Selective laser melting manufacturing method of particle reinforced titanium-based composite material component

Abstract

The invention discloses a selective laser melting manufacturing method of a particle reinforced titanium-based composite material component, which comprises the following steps of: controlling energy input of preheating laser and forming laser in a forming process, so that stress generated in the composite material component is fully released above a low-plasticity temperature interval of the composite material component; and cracks are prevented from being generated in the selective laser melting manufacturing process or after manufacturing is completed. The method comprises the following steps: performing selective laser melting process optimization on a composite material to obtain crack-free forming process parameters of a simple structure, and measuring a low-plasticity temperature interval of the material; based on the optimized process parameters, the laser power and the scanning speed of the preheated laser are adjusted, and the temperature of the powder bed is kept above the low-plasticity temperature interval of the composite material; manufacturing of the first layer is completed according to a preset scanning path; and the preheating and selective laser melting processes are repeated to complete manufacturing of the particle reinforced titanium-based composite material component. And after the formed component is cooled, the crack-free particle reinforced titanium-based composite material component is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal additive manufacturing, and particularly relates to a selective laser melting manufacturing method for a particulate-reinforced titanium matrix composite component. Background Art

[0002] Compared with titanium alloys, particulate-reinforced titanium matrix composites have better wear resistance, strength, modulus and other properties, which can further broaden the application fields of titanium alloys. However, titanium matrix composites have disadvantages such as poor thermal conductivity, high chemical activity, and large deformation resistance, and are typical difficult-to-machine materials. Selective laser melting technology can achieve moldless, rapid, high-density, and integrated near-net forming of high-performance complex metal components, and has broad application prospects in the fields of aerospace, aviation, medical, 3C, etc. It has received great attention and emphasis in the industrial community and is considered an ideal processing method for titanium alloys and titanium matrix composites. At present, the research and application of selective laser melting of titanium alloys have been relatively mature. However, due to the greater strength and modulus of particulate-reinforced titanium matrix composites, greater stresses are generated during the rapid heating / cooling process of selective laser melting. Therefore, most particulate-reinforced titanium matrix composites can only be formed into simple structures under laboratory conditions. For complex components with sudden changes in cross-sectional area that are commonly found, stress concentration is extremely likely to occur at the sudden change in cross-sectional area, causing microcracks or even overall cracking when the composite component cools, which is the main obstacle for selective laser melting of particulate-reinforced titanium matrix composites to move from the laboratory to practical applications.

[0003] In order to solve the problem that cracks are easily generated in the process of selective laser melting of difficult-to-machine particulate-reinforced titanium matrix composite components, a method of preheating the substrate is generally used, but the overall effect is not good. On the one hand, the preheating temperature of the substrate of current commercial selective laser melting equipment is generally lower than 200 o °C, and the preheating effect of the substrate decays severely along the deposition height direction; on the other hand, the selection of the preheating temperature does not fully consider the law of material properties changing with temperature. When the plasticity of the material is poor in the selected preheating temperature range, the problems of deformation and cracking of particulate-reinforced titanium matrix composites and components cannot be effectively solved. Summary of the Invention

[0004] The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and provide a selective laser melting manufacturing method for a particulate-reinforced titanium matrix composite component and a particulate-reinforced titanium matrix composite component obtained by the above selective laser melting manufacturing method. This method uses a dual-beam of preheating laser and forming laser, and by synergistically controlling the energy input of the preheating laser and the forming laser during the forming process, the stress generated inside the particulate-reinforced titanium matrix composite component is fully released above the temperature range of the low plasticity region of the material, thereby avoiding cold cracks from occurring during the process of the component cooling to room temperature.

[0005] To achieve the first above-mentioned objective, the present invention adopts the following technical solutions:

[0006] A selective laser melting manufacturing method for a difficult-to-machine particle-reinforced titanium matrix composite component. First, optimize the selective laser melting process for the particle-reinforced titanium matrix composite to obtain the forming process parameters of a crack-free single track. Measure its tensile properties at different temperatures according to the tensile test method for metallic materials, and determine the low-plasticity temperature range of this material (the temperature range where the elongation is less than 5%). Based on the selective laser melting process parameters, adjust the laser power and scanning speed of the preheating laser to keep the powder bed temperature above the low-plasticity temperature range of the printing material while avoiding sintering of the powder. Then, use the optimized selective laser melting process parameters to complete the manufacturing of the first layer according to the preset scanning path. Repeat the preheating and selective laser melting processes to complete the manufacturing of the particle-reinforced titanium matrix composite component. Finally, naturally cool the formed component to room temperature to obtain a crack-free particle-reinforced titanium matrix composite component.

[0007] The above-mentioned selective laser melting manufacturing method for a difficult-to-machine particle-reinforced titanium matrix composite component includes the following steps:

[0008] S1. In an inert gas protection chamber, optimize the selective laser melting process for the particle-reinforced titanium matrix composite to obtain the forming process parameters of a crack-free single track. The forming process parameters include the laser power and scanning speed of the preheating laser and the forming laser.

[0009] S2. Under normal conditions, use the above-optimized process parameters to complete the preparation of tensile specimens and test their tensile plasticity at different temperatures to clarify the temperature range where the elongation is less than 5%.

[0010] S3. Based on the forming process parameters, adjust the laser power and scanning speed of the preheating laser, scan the entire powder bed area, and keep the powder bed temperature above the low-plasticity temperature range of this composite material.

[0011] S4. Based on the forming process parameters, adjust the laser power and scanning speed of the forming laser, and complete the manufacturing of the first layer according to the preset scanning path.

[0012] S5. Repeat steps S3 and S4 to complete the multi-layer manufacturing of the particle-reinforced titanium matrix composite component.

[0013] S6. After the manufacturing is completed, naturally cool the formed component to room temperature to obtain a crack-free particle-reinforced titanium matrix composite component.

[0014] Furthermore, the reinforcing particles used in the particle-reinforced titanium matrix composite are ceramic materials including TiC (titanium carbide), SiC (silicon carbide), or TiB (titanium boride), etc., or high-melting-point metals such as W (tungsten). The scale of the reinforcing particles is nanoscale or micron-scale.

[0015] Further, the titanium matrix in the particle-reinforced titanium matrix composite is pure titanium or a titanium alloy, and the titanium alloy is selected from one of α-titanium alloy, β-titanium alloy, and α+β-titanium alloy.

[0016] Further, in step S3, the laser power of the preheating laser is 1000W - 3000W, the spot diameter is 1mm - 5mm, and the scanning speed is 0.1m / s - 2m. Applying the preheating laser within this parameter range can keep the temperature of the powder bed and the formed part above the low plastic zone of this material for stress release, while avoiding powder melting or sintering into blocks.

[0017] Further, in step S3, the temperature of the powder bed is obtained by a thermocouple or infrared thermal imaging technology, and is adjusted by PID (Proportional-Integral-Derivative) to keep the temperature of the powder bed and the formed part always above the low plastic temperature zone of this material.

[0018] Further, the low plastic temperature range of the composite material in step S2 is determined based on the tensile plasticity of the composite material at different temperatures. An elongation rate lower than 5% is considered low plasticity. When the elongation rate of the material is higher than 5%, the cracking sensitivity of its components at this temperature will be significantly reduced. The tensile plasticity of the composite material at different temperatures is obtained according to the metal material tensile test standard. The test temperature starts from room temperature and increases by 20 o °C - 50 o °C for testing, and the temperature range with an elongation rate lower than 5% is determined based on the test results.

[0019] Further, in step S4, the laser power of the forming laser is 200W - 1000W, the spot diameter is 20μm - 100μm, and the scanning speed is 0.1m / s - 5m / s. Forming within this parameter range can reduce the porosity and poor fusion defects in the formed part, and keep the composite material with good metallurgical quality.

[0020] Further, in step S3, the scanning times of the preheating laser are one or more times according to the temperature measurement results, so as to ensure that the temperature of the powder bed is above the low plastic temperature range of this composite material.

[0021] Further, the energy density of the preheating laser is lower than that of the forming laser, avoiding powder melting or sintering into blocks during preheating, thus ensuring the geometric accuracy of the formed part and reducing the workload of removing bonded powder during the post-treatment process.

[0022] In order to achieve the above second object, the present invention adopts the following technical solutions:

[0023] A particle-reinforced titanium matrix composite component is prepared by using the selective laser melting manufacturing method of the above-mentioned particle-reinforced titanium matrix composite component.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] (1) The selective laser melting manufacturing method of the difficult-to-machine particle-reinforced titanium matrix composite component provided by the present invention can fully release the stress generated inside the particle-reinforced titanium matrix composite component above the low-plasticity temperature range of the material by synergistically controlling the energy input of the preheating laser and the forming laser during the forming process, avoiding the generation of cold cracks during or after the selective laser melting manufacturing process, so as to realize the selective laser melting manufacturing of the crack-free particle-reinforced titanium matrix composite component.

[0026] (2) The selective laser melting manufacturing method of the difficult-to-machine particle-reinforced titanium matrix composite component provided by the present invention performs forming above the low-plasticity temperature range of the material. Under this temperature condition, the stress during the manufacturing process can be fully released. At the same time, the microstructure of the composite material will also fully evolve, realizing in-situ regulation of the microstructure of the composite material, thereby reducing the energy consumption in the subsequent heat treatment process. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a 1wt% nano-TiC reinforced TC4 alloy composite component in Embodiment 1 of the present invention;

[0029] Figure 2 It is a schematic diagram of the composite component in Comparative Example 1 of the present invention;

[0030] Figure 3 It is a 2wt% micron-TiB reinforced TA15 alloy composite component in Embodiment 2 of the present invention;

[0031] Figure 4 It is a schematic diagram of the composite component in Comparative Example 2 of the present invention;

[0032] Figure 5 It is a flow chart of the selective laser melting manufacturing method of a difficult-to-machine particle-reinforced titanium matrix composite component disclosed in the embodiments of the present invention. Detailed Embodiments

[0033] To enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of this application.

[0034] In this application, the mention of "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of this application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in this application can be combined with other embodiments.

[0035] Embodiment 1

[0036] As Figure 5 shown, this embodiment specifically discloses a selective laser melting manufacturing method for a 1wt% nano-TiC reinforced TC4 alloy composite component. The steps of this selective laser melting manufacturing method are as follows:

[0037] S1. Optimize the selective laser melting process for the 1wt% nano-TiC reinforced TC4 alloy composite to obtain the forming process parameters of a crack-free single pass: laser power 230W, scanning speed 800mm / s, and spot diameter 80μm. When forming, use TC4 alloy as the substrate, and the forming process is carried out in an argon atmosphere;

[0038] S2. Use the above optimized process parameters to complete the preparation of tensile specimens. After machining, measure their tensile properties at different temperatures according to the metal material tensile test method. The temperature range where the elongation of the 1wt% nano-TiC reinforced TC4 alloy composite is lower than 5% is from room temperature to 360°C.

[0039] S3. Based on the optimized forming process parameters, adjust the spot diameter (3mm), laser power (2000W), and scanning speed (1200mm / s) of the preheating laser, scan the entire powder bed surface, and the powder bed temperature measured by the infrared thermometer is maintained at 360 - 400 o °C, and the corresponding material elongation is 5 - 7.2%, which does not belong to the low plasticity temperature range of this material;

[0040] S4. Use the optimized crack-free single pass forming process parameters: laser power 230W, scanning speed 800mm / s, and spot diameter 80μm. Perform slicing and path planning based on the three-dimensional model of the formed part, and complete the first layer scan according to the preset scan path;

[0041] S5. Repeat steps S3 and S4 to complete the manufacturing of the particle-reinforced titanium matrix composite component;

[0042] S6. After manufacturing, naturally cool the formed component to room temperature to obtain a crack-free particle-reinforced titanium matrix composite component, as Figure 1 shown.

[0043] Comparative Example 1

[0044] For the 1wt% nano-TiC reinforced TC4 alloy composite, the selective laser melting process was optimized to obtain the forming process parameters for a crack-free single track: laser power 230W, scanning speed 800mm / s, and spot diameter 80μm; the component was manufactured using the above optimized selective laser melting process parameters according to the preset scanning path; the infrared thermometer measured that the powder bed temperature during the forming process remained at 80 - 300 o °C, and the corresponding material elongation was 0.2 - 4.5%, which belongs to the low plasticity temperature range of this material; after the forming was completed, the formed component was naturally cooled to room temperature to obtain a cracked 1wt% nano-TiC reinforced TC4 alloy composite component, as Figure 2 shown.

[0045] From the 1wt% nano-TiC reinforced TC4 alloy composite components obtained in Example 1 and Comparative Example 1, it can be seen that the method provided by the present invention can obtain a crack-free 1wt% nano-TiC reinforced TC4 alloy composite component.

[0046] Example 2

[0047] As Figure 5 shown, this example further specifically discloses another selective laser melting manufacturing method for a 2wt% micron-TiB reinforced TA15 alloy composite component. The steps of this selective laser melting manufacturing method are as follows:

[0048] S1. For the 2wt% TiB reinforced TA15 alloy composite, the selective laser melting process was optimized to obtain the forming process parameters for a crack-free single track: laser power 350W, scanning speed 900mm / s, and spot diameter 80μm. TA15 alloy was used as the substrate during forming, and the forming process was carried out in an argon atmosphere;

[0049] S2. Use the above optimized process parameters to complete the preparation of tensile specimens. After machining, measure their tensile properties at different temperatures according to the metal material tensile test method. The temperature range in which the elongation of the 2wt% nano-TiB reinforced TA15 alloy composite is less than 5% is from room temperature to 460°C.

[0050] S3. Based on the optimized forming process parameters, adjust the spot diameter (3 mm), laser power (2800 W), and scanning speed (1000 mm / s) of the preheating laser, scan the entire powder bed area, and the powder bed temperature measured by the infrared thermometer is 460 - 500 o °C, and the corresponding material elongation is 5 - 6.5%, which does not belong to the low - plasticity temperature range of this material;

[0051] S4. Adopt the optimized crack - free single - pass forming process parameters: laser power 350 W, scanning speed 900 mm / s, and spot diameter 80 μm. Based on the three - dimensional model of the formed part, perform slicing and path planning, and complete the first - layer scanning according to the preset scanning path;

[0052] S5. Repeat steps S3 and S4 to complete the manufacturing of the TiB - reinforced TA15 alloy composite component. After testing, the density of the formed part reaches 99.8% when formed with these parameters;

[0053] S6. After manufacturing, naturally cool the formed component to room temperature to obtain a crack - free particle - reinforced titanium - matrix composite component, as Figure 1 shown.

[0054] Comparative Example 2

[0055] Optimize the selective laser melting process for 2wt% micron TiB - reinforced TA15 alloy composite to obtain the crack - free single - pass forming process parameters: laser power 350 W, scanning speed 900 mm / s, and spot diameter 80 μm; use the above - optimized selective laser melting process parameters to complete the manufacturing of the component according to the preset scanning path; the infrared thermometer measures that the powder bed temperature remains at 100 - 430 o °C, and the corresponding material elongation is 0.2 - 4.7%, which belongs to the low - plasticity temperature range of this material; naturally cool the formed component to room temperature to obtain a cracked 2wt% nano - TiB - reinforced TA15 alloy composite component, as Figure 4 shown.

[0056] From the 2wt% micron TiB - reinforced TA15 alloy composite components obtained in Example 2 and Comparative Example 2, it can be seen that the method provided by the present invention can obtain crack - free 2wt% micron TiB - reinforced TA15 alloy composite components.

[0057] In summary, through the comparison of the above - mentioned examples and comparative examples, it can be seen that the method provided by the present invention avoids the cold cracks generated during or after the selective laser melting manufacturing of particle - reinforced titanium - matrix composites, thereby realizing the selective laser melting manufacturing of crack - free particle - reinforced titanium - matrix composite components.

[0058] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0059] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A selective laser melting manufacturing method for a particulate-reinforced titanium matrix composite component, characterized in that The selective laser melting manufacturing method described above includes the following steps: S1. In an inert gas protection chamber, optimize the selective laser melting process for the particle-reinforced titanium matrix composite material to obtain the forming process parameters of a crack-free single pass. The forming process parameters include the laser power and scanning speed of the preheating laser and the forming laser; S2. Under normal conditions, use the optimized forming process parameters described above to complete the preparation of tensile specimens, and test the tensile plasticity of the tensile specimens at different temperatures to determine the low plasticity temperature range where the elongation rate is less than 5%; S3. Based on the forming process parameters, adjust the laser power and scanning speed of the preheating laser, and scan the entire powder bed area to keep the powder bed temperature above the low plasticity temperature range of this composite material; S4. Based on the forming process parameters, adjust the laser power and scanning speed of the forming laser, and complete the manufacturing of the first layer according to the preset scanning path; S5. Repeat steps S3 and S4 to complete the multi-layer manufacturing of the particle-reinforced titanium matrix composite material component; S6. After the manufacturing is completed, naturally cool the formed component to room temperature to obtain a crack-free particle-reinforced titanium matrix composite material component.

2. The selective laser melting manufacturing method of a particle-reinforced titanium matrix composite component according to claim 1, characterized in that, The reinforcing particles used in the particle-reinforced titanium matrix composite material are ceramic materials or metals with a melting point as high as that of tungsten. The ceramic materials are TiC, SiC or TiB, and the scale of the reinforcing particles is nanoscale or micron-scale.

3. The selective laser melting manufacturing method of a particle-reinforced titanium matrix composite component according to claim 1, characterized in that, The titanium matrix is pure titanium or a titanium alloy.

4. The selective laser melting manufacturing method of a particulate reinforced titanium matrix composite component according to claim 1, characterized in that In step S3, the laser power of the preheating laser is 1000W to 3000W, the spot diameter is 1mm to 5mm, and the scanning speed is 0.5m to 2m.

5. The selective laser melting manufacturing method of a particulate reinforced titanium matrix composite component according to claim 1, characterized in that, In step S3, the powder bed temperature is obtained through a thermocouple or infrared thermal imaging technology, and is adjusted through proportional-integral-derivative control.

6. The selective laser melting manufacturing method of a particulate-reinforced titanium matrix composite component according to claim 1, characterized in that, The determination process of the low plastic temperature range of the composite material in step S2 is as follows: The test temperature starts from room temperature and increases by 20 o °C to 50 o °C for testing, and the temperature range with an elongation rate lower than 5% is determined based on the test results.

7. The selective laser melting manufacturing method of a particulate reinforced titanium matrix composite component according to claim 1, characterized in that, In step S4, the laser power of the forming laser is 200W to 1000W, the spot diameter is 20μm to 100μm, and the scanning speed is 0.1m / s to 5m / s.

8. The selective laser melting manufacturing method of a particulate reinforced titanium matrix composite component according to claim 1, characterized in that In step S3, the scanning times of the preheating laser are scanned once or multiple times according to the temperature measurement results.

9. The selective laser melting manufacturing method of a particle-reinforced titanium matrix composite component according to claim 1, characterized in that, The energy density of the preheating laser is lower than that of the forming laser to avoid melting or sintering of the powder during preheating.

10. A particulate-reinforced titanium matrix composite component, characterized in that, Prepared by using the selective laser melting manufacturing method for a particle-reinforced titanium matrix composite material component described in any one of claims 1 to 9 above.

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