Laser additive manufacturing titanium-steel multi-material component for improving interface bonding and forming performance by inhibiting element diffusion through middle layer and equipment and method of laser additive manufacturing titanium-steel multi-material component

Abstract

The invention discloses a laser additive manufacturing titanium-steel multi-material component, a device and a method thereof. According to the laser additive manufacturing titanium-steel multi-material component, element diffusion is inhibited through a middle layer, and interface bonding and forming performance are improved. The laser additive manufacturing titanium-steel multi-material component comprises a titanium alloy layer, a middle layer and a stainless steel layer, wherein the middle layer comprises an elemental metal Ce layer and an elemental metal Cr layer; the titanium alloy layer, the elemental metal Ce layer, the elemental metal Cr layer and the stainless steel layer are sequentially deposited through a laser directional energy deposition process. Therefore, according to the intermediate layer, the elemental metal Ce layer and the elemental metal Cr layer are designed, diffusion of Ti elements in the titanium alloy layer and Fe elements in the stainless steel layer is blocked through the characteristic that Ce and Cr are mutually soluble, and good metallurgical bonding between different materials is achieved; the problems of interface cracking, holes and the like caused by brittle intermetallic compounds when titanium alloy and stainless steel are directly connected are solved.

Description

Technical Field

[0001] The present invention relates to a laser additive manufacturing titanium-steel multi-material component and equipment and method thereof which improve interface bonding and forming performance through suppressing element diffusion through an intermediate layer, and belongs to the technical field of metal laser additive manufacturing. Background Art

[0002] Traditional technical methods can manufacture multi-material components with simple geometric structures, but cannot manufacture components with complex structures and multifunctional properties. Multi-material laser additive manufacturing technology provides a new way to prepare components with specific physical properties, can achieve good metallurgical bonding of multiple materials, and can also prepare complex structural parts. Over the past decade, laser additive manufacturing has been widely studied and used in manufacturing technology due to its inherent flexibility and high efficiency in producing complex components. Traditional laser additive manufacturing is limited to one material, so it cannot ensure that the components have properties such as wear resistance, high temperature resistance and corrosion resistance while maintaining strength and low cost. The emerging multi-material laser additive manufacturing technology can overcome the above problems.

[0003] Laser directed energy deposition is an advanced additive manufacturing technology that can directly produce high-density, functional components. During the manufacturing process, the laser beam is focused on the substrate to form a molten pool, and the powder flow is continuously input into the molten pool through the conveying system and melted, and finally printed into shape. Because of its advantages such as small heat-affected zone and fine solidification structure, it is conducive to the preparation of multi-material components. Titanium alloy has the advantages of light weight, high strength, corrosion resistance, and biocompatibility, and stainless steel has the advantages of high strength, corrosion resistance, easy processing, and low cost. Therefore, achieving a good metallurgical bonding between titanium alloy and stainless steel is of great significance for industrial development. However, due to the different metallurgical and thermophysical properties of the two materials, they cannot be mixed. When the two materials are directly connected, many Ti-Fe brittle intermetallic compounds will be produced, resulting in defects such as interface cracking and holes, which often reduce the interface bonding strength and seriously limit its industrial application. Summary of the invention

[0004] The purpose of the present invention is to provide a laser additive manufacturing titanium-steel multi-material component and its equipment and method, which can improve interface bonding and forming performance by inhibiting element diffusion through an intermediate layer. By arranging an intermediate layer that can block the diffusion of Ti and Fe elements between the titanium alloy layer and the stainless steel layer, harmful brittle cracking caused by mismatching atomic structure and thermal expansion coefficient can be effectively avoided, thereby obtaining a titanium-steel multi-material component with good interface metallurgical bonding and excellent performance.

[0005] In order to achieve the above technical objectives, the present invention will adopt the following technical solutions:

[0006] A laser additively manufactured titanium-steel multi-material component comprises a titanium alloy layer, an intermediate layer and a stainless steel layer, wherein the intermediate layer comprises a single metal Ce layer and a single metal Cr layer; the titanium alloy layer, the single metal Ce layer, the single metal Cr layer and the stainless steel layer are deposited in sequence from bottom to top by a laser directed energy deposition process.

[0007] Preferably, the titanium alloy layer is formed by laser sintering and melting titanium alloy powder, the elemental metal Ce layer is formed by laser sintering and melting elemental metal Ce powder, the elemental metal Cr layer is formed by laser sintering and melting elemental metal Cr powder, and the stainless steel layer is formed by laser sintering and melting stainless steel powder.

[0008] Preferably, the number of layers of the single metal Ce layer and the single metal Cr layer are both two.

[0009] Preferably, the titanium alloy powder is TC4 powder, the particle size of the TC4 powder is 53-150 μm, and the Al content of the TC4 powder is 6.75 wt.%, the V content is 4.5 wt.%, and the rest is Ti;

[0010] The stainless steel powder is SS316 powder, the particle size of the SS316 powder is 53-150 μm, and the SS316 powder contains 18.0 wt.%, 10.0 wt.%, 2.5 wt.% of Cr, and the rest is Fe.

[0011] Another technical purpose of the present invention is to provide a titanium-steel multi-material laser additive manufacturing device that improves interface bonding and forming performance by inhibiting element diffusion through an intermediate layer. The device is built based on a laser directional energy deposition process and is used for laser additive manufacturing of titanium-steel multi-material components, including a protective cavity, a powder feeder, a printing head, a forming substrate and a controller. The printing head is integrated with a powder delivery pipe, a laser and a protective gas delivery pipe; the forming substrate is placed in the protective cavity, the powder feeder is filled with powder to be printed, and the printing powder contained in the powder feeder can be transported to the printing area on the forming substrate through the powder delivery pipe; the laser beam spot emitted by the laser can fall on the printing area on the forming substrate; the protective gas can be transported to the printing area on the forming substrate through the protective gas delivery pipe; the forming substrate is a titanium alloy substrate; the powder feeder is filled with four types of printing powders, corresponding to titanium alloy powder, elemental metal Ce powder, elemental metal Cr powder and stainless steel powder;

[0012] The controller creates a powder processing file based on the structural characteristics of the titanium-steel multi-material component; the powder processing file integrates four powder processing data, each of which is configured with laser printing process parameters and corresponding laser scanning path planning;

[0013] The four sets of powder processing data correspond to the first to fourth powder processing data, wherein: the first powder processing data is used to deposit melted titanium alloy powder to form a titanium alloy layer; the second powder processing data is used to deposit melted single metal Ce powder to form a single metal Ce layer; the third powder processing data is used to deposit melted single metal Cr powder to form a single metal Cr layer; the fourth powder processing data is used to deposit melted stainless steel powder to form a stainless steel layer;

[0014] Under the control of the controller, after controlling the laser power and scanning speed of the laser beam output by the laser according to the laser printing process parameters in the first powder processing data, the powder conveying pipe is started to convey the titanium alloy powder contained in the powder feeder to the printing area, and then the working head is controlled to move according to the laser scanning path planning in the first powder processing data until the deposition of the titanium alloy layer is completed on the titanium alloy substrate; the type of powder conveyed by the powder conveying pipe is switched so that the powder conveying pipe conveys the elemental metal Ce powder contained in the powder feeder to the printing area, and the working head is controlled to move according to the laser scanning path planning in the second powder processing data until a preset number of layers of single powder are completed on the titanium alloy layer. Deposition of the elemental metal Ce layer; switching the type of powder transported by the powder delivery pipe so that the powder delivery pipe delivers the elemental metal Cr powder contained in the powder feeder to the printing area, and controls the movement of the working head according to the laser scanning path planning in the third powder processing data until the deposition of a preset number of elemental metal Cr layers is completed on the elemental metal Ce layer; switching the type of powder transported by the powder delivery pipe so that the powder delivery pipe delivers the stainless steel powder contained in the powder feeder to the printing area, and controls the movement of the working head according to the laser scanning path planning in the fourth powder processing data until the deposition of the stainless steel layer is completed on the elemental metal Cr layer, thereby obtaining a titanium-steel multi-material component.

[0015] Another technical purpose of the present invention is to provide a titanium-steel multi-material laser additive manufacturing method for improving interface bonding and forming performance by inhibiting element diffusion through an intermediate layer. The method is based on the titanium-steel multi-material laser additive manufacturing device for improving interface bonding and forming performance by inhibiting element diffusion through an intermediate layer. After cleaning the titanium alloy substrate, a laser directed energy deposition process is used to control the powder feeding rate, defocusing amount, overlap rate, and shielding gas flow rate to sequentially deposit a titanium alloy layer, a single metal Ce layer, a single metal Cr layer, and a stainless steel layer on the surface of the titanium alloy substrate, thereby obtaining a titanium-steel multi-material component with good interface metallurgical bonding and excellent performance. The method specifically includes the following steps:

[0016] Step 1: Powder drying:

[0017] Titanium alloy powder, elemental metal Ce powder, elemental metal Cr powder, and stainless steel powder were placed in a vacuum drying oven at 80°C for 10 hours to remove moisture and improve powder fluidity, and then placed in a powder feeder after drying;

[0018] Step 2: Create powder processing data:

[0019] Based on the laser directed energy deposition process, four independent powder processing data are created, each of which is configured with laser printing process parameters and laser scanning path planning;

[0020] The four sets of powder processing data correspond to the first to fourth powder processing data, where:

[0021] The first powder processing data is used to deposit melted titanium alloy powder to form a titanium alloy layer;

[0022] The second powder processing data is used to deposit and melt the single-element metal Ce powder to form a single-element metal Ce layer;

[0023] The third powder processing data is used to deposit and melt the single metal Cr powder to form a single metal Cr layer;

[0024] The fourth powder processing data is used to deposit the melted stainless steel powder to form a stainless steel layer;

[0025] Step 3: Place the titanium alloy substrate into the protective chamber, control the industrial robot to adjust the defocusing amount, close the door of the protective chamber after the adjustment, and introduce pure argon gas for deoxygenation;

[0026] Step 4: After the oxygen content in the protected cavity drops to 50 ppm, start the laser to sequentially deposit different materials on the titanium alloy substrate to obtain a titanium-steel multi-material component with good metallurgical bonding at the interface, which specifically includes the following steps:

[0027] Step 4.1, loading the first powder processing data in step 2 to first deposit a titanium alloy layer on the titanium alloy substrate;

[0028] Step 4.2, after the titanium alloy layer is deposited, the defocus amount is adjusted based on the top surface of the titanium alloy layer, and the second powder processing data in step 2 is loaded to deposit a single metal Ce layer on the surface of the titanium alloy layer;

[0029] Step 4.3, after the deposition of the single metal Ce layer is completed, the defocus amount is adjusted based on the top surface of the single metal Ce layer, and the third powder processing data in step 2 is loaded to deposit a single metal Cr layer on the surface of the single metal Ce layer;

[0030] Step 4.4, after the deposition of the single metal Cr layer is completed, the defocus amount is adjusted based on the top surface of the single metal Cr layer, and the fourth powder processing data in step 2 is loaded to deposit a stainless steel layer on the surface of the single metal Cr layer, and finally a titanium-steel multi-material component with a good metallurgical bonding interface is obtained.

[0031] Preferably, the powder feeding rate is 10 g / min, the defocusing amount is 2-3 mm, the overlapping rate is 50%, and the protective gas flow rate is 14-16 L / min.

[0032] Preferably, the particle size of the TC4 powder is 53-150 μm, and the Al content of the TC4 powder is 6.75 wt.%, the V content is 4.5 wt.%, and the rest is Ti; the particle size of the SS316 powder is 53-150 μm, and the SS316 powder has a Cr content of 18.0 wt.%, a Ni content of 10.0 wt.%, a Mo content of 2.5 wt.%, and the rest is Fe;

[0033] The particle size of the single-element metal Ce powder is 20 to 130 μm, and the particle size of the single-element metal Cr powder is 20 to 130 μm.

[0034] Preferably, in the first powder processing data, the laser power is 700 W and the scanning speed is 10 mm / s;

[0035] In the second powder processing data, the laser power is 700W and the scanning speed is 10mm / s;

[0036] In the third powder processing data, the laser power is 900W and the scanning speed is 10mm / s;

[0037] In the fourth powder processing data, the laser power is 1000 W and the scanning speed is 8 mm / s.

[0038] Preferably, after the titanium alloy layer is deposited on the titanium alloy substrate, step 4.2 is repeated to deposit two or more single metal Ce layers on the titanium alloy layer; after the single metal Ce layer is deposited, step 4.3 is repeated to deposit two or more single metal Cr layers on the single metal Ce layer.

[0039] Based on the above technical objectives, the present invention has the following advantages over the prior art:

[0040] 1. The laser additive manufacturing titanium-steel multi-material component of the present invention, which suppresses element diffusion through the intermediate layer to improve interface bonding and forming performance, deposits a single metal Ce layer and a single metal Cr layer in sequence between the titanium alloy layer and the stainless steel layer, thereby effectively blocking the diffusion of Ti and Fe elements, and finally prepares a titanium-steel multi-material component with a stainless steel layer and a titanium alloy layer as the outer layer. It can be seen that the titanium-steel multi-material component of the present invention can simultaneously have the advantages of both titanium alloy and stainless steel (usually, titanium alloy has the advantages of high specific strength, good heat and low temperature resistance, good impact resistance, etc., and stainless steel has the advantages of excellent mechanical properties, good corrosion resistance, low cost, etc.). On the other hand, by utilizing the mutual solubility of Ce and Cr, a single metal Ce layer and a single metal Cr layer are deposited in sequence between the titanium alloy layer and the stainless steel layer, which can effectively block the Ti and Fe elements. At the same time, the single metal Ce can improve the corrosion resistance and oxidation resistance of the titanium alloy material, and the single metal Cr can achieve good metallurgical bonding with the stainless steel material. Therefore, the present invention realizes good metallurgical bonding of titanium steel multi-materials under the action of the intermediate layer, and solves the problems of interface cracking and holes caused by brittle intermetallic compounds when titanium alloy and stainless steel are directly connected.

[0041] 2. The present invention uses laser directed energy deposition technology to prepare multi-material components, which can combine the advantages of different materials, such as local heat resistance, corrosion resistance, high thermal conductivity, wear resistance, etc., and can also accurately control the material distribution. Specific materials can be printed at designated locations with unique structures to achieve specific functions and achieve better comprehensive performance.

[0042] 3. Multi-material additive manufacturing technology, with its unique structural design and material distribution, can better adapt to different working conditions, especially under harsh working conditions that require multi-functions and multi-environment adaptability. Therefore, it provides a new option for the development of aerospace, nuclear industry, medical, automobile manufacturing and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic structural diagram of the titanium-steel multi-material laser additive manufacturing equipment of the present invention for depositing a titanium-steel multi-material component;

[0044] In the figure: 1-laser; 2-powder delivery pipe; 3-shielding gas delivery pipe; 4-substrate; 51-titanium alloy layer; 52-intermediate layer; 53-stainless steel layer;

[0045] Figure 2 It is a schematic diagram of the laser scanning strategy of the present invention;

[0046] Figure 3 This is the OM image of the Cr and SS316 interfaces of the titanium-steel multi-material component described in Example 3 of the present invention;

[0047] Figure 4 This is the OM image of the Cr and SS316 interfaces of the titanium-steel multi-material component described in Example 4 of the present invention;

[0048] Figure 5 This is the OM image of the Cr and SS316 interfaces of the titanium-steel multi-material component described in Example 5 of the present invention;

[0049] Figure 6 This is a macroscopic image of the direct connection between the laser directed energy deposition TC4 titanium alloy and the SS316 stainless steel according to the present invention. DETAILED DESCRIPTION

[0050] 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.

[0051] Titanium alloys have the advantages of high specific strength, good heat and low temperature resistance, and good impact resistance, while stainless steel has the advantages of excellent mechanical properties, good corrosion resistance, and low cost. If stainless steel and titanium alloys can be effectively connected, the advantages of both materials can be combined. However, due to the large difference in physical properties between titanium alloys and stainless steel (such as thermal expansion coefficient, thermal conductivity, etc.), when the two materials are directly connected, a large amount of brittle intermetallic compounds will be generated at their interface, and residual stress and a large amount of strain will be generated, resulting in connection failure. Figure 6 The macroscopic images of the direct connection between laser directed energy deposition TC4 titanium alloy and SS316 stainless steel were disclosed. It can be observed that many cracks appeared on the surface of SS316, the interface metallurgical bonding quality was very poor, and part of the SS316 fell off during wire cutting. This shows that a large amount of brittle intermetallic compounds were generated between the stainless steel and the titanium alloy, causing the connection to fail.

[0052] In order to achieve effective connection between stainless steel and titanium alloy, the present invention introduces single metal Ce and single metal Cr. It utilizes the mutual solubility characteristics between single metal Ce and single metal Cr to effectively block Ti and Fe elements and achieve good metallurgical bonding between stainless steel and titanium alloy, thereby solving the problems of interface cracking and holes caused by brittle intermetallic compounds when titanium alloy and stainless steel are directly connected.

[0053] To this end, the present invention discloses a laser additive manufacturing titanium-steel multi-material component and a device and method for laser additive manufacturing titanium-steel multi-material components. The technical solutions involved in the present invention will be described in detail below in conjunction with various embodiments.

[0054] Example 1

[0055] This embodiment discloses a laser additive manufacturing titanium-steel multi-material component, including a titanium alloy layer 51, an intermediate layer 52 and a stainless steel layer 53, wherein the intermediate layer 52 includes a single metal Ce layer and a single metal Cr layer; the titanium alloy layer 51, the single metal Ce layer, the single metal Cr layer and the stainless steel layer 53 are all deposited sequentially from bottom to top by a laser directional energy deposition process. Among them: the titanium alloy layer 51 is formed by laser sintering and melting titanium alloy powder, and the titanium alloy powder can be TC4 powder, and the particle size of TC4 powder is 53 to 150 μm, and in the TC4 powder, the Al content is 6.75wt.%, the V content is 4.5wt.%, and the rest is Ti. Of course, the titanium alloy powder can also be selected from other existing models of titanium alloy powder. The single metal Ce layer is formed by laser sintering and melting single metal Ce powder, and the particle size of the single metal Ce powder is 20 to 130 μm; the single metal Cr layer is formed by laser sintering and melting single metal Cr powder, and the particle size of the single metal Cr powder is 20 to 130 μm; and the stainless steel layer 53 is formed by laser sintering and melting stainless steel powder, and the stainless steel powder can be SS316 powder, and the particle size of SS316 powder is 53 to 150 μm, and the SS316 powder has a Cr content of 18.0 wt.%, a Ni content of 10.0 wt.%, a Mo content of 2.5 wt.%, and the rest is Fe. Of course, the stainless steel powder can be selected from stainless steel powders corresponding to other existing models.

[0056] The number of single metal Ce layers and single metal Cr layers can be determined according to actual needs. Through testing, it is found that when the number of single metal Ce layers and single metal Cr layers are both 2 layers, the interface metallurgical bonding of the titanium-steel multi-material component is good, with only some tiny holes and basically no defects. This shows that the use of 2 layers of single metal Ce layers and 2 layers of single metal Cr layers can effectively inhibit the diffusion of Ti and Fe elements, avoid the formation of brittle intermetallic compounds, reduce stress, and avoid crack generation and expansion, thereby achieving the purpose of improving the comprehensive mechanical properties.

[0057] Example 2

[0058] This embodiment discloses a titanium-steel multi-material laser additive manufacturing device that improves interface bonding and forming performance by inhibiting element diffusion through an intermediate layer, which is built based on a laser directed energy deposition process and is used for laser additive manufacturing of the titanium-steel multi-material component described in Example 1. Under the action of a focused laser beam 1, the printed powder flows into the molten pool and melts, and through the preferred intermediate layer 52, a substantially crack-free connection between the titanium alloy and the stainless steel can be achieved, and excellent mechanical properties are achieved.

[0059] like Figure 1 As shown, the titanium-steel multi-material laser additive manufacturing equipment described in this embodiment includes a protective cavity, a powder feeder, a printing head, a forming substrate and a controller, the printing head is integrated with a powder delivery pipe 2, a laser 1 and a protective gas delivery pipe 3; the forming substrate is placed in the protective cavity, the powder feeder is filled with powder to be printed, and the printing powder contained in the powder feeder can be transported to the printing area on the forming substrate through the powder delivery pipe 2; the laser beam spot emitted by the laser 1 can fall on the printing area on the forming substrate; the protective gas can be transported to the printing area on the forming substrate through the protective gas delivery pipe 3; the forming substrate is a titanium alloy substrate; the powder feeder contains four types of printing powders, corresponding to titanium alloy powder, elemental metal Ce powder, elemental metal Cr powder and stainless steel powder.

[0060] The controller creates a powder processing file based on the structural characteristics of the titanium-steel multi-material component; the powder processing file integrates four powder processing data, each of which is configured with laser printing process parameters and corresponding laser scanning path planning. The laser printing process parameters include laser power and scanning speed. The laser scanning path planning adopts a reciprocating scanning strategy, refer to the attached Figure 2 The initial point of laser melting of each layer is different, and each layer is rotated 90° to ensure uniform heating of the sample and a smooth surface.

[0061] The four sets of powder processing data correspond to the first to fourth powder processing data, wherein: the first powder processing data is used to deposit melted titanium alloy powder to form a titanium alloy layer 51; the second powder processing data is used to deposit melted single metal Ce powder to form a single metal Ce layer; the third powder processing data is used to deposit melted single metal Cr powder to form a single metal Cr layer; the fourth powder processing data is used to deposit melted stainless steel powder to form a stainless steel layer 53.

[0062] Under the control of the controller, after controlling the laser power and scanning speed of the laser beam output by the laser 1 according to the laser printing process parameters in the first powder processing data, the powder conveying pipe 2 is started to convey the titanium alloy powder contained in the powder feeder to the printing area, and then the working head is controlled to move according to the laser scanning path planning in the first powder processing data until the deposition of the titanium alloy layer 51 is completed on the titanium alloy substrate; the type of powder conveyed by the powder conveying pipe 2 is switched so that the powder conveying pipe 2 conveys the elemental metal Ce powder contained in the powder feeder to the printing area, and the working head is controlled to move according to the laser scanning path planning in the second powder processing data until a preset number of layers are completed on the titanium alloy layer 51. Deposition of a single metal Ce layer; switching the type of powder delivered by the powder delivery pipe 2 so that the powder delivery pipe 2 delivers the single metal Cr powder contained in the powder feeder to the printing area, and controls the movement of the working head according to the laser scanning path planning in the third powder processing data until a preset number of single metal Cr layers are deposited on the single metal Ce layer; switching the type of powder delivered by the powder delivery pipe 2 so that the powder delivery pipe 2 delivers the stainless steel powder contained in the powder feeder to the printing area, and controls the movement of the working head according to the laser scanning path planning in the fourth powder processing data until a stainless steel layer 53 is deposited on the single metal Cr layer, thereby obtaining a titanium-steel multi-material component.

[0063] Example 3

[0064] This embodiment discloses a titanium-steel multi-material laser additive manufacturing method for improving interface bonding and forming performance by inhibiting element diffusion through an intermediate layer. It is realized based on the titanium-steel multi-material laser additive manufacturing device for improving interface bonding and forming performance by inhibiting element diffusion through an intermediate layer. After cleaning the titanium alloy substrate, a laser directional energy deposition process is used to control the powder feeding rate, defocusing amount, overlap rate, and shielding gas flow rate to sequentially deposit a titanium alloy layer 51, a single metal Ce layer, a single metal Cr layer, and a stainless steel layer 53 on the surface of the titanium alloy substrate, thereby obtaining a titanium-steel multi-material component with good metallurgical bonding at the interface and excellent performance. Among them: the powder feeding rate is 10g / min, the defocusing amount is 2-3mm, the overlap rate is 50%, and the shielding gas flow rate is 14-16L / min.

[0065] Specifically, the titanium-steel multi-material laser additive manufacturing method described in this embodiment improves interface bonding and forming performance by inhibiting element diffusion through an intermediate layer, including the following steps:

[0066] Step 1: Powder drying:

[0067] Titanium alloy powder, elemental metal Ce powder, elemental metal Cr powder and stainless steel powder were placed in a vacuum drying oven at 80°C for 10 hours to remove moisture and improve powder fluidity. After drying, they were placed in a powder feeder; the powder feeding rate of the powder feeder was 10g / min;

[0068] Step 2: Create powder processing data:

[0069] Based on the laser directed energy deposition process, four independent powder processing data are created, each of which is configured with laser printing process parameters and laser scanning path planning; then a controller is used to integrate the above four powder processing data into a powder processing file to control the corresponding printing powder of each layer one by one to complete the deposition;

[0070] The four sets of powder processing data correspond to the first to fourth powder processing data, where:

[0071] The first powder processing data is used to deposit melted titanium alloy powder to form a titanium alloy layer 51;

[0072] The second powder processing data is used to deposit and melt the single-element metal Ce powder to form a single-element metal Ce layer;

[0073] The third powder processing data is used to deposit and melt the single metal Cr powder to form a single metal Cr layer;

[0074] The fourth powder processing data is used to deposit the melted stainless steel powder to form a stainless steel layer 53;

[0075] Step 3: After cleaning, place the titanium alloy substrate in the protective chamber, and then control the industrial robot to adjust the defocus of the working head to 2-3 mm. After the adjustment, close the door and introduce pure argon gas for deoxygenation. The protective gas flow rate is 14-16 L / min.

[0076] Step 4: After the oxygen content in the cavity to be protected drops to 50 ppm, the laser 1 is started to sequentially deposit different materials on the titanium alloy substrate to obtain a titanium-steel multi-material component with good metallurgical bonding at the interface, which specifically includes the following steps:

[0077] Step 4.1, loading the first powder processing data in step 2 to first deposit a titanium alloy layer 51 on the titanium alloy substrate;

[0078] Step 4.2: After the titanium alloy layer 51 is deposited, the defocus amount is adjusted based on the top surface of the titanium alloy layer 51, and the second powder processing data in step 2 is loaded to deposit a single metal Ce layer on the surface of the titanium alloy layer 51;

[0079] Step 4.3, after the deposition of the single metal Ce layer is completed, the defocus amount is adjusted based on the top surface of the single metal Ce layer, and the third powder processing data in step 2 is loaded to deposit a single metal Cr layer on the surface of the single metal Ce layer;

[0080] Step 4.4, after the deposition of the elemental metal Cr layer is completed, the defocus amount is adjusted based on the top surface of the elemental metal Cr layer, and the fourth powder processing data in step 2 is loaded to deposit a stainless steel layer 53 on the surface of the elemental metal Cr layer, and finally a titanium-steel multi-material component with a good metallurgical bonding interface is obtained.

[0081] Step 5: After the preparation is completed, the sample is cut from the substrate using an electric spark wire, and is placed in an oil cleaning agent for ultrasonic cleaning to remove surface stains. The titanium steel multi-material sample is then ground and polished according to the standard metallographic preparation method, and the interface is observed under an optical microscope.

[0082] Example 4

[0083] The difference between this embodiment and embodiment 3 is that:

[0084] In step 1, the titanium alloy powder is TC4 powder, the particle size of TC4 powder is 53-150 μm, and the Al content of TC4 powder is 6.75 wt.%, the V content is 4.5 wt.%, and the rest is Ti; the stainless steel powder is SS316 powder, the particle size of SS316 powder is 53-150 μm, and the SS316 powder has a Cr content of 18.0 wt.%, a Ni content of 10.0 wt.%, a Mo content of 2.5 wt.%, and the rest is Fe. The particle size of the single metal Ce powder is 20-130 μm, and the particle size of the single metal Cr powder is 20-130 μm.

[0085] In step 4, step 4.1 is repeated to continuously deposit 4 layers of titanium alloy layers 51 on the titanium alloy substrate. The laser process parameters for depositing the titanium alloy layers 51 are: laser power 700 W, scanning speed 10 mm / s; after the deposition of the 4 layers of titanium alloy layers 51 is completed, the surface of the top layer of titanium alloy layer 51 is used as a reference, and step 4.2 is repeated to continuously deposit 2 layers of single metal Ce layers on the titanium alloy layer 51. The laser process parameters for depositing the single metal Ce layer are: laser power 700 W, scanning speed 10 mm / s; after the deposition of the 2 layers of single metal Ce layers is completed, the surface of the top layer of single metal Ce layer is used as a reference. Taking the surface of the uppermost layer of the Cr layer as a reference, step 4.4 is implemented to deposit two layers of stainless steel layer 53 on the Cr layer, and finally a titanium-steel multi-material component with good metallurgical bonding at the interface and excellent performance is formed. The laser process parameters for depositing the stainless steel layer 53 are: laser power 1000 W, scanning speed 8 mm / s.

[0086] In the titanium-steel multi-material component manufactured in this embodiment, the average thickness of the two single-element metal Ce layers is 1.06 mm, and the average thickness of the two single-element metal Cr layers is 1.05 mm.

[0087] After the preparation, the sample was cut from the substrate using an electric spark wire, and then ultrasonically cleaned with an oil cleaning agent to remove surface stains. Then, the titanium steel multi-material sample was ground and polished according to the standard metallographic preparation method. The interface was observed under an optical microscope. Figure 3 shown.

[0088] By observation Figure 3 From the optical image of the interface of the titanium-steel multi-material component shown, it can be seen that the interface has good metallurgical bonding, with only some tiny holes and basically no defects, which means that the use of two intermediate layers 52 can effectively inhibit the diffusion of Ti and Fe elements, avoid the formation of brittle intermetallic compounds, reduce stress, and avoid crack generation and expansion, thereby achieving the purpose of improving the comprehensive mechanical properties.

[0089] Example 5

[0090] The difference between this embodiment and embodiment 4 is that the single metal Ce layer and the single metal Cr layer are both one layer. The titanium-steel multi-material component is ground and polished according to the standard metallographic preparation method, and the interface is observed under an optical microscope. Figure 4 shown.

[0091] In the titanium-steel multi-material component manufactured in this embodiment, the average thickness of one single metal Ce layer is 0.45 mm, and the average thickness of one single metal Cr layer is 0.5 mm.

[0092] By comparing the OM images of Example 4 and Example 5, it can be seen that vertical cracks and holes appeared in the titanium-steel multi-material component prepared in this example, indicating that when the intermediate barrier layer (1 layer of single metal Ce layer and 1 layer of single metal Cr layer) is thin, the barrier element effect is limited, and brittle intermetallic compounds are generated at the interface, which will greatly reduce the comprehensive mechanical properties of the titanium steel multi-material.

[0093] Example 6

[0094] The difference between this embodiment and embodiment 4 is that the single metal Ce layer and the single metal Cr layer are both 3 layers. The titanium-steel multi-material component is ground and polished according to the standard metallographic preparation method, and the interface is observed under an optical microscope. Figure 5 shown.

[0095] In the titanium-steel multi-material component manufactured in this embodiment, the average thickness of the three single-element metal Ce layers is 1.2 mm, and the average thickness of the three single-element metal Cr layers is 1.5 mm.

[0096] By comparing the OM images of Example 4 and Example 6, it can be seen that the titanium-steel multi-material component prepared in this example has large holes in the middle barrier layer, which means that the thickness of the middle barrier layer is too large and the defects will increase accordingly. Therefore, when connecting multiple materials, it is necessary to control the thickness of the middle barrier layer, which can not only control the defects but also improve the comprehensive mechanical properties of the titanium-steel multi-material.

[0097] A comprehensive comparison of Examples 4-6 shows that for specific powder materials (TC4 titanium alloy powder, SS316 stainless steel powder), under the control of specific laser power, scanning speed, and defocus, a single metal Ce layer and a single metal Cr layer with a thickness of 1-1.2 mm are sequentially formed between the titanium alloy layer 51 and the stainless steel layer 53, which can effectively achieve effective isolation of Ti and Fe elements between the titanium alloy layer 51 and the stainless steel layer 53, thereby obtaining a titanium steel multi-material component with good interface bonding and excellent performance. In fact, for different powder materials and different process conditions (laser power, scanning speed, defocus), the thickness of the intermediate barrier layer varies, but the overall control goal is to achieve effective isolation of Ti and Fe elements.

[0098] Comparative Example

[0099] This comparative example provides a method for depositing a titanium-steel multi-material component by laser directed energy, wherein after melting and depositing TC4 titanium alloy powder on a titanium alloy substrate to form a titanium alloy layer 51, SS316 stainless steel powder is directly melted and deposited on the titanium alloy layer 51, and specifically comprises the following steps:

[0100] (1) Take appropriate amount of TC4 and SS316 powders, place them in a vacuum drying oven at 80°C for 10 h to remove moisture and improve powder fluidity, and place them in a powder feeder after drying;

[0101] (2) Start the industrial robot (i.e., the controller mentioned above) and program the laser power, scanning speed, and scanning path for different materials, which are divided into two processing data files: TC4 and SS316;

[0102] (3) Start the powder feeder, water cooler, laser 1, and oxygen content detector in sequence, put the titanium alloy substrate into the protective chamber after cleaning, and then control the industrial robot to adjust the defocus amount. After the adjustment is completed, close the cabin door, introduce 99.9% pure argon gas, and start printing when the oxygen content drops below 50 ppm;

[0103] (4) First, 4 layers of TC4 were deposited on the titanium alloy substrate with a laser power of 700 W and a scanning speed of 10 mm / s. Then, based on the TC4 surface, 2 layers of SS316 were deposited with a laser power of 1000 W and a scanning speed of 8 mm / s. Finally, the printed image was formed. The macroscopic image is shown in FIG. Figure 6 It can be observed that many cracks appear on the surface of SS316, the metallurgical bonding quality of the interface is very poor, and the SS316 part falls off during wire cutting, indicating that stainless steel and titanium alloy will generate a large amount of brittle intermetallic compounds without the barrier element of the intermediate layer 52, causing the connection failure.

Claims

1. A laser additive manufacturing titanium-steel multi-material component that improves interface bonding and forming performance by inhibiting element diffusion through an intermediate layer, comprising a titanium alloy layer, an intermediate layer and a stainless steel layer, characterized in that: The intermediate layer includes a single metal Ce layer and a single metal Cr layer; the titanium alloy layer, the single metal Ce layer, the single metal Cr layer and the stainless steel layer are all deposited in sequence from bottom to top through a laser directed energy deposition process.

2. The laser additive manufacturing titanium-steel multi-material component according to claim 1, characterized in that: The titanium alloy layer is formed by laser sintering and melting titanium alloy powder, the single metal Ce layer is formed by laser sintering and melting single metal Ce powder, the single metal Cr layer is formed by laser sintering and melting single metal Cr powder, and the stainless steel layer is formed by laser sintering and melting stainless steel powder.

3. The laser additive manufacturing titanium-steel multi-material component according to claim 1 or 2, characterized in that: The number of layers of the single metal Ce layer and the single metal Cr layer are both two.

4. The laser additive manufacturing titanium-steel multi-material component according to claim 2, characterized in that: The titanium alloy powder is TC4 powder, the particle size of the TC4 powder is 53-150 μm, and the content of Al in the TC4 powder is 6.75 wt.%, the content of V is 4.5 wt.%, and the rest is Ti; The stainless steel powder is SS316 powder, the particle size of the SS316 powder is 53-150 μm, and the SS316 powder contains 18.0 wt.%, 10.0 wt.%, 2.5 wt.% of Cr, and the rest is Fe.

5. A titanium-steel multi-material laser additive manufacturing device that improves interface bonding and forming performance by inhibiting element diffusion through an intermediate layer, which is built based on a laser directed energy deposition process and is used for laser additive manufacturing of titanium-steel multi-material components, including a protective cavity, a powder feeder, a printing head, a forming substrate and a controller, wherein the printing head is integrated with a powder delivery pipe, a laser and a protective gas delivery pipe 3; the forming substrate is placed in the protective cavity, the powder feeder is filled with powder to be printed, and the printing powder contained in the powder feeder can be delivered to the printing area on the forming substrate through the powder delivery pipe; the laser beam spot emitted by the laser can fall on the printing area on the forming substrate; the protective gas can be delivered to the printing area on the forming substrate through the protective gas delivery pipe 3; it is characterized in that The forming substrate is a titanium alloy substrate; the powder feeder contains four types of printing powders, which correspond to titanium alloy powder, single metal Ce powder, single metal Cr powder and stainless steel powder; The controller creates a powder processing file based on the structural characteristics of the titanium-steel multi-material component; the powder processing file integrates four powder processing data, each of which is configured with laser printing process parameters and corresponding laser scanning path planning; The four sets of powder processing data correspond to the first to fourth powder processing data, wherein: the first powder processing data is used to deposit melted titanium alloy powder to form a titanium alloy layer; the second powder processing data is used to deposit melted single metal Ce powder to form a single metal Ce layer; the third powder processing data is used to deposit melted single metal Cr powder to form a single metal Cr layer; the fourth powder processing data is used to deposit melted stainless steel powder to form a stainless steel layer; Under the control of the controller, after controlling the laser power and scanning speed of the laser beam output by the laser according to the laser printing process parameters in the first powder processing data, the powder conveying pipe is started to convey the titanium alloy powder contained in the powder feeder to the printing area, and then the working head is controlled to move according to the laser scanning path planning in the first powder processing data until the deposition of the titanium alloy layer is completed on the titanium alloy substrate; the type of powder conveyed by the powder conveying pipe is switched so that the powder conveying pipe conveys the elemental metal Ce powder contained in the powder feeder to the printing area, and the working head is controlled to move according to the laser scanning path planning in the second powder processing data until a preset number of layers of single powder are completed on the titanium alloy layer. Deposition of the elemental metal Ce layer; switching the type of powder transported by the powder delivery pipe so that the powder delivery pipe delivers the elemental metal Cr powder contained in the powder feeder to the printing area, and controls the movement of the working head according to the laser scanning path planning in the third powder processing data until the deposition of a preset number of elemental metal Cr layers is completed on the elemental metal Ce layer; switching the type of powder transported by the powder delivery pipe so that the powder delivery pipe delivers the stainless steel powder contained in the powder feeder to the printing area, and controls the movement of the working head according to the laser scanning path planning in the fourth powder processing data until the deposition of the stainless steel layer is completed on the elemental metal Cr layer, thereby obtaining a titanium-steel multi-material component.

6. A titanium-steel multi-material laser additive manufacturing method for improving interface bonding and forming performance by suppressing element diffusion through an intermediate layer, which is realized based on the titanium-steel multi-material laser additive manufacturing device for improving interface bonding and forming performance by suppressing element diffusion through an intermediate layer as claimed in claim 5, characterized in that: After cleaning the titanium alloy substrate, a laser directed energy deposition process is used to sequentially deposit a titanium alloy layer, a single metal Ce layer, a single metal Cr layer, and a stainless steel layer on the surface of the titanium alloy substrate by controlling the powder feeding rate, defocusing amount, overlap rate, and shielding gas flow rate, thereby obtaining a titanium steel multi-material component with good interface metallurgical bonding and excellent performance, which specifically includes the following steps: Step 1: Powder drying: Titanium alloy powder, elemental metal Ce powder, elemental metal Cr powder, and stainless steel powder were placed in a vacuum drying oven at 80°C for 10 hours to remove moisture and improve powder fluidity, and then placed in a powder feeder after drying; Step 2: Create powder processing data: Based on the laser directed energy deposition process, four independent powder processing data are created, each of which is configured with laser printing process parameters and laser scanning path planning; The four sets of powder processing data correspond to the first to fourth powder processing data, where: The first powder processing data is used to deposit melted titanium alloy powder to form a titanium alloy layer; The second powder processing data is used to deposit and melt the single-element metal Ce powder to form a single-element metal Ce layer; The third powder processing data is used to deposit and melt the single metal Cr powder to form a single metal Cr layer; The fourth powder processing data is used to deposit the melted stainless steel powder to form a stainless steel layer; Step 3: Place the titanium alloy substrate into the protective chamber, control the industrial robot to adjust the defocusing amount, close the door of the protective chamber after the adjustment, and introduce pure argon gas for deoxygenation; Step 4: After the oxygen content in the protected cavity drops to 50 ppm, start the laser to sequentially deposit different materials on the titanium alloy substrate to obtain a titanium-steel multi-material component with good metallurgical bonding at the interface, which specifically includes the following steps: Step 4.1, loading the first powder processing data in step 2 to first deposit a titanium alloy layer on the titanium alloy substrate; Step 4.2, after the titanium alloy layer is deposited, the defocus amount is adjusted based on the top surface of the titanium alloy layer, and the second powder processing data in step 2 is loaded to deposit a single metal Ce layer on the surface of the titanium alloy layer; Step 4.3, after the deposition of the single metal Ce layer is completed, the defocus amount is adjusted based on the top surface of the single metal Ce layer, and the third powder processing data in step 2 is loaded to deposit a single metal Cr layer on the surface of the single metal Ce layer; Step 4.4, after the deposition of the single metal Cr layer is completed, the defocus amount is adjusted based on the top surface of the single metal Cr layer, and the fourth powder processing data in step 2 is loaded to deposit a stainless steel layer on the surface of the single metal Cr layer, and finally a titanium-steel multi-material component with a good metallurgical bonding interface is obtained.

7. The titanium-steel multi-material laser additive manufacturing method of claim 6, characterized in that: The powder feeding rate is 10 g / min, the defocusing amount is 2-3 mm, the overlapping rate is 50%, and the protective gas flow rate is 14-16 L / min.

8. The titanium-steel multi-material laser additive manufacturing method of claim 6, wherein the method comprises: The particle size of the TC4 powder is 53-150 μm, and the Al content of the TC4 powder is 6.75 wt.%, the V content is 4.5 wt.%, and the rest is Ti; the particle size of the SS316 powder is 53-150 μm, and the SS316 powder has a Cr content of 18.0 wt.%, a Ni content of 10.0 wt.%, a Mo content of 2.5 wt.%, and the rest is Fe; The particle size of the single-element metal Ce powder is 20 to 130 μm, and the particle size of the single-element metal Cr powder is 20 to 130 μm.

9. The titanium-steel multi-material laser additive manufacturing method of claim 6, characterized in that: In the first powder processing data, the laser power is 700W and the scanning speed is 10mm / s; In the second powder processing data, the laser power is 700W and the scanning speed is 10mm / s; In the third powder processing data, the laser power is 900W and the scanning speed is 10mm / s; In the fourth powder processing data, the laser power is 1000 W and the scanning speed is 8 mm / s.

10. The titanium-steel multi-material laser additive manufacturing method of claim 6, wherein the method suppresses element diffusion through an intermediate layer to improve interface bonding and forming performance, is characterized in that: After the titanium alloy layer is deposited on the titanium alloy substrate, step 4.2 is repeated to deposit two or more single metal Ce layers on the titanium alloy layer; after the single metal Ce layer is deposited, step 4.3 is repeated to deposit two or more single metal Cr layers on the single metal Ce layer.

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