim 1, characterized in that, The process forming parameters in the grain boundary disordered interface slicing data processing file are as follows: laser power is 170-190 W, laser scanning speed is 2400-2600 mm / s, scanning spacing is 50 μm, powder thickness is 25-35 μm, and the number of forming layers is 6-9.

4. The method for disordered laser additive manufacturing of high-strength and high-toughness titanium alloy-aluminum alloy heteromaterial interfaces according to claim 1, characterized in that, The process forming parameters in the aluminum alloy slice data processing file are: laser power of 180-200 W, laser scanning speed of 800-1000 mm / s, scanning interval of 50 μm, and powder thickness of 25-35 μm.

5. The method for disordered laser additive manufacturing of high-strength and high-toughness titanium alloy-aluminum alloy heteromaterial interfaces according to claim 1, characterized in that, In steps four through six, the scanning strategy adopts a partitioned island strategy, with each island measuring 5 mm × 5 mm.

6. The method for disordered laser additive manufacturing of high-strength and high-toughness titanium alloy-aluminum alloy heteromaterial interfaces according to claim 1, characterized in that, In steps four through six, the oxygen content inside the forming cavity is controlled to be below 50 ppm.

7. The method for disordered laser additive manufacturing of high-strength and high-toughness titanium alloy-aluminum alloy heteromaterial interfaces according to claim 1, characterized in that, In step two, titanium alloy powder, aluminum alloy powder, and grain boundary disordered powder need to be placed in a vacuum drying oven at 80°C for 10 hours to remove moisture and improve powder flowability.

8. A laser additive manufacturing apparatus for implementing the high-strength and high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordered laser additive manufacturing method according to claim 1, comprising a control device, a laser, a galvanometer, a powder supply system, and a forming cavity, characterized in that, The powder supply system adopts a three-cylinder powder supply system, which includes three powder supply cylinders, corresponding to the first to the third powder supply cylinders. The first powder supply cylinder contains titanium alloy powder, the second powder supply cylinder contains grain boundary disordered powder, and the third powder supply cylinder contains aluminum alloy powder. The control device integrates a computer, which imports slicing and processing files. The slicing processing files are constructed based on the laser melting strategy of the target component, including titanium alloy slice data processing files, grain boundary disordered slice data processing files, and aluminum alloy slice data processing files; The target component is divided into three parts from top to bottom: the titanium alloy part at the bottom, the aluminum alloy part at the top, and the grain boundary disordered interface part in the middle. Titanium alloy slice data processing file, used for laser melting and forming the titanium alloy part of the target component layer by layer; each slice layer included in the titanium alloy part is fed with powder through the first powder supply cylinder. The grain boundary disordered slicing data processing file is used for the grain boundary disordered interface part of the target component to be laser melted layer by layer; each slice layer of the grain boundary disordered interface part is fed with powder through the second powder supply cylinder. Aluminum alloy slice data processing file, used for layer-by-layer laser melting and forming of the aluminum alloy part of the target component; each slice layer of the aluminum alloy part is fed with powder through a third powder supply cylinder.

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