Method for preparing TA10 titanium alloy with high strength and high corrosion resistance through selective laser melting

Abstract

The invention discloses a method for preparing TA10 titanium alloy with high strength and high corrosion resistance through selective laser melting, and relates to the technical field of metal material preparation. The invention aims to solve the problem that the mechanical property and the corrosion resistance of the material are difficult to improve in the preparation of the existing selective laser melting titanium alloy. TA10 titanium alloy powder is prepared through an argon atomization method to serve as a raw material for selective laser melting forming. Titanium alloy powder is melted and accumulated layer by layer by means of selective laser melting equipment, and finally the selective laser melting titanium alloy block with excellent mechanical property and corrosion resistance is obtained. Compared with the prior art, the prepared selective laser melting titanium alloy does not need subsequent heat treatment, has excellent plasticity and tensile property isotropy in the form forming process, and also has good corrosion resistance. The alloy is prepared through a selective laser melting method, parts with precise structures can be directly formed, and meanwhile the performance is improved. The method is used for preparing the titanium alloy.

Description

Technical Field

[0001] The present invention relates to a preparation method of a novel titanium alloy, belonging to the technical field of metal material preparation, and specifically to a special preparation process for enhancing comprehensive performance by changing the internal microstructure of a TA10 titanium alloy, wherein the alloy has high yield strength and high corrosion resistance at room temperature. Background Art

[0002] my country has rich marine resources, and how to effectively develop and utilize them is a topic worth exploring. In the process of exploring the ocean, the service environment of components is complex and harsh, and the engineering materials used must have good mechanical properties and good corrosion resistance. Usually in the ocean, metal components are subject to large hydrostatic pressure, which affects the adsorption and penetration of hydrogen, thereby increasing the possibility of corrosion. At the same time, as a ship hull or a pipeline material for transporting oil and gas, its service environment is often an acidic medium, so it is necessary to have good and stable corrosion resistance. Titanium alloys are widely used in the preparation of large-scale equipment and components in the field of marine engineering because of their good corrosion resistance, high specific strength and non-magnetic properties. In marine engineering, the use of titanium alloys instead of steel materials can significantly reduce the overall weight of components and extend their service life, and has good development prospects.

[0003] In recent years, people have continuously optimized the corrosion resistance and mechanical properties of titanium alloys through alloying and improving rolling and smelting parameters, giving them a broader application prospect. The continuous improvement of mechanical properties has enabled TA10 titanium alloy, which has good corrosion resistance, to undertake more structural parts manufacturing in the field of marine ships. However, rolling and traditional casting processes are difficult to meet the manufacturing of precision parts and the production of key structural parts in this field.

[0004] The publication number is CN112981177A, and the name is the invention patent of titanium alloy powder that can be used for selective laser melting 3D printing, selective laser melting titanium alloy and its preparation. Although it greatly improves the anisotropy of the material by selective laser melting titanium alloy to improve the alloy performance, the matrix material it uses is Ti-6Al-4V (TC4), and the corresponding preparation process is carried out for the performance required by industrial fields such as aviation, aerospace, military industry and biomedicine. Although it has certain corrosion resistance, if the product prepared by it is used in the seabed, due to the presence of α+β phases in the alloy structure, it is more prone to galvanic corrosion under long-term corrosion in seawater, resulting in a continuous decline in corrosion resistance. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the mechanical properties and corrosion resistance of the material itself are difficult to improve in the preparation of existing selective laser melting titanium alloys, and further provide a method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting.

[0006] The technical solution of the present invention is: a method for preparing a high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting, which comprises the following steps:

[0007] Step 1: Raw materials preparation;

[0008] TA10 titanium alloy powder prepared by argon atomization method was selected as the raw material for selective laser melting and dried. The oven temperature was set to 60°C and the holding time was 2 hours.

[0009] Step 2: Establish a structural model for the target part, then perform two-dimensional slicing on the three-dimensional model of the target part, and then import the two-dimensional slicing into the selective laser melting forming equipment;

[0010] Step 3: Setting the processing parameters of the selective laser melting process and performing the selective laser melting process;

[0011] Among them, the processing parameters are: the preset temperature of the substrate is 200-260°C, the laser power is 260-350W, the powder layer thickness is 30μm-60μm, the scanning rate is 1000mm / s-1600mm / s, and the scanning spacing is 90μm-130μm;

[0012] Step 4: Perform wire cutting and surface treatment on the processed parts in sequence: After removing the support from the parts, perform surface treatment to obtain TA10 titanium alloy parts.

[0013] Furthermore, the TA10 titanium alloy powder in step one is composed of 3-6wt% of powder with a particle size less than 15μm, 0-5wt% of powder with a particle size greater than 53μm, and the remainder of powder with a particle size of 15μm-53μm.

[0014] Preferably, the bulk density of the TA10 titanium alloy powder prepared by the argon atomization method in step 1 is 1.9 g / cm 3 -2.5g / cm 3 , tap density is 2.5g / cm 3 -2.9g / cm 3 .

[0015] Furthermore, in step 2, a structural model of the desired target part is constructed using 3D software and saved in STL format. Support is added to the constructed model through additive manufacturing processing software, and then 2D slicing is performed. After 2D slicing, the model is imported into a selective laser melting device.

[0016] Furthermore, in the selective laser melting forming process described in step three, high-purity argon gas is introduced into the laser selection equipment, and the selective laser melting equipment is purged with high-purity argon gas. The purging operation reduces the oxygen content in the selective laser melting equipment to below 1000 ppm.

[0017] Preferably, in step three, the substrate is made of TC4 titanium alloy.

[0018] Preferably, in step three, the substrate is preheated to 200-260°C.

[0019] Preferably, the parameters of the laser selective melting equipment in step three are: the power of the laser is 260-350W; a cross scanning method is adopted and each layer is rotated 67°, the scanning speed is 1000-1600mm / s, the scanning spacing is 90μm-130μm, the thickness of each titanium alloy powder layer is 30μm-60μm, and the oxygen content inside the working chamber is less than 1000ppm.

[0020] Furthermore, the surface treatment in step 4 is surface cleaning, surface grinding and surface sandblasting in sequence, wherein the surface cleaning process is: ultrasonic cleaning with anhydrous ethanol as the cleaning medium, and the cleaning time is 10min-60min; the surface grinding process is: grinding on #400, #800, #1000, #2000 and #3000 sandpaper in sequence until the surface is flat and smooth.

[0021] Compared with the prior art, the present invention has the following effects:

[0022] 1. The substantial improvement in the TA10 titanium alloy manufactured by SLM proposed in the present invention is due to the anisotropy of the performance of the material produced by 3D printing. Specifically, the TA10 titanium alloy formed by 3D printing has differences in mechanical properties parallel to the stacking direction (i.e., along the xy plane) and perpendicular to the stacking direction (i.e., along the xz plane) during the forming process. In addition to the lack of significant differences in mechanical properties, the TA10 parts produced using this process were immersed in 5M HCl for ten days for a static immersion test, and the corrosion levels of the various surfaces of the parts were similar. This proves that its corrosion resistance is less affected by the forming direction during 3D printing and is also isotropic.

[0023] 2. The elongation of the TA10 titanium alloy manufactured by the selective laser melting proposed in the present invention is significantly improved compared with the Ti-6Al-4V alloy manufactured by the selective laser melting. Specifically, through the tensile test, the results obtained are as follows: the tensile strength perpendicular to the stacking direction is not less than 964.13MPa, and the total elongation at break is 14.61%; the tensile strength parallel to the stacking direction is not less than 990.51MPa, and the total elongation at break is 13.44%.

[0024] 3. The present invention selects and optimizes the printing parameters for the selective laser melting process, and selects the SLM printing parameters suitable for TA10 titanium alloy powder. The micromorphology of the titanium alloy can be adjusted by changing the printing parameters, and the grains of the alloy can be refined to a great extent, and finally a titanium alloy with high elongation and isotropic performance is obtained. Through the optimization and adjustment of the printing parameters, the titanium alloy parts printed by the SLM method directly meet the design requirements of titanium alloys for aviation, such as the standard "GJB2218A-2008-Aerospace Titanium and Titanium Alloy Bars and Forgings", which requires that the titanium alloy parts printed by the SLM method have a tensile strength of not less than 895MPa and an elongation of not less than 10%.

[0025] 4. The present invention adopts the technology of selective laser melting (SLM). The present invention provides a method for preparing TA10 titanium alloy parts by selective laser melting forming technology. TA10 titanium alloy powder is prepared as raw material by argon atomization method. By optimizing the process parameters of selective laser melting, TA10 titanium alloy structural parts are prepared, which can not only prevent element segregation, eliminate defects such as cracks, looseness, shrinkage cavities in material structure, but also refine the grain size of the structure to a certain extent, and improve the corrosion resistance and mechanical properties of the material. The parts produced by the present invention have a forming accuracy of ±0.05mm, a surface roughness Ra of less than 10μm, a density of more than 98%, no obvious microcracks in the sample microstructure, and a pore defect size of less than 2μm. When forming, the parts parallel to the stacking direction or perpendicular to the stacking direction have a tensile strength greater than 964.13MPa and an elongation greater than 13.44%, and finally obtain TA10 titanium alloy parts with dense structure, few defects and good comprehensive performance.

[0026] Description of the drawings

[0027] Figure 1 It is the XRD diagram of the sample manufactured by SLM process in the present invention, SLM-XY represents the components parallel to the stacking direction during the forming process, and SLM-XZ represents the components perpendicular to the stacking direction during the forming process.

[0028] Figure 2 It is a sample organization diagram manufactured by SLM process in the present invention. Among them, a1 and a2 are samples printed along the XY plane; b1 and b2 are samples printed along the XZ plane.

[0029] Figure 3is the room temperature tensile stress-strain curve of the alloy manufactured by the SLM process in the present invention. Among them, SLM-XY represents the component parallel to the stacking direction when forming, and SLM-XZ represents the component perpendicular to the stacking direction when forming. SLM-AN represents the component after heat treatment and annealing. SLM-HIP represents the component after hot isostatic pressing.

[0030] Figure 4 The TA10 titanium alloy manufactured by the SLM process in the present invention is shown in the microstructure diagram (a) after being immersed in 5M HCl for 10 days, and the corrosion depth cross-sectional diagram (b). DETAILED DESCRIPTION

[0031] Specific implementation method 1: A method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting in this implementation method comprises the following steps:

[0032] Step 1: Raw materials preparation;

[0033] TA10 titanium alloy powder prepared by argon atomization method was selected as the raw material for selective laser melting and dried. The oven temperature was set to 60°C and the holding time was 2 hours.

[0034] Step 2: Establish a structural model for the target part, then perform two-dimensional slicing on the established three-dimensional model of the target part, and import the two-dimensional slicing into the selective laser melting forming equipment;

[0035] Step 3: Setting the processing parameters of the selective laser melting process and performing the selective laser melting process;

[0036] Among them, the processing parameters are: the preset temperature of the substrate is 200-260°C, the laser power is 260-350W, the powder layer thickness is 30μm-60μm, the scanning rate is 1000mm / s-1600mm / s, and the scanning spacing is 90μm-130μm;

[0037] Step 4: Perform wire cutting and surface treatment on the processed parts in sequence: After removing the support from the parts, perform surface treatment to obtain TA10 titanium alloy parts.

[0038] The present invention uses the technology of selective laser melting (SLM) to provide a method for preparing TA10 titanium alloy parts by selective laser melting forming technology, selects argon atomization method to prepare TA10 titanium alloy powder as raw material, and prepares TA10 titanium alloy structural parts by optimizing the process parameters of selective laser melting, which can not only prevent element segregation, eliminate defects such as cracks, looseness, shrinkage cavities in material structure, but also refine the structure grains to a certain extent, and improve the corrosion resistance and mechanical properties of the material. The parts produced by the present invention have a forming accuracy of ±0.05mm, a surface roughness Ra of less than 10μm, a density of more than 98%, no obvious microcracks in the sample microstructure, a pore defect size of less than 2μm, a tensile strength of more than 960MPa, and an elongation of more than 13%, and finally obtain TA10 titanium alloy parts with dense structure, few defects and good comprehensive performance.

[0039] Specific implementation method 2: The TA10 titanium alloy powder in step 1 of this implementation method is composed of 3-6wt% of powder with a particle size less than 15μm, 0-5wt% of powder with a particle size greater than 53μm and the remainder of powder with a particle size of 15μm-53μm.

[0040] With such a configuration, the powder with a particle size less than 15 μm should control its content ratio in the overall powder. A high ratio can easily cause a large distribution range of powder particle size. During the selective laser melting forming process, the powder has different absorption rates of laser, which makes the performance of the formed part unstable. However, fine powder has a large sintering driving force, which is conducive to laser sintering. At the same time, fine particles fill the gaps in large particles, which can reduce the gaps in the formed part and improve the density and strength of the formed part. Therefore, a portion of fine particle powder needs to be retained. Powder with a particle size greater than 53 μm is one of the main reasons for the rough surface and poor forming accuracy of the formed part. Therefore, it is necessary to control it through vibration screening and airflow classification technology to reduce its content as much as possible. Other components and connection relationships are the same as those in the first specific implementation method.

[0041] Specific embodiment 3: The bulk density of the TA10 titanium alloy powder prepared by the argon atomization method in step 1 of this embodiment is 1.9 g / cm 3 -2.5g / cm 3 , tap density is 2.5g / cm 3 -2.9g / cm 3 .

[0042] In this way, during the printing process of each powder layer, the loose / tapped density affects the stability of the forming process, and the powder that meets the requirements can avoid stress cracking during printing and ensure a good internal state of the tissue. Other components and connection relationships are the same as those of the first or second specific implementation.

[0043] Specific implementation method 4: In step 2 of this implementation method, a structural model of the desired target part is constructed using 3D software and saved in STL format. The constructed model is supported by additive manufacturing processing software, and then two-dimensional slicing is performed. After two-dimensional slicing, the selective laser melting device is introduced. In this way, the selective laser melting forming device in step 2 is the Farsoon FS271M device. The other components and connection relationships are the same as those of specific implementation methods 1, 2 or 3.

[0044] Specific embodiment 5: In the selective laser melting forming process described in step 3 of this embodiment, high-purity argon gas is introduced into the laser selection equipment, and the selective laser melting equipment is purged with high-purity argon gas, and the purging operation reduces the oxygen content in the selective laser melting equipment to less than 1000 ppm. The other components and connection relationships are the same as those of specific embodiments 1, 2, 3 or 4.

[0045] Specific implementation method six: In step three of this implementation method, the substrate is made of TC4 titanium alloy.

[0046] In this way, using a TC4 alloy plate having similar thermophysical properties to the TA10 titanium alloy used in the parts as the substrate can prevent the parts from warping in the part close to the substrate due to rapid cooling during the printing process. Other components and connection relationships are the same as those in the first, second, third, fourth or fifth embodiments.

[0047] The base alloy TA10 used in the present invention is derived from an experimental alloy with a nominal composition of Ti-0.3Mo-0.8Ni, which was announced by the Timet Division of the American Titanium Metal Company in October 1974. This alloy has good processing performance, has a low cathode overvoltage compared to pure titanium, and has good corrosion resistance in chloride solutions and weak reducing acids. It was found from the study that in a 40%-70% HNO3 solution, the corrosion rate of the TA10 titanium alloy was significantly lower than that of the Ti-0.2Pd alloy. Therefore, this alloy will be used as a base alloy and prepared by the SLM method to further improve its mechanical properties and corrosion resistance.

[0048] It can be seen that in the currently developed titanium alloy production process, the mechanical properties of TA10 titanium alloy are generally poor, or there are still casting defects such as element segregation and shrinkage and shrinkage cavities, which makes it difficult to meet the requirements of marine ship materials for both corrosion resistance and mechanical properties of structural parts. According to literature research, the tensile strength of the cast TA10 titanium alloy is 200-380MPa, and the tensile strength of the rolled state is about 500MPa. Therefore, the present invention adopts a TA10 titanium alloy with good corrosion resistance and good plasticity as the base alloy, manufactures it through a selective laser melting process, selects appropriate manufacturing parameters to eliminate defects such as more pores, improves the microstructure of the alloy, and finally obtains a TA10 titanium alloy with high corrosion resistance, high yield strength at room temperature and high tensile ductility.

[0049] The alloy prepared by the present invention has high corrosion resistance, high strength and good room temperature tensile ductility. The prepared corrosion-resistant titanium alloy has a stable close-packed hexagonal lattice structure; the TA10 titanium alloy parts manufactured by selective laser melting have excellent comprehensive mechanical properties, and the tensile strength is maintained at about 960MPa, achieving 13%-14% plasticity. This patent first prepares TA10 titanium alloy powder as raw material by argon atomization; then uses selective laser melting equipment for production; finally, the printed finished product sample block is separated from the printed substrate by wire cutting.

[0050] Specific implementation method seven: In step three of this implementation method, the substrate is first preheated to 200-260°C.

[0051] This arrangement can reduce the deformation of the bottom of the part caused by the large temperature difference between the substrate and the first few layers of powder bed that have just melted and are close to the substrate. Other components and connection relationships are the same as those of the first, second, third, fourth, fifth or sixth embodiments.

[0052] Specific implementation method eight: In step three of this implementation method, the parameters of the laser selective melting equipment are: the power of the laser is 260-350W;

[0053] A cross scanning method is adopted and each layer is rotated 67°. The scanning speed is 1000-1600mm / s, the scanning interval is 90μm-130μm, the thickness of each titanium alloy powder layer is 30μm-60μm, and the oxygen content inside the working chamber is less than 1000ppm.

[0054] With such arrangement, the present invention uses a selective laser melting device to melt and deposit the titanium alloy powder bed layer by layer to obtain a TA10 titanium alloy component, which is the target product.

[0055] Furthermore, the preparation process of the TA10 titanium alloy block is specifically as follows:

[0056] The TA10 titanium alloy powder is dried, sieved and placed in the powder feeding cylinder of the laser selective melting equipment;

[0057] Preheat the substrate of the laser selective melting equipment, and introduce argon gas into the working chamber to prevent oxidation during the printing process. During the printing process, the bed of titanium alloy powder is scanned and melted by laser, and after each layer is scanned, the substrate is lowered by one layer thickness, the powder feeding bin is raised by one layer thickness, and a new layer of titanium alloy powder is laid by reciprocating motion of a scraper. During the processing, the laser is controlled to use a cross-scanning method, and after each layer is scanned, it rotates 67° and then scans the next layer. This operation is repeated until all preset slices are completed, and a titanium alloy block of the target size is obtained by stacking layer by layer, which is the target product. The other components and connection relationships are the same as any one of the specific implementation methods one to seven.

[0058] Specific implementation nine: The surface treatment described in step four of this implementation is surface cleaning, surface grinding and surface sandblasting in sequence, wherein the surface cleaning process is: ultrasonic cleaning with anhydrous ethanol as the cleaning medium, and the cleaning time is 10min-60min; the surface grinding process is: grinding on #400, #800, #1000, #2000 and #3000 sandpaper in sequence until the surface is flat and smooth. Such an arrangement can form parts with good surface quality, excellent performance and service conditions. Other components and connection relationships are the same as any one of the specific implementations one to eight.

[0059] Combination Figures 1 to 4 Describe the embodiments of the present invention:

[0060] Example 1

[0061] Step 1: Raw material pretreatment. Before selective laser melting 3D printing, the TA10 titanium alloy powder is first dried, and the oven temperature is set to 60°C for 2 hours.

[0062] Step 2: Pour the dried titanium alloy powder into a sieve with an aperture of 53 μm to obtain powder that meets the standard of "BD32 / T3599-2019 Powder for Laser Selection of Titanium Alloy Parts". Place the screened titanium alloy powder in the powder feeding cylinder of the selective laser melting equipment.

[0063] Step 3: Install the substrate for the selective laser melting equipment. Install the substrate used by the equipment and calibrate the substrate working platform. After the substrate debugging is completed, close the working chamber door of the selective laser melting equipment.

[0064] Step 4: Turn on the selective laser melting equipment and use it to preheat the substrate. The preset temperature is set to 100°C and the holding time is 30 minutes. At the same time, high-purity argon is introduced into the working chamber of the equipment, and the selective laser melting equipment is purged with high-purity argon. The purging operation reduces the oxygen content in the selective laser melting equipment to below 1000ppm to prevent oxidation of the titanium alloy during the manufacturing process. Import the part structure file.

[0065] Step 5: When the oxygen content meets the equipment requirements and the part structure file is imported, pre-powdering can be performed. Pre-powdering can ensure good fusion between the first powder layer and the substrate.

[0066] Step 6. After the pre-powdering is completed, start the selective laser melting printing of parts. During the printing process, it is necessary to ensure the introduction of argon gas so that the oxygen content in the printing chamber remains at a normal level. Set the processing parameters of the selective laser melting process and perform selective laser melting; the processing parameters are: the preset temperature of the substrate is 200-260℃, the laser power is 260-350W, the powder layer thickness is 30μm-60μm, the scanning rate is 1000mm / s-1600mm / s, and the scanning spacing is 90μm-130μm; the scanning method is cross scanning.

[0067] Step 7, the specific process of selective laser melting can be described as follows: after the laser heat source completes the scanning of the previous layer of metal powder, the substrate drops a layer thickness (30μm-60μm), and the powder feeding cylinder rises a layer thickness (30μm-60μm), so that the scraper moves to spread the powder in the powder cylinder. After the powder is spread, the laser adjusts the scanning path angle of the next layer by rotating 67° relative to the scanning path of the previous layer, and then starts scanning the next layer, repeating the powder spreading-scanning operation until all preset slices are completed. The 30×12×30mm is finally obtained through the layer-by-layer accumulation of metal powder. 3 After 3D printing is completed, the titanium alloy block and the substrate are separated by wire cutting.

[0068] The obtained TA10 titanium alloy block was subjected to wire cutting to obtain tensile specimens and static immersion corrosion specimens. The tensile mechanical properties test was carried out on the tensile specimens, and the static immersion corrosion test of 5M HCl was carried out on the corrosion specimens. The mechanical properties test results are shown in Figure 3 As shown. Figure 3It can be seen that the TA10 titanium alloy obtained by selective laser melting in this embodiment has good elongation when it is formed, and the elongation parallel to the stacking direction is slightly different from the elongation perpendicular to the stacking direction, indicating that Example 1 has good isotropy. The material obtained in this embodiment has a tensile strength of 964.13 MPa parallel to the stacking direction (hereinafter marked as XY direction, SLM-XY) and a total elongation at break of 14.61% when formed; the tensile strength perpendicular to the stacking direction (hereinafter marked as XZ direction, SLM-XZ) is 990.51 MPa, and the total elongation at break is 13.44%. At the same time, a static immersion test in accordance with GB-T 42912-2023 standard was carried out in a 5M HCl solution. The corrosion results are as follows. Figure 4 The data results are as follows: The total weight loss of TA10 titanium alloy prepared by SLM is 34.83±0.8mg / cm 2 , which is significantly lower than the total weight loss of the casting alloy (45.28±0.4mg / cm 2 ). From the weight loss results after 10 days of experiment, the TA10 titanium alloy prepared by SLM method has better corrosion resistance than the cast TA10 titanium alloy.

[0069] In this embodiment, the reason why the TA10 titanium alloy has both good mechanical properties and corrosion resistance is that the SLM process improves the microstructure of the alloy, greatly refines the grains, changes the lamellar structure of the cast TA10 titanium alloy, and produces a basket structure, such as Figure 2 As shown. Since TA10 titanium alloy mainly has α phase, Figure 1 As shown. Therefore, the refinement of the α phase makes the long α phase shorter and more oriented, and the material has more slip systems that can be activated during the tensile deformation process. The increase of slip systems inside the organization allows the deformation of the material to be more evenly distributed during the deformation process, thereby enhancing the mechanical properties. At the same time, the refined grains can reduce the segregation tendency of elements in the organization, make the distribution of elements more even, and reduce the potential difference between different organizations, thereby reducing the tendency of galvanic corrosion in the alloy matrix and improving corrosion resistance. At the same time, the grain boundary, as a defect, is a channel for reaction and also has higher energy. The increase in grain boundaries provides reaction channels and energy for the formation of a passivation film, allowing oxygen atoms to more easily form a passivation film (surface oxide) with alloy elements to protect the alloy surface from corrosion.

[0070] Example 2

[0071] The TA10 titanium alloy powder and most of the processes used are the same as those in Example 1, except that in this embodiment, the TA10 titanium alloy sample manufactured by selective laser melting is placed in a box-type heat treatment furnace for heat treatment at a temperature of 800°C. First, the heat treatment furnace is heated at a rate of 10°C / min. When the temperature of the heat treatment furnace rises to 800°C, the printed block is placed in the heat treatment furnace and kept at 800°C for 2h. After that, the power of the heat treatment furnace is turned off, and the titanium alloy tensile specimen is cooled to room temperature with the furnace, and the heat-treated specimen is taken out. The heat-treated specimen is cut into tissue specimens and tensile specimens, and the specimens are polished smooth with sandpaper, and then the performance test is performed.

[0072] In this embodiment, the selective laser melted titanium alloy component prepared by heat treatment has a higher elongation, but the strength is significantly lower than that of Example 1. Figure 3 As shown in (SLM-AN), the specimen has a higher elongation of 25.75%, but the strength decreases more to 616.04MPa. From the tensile results, it can be seen that the strength of the alloy after high-temperature heat treatment is significantly reduced. After analysis and testing, it is found that this is caused by the coarsening of its structure due to heat. Therefore, the results of selective laser melting in Example 1 are highly innovative, balance strength and plastic toughness, simplify the process, and have high practical value.

[0073] Example 3

[0074] The TA10 titanium alloy powder and most of the processes used are the same as those in Example 1, except that in this example, the TA10 titanium alloy sample manufactured by selective laser melting is subjected to hot isostatic pressing, and the processing parameters are 930±10°C, 140±10MPa, and the holding time is 2-2.5 hours. After that, the hot isostatic pressed specimen is wire cut to cut into tensile specimens, and the specimens are polished smooth with sandpaper for mechanical property testing.

[0075] In this embodiment, the selective laser melted titanium alloy component prepared by hot isostatic pressing has a higher elongation, but the strength is significantly lower than that of Example 1. After hot isostatic pressing, the internal structure of the sample is also coarsened, and the porosity is significantly reduced. The tensile results are shown in Figure 2. Figure 3 As shown in (SLM-HIP), the specimen has a higher elongation of 24.8%, but the strength decreases more to 643.05MPa, the yield point moves forward, and the yield platform becomes longer. From the tensile results, it can be seen that the strength of the alloy after hot isostatic pressing is significantly reduced. After analysis and testing, it is found that this is caused by the coarsening of its structure due to heat. Therefore, the results of selective laser melting in Example 1 are highly innovative, balance strength and plastic toughness, simplify the process, and have high practical value.

[0076] Comparative Example 1

[0077] In this comparison, Ti-6Al-4V alloy powder and Fe powder prepared by Polylite Additive Manufacturing Co., Ltd. were selected, and the powder diameter was 15-53μm. After mixing, Ti-6Al-4V+Fe powder was prepared.

[0078] Similar to the selective laser melting process in Example 1, before manufacturing, the titanium alloy powder is first dried, and the oven temperature is set to 80°C for a holding time of 2 hours. Afterwards, the dried titanium alloy powder is poured into a sieve with an aperture of 53μm for sieving, and the sieved powder is placed in the powder feeding cylinder of the selective laser melting equipment. Install the substrate for the selective laser melting equipment. Install the substrate used by the equipment and calibrate the substrate working platform. After the substrate is debugged, close the working chamber door of the selective laser melting equipment. Then, turn on the selective laser melting equipment, and use the selective laser melting equipment to preheat the substrate. The preheating temperature is set to 100°C and the holding time is 30min. At the same time, high-purity argon gas is introduced into the working chamber of the equipment, and the selective laser melting equipment is purged with high-purity argon gas. The purge operation reduces the oxygen content in the selective laser melting equipment to below 1000ppm to prevent oxidation of the titanium alloy during the manufacturing process. Import the part structure file. When the oxygen content meets the equipment requirements and the part structure file is imported, pre-powdering can be performed. Pre-powdering can ensure good fusion between the first layer of powder and the substrate. When pre-powdering is completed, start selective laser melting to print parts. During the printing process, it is necessary to ensure the introduction of argon gas so that the oxygen content in the printing chamber remains at a normal level. Set the processing parameters of the selective laser melting process and perform selective laser melting; the processing parameters are: the preset temperature of the substrate is 200-260℃, the laser power is 300-450W, the powder layer thickness is 30μm, the scanning rate is 1200mm / s, and the spot diameter is 70μm; the scanning mode is cross scanning. The specific selective laser melting process can be described as follows: after the laser heat source completes the scanning of the previous layer of metal powder, the substrate drops a layer thickness (30μm), and the powder feeding cylinder rises a layer thickness (30μm), so that the scraper moves to spread the powder in the powder cylinder. After the powder is applied, the laser adjusts the scanning path angle of the next layer, rotates the optical path 67° relative to the previous layer scanning path, and then starts scanning the next layer. The powder application-scanning operation is repeated until all preset slices are completed. The 30×12×30mm 3 After 3D printing is completed, the titanium alloy block and the substrate are separated by wire cutting.

[0079] The titanium alloy block obtained in Comparative Example 1 was wire cut to obtain a metal tensile specimen, and the tensile performance test was carried out on the tensile specimen. The alloy in this comparative example has a tensile strength of 1150MPa parallel to the stacking direction when it is formed, and a total elongation at break of 7.8%; the tensile strength perpendicular to the stacking direction is 1215MPa, but the total elongation at break is only 6.1%. The elongation at break of the laser selectively melted Ti-6Al-4V-Fe titanium alloy obtained in this comparative example is significantly lower than the elongation at break of the titanium alloy in Example 1, and the elongation parallel to the stacking direction in Comparative Example 1 is significantly lower than the elongation perpendicular to the stacking direction, indicating that Comparative Example 1 has a large anisotropy.

[0080] Although the present invention has been disclosed as above in terms of preferred embodiments, this is not intended to limit the present invention. Those skilled in the art may also make other changes within the spirit of the present invention, and apply the present invention to fields not mentioned herein. Of course, these changes made in accordance with the spirit of the present invention should be included in the scope of protection claimed by the present invention.

Claims

1. A method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting, comprising the following steps: Step 1: Raw materials preparation; TA10 titanium alloy powder prepared by argon atomization method was selected as the raw material for selective laser melting and dried. The oven temperature was set to 60°C and the holding time was 2 hours. Step 2: Establish a structural model for the target part, then perform two-dimensional slicing on the three-dimensional model of the target part, and then import the two-dimensional slicing into the selective laser melting forming equipment; Step 3: Setting the processing parameters of the selective laser melting process and performing the selective laser melting process; Among them, the processing parameters are: the preset temperature of the substrate is 200-260°C, the laser power is 260-350W, the powder layer thickness is 30μm-60μm, the scanning rate is 1000mm / s-1600mm / s, and the scanning spacing is 90μm-130μm; Step 4: Perform wire cutting and surface treatment on the processed parts in sequence: After removing the support from the parts, perform surface treatment to obtain TA10 titanium alloy parts.

2. The method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting according to claim 1, characterized in that: The TA10 titanium alloy powder in step 1 is composed of 3-6wt% of powder with a particle size less than 15μm, 0-5wt% of powder with a particle size greater than 53μm, and the remainder of powder with a particle size of 15μm-53μm.

3. The method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting according to claim 2, characterized in that: The bulk density of the TA10 titanium alloy powder prepared by the argon atomization method in step 1 is 1.9 g / cm 3 -2.5g / cm 3 , tap density is 2.5g / cm 3 -2.9g / cm 3 .

4. A method for preparing a high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting according to claim 1 or 3, characterized in that: In step 2, a structural model of the target part is constructed using 3D software and saved in STL format. The constructed model is supported by additive manufacturing processing software, and then two-dimensional slicing is performed. After two-dimensional slicing, the model is imported into the selective laser melting device.

5. The method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting according to claim 4, characterized in that: In the selective laser melting forming process described in step 3, high-purity argon gas is introduced into the laser selection equipment, and the selective laser melting equipment is purged with high-purity argon gas. The purging operation reduces the oxygen content in the selective laser melting equipment to below 1000 ppm.

6. The method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting according to claim 5, characterized in that: In step three, the substrate is made of TC4 titanium alloy.

7. The method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting according to claim 6, characterized in that: In step 3, the substrate is preheated to 200-260°C.

8. The method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting according to claim 7, characterized in that: The parameters of the laser selective melting equipment in step 3 are: the power of the laser is 260-350W; A cross scanning method is adopted and each layer is rotated 67°. The scanning speed is 1000-1600mm / s, the scanning interval is 90μm-130μm, the thickness of each titanium alloy powder layer is 30μm-60μm, and the oxygen content inside the working chamber is less than 1000ppm.

9. The method for preparing high-strength and high-corrosion-resistant TA10 titanium alloy by selective laser melting according to claim 1 or 8, characterized in that: The surface treatment described in step 4 is surface cleaning, surface grinding and surface sandblasting in sequence, wherein the surface cleaning process is: ultrasonic cleaning with anhydrous ethanol as the cleaning medium, and the cleaning time is 10min-60min; the surface grinding process is: grinding on #400, #800, #1000, #2000 and #3000 sandpaper in sequence until the surface is flat and smooth.

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