Method for preparing B4C / Ti6Al4V composite material through laser melting deposition and application of B4C / Ti6Al4V composite material

Abstract

The invention discloses a method for preparing a B4C / Ti6Al4V composite material through laser melting deposition and application of the B4C / Ti6Al4V composite material, and belongs to the technical field of additive manufacturing. According to the preparation method disclosed by the invention, the B4C / Ti6Al4V composite material synergistically enhanced by B4C, TiB and TiC is prepared from B4C powder of 65-73 microns and spherical Ti6Al4V alloy powder of 45-75 microns by adopting a laser melting deposition technology; the volume fraction of B4C in the B4C / Ti6Al4V composite material is 1 to 5 vol.%. The B4C powder is added into the Ti6Al4V alloy, so that TiB and TiC reinforced phases are generated in the composite material in situ, and undissolved B4C exists. After the B4C is added, beta-Ti and alpha-Ti grains in the composite material are refined. The C element is subjected to solid solution in a matrix, and TiB generated in situ plays a bearing role in the stretching process. And the laser melting deposition technology of the method adopts two paths of powder feeding, so that the uniformity of B4C in the composite material is improved. By adopting the method for preparing the B4C / Ti6A14V composite material, rapid forming can be realized, the subsequent processing time is shortened, and the cost is saved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of additive manufacturing, and particularly relates to a method for preparing B4C / Ti6Al4V composite material by laser melting deposition and application thereof. BACKGROUND

[0002] Ti6Al4V alloy has been widely used in the aviation industry as an important material for manufacturing fuselages, wings and engine blades due to its high specific strength, high fracture toughness and excellent corrosion resistance. However, the low hardness, poor wear resistance and high temperature performance of Ti6Al4V alloy limit its application range. The performance of Ti6Al4V alloy can be improved by adding ceramic particle reinforcements to Ti6Al4V alloy to prepare titanium matrix composites (TMCs). TMCs have higher hardness, wear resistance and higher service temperature than traditional titanium alloys.

[0003] Traditional methods for preparing titanium matrix composites include self-propagating high-temperature synthesis and spark plasma sintering. However, due to the high hardness of titanium matrix composites, it is difficult to achieve mechanical processing and rapid forming of complex parts of the composite material by traditional methods. Additive manufacturing technology (AM) has the characteristics of layer-by-layer accumulation and has significant advantages in the integrated manufacturing of complex structure parts, making it suitable for the manufacturing of difficult-to-machine titanium matrix composites. Laser additive manufacturing technology (LAM) uses a laser beam as a heat source. Laser additive manufacturing technology is mainly divided into two types: powder laying and powder feeding. Compared with powder laying LAM technology, laser melting deposition (LMD) as a powder feeding LAM technology can freely adjust the proportion of different powders through a powder feeder, and can realize the manufacturing of large-size components, functional gradient materials and composite materials. Therefore, the preparation of titanium matrix composites by LMD technology has attracted widespread attention.

[0004] Currently, common reinforcing phases in titanium-based composites include TiB, TiC, B4C, SiC, Al2O3, TiB2, Si3N4, and TiN. B4C, as a ceramic material, possesses low density, high hardness, and good high-temperature stability. Research results show that during laser melting deposition (LMD), B4C can react with titanium to simultaneously introduce both TiB and TiC reinforcing phases into titanium-based composites. Furthermore, the β-Ti in B4C-reinforced titanium-based composites is refined, and these microstructures improve the mechanical properties of the composites. Therefore, B4C is suitable as a reinforcement for titanium alloys in the preparation of titanium-based composites. Although previous studies have used LMD technology to synthesize (TiB+TiC) reinforced titanium-based composites in situ, the B4C particles used were small, and the particles completely dissolved, resulting in the composites containing no B4C particles, thus preventing them from fulfilling their role as a reinforcing phase. Using larger B4C particles, titanium-based composites with synergistic reinforcement from B4C, TiB, and TiC can be prepared, thereby improving the high-temperature tensile properties of Ti6Al4V alloys. Summary of the Invention

[0005] The purpose of this invention is to provide a titanium-based composite material that can be synergistically reinforced by B4C, TiB and TiC, thereby improving the high-temperature tensile properties of Ti6Al4V alloy.

[0006] This invention provides a method for preparing B4C / Ti6Al4V composite materials using laser melting deposition. The method involves preparing a B4C / Ti6Al4V composite material with synergistic reinforcement of B4C, TiB, and TiC by combining 65–73 μm B4C powder and spherical Ti6Al4V alloy powder using laser melting deposition technology. The volume fraction of B4C in the B4C / Ti6Al4V composite material is 1–5 vol.%.

[0007] Furthermore, including:

[0008] Step 1: Mix 65-73 μm B4C powder with 45-75 μm spherical Ti6Al4V alloy powder using a ball mill to obtain composite powder; the volume fraction of B4C powder in the composite powder of B4C powder and Ti6Al4V alloy powder is 2%-20%;

[0009] Step 2: Use pure Ti or Ti6Al4V alloy as the substrate for laser melting deposition, and pretreat the substrate;

[0010] Step 3: Using a dual-coaxial powder feeder under the protection of a protective gas, composite powder and Ti6Al4V alloy powder are deposited onto the substrate using laser melting deposition technology; the deposition cycle is repeated layer by layer along the X-axis to obtain a single-pass multilayer structure, which is then cooled to room temperature to finally obtain the B4C / Ti6Al4V composite material.

[0011] Furthermore, the ball mill is a planetary ball mill with a milling speed of 180-220 r / min and a milling time of 3-5 h.

[0012] Furthermore, before the composite powder and spherical Ti6Al4V alloy powder are fed into the two coaxial powder feeders, they need to be pre-treated by drying. The drying temperature is 90-110℃ and the drying time is 2-5h.

[0013] Furthermore, in the laser melting deposition method, the laser power is 900–1500 W and the scanning speed is 500–1000 m / min.

[0014] Furthermore, the ratio of the rotational speed of the composite powder to the Ti6Al4V alloy powder in the two powder feeders is 1:1 to 9.

[0015] Furthermore, in the laser melting deposition process, a water chiller is used for real-time water cooling; the entire laser melting deposition process is carried out in an argon-filled chamber, in which air is discharged and argon gas is filled in.

[0016] The present invention also provides a B4C / Ti6Al4V composite material prepared by the above method.

[0017] Furthermore, the B4C / Ti6Al4V composite material exhibits a tensile strength of 700–800 MPa and an elongation of 4–10% at 500°C; the wear rate of the B4C / Ti6Al4V composite material is 8 × 10⁻⁶. -4 ~10×10 -4 mm 3 ·N -1 ·m -1 .

[0018] The present invention also provides an application of the B4C / Ti6Al4V composite material, which is used in engine blades.

[0019] The beneficial effects of this invention are as follows:

[0020] The present invention discloses a method for preparing B4C / Ti6Al4V composite materials by laser melting deposition. B4C particles are introduced into Ti6Al4V alloy, and titanium-based composite materials are prepared by laser melting deposition. TiB whiskers and TiC particles are generated through the in-situ reaction of B4C with Ti6Al4V. At the same time, some undissolved B4C is retained in the matrix, so that there are three reinforcing phases, TiB, TiC and B4C, in the composite material, which synergistically enhance the high-temperature tensile properties of Ti6Al4V alloy.

[0021] The present invention discloses a method for preparing B4C / Ti6Al4V composite materials using laser melting deposition. This method employs a two-powder feeding approach: one feeding is a composite powder of B4C and Ti6Al4V powder, and the other is Ti6Al4V powder. This method improves the flowability and uniformity of B4C powder distribution during feeding, thereby enhancing the performance of the B4C / Ti6Al4V composite material. Furthermore, this method allows for the premixing and storage of sufficient high-volume-fraction powder in a single step, with the powder feeding rate only needing to be controlled during deposition. This enables the preparation of composite materials with different volume fractions, significantly reducing powder mixing time and manufacturing complexity.

[0022] This invention employs a method for preparing B4C / Ti6Al4V composite materials using laser melting deposition, which can rapidly obtain B4C / Ti6Al4V composite material parts with a certain shape. The manufacturing process has advantages such as high efficiency, high material utilization, and saving a large amount of post-processing, thereby reducing actual production costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of laser melting deposition using the method of the present invention;

[0024] Figure 2 Microstructure diagrams of B4C / Ti6Al4V composites with different B4C volume fractions are shown, where: (a)(b)(c) 1 vol.% B4C / Ti6Al4V; (d)(e)(f) 3.5 vol.% B4C / Ti6Al4V; (g)(h)(i) 10 vol.% B4C / Ti6Al4V;

[0025] Figure 3 Bright field plots of Ti6Al4V alloy and 1 vol.% B4C / Ti6Al4V composite material, where: (a) Ti6Al4V; (b) 1 vol.% B4C / Ti6Al4V composite material;

[0026] Figure 4TEM images of 1 vol.% B4C / Ti6Al4V composite material, where: (a) microstructure at the interface between TiB and the matrix; (b) high-resolution image of the interface between TiB and α-Ti; (c) high-resolution FFT image of the interface between TiB and α-Ti in Figure (b); (dh) EDS spectrum of Figure (a).

[0027] Figure 5 The TEM microstructure of the 3.5 vol.% B4C / Ti6Al4V composite material is shown in the following figures: (a) bright-field image of the composite material; (b) high-angle annular dark-field image of Figure (a); (c) bright-field image of the blue box region in Figure (b) at high magnification; (c1) and (c2) are the diffraction spots of the corresponding phases in Figure (c); and (dh) is the EDS spectrum of Figure (a).

[0028] Figure 6 Microstructures of B4C / Ti6Al4V composites with different B4C volume fractions in the direction perpendicular to the high-temperature tensile fracture surface, wherein: (a)(b)(c) 1 vol.% B4C / Ti6Al4V; (d)(e) 3.5 vol.% B4C / Ti6Al4V; (f) 10 vol.% B4C / Ti6Al4V;

[0029] Figure 7 Tensile stress-strain curves of B4C / Ti6Al4V composites with different B4C volume fractions are shown. Detailed Implementation

[0030] The present invention will now be further described with reference to the accompanying drawings.

[0031] This invention discloses a design method to improve the high-temperature tensile properties of Ti6Al4V alloy. By adding 65-73μm B4C powder to a 45-75μm Ti6Al4V alloy, TiB and TiC reinforcing phases are generated in situ in the composite material, and undissolved B4C is present. This results in a titanium-based composite material with synergistic reinforcement from B4C, TiB, and TiC. The addition of B4C refines the β-Ti and α-Ti grains in the composite material. C element is dissolved into the matrix, and the in-situ generated TiB plays a load-bearing role during tensile testing.

[0032] Specifically:

[0033] S1. Prepare Ti6Al4V alloy powder (45–75 μm) and B4C powder (65–73 μm). Use a planetary ball mill to uniformly mix the B4C powder and spherical Ti6Al4V powder at a B4C powder volume fraction of 2–20% in the composite powder to improve powder flowability. The ball mill speed is 180–220 r / min, and the milling time is 3–5 h. Perform a drying pretreatment on the composite powder and Ti6Al4V alloy powder at a drying temperature of 90–110℃ for 2–5 h.

[0034] S2. A laser melting deposition test system consisting of a laser, a water chiller, a double-barrel powder feeder, a robotic arm, a control system, a laser cladding head, and an argon-filled chamber was used to prepare Ti6Al4V alloy and B4C / Ti6Al4V composite material. Pure Ti or Ti6Al4V alloy plates were selected as the substrates. The substrate surface was cleaned with anhydrous ethanol before preparation.

[0035] S3. The energy required for laser melting deposition is provided by a fiber laser. During the experiment, the powder is fed onto the substrate surface by the cladding head. To ensure the stability of the cladding head during long-term continuous operation, a water chiller is used for real-time cooling. To prevent oxidation of the Ti6Al4V alloy during high-temperature processing, the entire deposition experiment is conducted in an argon-filled chamber. Before the experiment begins, argon gas is used to purge the air from the chamber. One of the dual-barrel powder feeders contains a composite powder of Ti6Al4V alloy powder and B4C powder, while the other feeder contains Ti6Al4V alloy powder.

[0036] S4. Set appropriate process parameters and a suitable deposition path; laser power is 900-1500W, and scanning speed is 500-1000mm / min.

[0037] S5. Sample preparation is performed according to the path and predetermined parameters. Under the control of the robot, the cladding head moves along the X direction parallel to the substrate surface. After completing single-layer deposition, the cladding head automatically rises a specified distance in the Z-axis direction and returns to the starting position. By repeating the deposition cycle layer by layer, a single-pass multilayer structure sample with stable metallurgical bonding is finally obtained.

[0038] In step S4 above, Ti6Al4V powder and the mixed 2% to 20% B4C / Ti6Al4V composite powder are poured into powder feeders respectively. The powder disc rotation ratio of the two powder feeders is set according to the designed B4C / Ti6Al4V composite material composition. The volume fraction of B4C in the composite material is 1% to 5%. The powder disc rotation ratio of the 2% to 20% B4C / Ti6Al4V composite powder to the Ti6Al4V alloy powder in the two powder feeders is 1:1 to 9.

[0039] Example 1

[0040] A method for preparing a B4C / Ti6Al4V composite material, comprising:

[0041] S1. Using a planetary ball mill, 45-75 μm Ti6Al4V alloy powder and 65-73 μm B4C powder are uniformly mixed at a ratio of 10% by volume of B4C powder in the composite powder.

[0042] S2. Use pure Ti board as substrate, with substrate size of approximately 200mm×100mm×10mm; clean the substrate surface with anhydrous ethanol.

[0043] S3. Using a dual-powder feeder under protective gas conditions, composite powder and Ti6Al4V alloy powder are deposited onto the substrate via laser melting deposition technology. During the laser melting deposition process, a water chiller provides real-time water cooling to the cladding head, and the deposition process is carried out in an argon-filled chamber. Laser power P L The W was set to 1200W, and the scanning speed v was set to 750 mm / min. The deposition cycle was repeated layer by layer along the X-axis to obtain a single-pass multilayer structure. After cooling to room temperature, a B4C / Ti6Al4V composite material with a volume fraction of 1% was finally obtained.

[0044] Example 2

[0045] A method for preparing a B4C / Ti6Al4V composite material, comprising:

[0046] S1. Using a planetary ball mill, 45-75 μm Ti6Al4V alloy powder and 65-73 μm B4C powder are uniformly mixed at a ratio of 10% by volume of B4C powder in the composite powder.

[0047] S2. Use pure Ti board as substrate, with substrate size of approximately 200mm×100mm×10mm; clean the substrate surface with anhydrous ethanol.

[0048] S3. Using a dual-powder feeder under protective gas, composite materials and Ti6Al4V alloy powder are deposited onto a substrate via laser melting deposition technology. During the laser melting deposition process, a water chiller provides real-time water cooling to the cladding head. The deposition process takes place in an argon-filled chamber, and the air in the chamber is purged using argon gas before deposition. Laser power P L The W was set to 1200W, and the scanning speed v was set to 750 mm / min. The deposition cycle was repeated layer by layer along the X-axis to obtain a single-pass multilayer structure. After cooling to room temperature, a B4C / Ti6Al4V composite material with a volume fraction of 3.5% was finally obtained.

[0049] Comparative Example 1

[0050] A method for preparing Ti6Al4V material, comprising:

[0051] S1. Ball mill spherical Ti6Al4V alloy powder with a diameter of 45-75 μm and then dry it.

[0052] S2. Using a single powder feeder under protective gas, Ti6Al4V alloy powder is deposited onto a substrate via laser melting deposition technology. During the laser melting deposition process, a water chiller provides real-time water cooling to the cladding head. The deposition process is carried out in an argon-filled chamber, and the air in the chamber is purged using argon gas before deposition. Laser power P L The W was set to 1200W, and the scanning speed v was set to 750 mm / min. A single-pass multilayer structure was obtained by repeatedly depositing layers along the X-axis, and then cooled to room temperature to finally obtain Ti6Al4V material.

[0053] Comparative Example 2

[0054] A method for preparing a B4C / Ti6Al4V composite material, comprising:

[0055] S1. Using a planetary ball mill, 45-75 μm Ti6Al4V alloy powder and 65-73 μm B4C powder are uniformly mixed at a ratio of 10% by volume of B4C powder in the composite powder.

[0056] S2. Use pure Ti board as substrate, with substrate size of approximately 200mm×100mm×10mm; clean the substrate surface with anhydrous ethanol.

[0057] S3. A single-path powder feeder is used to deposit composite powder onto the substrate under protective gas conditions via laser melting deposition technology. During the laser melting deposition process, a water chiller provides real-time water cooling to the cladding head. The deposition process takes place in an argon-filled chamber, and the air in the chamber is purged using argon gas before deposition. Laser power P L The W was set to 1200W, and the scanning speed v was set to 750 mm / min. A single-pass multilayer structure was obtained by repeating the deposition cycle layer by layer along the X-axis. After cooling to room temperature, a B4C / Ti6Al4V composite material with a volume fraction of 10% was finally obtained.

[0058] Depend on Figure 2 It is evident that the reinforcing phases of the composite material consist entirely of TiB, TiC, and undissolved B4C. The residual B4C in the composite material is smaller than the original powder, indicating partial dissolution of B4C within the composite. Furthermore, with increasing B4C volume fraction, both the volume fraction and size of the residual B4C increase.

[0059] Depend on Figure 3 As can be seen in the bright-field image of the composite material with a B4C volume fraction of 1%, the distribution of the in-situ generated reinforcing phase in the composite matrix can be observed. Compared with Ti6Al4V, the α-Ti grains of the composite material are significantly refined;

[0060] Depend on Figure 4 It is evident that the interface between TiB and α-Ti is clean and smooth, which facilitates load transfer. Furthermore, a significant amount of carbon (C) dissolves into the Ti matrix, while the Ti6Al4V alloy contains no C, further demonstrating that B4C dissolves. Moreover, the interface between the in-situ formed TiB and α-Ti exhibits excellent atomic-scale bonding.

[0061] Depend on Figure 5 It is evident that, compared to the 1 vol.% B4C / Ti6Al4V composite, the composite with a B4C volume fraction of 3.5% shows a significant increase in both the number and size of the reinforcing phase.

[0062] Depend on Figure 6 It can be seen that fractured TiB was observed, but no signs of debonding of the TiB-reinforced phase were observed, and crack propagation around B4C particles was observed.

[0063] Depend on Figure 7 As shown in Table 1, the 1-5 vol.% B4C-reinforced Ti6Al4V composite material prepared by the method of the present invention improves the high-temperature tensile strength of Ti6Al4V. At 500℃, the addition of 1 vol.% B4C increases the tensile strength of Ti6Al4V while retaining good plasticity, and the addition of 3.5 vol.% B4C further improves the high-temperature tensile strength of the composite material. In contrast, the addition of 10 vol.% B4C in Comparative Example 2 causes the composite material to exhibit severe brittle fracture.

[0064] Table 1 High-temperature tensile properties of B4C / Ti6Al4V composites with different volume fractions

[0065]

[0066] As shown in Table 2, the B4C / Ti6Al4V composite material prepared by the method of the present invention with 1-5 vol.% B4C reinforced Ti6Al4V alloy has improved the wear resistance of the composite material.

[0067] Table 2 Wear test results of B4C / Ti6Al4V composites with different B4C volume fractions

[0068]

[0069] The wear rate of the B4C / Ti6Al4V composite material in Examples 1 and 2 was significantly reduced. The wear resistance of the B4C / Ti6Al4V composite material with 10 vol.% B4C added in Comparative Example 2 was significantly lower than that in Examples 1 and 2.

[0070] This invention provides a method for improving the high-temperature tensile properties of Ti6Al4V alloy. It utilizes laser melting deposition technology to rapidly form B4C / Ti6Al4V composite materials, overcoming the difficulties of traditional processing methods in machining and rapidly forming complex composite parts. Grain refinement, load transfer strengthening, and solid solution strengthening effectively improve the high-temperature tensile strength of the composite material. This method for improving the high-temperature tensile properties of Ti6Al4V alloy can be used, but is not limited to, laser melting deposition technology for B4C powder-reinforced Ti6Al4V alloys. The design concept can be extended to other preparation methods and Ti6Al4V alloys reinforced with other reinforcing phases.

[0071] The above embodiments are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A method for preparing B4C / Ti6Al4V composite materials by laser melting deposition, characterized in that, B4C / Ti6Al4V composite materials, synergistically reinforced by B4C, TiB, and TiC, were prepared by laser melting deposition technology using 65–73 μm B4C powder and spherical Ti6Al4V alloy powder; the volume fraction of B4C in the B4C / Ti6Al4V composite material was 1–5 vol.%.

2. The method for preparing B4C / Ti6Al4V composite material by laser melting deposition according to claim 1, characterized in that, include: Step 1: Mix 65-73 μm B4C powder with 45-75 μm spherical Ti6Al4V alloy powder using a ball mill to obtain composite powder; the volume fraction of B4C powder in the composite powder of B4C powder and Ti6Al4V alloy powder is 2%-20%; Step 2: Use pure Ti or Ti6Al4V alloy as the substrate for laser melting deposition, and pretreat the substrate; Step 3: Using a dual-feeder under the protection of a protective gas, composite powder and Ti6Al4V alloy powder are deposited onto the substrate using laser melting deposition technology; the deposition cycle is repeated layer by layer along the X-axis to obtain a single-pass multilayer structure, which is then cooled to room temperature to finally obtain the B4C / Ti6Al4V composite material.

3. The method for preparing B4C / Ti6Al4V by laser melting deposition according to claim 2, characterized in that, The ball mill is a planetary ball mill with a milling speed of 180-220 r / min and a milling time of 3-5 h.

4. The method for preparing B4C / Ti6Al4V by laser melting deposition according to claim 2, characterized in that, Before the composite powder and spherical Ti6Al4V alloy powder are fed into the two-way powder feeder, they need to be pre-treated by drying. The drying temperature is 90-110℃ and the drying time is 2-5h.

5. The method for preparing B4C / Ti6Al4V by laser melting deposition according to claim 2, characterized in that, In the laser melting deposition method, the laser power is 900-1500W and the scanning speed is 500-1000m / min.

6. The method for preparing B4C / Ti6Al4V by laser melting deposition according to claim 2, characterized in that, In the laser melting deposition method, the powder disk rotation ratio of composite powder to Ti6Al4V alloy powder in the two powder feeders is 1:1 to 9.

7. The method for preparing B4C / Ti6Al4V by laser melting deposition according to claim 2, characterized in that, During the laser melting deposition process, a water chiller is used for real-time water cooling; the entire laser melting deposition process is carried out in an argon-filled chamber, where air is discharged and argon gas is filled in.

8. A B4C / Ti6Al4V composite material prepared by the method according to any one of claims 1 to 7.

9. The B4C / Ti6Al4V composite material according to claim 8, characterized in that, The B4C / Ti6Al4V composite material has a tensile strength of 700–800 MPa and an elongation of 4–10% at 500℃; the wear rate of the B4C / Ti6Al4V composite material is 8 × 10⁻⁶. -4 ~10×10 -4 mm 3 ·N -1 ·m -1 .

10. An application of the B4C / Ti6Al4V composite material as described in claim 8, characterized in that, The B4C / Ti6Al4V composite material is used in engine blades.

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