High-toughness titanium alloy-aluminum alloy heterogeneous material interface disordering laser additive manufacturing device and method thereof

Abstract

The invention discloses a high-strength and high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordered laser additive manufacturing device and method, and the method comprises the following steps: step 1, integrally planning a laser printing strategy of a target part, step 2, preparing laser printing powder, step 3, preparing laser printing, step 4, printing and forming a titanium alloy part, and step 5, manufacturing a high-strength and high-toughness titanium alloy-aluminum alloy heterogeneous material interface disordered laser additive manufacturing device. 5, printing and forming a grain boundary disordered interface part; and 6, printing and forming an aluminum alloy part. Grain boundary disordered powder formed by mixing metered aluminum alloy powder and metal B powder is adopted for printing and forming a grain boundary disordered interface part, so that a disordered grain boundary layer is formed on an interface ordered metal boundary compound grain through an in-situ segregation phenomenon at a B element grain boundary in the laser additive manufacturing process, and the laser additive manufacturing effect is improved. And the grain boundary disorder degree of intermetallic compounds is increased, so that the dislocation migration capability is enhanced, the critical stress of dislocation transfer is reduced, and the mechanical property of the titanium alloy-aluminum alloy heterogeneous material is improved.

Description

Technical Field

[0001] The invention relates to a laser additive manufacturing device and method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials. Background Art

[0002] Light alloy materials are the first choice for achieving lightweight modern aerospace equipment. The level of development and application not only reflects the country's scientific and technological progress, but also reflects its economic strength. The amount of light alloy materials used by a country is often an important indicator of its aerospace and military strength. Titanium alloys are widely favored for their high specific strength, good corrosion resistance and high temperature resistance; aluminum alloys are widely used for their low density, excellent electrical and thermal conductivity and good processing performance. Both have become indispensable key materials in the fields of aerospace, automobiles, ships, and national defense. As the aerospace field puts forward lighter and higher performance requirements for metal components, titanium alloy / aluminum alloy heterogeneous materials have come into being. However, there are still many technical difficulties in the preparation of titanium-aluminum heterogeneous materials.

[0003] The metallurgical reaction between aluminum alloy and titanium alloy at the interface of heterogeneous materials will generate a large number of brittle intermetallic compounds. The atomic arrangement of these intermetallic compounds is long-range orderly, resulting in a small number of slip systems and high energy required for dislocation activation, resulting in poor overall mechanical properties of the component. In order to fully realize the potential of titanium-aluminum heterogeneous materials, it is urgent to develop new preparation methods to overcome this technical difficulty.

[0004] In recent years, Laser Powder Bed Fusion (LPBF) technology has shown significant advantages in the manufacture of complex parts. This process uses a high-energy laser beam along a pre-set path to quickly melt and solidify the laid thin layer of powder point by point, line by line, and layer by layer, and finally forms a three-dimensional solid component with the characteristics of highly free design, high material utilization and precision 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 alloys, aluminum alloys and nickel-based high-temperature alloys. However, since the titanium alloy-aluminum alloy heterogeneous materials inevitably generate brittle ordered intermetallic compound phases due to metallurgical reactions during the LPBF manufacturing process, resulting in performance degradation, it is urgent to develop a suitable disordering method for interfacial intermetallic compounds to improve the mechanical properties of titanium alloy-aluminum alloy heterogeneous materials. Summary of the invention

[0005] The purpose of the present invention is to provide a laser additive manufacturing method for disordered interface of high-strength and toughness titanium alloy-aluminum alloy heterogeneous materials, so as to solve the problem of low mechanical properties caused by intermetallic compounds at the interface of the current LPBF preparation of titanium alloy-aluminum alloy heterogeneous materials.

[0006] In order to achieve the above technical objectives, the present invention will adopt the following technical solutions:

[0007] A laser additive manufacturing method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials, comprising the following steps:

[0008] Step 1: Overall planning of the laser printing strategy for the target parts:

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

[0010] Using 3D modeling software to build a 3D solid geometric model of the target part, and using slicing software to slice and layer the built 3D solid geometric model to obtain a series of slice layers stacked one by one, and setting a corresponding laser printing strategy for each slice layer;

[0011] Constructing titanium alloy slice data processing files for each slice layer included in the titanium alloy part; constructing grain boundary disordered interface slice data processing files for each slice layer included in the grain boundary disordered interface part; constructing aluminum alloy slice data processing files for each slice layer included in the aluminum alloy part;

[0012] Step 2: Prepare laser printing powder:

[0013] Laser printing powder includes three categories, namely titanium alloy powder, grain boundary disordered powder and aluminum alloy powder; the grain boundary disordered powder is made by uniformly mixing aluminum alloy powder and metal B powder, and the mass of metal B powder is 0.15-0.25wt.% of the aluminum alloy powder;

[0014] Step 3: Laser printing preparation:

[0015] Importing 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 1 into the control device of the laser powder bed fusion forming equipment;

[0016] Place the laser printing powder prepared in step 2 into the three-cylinder powder supply system of the laser powder bed fusion forming equipment;

[0017] Step 4: Printing the titanium alloy part:

[0018] Load titanium alloy slice data processing file;

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

[0020] Step 5: Printing the disordered interface of grain boundaries:

[0021] Switch the processing file to the grain boundary disordered interface slice data processing file;

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

[0023] Step 6: Print the aluminum alloy part:

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

[0025] The laser powder bed fusion forming equipment is started, and under the control of the aluminum alloy slicing data processing file, the aluminum alloy powder is melted and solidified layer by layer on the grain boundary disordered 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 spacing is 50μm, and powder thickness is 25-35μm.

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

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

[0029] Preferably, in step 4 to step 6, the scanning strategy adopts a partitioned island strategy, and the size of the island is 5 mm×5 mm.

[0030] Preferably, in steps 4 to 6, the oxygen content in the forming cavity is controlled to be lower than 50 ppm.

[0031] Preferably, in step 2, the titanium alloy powder, aluminum alloy powder and grain boundary disordered powder need to be placed in a vacuum drying oven at 80° C. and dried for 10 hours to remove moisture and improve powder fluidity.

[0032] Another technical purpose of the present invention is to provide a high-strength and tough titanium alloy-aluminum alloy heterogeneous material interface disordered laser additive manufacturing device, which is built based on a laser powder bed fusion forming device, including 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, including three powder supply cylinders, corresponding to the first to third powder supply cylinders, the first powder supply cylinder is filled with titanium alloy powder, the second powder supply cylinder is filled with grain boundary disordered powder, and the third powder supply cylinder is filled with aluminum alloy powder;

[0033] A computer is integrated in the control device, and the slice processing file is imported into the computer;

[0034] The slicing processing files are constructed based on the laser melting strategy of the target component, including titanium alloy slicing data processing files, grain boundary disordered slicing data processing files, and aluminum alloy slicing data processing files;

[0035] The target component is divided into three parts from top to bottom, corresponding to: a titanium alloy part at the bottom, an aluminum alloy part at the top, and a grain boundary disordered interface part in the middle;

[0036] The titanium alloy slice data processing file is used for layer-by-layer laser melting forming of the titanium alloy part of the target component; each slice layer included in the titanium alloy part is supplied with powder through the first powder supply cylinder;

[0037] The grain boundary disordered slicing data processing file is used for the grain boundary disordered interface part of the target component to be formed by laser melting layer by layer; each slicing layer of the grain boundary disordered interface part is supplied with powder through the second powder supply cylinder;

[0038] The aluminum alloy slicing data processing file is used for forming the aluminum alloy part of the target component by laser melting layer by layer; each slicing layer of the aluminum alloy part is supplied with powder through the third powder supply cylinder.

[0039] Preferably, the grain boundary disordered powder is formed by uniformly mixing 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 objectives, the present invention has the following advantages over the prior art:

[0041] 1. The present invention uses a grain boundary disordering method to disorder the heterogeneous interface of titanium alloy-aluminum alloy heterogeneous materials, thereby solving 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 during laser additive manufacturing, and realizes laser additive manufacturing of titanium alloy-aluminum alloy heterogeneous materials with high density and high mechanical properties.

[0042] 2. The present invention is different from traditional heterogeneous material connection processes such as welding and riveting. It innovatively adopts laser powder bed melting technology to realize the preparation of integrated heterogeneous material components. This method gives full play to the advantages of laser additive manufacturing in design freedom and structural 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 integrated characteristics of formed parts. This process is suitable for aerospace, automobiles, ships, medical and other fields that have high requirements for complex structures, fine dimensions and small batch production, further expanding the application scope of titanium alloy-aluminum alloy heterogeneous materials.

[0043] 3. The method of adding grain boundary disordering elements to the Ti-Al system to regulate the ordered intermetallic compound phase of the present invention can be further extended and applied to other heterogeneous material systems that are prone to form brittle ordered intermetallic compounds in laser additive manufacturing, thereby broadening the scope of laser additive manufacturing heterogeneous materials, improving the mechanical properties of laser additive manufacturing heterogeneous materials, and promoting the development of laser additive manufacturing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic structural diagram of the laser additive manufacturing device for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials used in the present invention.

[0045] Figure 2 The transmission electron microscope image and mechanical properties of the titanium alloy-aluminum alloy heterogeneous material block sample interface prepared in Example 1, wherein (a) is the transmission electron microscope image of the block sample interface, 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, 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, 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 Optical microscope images and mechanical properties of the titanium alloy-aluminum alloy heterogeneous material block sample interface prepared in Example 3, wherein (a) is a transmission electron microscope image of the interface of the block sample, and (b) is a mechanical property curve of the block sample.

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

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

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

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

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

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

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

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

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

[0058] Fig.15 These are the interface optical microscope images and mechanical properties of the titanium alloy-aluminum alloy heterogeneous material block sample prepared in Example 13, wherein (a) is the interface optical microscope image of the block sample, and (b) is the mechanical property curve of the block 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 disordered interface layer; 53, titanium alloy layer; 54, titanium alloy substrate; 6, powder recovery cavity. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means any limitation to the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise specified, the relative arrangement, expressions and numerical values ​​of the components and steps described in these embodiments do not limit the scope of the present invention. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but in appropriate cases, the techniques, methods and equipment should be regarded as part of the specification. 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 may have different values.

[0061] The laser additive manufacturing method for disordered interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials of the present invention is based on Figure 1 The high-strength and toughness titanium alloy-aluminum alloy heterogeneous material interface disordered laser additive manufacturing device shown is implemented, and the high-strength and toughness titanium alloy-aluminum alloy heterogeneous material interface disordered laser additive manufacturing device is built based on the existing laser powder bed fusion forming equipment.

[0062] Specifically, the laser powder bed fusion forming equipment includes a control device, a laser, a galvanometer, a powder supply system and a forming cavity. Among them: the powder supply system adopts a three-cylinder powder supply system. The three-cylinder powder supply system includes three powder supply cylinders, corresponding to the first to third powder supply cylinders, the first powder supply cylinder is filled with titanium alloy powder, the second powder supply cylinder is filled with grain boundary disordered powder, and the third powder supply cylinder is filled with aluminum alloy powder. The control device is integrated with a computer, which can import slicing processing files. The powders contained in each powder supply cylinder of the three-cylinder powder supply system can be spread on the titanium alloy substrate through the powder spreading arm to spread the powder required for the current slicing layer, and then according to the control strategy of the corresponding slicing processing file, the laser beam emitted by the laser is controlled to be projected through the galvanometer onto the powder layer corresponding to the current slicing layer for laser melting, thereby obtaining the current slicing layer. Specifically, the slicing processing file is constructed based on the laser melting strategy of the target component, including titanium alloy slicing data processing files, grain boundary disordered slicing data processing files, and aluminum alloy slicing data processing files. The target component is divided into three parts from top to bottom, corresponding to: the titanium alloy part at the bottom, the aluminum alloy part at the top, and the grain boundary disordered interface part in the middle; the titanium alloy slicing data processing file is used for the titanium alloy part of the target component to be laser melted layer by layer; each slicing layer included in the titanium alloy part is supplied 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 slicing layer of the grain boundary disordered interface part is supplied with powder through the second powder supply cylinder; the aluminum alloy slicing data processing file is used for the aluminum alloy part of the target component to be laser melted layer by layer; each slicing layer of the aluminum alloy part is supplied with powder through the third powder supply cylinder.

[0063] In the present invention, the titanium alloy powder used is Ti6Al4V, wherein the Al content is 5.8wt.%, the V content is 4.1wt.%, and the balance is Ti; the aluminum alloy powder used is AlMgScZr, wherein the Mg content is 4.2wt.%, the Sc content is 0.4wt.%, the Zr content is 0.2wt.%, and the balance is Al. The grain boundary disordered 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 three slice data processing files of titanium alloy, grain boundary disordered interface and aluminum alloy into a computer and loading the slice data processing file of titanium alloy;

[0066] (b) The scraper (or powder spreading arm) spreads 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 part of the powder layer, so that the powder melts and solidifies to form a two-dimensional plane entity;

[0068] (d) the forming cavity driving system controls the forming cavity to move downward by a powder spreading thickness, and repeats steps (b) and (c) until the titanium alloy part is formed;

[0069] (e) loading the grain boundary disordered slice data processing file and repeating steps (b) and (c) until the grain boundary disordered interface is partially formed;

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

[0071] (g) The parts are cut from the substrate using wire-cut electric discharge technology and ultrasonically cleaned in acetone to remove surface stains, thereby obtaining titanium alloy-aluminum alloy heterogeneous material parts.

[0072] The preparation principle of the present invention is to disorder the grain boundaries of the intermetallic compounds through in-situ grain boundary segregation of the B element in the molten pool. On the one hand, the segregation of the B element will form a disordered layer on the grain boundary of the intermetallic compound. Compared with the long-range ordered intermetallic compound, this disordered layer can increase the antiphase domain boundary energy, enhance the dislocation migration ability, and reduce the critical stress of dislocation transfer to a level lower than that required for fracture, thereby improving plasticity. On the other hand, the disordered B element grain boundary acts as a buffer zone between the ordered intermetallic compound grains, which can prevent the premature fracture of the ordered intermetallic compound grains and improve the grain boundary damage resistance.

[0073] The laser additive manufacturing method for disordering the interface of high-strength and toughness titanium alloy-aluminum alloy heterogeneous materials described in the present invention will be described in detail below in conjunction with several embodiments.

[0074] Example 1

[0075] The laser additive manufacturing method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials of the present invention comprises the following steps:

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

[0077] Weigh an appropriate amount of aluminum alloy powder and weigh 0.2 wt.% of metal B powder according to the weight of the aluminum alloy powder, place it in an argon-protected planetary ball mill and start ball milling to prepare grain boundary disordered powder, the ball milling speed is 250 rpm, and the ball milling time is 4 hours. After ball milling, store it for future use.

[0078] (2) Dry printing powder:

[0079] Titanium alloy powder, grain boundary disordered powder and aluminum alloy powder of appropriate mass were taken and dried in a vacuum drying oven at 80° C. for 10 h to remove moisture and improve the fluidity of the powder.

[0080] (3) Construct slice processing files:

[0081] A 3D solid geometric model of the target part is established using 3D modeling software, and the established 3D solid geometric model is sliced ​​and layered using slicing software to obtain a series of slice layers stacked one by one, and a corresponding laser printing strategy is set for each slice layer.

[0082] The target part is composed of three parts from top to bottom, which correspond to: the titanium alloy part at the bottom, the aluminum alloy part at the top, and the grain boundary disordered interface part in the middle;

[0083] Each slicing layer included in the titanium alloy part is formed by laser melting titanium alloy powder, each slicing layer in the grain boundary disordered interface part is formed by laser melting grain boundary disordered powder, and each slicing layer included in the aluminum alloy part is formed by laser melting grain boundary aluminum alloy powder.

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

[0085] (a) Titanium alloy part, laser power 170W, laser scanning speed 900mm / s, scanning spacing 50μm, powder thickness 30μm, interlayer rotation 67°, partitioned island strategy, island size 5mm×5mm;

[0086] (b) The grain boundary disordered interface part, laser power 180W, laser scanning speed 2500mm / s, scanning spacing 50μm, powder thickness 30μm, interlayer rotation 67°, partitioned island strategy, island size 5mm×5mm, 8 layers printed;

[0087] (c) Aluminum alloy part, laser power 200W, laser scanning speed 1000mm / s, scanning spacing 50μm, powder thickness 30μm, interlayer rotation 67°, partitioned island strategy, island size 5mm×5mm.

[0088] (4) The slicing data processing file in step (3) is imported into the computer system of the laser powder bed fusion forming equipment, and the titanium alloy powder, grain boundary disordered powder and aluminum alloy powder dried in step (2) are successively loaded into the three-cylinder powder supply system for forming, and then high-purity Ar gas is introduced into the laser forming chamber as a protective atmosphere to keep the oxygen content below 50 ppm.

[0089] (5) Load the titanium alloy slicing data processing file, turn on the laser, select the set powder area according to the path of the slicing data processing file for melting / solidification, and pause after completing the printing of the titanium alloy part.

[0090] (6) Switch the processing data processing file to the grain boundary disordered interface slice data processing file, turn on the laser, and pause after completing the printing of the grain boundary disordered interface part.

[0091] (7) Switch the processing data processing file to the aluminum alloy slicing 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, the component is separated from the substrate by electric spark wire cutting process, ultrasonically cleaned in acetone to remove surface stains, and ground and polished according to the standard metallographic sample preparation procedure to obtain a titanium alloy-aluminum alloy heterogeneous material component with high density and high mechanical properties.

[0093] (9) The intermetallic compound interface of the titanium alloy-aluminum alloy heterogeneous material component was sliced ​​using a focused ion beam, and the heterogeneous material interface was observed under a transmission electron microscope. Figure 2 shown.

[0094] By observing the transmission electron microscope photograph of the heterogeneous material interface in Example 1, it can be found that the titanium alloy-aluminum alloy heterogeneous material interface has good metallurgical bonding, and there is a disordered grain boundary layer with a thickness of about 20nm formed by the B element between the brittle intermetallic compound and the matrix. This disordered grain boundary layer can increase the antiphase domain boundary energy, enhance the dislocation migration ability, and reduce the critical stress of dislocation transfer to below the level required for fracture, thereby improving the mechanical properties. In this case, the tensile strength of the sample reaches 349MPa.

[0095] Comparative Example 1

[0096] Comparative Example 1 is basically the same as Example 1, except that the grain boundary disordering method is not used, that is, the aluminum alloy part is directly formed after the titanium alloy part is formed. The intermetallic compound interface of the titanium alloy-aluminum alloy heterogeneous material component is sliced ​​by using a focused ion beam, and the heterogeneous material interface is observed under a transmission electron microscope. Figure 3 shown.

[0097] By comparing the transmission electron microscope photos and mechanical property data of the samples obtained in Example 1 and Comparative Example 1, it can be found that without adopting the grain boundary disordering method, there is no disordered interface between the brittle intermetallic compounds in the sample and the matrix, and the highly ordered brittle intermetallic compounds make the mechanical properties of the sample poor, and the tensile strength is only 187MPa.

[0098] Example 2

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

[0100] By comparing the transmission electron microscope and mechanical property data of the samples obtained in Example 2 with those in Example 1, it can be found that increasing the amount of B element added can increase the thickness of the grain boundary disordered interface layer. However, since the thickness of the grain boundary disordered layer increases with the amount of B element added, it is not conducive to the movement and cross-slip of dislocations after activation, and the effect of improving the mechanical properties is reduced, and the tensile strength is reduced to 302MPa. However, compared with the laser melting formed components without the grain boundary disordered interface layer, the mechanical properties are still improved.

[0101] Example 3

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

[0103] By comparing the transmission electron microscope and mechanical property data of the samples obtained in Example 3 with those in Example 1, it can be found that increasing the addition amount of element B can increase the thickness of the grain boundary disordered interface layer. However, since the thickness of the grain boundary disordered layer is too large (about 75nm), it is not conducive to the movement and cross-slip of dislocations after activation, and the mechanical property improvement effect is reduced, 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] The scheme of Example 4 is basically the same as that of Example 1, except that the addition amount of element B is reduced from 0.2wt.% to 0.1wt.%. The intermetallic compound interface of the titanium alloy-aluminum alloy heterogeneous material component is sliced ​​by using a focused ion beam, and the heterogeneous material interface is observed under a transmission electron microscope. Figure 6 shown.

[0106] By comparing the transmission electron microscopy and mechanical property data of the samples obtained in Example 4 with those in 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 excessive thickness of the grain boundary disordered interface layer, the mechanical property improvement effect is small, and the tensile strength is reduced to 223MPa. However, compared with the laser melt-formed component without the grain boundary disordered interface layer, the mechanical properties are still improved.

[0107] Example 5

[0108] Example 5 is basically the same as Example 1, except that the laser power of the grain boundary disordered interface is increased to 200W, and an optical microscope is used to observe the disordered interface. Figure 7 shown.

[0109] By comparing the mechanical property data of the samples obtained in Example 5 with those in Example 1, it can be found that the addition of metal B powder significantly changes the laser-powder interaction behavior. Under higher laser power, the degree of heat accumulation in the disordered interface of the grain boundary increases, a microcrack is formed along the direction parallel to the interface, and the tensile strength drops to 78 MPa.

[0110] Example 6

[0111] Example 6 is basically the same as Example 1, except that the laser power of the grain boundary disordered interface is further increased to 220W, and an optical microscope is used to observe the disordered interface. Figure 8 shown.

[0112] By comparing the mechanical property data of the samples obtained in Example 6 with those in Example 1, it can be found that the addition of metal B powder significantly changes the laser-powder interaction behavior. At a higher laser power, the degree of heat accumulation in the disordered interface of the grain boundary is further increased, and a through-crack microcrack is formed along the direction parallel to the interface, and the tensile strength is only 18 MPa.

[0113] Example 7

[0114] Example 7 is basically the same as Example 1, except that the laser power of the grain boundary disordered interface is reduced to 160W, and an optical microscope is used to observe the disordered interface. Fig. 9 shown.

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

[0116] Example 8

[0117] Example 8 is basically the same as Example 1, except that the laser power at the grain boundary disordered interface is further reduced to 140 W, and an optical microscope is used to observe the grain boundary disordered interface. Fig.10 shown.

[0118] By comparing the mechanical property data of the samples obtained in Example 8 with those in Example 1, it can be found that further reducing the laser energy input leads to a large number of unfused defects in the grain boundary disordered interface layer, which reduces the mechanical properties and the tensile strength is only 56 MPa.

[0119] Example 9

[0120] Example 9 is basically the same as Example 1, except that the laser power of the grain boundary disordered interface is 170 W, and an optical microscope is used to observe the grain boundary disordered interface. Fig.11 shown.

[0121] By comparing the mechanical property data of the samples obtained in Example 9 with those in Example 1, it can be found that under the process parameters, the multi-material interface has good metallurgical bonding, moderate residual stress, and a tensile strength of 325 MPa.

[0122] Example 10

[0123] Example 10 is basically the same as Example 1, except that the laser power of the grain boundary disordered interface is 190 W, and an optical microscope is used to observe the grain boundary disordered interface. Fig.12 shown.

[0124] By comparing the mechanical property data of the samples obtained in Example 10 with those in Example 1, it can be found that the metallurgical bonding of the multi-material interface is good, the residual stress is moderate, and the tensile strength reaches 342 MPa.

[0125] Embodiment 11

[0126] Example 11 is basically the same as Example 1, except that the number of layers formed in the grain boundary disordered interface is reduced to 5 layers. The grain boundary disordered interface is observed using an optical microscope. Fig.13 shown.

[0127] By comparing the mechanical property data of the samples obtained in Example 11 with those in Example 1, it can be found that after increasing the number of layers of the grain boundary disordered interface, the residual stress relief and the effect of improving dislocation activation produced by the thinner grain boundary disordered interface are not enough to offset the thermal stress during laser additive manufacturing. A crack was generated in the multi-material sample along the direction parallel to the interface, and the tensile strength was only 110 MPa.

[0128] Example 12

[0129] Example 12 is basically the same as Example 1, except that the number of layers formed in the grain boundary disordered interface is reduced to 3 layers. The grain boundary disordered interface is observed using an optical microscope. Fig.14 shown.

[0130] By comparing the mechanical property data of the samples obtained in Example 12 with those in Example 1, it can be found that, similar to Example 11, the effect is further reduced after the number of layers of the grain boundary disordered interface part is further reduced, and the crack width generated in the multi-material sample along the direction parallel to the interface is larger, and the tensile strength is only 14 MPa.

[0131] Embodiment 13

[0132] Example 13 is basically the same as Example 1, except that the number of layers formed in the grain boundary disordered interface is increased to 10 layers. The grain boundary disordered interface is observed using an optical microscope. Fig.15 shown.

[0133] By comparing the mechanical property data of the samples obtained in Example 13 with those in Example 1, it can be found that after increasing the number of layers of the grain boundary disordered interface part, although the metallurgical bonding of multiple materials can still be achieved at the bottom of this part, the top of this part is far away from the titanium alloy part, and the heat conduction speed is accelerated, resulting in less heat in this part, insufficient energy, and more unfused defects. The tensile strength is only 56MPa.

[0134] By comparing the tensile strength of the titanium alloy-aluminum alloy heterogeneous material components obtained in the above-mentioned Examples 1-13 and Comparative Example 1, it can be seen that in order to obtain laser-printed components with excellent mechanical properties, we not only need to consider adding a grain boundary disordered interface layer between the titanium alloy slice layer and the aluminum alloy slice layer, but also need to pay special attention to the process forming parameters of the molten grain boundary disordered interface (especially the setting of laser power), thereby solving 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 during laser additive manufacturing, thereby achieving laser additive manufacturing of titanium alloy-aluminum alloy heterogeneous materials with high density and high mechanical properties.

[0135] The present invention provides a method and idea for a laser additive manufacturing method for disordered interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A laser additive manufacturing method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials, characterized in that: The steps include: Step 1: Overall planning of the laser printing strategy for the target parts: The target part is divided into three parts from top to bottom, corresponding to: the titanium alloy part at the bottom, the aluminum alloy part at the top, and the grain boundary disordered interface part in the middle; Using 3D modeling software to build a 3D solid geometric model of the target part, and using slicing software to slice and layer the built 3D solid geometric model to obtain a series of slice layers stacked one by one, and setting a corresponding laser printing strategy for each slice layer; Constructing titanium alloy slice data processing files for each slice layer included in the titanium alloy part; constructing grain boundary disordered interface slice data processing files for each slice layer included in the grain boundary disordered interface part; constructing aluminum alloy slice data processing files for each slice layer included in the aluminum alloy part; Step 2: Prepare laser printing powder: Laser printing powder includes three categories, namely titanium alloy powder, grain boundary disordered powder and aluminum alloy powder; the grain boundary disordered powder is made by uniformly mixing aluminum alloy powder and metal B powder, and the mass of metal B powder is 0.15-0.25wt.% of the aluminum alloy powder; Step 3: Laser printing preparation: Importing 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 1 into the control device of the laser powder bed fusion forming equipment; Place the laser printing powder prepared in step 2 into the three-cylinder powder supply system of the laser powder bed fusion forming equipment; Step 4: Printing the titanium alloy part: Load titanium alloy slice data processing file; The laser powder bed fusion forming equipment is started to melt and solidify the titanium alloy powder layer by layer on the substrate to form a titanium alloy part under the control of the titanium alloy slice data processing file; Step 5: Printing the disordered interface of grain boundaries: Switch the processing file to the grain boundary disordered interface slice data processing file; The laser powder bed fusion forming equipment is started, and under the control of the grain boundary disordered interface slice data processing file, the grain boundary disordered powder is melted and solidified layer by layer on the titanium alloy part to form a grain boundary disordered interface part; Step 6: Printing the aluminum alloy part: Switch the processing file to the aluminum alloy slice data processing file; The laser powder bed fusion forming equipment is started, and under the control of the aluminum alloy slicing data processing file, the aluminum alloy powder is melted and solidified layer by layer on the grain boundary disordered interface part to form the aluminum alloy part.

2. The laser additive manufacturing method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials according to claim 1 is characterized in that: The process forming parameters in the titanium alloy slicing data processing file are: laser power is 170-180W, laser scanning speed is 900-1000mm / s, scanning spacing is 50μm, and powder thickness is 25-35μm.

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

4. The laser additive manufacturing method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials according to claim 1 is characterized in that: The process forming parameters in the aluminum alloy slicing data processing file are: laser power is 180-200W, laser scanning speed is 800-1000mm / s, scanning spacing is 50μm, and powder thickness is 25-35μm.

5. The laser additive manufacturing method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials according to claim 1 is characterized in that: In step 4 to step 6, the scanning strategy adopts a partitioned island strategy, and the size of the island is 5 mm×5 mm.

6. The laser additive manufacturing method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials according to claim 1 is characterized in that: In steps 4 to 6, the oxygen content in the forming cavity is controlled to be lower than 50 ppm.

7. The laser additive manufacturing method for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials according to claim 1 is characterized in that: In step 2, the titanium alloy powder, aluminum alloy powder, and grain boundary disordered powder need to be placed in a vacuum drying oven at 80° C. and dried for 10 hours to remove moisture and improve powder fluidity.

8. A laser additive manufacturing device for disordered interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials, built based on laser powder bed fusion forming equipment, including 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, including three powder supply cylinders, corresponding to the first to third powder supply cylinders, the first powder supply cylinder is filled with titanium alloy powder, the second powder supply cylinder is filled with grain boundary disordered powder, and the third powder supply cylinder is filled with aluminum alloy powder; A computer is integrated in the control device, and the slice processing file is imported into the computer; The slicing processing files are constructed based on the laser melting strategy of the target component, including titanium alloy slicing data processing files, grain boundary disordered slicing data processing files, and aluminum alloy slicing data processing files; The target component is divided into three parts from top to bottom, corresponding to: a titanium alloy part at the bottom, an aluminum alloy part at the top, and a grain boundary disordered interface part in the middle; The titanium alloy slice data processing file is used for layer-by-layer laser melting forming of the titanium alloy part of the target component; each slice layer included in the titanium alloy part is supplied with powder through the first powder supply cylinder; Grain boundary disordered slicing data processing file, used for the grain boundary disordered interface part of the target component formed by laser melting layer by layer; Each slice layer of the grain boundary disordered interface part is supplied with powder through the second powder supply cylinder; The aluminum alloy slicing data processing file is used for forming the aluminum alloy part of the target component by laser melting layer by layer; each slicing layer of the aluminum alloy part is supplied with powder through the third powder supply cylinder.

9. The laser additive manufacturing device for disordering the interface of high-strength and tough titanium alloy-aluminum alloy heterogeneous materials according to claim 8 is characterized in that: The grain boundary disordered powder is prepared by uniformly mixing 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.

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