A preparation process for obtaining titanium-based composite material with excellent high-temperature tensile property

Abstract

The invention discloses a preparation process for obtaining a titanium matrix composite material with excellent high-temperature tensile properties. B4C powder and TA15 powder are placed in a ball mill according to a certain ratio for low-energy ball milling to make them fully mixed; the mixed powder is prepared into a shape through a laser melting deposition process; the formed composite material is placed in liquid nitrogen at -196°C, and the holding time is 0 < t ≤ 11 days to obtain a B4C-TA15 titanium matrix composite material. The tensile strength (tensile strength) and elongation (tensile plasticity) of the B4C-TA15 titanium matrix composite material obtained by additive manufacturing and cryogenic treatment are both improved under a high-temperature environment of 600°C.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation and processing of metal composite materials, and particularly relates to a preparation process for obtaining a titanium matrix composite material with excellent high-temperature tensile properties. Background Art

[0002] Titanium matrix composites are prepared with titanium and titanium alloys as the matrix and by adding ceramic powders such as TiB and TiC as reinforcement. Compared with other metal materials, they have the advantages of light weight, high strength, high heat resistance, good corrosion resistance, and excellent comprehensive mechanical properties, and are thus widely used in engineering fields such as aerospace, national defense, and biomedicine.

[0003] In the prior art, there is little research on additive manufacturing of titanium matrix composites, and even less research on the high-temperature mechanical properties at 600°C of titanium matrix composites prepared by additive manufacturing processes. Currently, the preparation processes for titanium matrix composites still focus on traditional manufacturing processes such as squeeze casting and powder metallurgy. Titanium matrix composites manufactured by these preparation processes often have disadvantages such as internal microcracks, voids, and low density. In contrast, titanium matrix composites prepared by additive manufacturing processes have high density and excellent properties. Therefore, additive manufacturing processes will be in an advantageous position among numerous preparation processes for titanium matrix composites in the future for some time.

[0004] Currently, the post-treatment process for titanium matrix composites mainly focuses on heat treatment. After heat treatment, the high-temperature mechanical properties of the titanium matrix composites are improved, but the improvement is limited and usually only the strength or only the plasticity can be improved. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation process for obtaining a titanium matrix composite material with excellent high-temperature tensile properties, in which the tensile strength (tensile strength) and elongation (tensile plasticity) of the B4C-TA15 titanium matrix composite material obtained by additive manufacturing and through cryogenic treatment are both improved in a 600°C high-temperature environment.

[0006] The present invention discloses a preparation process for obtaining a titanium matrix composite material with excellent high-temperature tensile properties, including the following steps:

[0007] Step 1: Place B4C powder and TA15 powder in a ball mill in a certain proportion for low-energy ball milling to fully mix them;

[0008] Step 2: Prepare and form the mixed powder by laser melting deposition process;

[0009] Step 3: Place the formed composite material in liquid nitrogen at -196°C, with a holding time of 0 < t ≤ 11 days, to obtain a B4C-TA15 titanium matrix composite material.

[0010] Preferably, the particle size of the B4C powder is 5 - 50 μm, and the particle size of the TA15 powder is 53 - 105 μm. More preferably, the particle size of the B4C powder is 5 μm and 50 μm.

[0011] Preferably, the mass ratio of the B4C powder to the TA15 powder is 2:98 - 5:95, more preferably 3:97.

[0012] Preferably, the ball mill is a drum ball mill, the mass ratio of balls to powder is 3:1 - 6:1, the rotation speed is 100 - 200 rpm, and the ball milling time is 4 - 8 h. More preferably, the mass ratio of balls to powder is 5:1 and the rotation speed is 200 rpm.

[0013] Preferably, before ball milling, the B4C powder and the TA15 powder are respectively dried.

[0014] Preferably, the process parameters of laser melting deposition are as follows: the laser power is 430 - 480 W, the scanning speed is 6 - 10 mm / s, the powder feeding speed is 8 - 12 g / min, the scanning spacing is 0.6 - 1 mm, the spot diameter is 1 mm, the phase angle is 90°, the distance between the powder outlet of the nozzle and the sample is constantly 8 - 10 mm, the overlapping rate is 40%, the shielding gas is 99.999% high-purity argon, the gas flow rate of powder feeding is 1 - 4 L / min, and the gas flow rate of shielding gas is 6 - 10 L / min. More preferably, the laser power is 450 W, the scanning speed is 8 mm / s, the powder feeding speed is 11.8 g / min, the scanning spacing is 0.8 mm, the distance between the powder outlet of the nozzle and the sample is constantly 10 mm, the gas flow rate of powder feeding is 2 L / min, and the gas flow rate of shielding gas is 8 L / min.

[0015] Preferably, the heat preservation time can be 3 days, 7 days, or 11 days.

[0016] The beneficial effects of the present invention:

[0017] 1. The tensile strength (tensile strength) and elongation (tensile plasticity) of the B4C-TA15 titanium matrix composite prepared by additive manufacturing (laser melting deposition process) and through cryogenic treatment (holding in liquid nitrogen at -196 °C for 0 < t ≤ 7 days) are both improved at a high temperature of 600 °C; this is because the microstructure of the B4C-TA15 titanium matrix composite prepared by additive manufacturing presents a network structure, formed by the enrichment of TiB and TiC at the grain boundaries.

[0018] 2. Through cryogenic treatment, the internal residual stress of the B4C-TA15 titanium matrix composite can also be reduced and the density can be increased; this is because cryogenic treatment causes a martensitic transformation inside the material and generates a large number of dislocations, thereby releasing the internal residual stress of the material.

[0019] 3. Through the combination of additive manufacturing and cryogenic treatment, the composite material exhibits grain growth, while the network distribution of the reinforcing phase restricts the growth of the surrounding grains, thus forming a bimodal mixed-crystal structure with varying grain sizes, which can improve the strength and toughness of the material. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the preparation process of the titanium-based composite material of the present invention.

[0021] Figure 2 This is a process flow diagram of the present invention.

[0022] Figure 3 The stress-strain curve of TA15 titanium alloy in Comparative Example 1 is shown.

[0023] Figure 4 The stress-strain curve of the B4C-TA15 titanium-based composite material in Example 1 is shown.

[0024] Figure 5 The stress-strain curve of the B4C-TA15 titanium-based composite material in Example 2 is shown.

[0025] Figure 6 The stress-strain curve of the B4C-TA15 titanium-based composite material in Example 3 is shown.

[0026] Figure 7 The stress-strain curve of the B4C-TA15 titanium-based composite material in Example 4 is shown.

[0027] Figure 8 Scanning electron microscope image of a material prepared by laser fused deposition process.

[0028] Figure 9 Scanning electron microscope (SEM) image of the microstructure of B4C-TA15 titanium-based composite material prepared by existing laser fused deposition modeling.

[0029] Figure 10 This is a grain boundary distribution diagram of the B4C-TA15 titanium-based composite material in Example 3 before cryogenic treatment.

[0030] Figure 11 This is a grain boundary distribution diagram of the B4C-TA15 titanium-based composite material after cryogenic treatment in Example 3. Detailed Implementation

[0031] The embodiments of the present invention will be illustrated below through specific examples.

[0032] Figure 1 This is a flowchart illustrating the preparation process of the titanium-based composite material of the present invention.

[0033] Figure 2This is a process flow diagram of the present invention. Laser fused deposition modeling (LMD) is a type of additive manufacturing process. The equipment used in LMD is an additive manufacturing process (EDM). The processing head provides the laser and delivers the metal powder. The scanning path is controlled by moving the processing head to obtain a finished product with the required size and shape. The molten pool is an area formed by the laser striking the surface of the base material. The metal powder melts, cools, and solidifies within the molten pool, thus forming a metal deposition layer. LMD equipment is a mature existing technology and will not be described in detail here.

[0034] Comparative Example 1

[0035] This comparative example does not include B4C, and the material preparation includes the following steps:

[0036] Step 1: After drying TA15 powder with a particle size of 53-105μm, TA15 titanium alloy was prepared by laser fused deposition process. The laser fused deposition process parameters were as follows: laser power of 450W, scanning speed of 8mm / s, powder feed rate of 11.8g / min, scanning interval of 0.8mm, spot diameter of 1mm, phase angle of 90°, constant distance between the nozzle powder outlet and the sample of 10mm, overlap rate of 40%, protective gas of 99.999% high-purity argon, powder feed gas flow rate of 2L / min, and protective gas flow rate of 8L / min.

[0037] Step 2: Place the TA15 titanium alloy from room temperature into a liquid nitrogen environment at -196°C for 7 days.

[0038] Step 3: After processing, remove the sample and place it in a room temperature environment until the sample temperature returns to room temperature.

[0039] The performance of the obtained TA15 titanium alloy was tested. The results showed that its high-temperature tensile strength at 600℃ was 728 MPa and its high-temperature elongation at 600℃ was 27.11% after cryogenic treatment.

[0040] Example 1

[0041] A preparation process for obtaining titanium-based composite materials with excellent high-temperature tensile properties includes the following steps:

[0042] Step 1: After drying TA15 powder with a particle size of 53-105μm and B4C powder with a particle size of 5μm, place B4C powder and TA15 powder in a drum ball mill at a mass ratio of 3:97 and ball mill at a low energy ratio of 5:1. The speed is 200rpm and the milling time is 6h to ensure thorough mixing.

[0043] Step 2: The mixed powder is shaped using laser fused deposition process. The laser fused deposition process parameters are as follows: laser power 450W, scanning speed 8mm / s, powder feed rate 11.8g / min, scanning interval 0.8mm, spot diameter 1mm, phase angle 90°, constant distance between the nozzle powder outlet and the sample 10mm, overlap rate 40%, protective gas 99.999% high-purity argon, powder feed gas flow rate 2L / min, and protective gas flow rate 8L / min.

[0044] Step 3: Place the molded material sample from room temperature into a liquid nitrogen environment at -196°C for 7 days.

[0045] Step 4: After processing, remove the sample and place it in a room temperature environment until the sample temperature returns to room temperature.

[0046] The performance of the obtained 5μm B4C-TA15 titanium-based composite material was tested. The results showed that after cryogenic treatment, its high-temperature tensile strength at 600℃ was 876 MPa and its high-temperature elongation at 600℃ was 19.61%.

[0047] Example 2

[0048] The difference between this embodiment and Embodiment 1 is that the particle size of the B4C powder is different.

[0049] A preparation process for obtaining titanium-based composite materials with excellent high-temperature tensile properties includes the following steps:

[0050] Step 1: After drying TA15 powder with a particle size of 53-105μm and B4C powder with a particle size of 50μm, place B4C powder and TA15 powder in a drum ball mill at a mass ratio of 3:97 and ball mill at a low energy ratio of 5:1. The speed is 200rpm and the milling time is 6h to ensure thorough mixing.

[0051] Step 2: The mixed powder is shaped using laser fused deposition process. The laser fused deposition process parameters are as follows: laser power 450W, scanning speed 8mm / s, powder feed rate 11.8g / min, scanning interval 0.8mm, spot diameter 1mm, phase angle 90°, constant distance between the nozzle powder outlet and the sample 10mm, overlap rate 40%, protective gas 99.999% high-purity argon, powder feed gas flow rate 2L / min, and protective gas flow rate 8L / min.

[0052] Step 3: Place the molded material sample from room temperature into a liquid nitrogen environment at -196°C for 3 days.

[0053] Step 4: After processing, remove the sample and place it in a room temperature environment until the sample temperature returns to room temperature. Performance tests were performed on the obtained 50μm B4C-TA15 titanium-based composite material. The results showed that after cryogenic treatment, its tensile strength at 600℃ was 875 MPa, and its elongation at 600℃ was 15.80%.

[0054] Example 3

[0055] The difference between this embodiment and embodiment 2 is that the holding time in step 3 is different.

[0056] A preparation process for obtaining titanium-based composite materials with excellent high-temperature tensile properties includes the following steps:

[0057] Step 1: After drying TA15 powder with a particle size of 53-105μm and B4C powder with a particle size of 50μm, place B4C powder and TA15 powder in a drum ball mill at a mass ratio of 3:97 and ball mill at a low energy ratio of 5:1. The speed is 200rpm and the milling time is 6h to ensure thorough mixing.

[0058] Step 2: The mixed powder is shaped using laser fused deposition process. The laser fused deposition process parameters are as follows: laser power 450W, scanning speed 8mm / s, powder feed rate 11.8g / min, scanning interval 0.8mm, spot diameter 1mm, phase angle 90°, constant distance between the nozzle powder outlet and the sample 10mm, overlap rate 40%, protective gas 99.999% high-purity argon, powder feed gas flow rate 2L / min, and protective gas flow rate 8L / min.

[0059] Step 3: Place the molded material sample from room temperature into a liquid nitrogen environment at -196°C for 7 days.

[0060] Step 4: After processing, remove the sample and place it in a room temperature environment until the sample temperature returns to room temperature.

[0061] The performance of the obtained 50μm B4C-TA15 titanium-based composite material was tested. The results showed that after cryogenic treatment, its high-temperature tensile strength at 600℃ was 893MPa and its high-temperature elongation at 600℃ was 17.21%.

[0062] Example 4

[0063] The difference between this embodiment and embodiments 2 and 3 is that the holding time in step 3 is different.

[0064] A preparation process for obtaining titanium-based composite materials with excellent high-temperature tensile properties includes the following steps:

[0065] Step 1: After drying TA15 powder with a particle size of 53-105μm and B4C powder with a particle size of 50μm, place B4C powder and TA15 powder in a drum ball mill at a mass ratio of 3:97 and ball mill at a low energy ratio of 5:1. The speed is 200rpm and the milling time is 6h to ensure thorough mixing.

[0066] Step 2: The mixed powder is shaped using laser fused deposition process. The laser fused deposition process parameters are as follows: laser power 450W, scanning speed 8mm / s, powder feed rate 11.8g / min, scanning interval 0.8mm, spot diameter 1mm, phase angle 90°, constant distance between the nozzle powder outlet and the sample 10mm, overlap rate 40%, protective gas 99.999% high-purity argon, powder feed gas flow rate 2L / min, and protective gas flow rate 8L / min.

[0067] Step 3: Place the molded material sample from room temperature into a liquid nitrogen environment at -196°C for 11 days.

[0068] Step 4: After processing, remove the sample and place it in a room temperature environment until the sample temperature returns to room temperature.

[0069] The performance of the obtained 50μm B4C-TA15 titanium-based composite material was tested. The results showed that after cryogenic treatment, its high-temperature tensile strength at 600℃ was 869MPa and its high-temperature elongation at 600℃ was 17.00%.

[0070] Figure 3 The stress-strain curve of TA15 titanium alloy in Comparative Example 1 is shown. The stress is the tensile strength at 600℃, and the strain is the elongation at 600℃. Figure 3 In the diagram, the dashed line represents the TA15 titanium alloy without cryogenic treatment, with a stress of 647 MPa and a strain of 20.45%; the solid line represents the TA15 titanium alloy after cryogenic treatment, with a stress of 728 MPa and a strain of 27.11%. It can be seen that after cryogenic treatment, the high-temperature tensile strength increases by 12.52%, and the elongation increases by 32.57%.

[0071] Figure 4 The image shows the stress-strain curve of the B4C-TA15 titanium-based composite material in Example 1. The stress represents the tensile strength at 600°C, and the strain represents the elongation at 600°C. Figure 4 In the diagram, the dashed line represents the composite material without cryogenic treatment, with a stress of 827 MPa and a strain of 17.15%; the solid line represents the B4C-TA15 titanium-based composite material after cryogenic treatment, with a stress of 876 MPa and a strain of 19.61%. It can be seen that after cryogenic treatment, the high-temperature tensile strength increased by 5.93%, and the elongation increased by 14.34%.

[0072] Figure 5 The image shows the stress-strain curve of the B4C-TA15 titanium-based composite material in Example 2. The stress represents the tensile strength at 600°C, and the strain represents the elongation at 600°C. Figure 5 In the diagram, the dashed line represents the composite material without cryogenic treatment, with a stress of 822 MPa and a strain of 14.87%; the solid line represents the B4C-TA15 titanium-based composite material after cryogenic treatment, with a stress of 875 MPa and a strain of 15.80%. It can be seen that cryogenic treatment increases the high-temperature tensile strength by 6.48% and the elongation by 6.25%.

[0073] Figure 6 The image shows the stress-strain curve of the B4C-TA15 titanium-based composite material in Example 3. The stress represents the tensile strength at 600°C, and the strain represents the elongation at 600°C. Figure 5 In the diagram, the dashed line represents the composite material without cryogenic treatment, with a stress of 822 MPa and a strain of 14.87%; the solid line represents the B4C-TA15 titanium-based composite material after cryogenic treatment, with a stress of 893 MPa and a strain of 17.21%. It can be seen that after cryogenic treatment, the high-temperature tensile strength increases by 8.64%, and the elongation increases by 15.74%.

[0074] Figure 7 The image shows the stress-strain curve of the B4C-TA15 titanium-based composite material in Example 4. The stress represents the tensile strength at 600°C, and the strain represents the elongation at 600°C. Figure 6 In the diagram, the dashed line represents the composite material without cryogenic treatment, with a stress of 822 MPa and a strain of 14.87%; the solid line represents the B4C-TA15 titanium-based composite material after cryogenic treatment, with a stress of 869 MPa and a strain of 17.00%. It can be seen that after cryogenic treatment, the high-temperature tensile strength increased by 5.72%, and the elongation increased by 14.32%.

[0075] Figure 3 For Comparative Example 1, TA15 titanium alloy without added B4C, Figure 4-7 The examples are titanium-based composite materials with added B4C, as shown in Examples 1-4. Figure 3-7 It can be seen that, compared with TA15 titanium alloy without B4C, after the same treatment, the stress and strain of the B4C-TA15 titanium-based composite materials in Examples 1-4 are improved, and the high-temperature tensile strength is better than that of TA15 titanium alloy without B4C.

[0076] Figure 8 This is a scanning electron microscope image of the material prepared by the laser fused deposition process of this invention. Figure 9This is a scanning electron microscope (SEM) image of the microstructure of B4C-TA15 titanium matrix composite material prepared by laser melt deposition, as described in the article "Microstructure and Wear Resistance of Laser-Surrounded In-situ Synthesized TiB-TiC Particle-Reinforced Titanium Matrix Composites". Figure 8 As can be seen, the B4C-TA15 titanium-based composite material prepared by laser fused deposition process exhibits a network structure, while Figure 9 No network structure was found. (Combined) Figure 8 9. Composite materials prepared by laser fused deposition process exhibit a network structure, which can improve the strength and plasticity of the material, thereby enhancing its mechanical properties.

[0077] Figure 10 This is a grain boundary distribution diagram of the B4C-TA15 titanium-based composite material in Example 3 before cryogenic treatment. Figure 11 This is a grain boundary distribution diagram of the B4C-TA15 titanium-based composite material after cryogenic treatment in Example 3. It can be observed that some grains grew after cryogenic treatment, forming a mixed-grain structure with both large and small grains coexisting.

[0078] The above embodiments are not intended to limit the present invention, but are merely preferred embodiments of the present invention. The present invention is not limited to the above examples, and those skilled in the art can design many other modifications, as long as they meet the requirements of the present invention, they all fall within the protection scope of the present invention.

Claims

1. A preparation process for obtaining titanium-based composite materials with excellent high-temperature tensile properties, characterized in that: It includes the following steps: Step 1: Place B4C powder and TA15 powder in a ball mill in a certain proportion for low-energy ball milling to make them fully mixed; Step 2: Prepare and form the mixed powder through a laser melting deposition process; Step 3: Put the formed composite material into liquid nitrogen at -196°C, with the holding time 0 < t ≤ 11 days, to obtain the B4C-TA15 titanium matrix composite material; Among them, the mass ratio of B4C powder to TA15 powder is 2:98 - 5:

95.

2. The preparation process for obtaining titanium-based composite materials with excellent high-temperature tensile properties as described in claim 1, characterized in that: The particle size of B4C powder is 5 - 50μm, and the particle size of TA15 powder is 53 - 105μm.

3. The preparation process for obtaining a titanium-based composite material with excellent high-temperature tensile properties as described in claim 1, characterized in that: The ball mill is a drum ball mill, the ball-to-powder mass ratio is 3:1 - 6:1, the rotation speed is 100 - 200 rpm, and the ball milling is carried out for 4 - 8 h.

4. The preparation process for obtaining titanium-based composite materials with excellent high-temperature tensile properties as described in claim 1, characterized in that: Before ball milling, the B4C powder and TA15 powder are respectively dried.

5. The preparation process for obtaining a titanium-based composite material with excellent high-temperature tensile properties as described in claim 1, characterized in that: The laser melting deposition process parameters are: laser power is 430 - 480 W, scanning speed is 6 - 10 mm / s, powder feeding speed is 8 - 12 g / min, scanning spacing is 0.6 - 1 mm, spot diameter is 1 mm, phase angle is 90°, the distance between the powder outlet of the nozzle and the sample is constantly 8 - 10 mm, the overlapping rate is 40%, the shielding gas is 99.999% high-purity argon, the powder feeding gas flow rate is 1 - 4 L / min, and the shielding gas flow rate is 6 - 10 L / min.

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