A titanium-based composite part, its preparation method and application

Abstract

The present invention belongs to the technical field of powder metallurgy, and particularly relates to a titanium-based composite part, a preparation method thereof and an application. The present invention uses the gas atomization method to prepare and preferably selects fine-grained high-entropy alloy powder as the reinforcing phase powder after vibrating screening. The particle size of the reinforcing phase powder and the grains inside the particles are fine. After being uniformly mixed with the titanium alloy powder, it is then subjected to hot isostatic pressing and low-temperature sintering treatment, so that the fine grain structure inside the reinforcing phase powder particles can be retained in the titanium-based composite master alloy bar. Then, the titanium-based composite powder with uniform composition and finer grain size structure is obtained by using the secondary plasma rotating electrode method for powder making; the titanium-based composite master alloy bar after homogenization after mixing is made into powder by the secondary plasma rotating electrode method, and the chemical composition is further dispersed and homogenized, and the reinforcing phase is distributed inside each titanium-based composite powder particle. This unconventional surface contact type strengthening method can further improve the strengthening effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of powder metallurgy, and particularly relates to a titanium-based composite part, a preparation method thereof, and an application thereof. Background Art

[0002] Particle-reinforced titanium matrix composites usually use carbide, nitride, oxide ceramic particles and whiskers as reinforcements, which can greatly improve the strength, hardness, wear resistance and creep resistance of titanium matrix composites. Therefore, titanium matrix composites have been widely used in key components such as aeroengine turbine blades and high-pressure compressor disks, and have gradually become one of the key strategic materials that are irreplaceable in major equipment fields such as aerospace. The composite design concept of particle-reinforced titanium matrix composites pursues uniform dispersion of reinforcements in the matrix. By optimizing the type, morphology and content ratio of the reinforcements, the pinning and bearing effects of the reinforcements on grain boundaries are exerted, so that the material obtains uniform and stable properties. However, the strengthening effect of the homogenization design concept has certain limitations: that is, the improvement of material strength and heat-resistant temperature often comes at the expense of plasticity. With the increase of the volume fraction of the reinforcements, the reinforcements will inevitably coarsen and agglomerate, thus inducing stress concentration and introducing defects, seriously affecting the plasticity of the material. This makes it impossible for particle-reinforced titanium matrix composites to break through the bottleneck of "strength-plasticity inversion". In addition, due to the difficulty in controlling the uniformity of particle distribution in the matrix, when ceramic reinforcement particles are unevenly distributed or even seriously aggregated, an arching effect will be formed, resulting in non-uniform microstructure. When the aggregated reinforcement phase in the titanium matrix composite resists external forces unevenly with the titanium matrix, stress concentration will be caused and the anti-plastic deformation ability of the material will be weakened.

[0003] As a new type of alloy material, high-entropy alloys usually have excellent mechanical properties, corrosion resistance, thermal stability and high-temperature oxidation resistance, and have gradually become a research hotspot in the material field. Therefore, by introducing high-entropy alloy particles into titanium matrix composites, the hardness and strength of titanium matrix composites can be effectively improved, while maintaining or increasing the plasticity of titanium matrix composites. Therefore, the preparation of titanium matrix composites with uniformly dispersed reinforcing particles is of great significance for improving the comprehensive mechanical properties of materials.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned disadvantages of the prior art and provide a titanium-based composite part, a preparation method thereof, and an application thereof.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] On the one hand, the present invention provides a method for preparing a titanium-based composite material, comprising the following steps:

[0008] Step 1: Prepare by gas atomization method and obtain high-entropy alloy powder with a particle size of 10 - 50 μm by air flow screening or vibration screening in a high-purity argon atmosphere;

[0009] Parameters for preparing high-entropy alloy powder by the gas atomization method: The diameter of the master alloy bar of the high-entropy alloy powder is 50 mm - 80 mm, the length is 100 mm - 600 mm, the powder-making power efficiency is 50% - 80%, the feeding speed is 50 mm / min - 100 mm / min, and the gas flow rate during air flow screening is 600 Nm 3 / h - 1200 Nm 3 / h;

[0010] Step 2: Prepare by plasma rotating electrode method and obtain titanium alloy powder with a particle size of 10 μm - 150 μm by vibration screening in a high-purity argon atmosphere;

[0011] Parameters for preparing titanium alloy powder by the plasma rotating electrode method: The diameter of the master alloy bar of the titanium alloy powder is 50 mm - 80 mm, the rotation speed is 20000 r / min - 32000 r / min, the feeding speed is 20 mm / min - 50 mm / min, the arc distance is 30 mm - 50 mm, the current is 1000 A - 1400 A, the voltage is 80 V - 90 V, and the vacuum degree < 5×10 -3 Pa;

[0012] Step 3: Mix the high-entropy alloy powder and titanium alloy powder in a double-cone mixer according to a specific ratio to obtain titanium-based mixed powder with a particle size of 10 μm - 150 μm; wherein, the mass fraction of the high-entropy alloy powder in the titanium-based mixed powder is 0.1% - 8.0%; Parameters of the double-cone mixer during mixing: The rotation speed is 10 r / min - 30 r / min, and the mixing duration is 60 min - 180 min;

[0013] Step 4: First, load the titanium-based mixed powder into the first steel sleeve, then successively perform mechanical compaction, vacuum degassing, and micro-beam plasma sealing welding on the first steel sleeve, and then perform hot isostatic pressing. After furnace cooling, machine-process to remove the first steel sleeve to obtain a titanium-based composite master alloy bar with a diameter of 50 mm - 80 mm and a length of 500 mm - 700 mm;

[0014] Step 5: Use the plasma rotating electrode process to powder the titanium-based composite master alloy bar and perform vibration screening to obtain titanium-based composite powder with a particle size of 10 μm to 150 μm. Among them, the parameters for preparing titanium-based composite powder by the plasma rotating electrode process are as follows: the rotation speed of the titanium-based composite master alloy bar is 20,000 r / min to 32,000 r / min, the feeding speed is 20 mm / min to 50 mm / min, the arc distance is 30 mm to 50 mm, the current is 1000 A to 1400 A, the voltage is 80 V to 90 V, and the vacuum degree < 5×10 - 3 Pa;

[0015] Step 6: First, load the titanium-based composite powder into the second steel jacket, then perform mechanical vibration compaction, vacuum degassing, and micro-plasma sealing welding on the second steel jacket in sequence. Then, perform hot isostatic pressing, and after furnace cooling, machine-process to remove the second steel jacket to finally obtain the required titanium-based composite part.

[0016] Specifically, in Step 2, the titanium alloy powder is one of α-type titanium alloy, α + β-type titanium alloy, and β-type titanium alloy. Preferably, the α-type titanium alloy is selected from TA series titanium alloys, such as one of Ti-5Al-2.5Sn and Ti-6.5Al-1Mo-1V-2Zr; the α + β-type titanium alloy is selected from TC series titanium alloys, such as one of Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo, and Ti-6.5Al-2Zr-1Mo-1V; the β-type titanium alloy is selected from TB series titanium alloys, such as one of Ti-10V-2Fe-3Al and Ti-15V-3Cr-3Sn-3Al.

[0017] Specifically, the high-entropy alloy powder includes one of AlCoCrFeNi, AlCrCoNiCu, CuCrFeTiNi, CoCrMoNbTi, and FeCoNiTaAl.

[0018] Specifically, in Steps 2 and 4, the degassing process is divided into two steps: the first step is to heat up to 300 °C to 400 °C, with a heating rate of 2 °C / min to 10 °C / min, and degas until the vacuum degree ≤ 1.0×10 -3 Pa; the second step is to heat up to 400 °C to 500 °C, with a heating rate of 2 °C / min to 5 °C / min, and degas until the vacuum degree ≤ 1.0×10 -4 Pa.

[0019] Specifically, in Steps 2 and 4, the parameters for micro-plasma sealing welding are as follows: the welding current is 10 A to 20 A, the arc voltage is 15 V to 30 V, and the welding speed is 0.5 mm / s to 2.5 mm / s;

[0020] Specifically, in step 4 and step 6, the parameters of the hot isostatic pressing are: temperature of 850°C to 950°C, heating rate of 2°C / min to 20°C / min, pressure of 100MPa to 150MPa, and holding time of 120min to 180min; the materials of the first ladle jacket and the second ladle jacket are both 20 steel.

[0021] It should be noted that there is no strict order between step 1 and step 2 in the preparation method of the present invention, and the order is subject to actual production.

[0022] On the other hand, the present invention provides a titanium-based composite product, which is prepared by the preparation method described above.

[0023] On the other hand, the present invention provides an application of a titanium-based composite product, which is used in aircraft engine turbine blades and high-pressure compressor disks.

[0024] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0025] The invention adopts a gas atomization method to prepare a high-entropy alloy powder with fine grains after vibration screening as the reinforcing phase powder. The particle size of the reinforcing phase powder and the grains inside the particles are fine. After being evenly mixed with the titanium alloy powder, the powder is subjected to hot isostatic pressing and low-temperature sintering treatment, so that the fine grain structure inside the reinforcing phase powder particles can be retained in the titanium-based composite master alloy rod. Then, the secondary plasma rotating electrode method is used to prepare the powder to obtain a titanium-based composite powder with uniform composition and finer grain size. The titanium-based composite powder is formed by hot isostatic pressing, and the forming temperature is controlled at a level lower than 950°C, thereby avoiding the traditional hot pressing sintering. The titanium-based composite master alloy rods that have been homogenized after mixing are powdered by the secondary plasma rotating electrode method, and the chemical composition is further dispersed and homogenized, and the reinforcing phase is distributed inside each titanium-based composite powder particle. The unconventional surface contact strengthening method can further improve the strengthening effect; and the titanium-based composite powder particles prepared by the secondary method retain the characteristics of density, high sphericity, good fluidity, etc. of the plasma rotating electrode method powder preparation, which is suitable for effective filling of various shapes of packages, and has a higher tap density, which is conducive to further hot isostatic pressing densification molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the present invention.

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the description of the embodiments or the prior art. Obviously, 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 flowchart of the preparation method of the present invention;

[0029] Figure 2 It is a scanning electron microscope image of the titanium-based composite powder prepared in Example 1 of the present invention;

[0030] Figure 3 It is a microstructural image of the titanium-based composite part A prepared in Example 1 of the present invention;

[0031] Figure 4 It is a scanning electron microscope image of the titanium-based composite powder prepared in Example 2 of the present invention;

[0032] Figure 5 It is a microstructural image of the titanium-based composite part B prepared in Example 2 of the present invention;

[0033] Figure 6 It is a scanning electron microscope image of the titanium-based composite powder prepared in Example 3 of the present invention;

[0034] Figure 7 It is a microstructural image of the titanium-based composite part C prepared in Example 3 of the present invention. Detailed implementation manners

[0035] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present invention. On the contrary, they are only examples consistent with some aspects of the present invention detailed in the appended claims.

[0036] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0037] The present invention provides a preparation method for a titanium-based composite part, including the following steps:

[0038] Step 1: Prepare a high-entropy alloy powder with a particle size of 10 μm to 50 μm by gas atomization method and use air flow sieving or vibration sieving in a high-purity argon atmosphere;

[0039] Parameters for preparing high-entropy alloy powder by gas atomization method: The diameter of the master alloy rod of the high-entropy alloy powder is 50 mm to 80 mm, the length is 100 mm to 600 mm, the power efficiency of powder making is 50% to 80%, the feeding speed is 50 mm / min to 100 mm / min, and the gas flow rate during air screening is 600 Nm 3 / h to 1200 Nm 3 / h;

[0040] Step 2: Prepare titanium alloy powder with a particle size of 10 μm to 150 μm by plasma rotating electrode method and perform vibration screening in an atmosphere of high-purity argon;

[0041] Parameters for preparing titanium alloy powder by plasma rotating electrode method: The diameter of the master alloy rod of the titanium alloy powder is 50 mm to 80 mm, the rotation speed is 20000 r / min to 32000 r / min, the feeding speed is 20 mm / min to 50 mm / min, the arc distance is 30 mm to 50 mm, the current is 1000 A to 1400 A, the voltage is 80 V to 90 V, and the vacuum degree < 5×10 -3 Pa;

[0042] Step 3: Mix the high-entropy alloy powder and titanium alloy powder in a double-cone mixer according to a specific ratio to obtain titanium-based mixed powder with a particle size of 10 μm to 150 μm; wherein, the mass fraction of high-entropy alloy powder in the titanium-based mixed powder is 0.1% to 8.0%; Parameters of the double-cone mixer during mixing: the rotation speed is 10 r / min to 30 r / min, and the mixing duration is 60 min to 180 min;

[0043] Step 4: First, load the titanium-based mixed powder into the first steel jacket, then perform mechanical compaction, vacuum degassing, and micro-beam plasma sealing welding on the first steel jacket in sequence, and then perform hot isostatic pressing. After furnace cooling, machine process to remove the first steel jacket to obtain a titanium-based composite master alloy rod with a diameter of 50 mm to 80 mm and a length of 500 mm to 700 mm;

[0044] Step 5: Use the plasma rotating electrode method to make powder from the titanium-based composite master alloy rod and perform vibration screening to obtain titanium-based composite powder with a particle size of 10 μm to 150 μm; wherein, parameters for preparing titanium-based composite powder by plasma rotating electrode method: the rotation speed of the titanium-based composite master alloy rod is 20000 r / min to 32000 r / min, the feeding speed is 20 mm / min to 50 mm / min, the arc distance is 30 mm to 50 mm, the current is 1000 A to 1400 A, the voltage is 80 V to 90 V, and the vacuum degree < 5×10 - 3 Pa;

[0045] Step 6: First, load the titanium-based composite powder into the second steel sleeve, then successively perform mechanical vibration compaction, vacuum degassing, and microbeam plasma sealing welding on the second steel sleeve, and then perform hot isostatic pressing. After furnace cooling, machine-process to remove the second steel sleeve to finally obtain the required titanium-based composite part.

[0046] Specifically, in step 2, the titanium alloy powder is one of α-type titanium alloy, α+β-type titanium alloy, and β-type titanium alloy; preferably, the α-type titanium alloy is selected from TA series titanium alloys, such as one of Ti-5Al-2.5Sn and Ti-6.5Al-1Mo-1V-2Zr; the α+β-type titanium alloy is selected from TC series titanium alloys, such as one of Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo, and Ti-6.5Al-2Zr-1Mo-1V; the β-type titanium alloy is selected from TB series titanium alloys, such as one of Ti-10V-2Fe-3Al and Ti-15V-3Cr-3Sn-3Al.

[0047] Specifically, the high-entropy alloy powder includes one of AlCoCrFeNi, AlCrCoNiCu, CuCrFeTiNi, CoCrMoNbTi, and FeCoNiTaAl.

[0048] Specifically, in steps 2 and 4, the degassing process is divided into two steps: the first step is to heat up to 300°C to 400°C, with a heating rate of 2°C / min to 10°C / min, and degas until the vacuum degree ≤ 1.0×10 -3 Pa; the second step is to heat up to 400°C to 500°C, with a heating rate of 2°C / min to 5°C / min, and degas until the vacuum degree ≤ 1.0×10 -4 Pa.

[0049] Specifically, in steps 2 and 4, the parameters of the microbeam plasma sealing welding are: welding current is 10A to 20A, arc voltage is 15V to 30V, and welding speed is 0.5mm / s to 2.5mm / s;

[0050] Specifically, in steps 4 and 6, the parameters of the hot isostatic pressing are: temperature is 850°C to 950°C, heating rate is 2°C / min to 20°C / min, pressure is 100MPa to 150MPa, and holding time is 120min to 180min; the materials of the first steel sleeve and the second steel sleeve are both 20 steel.

[0051] To prove the effect of the preparation method of the present invention, the following examples are provided for verification. Example 1

[0052] This embodiment provides a method for preparing a titanium-based composite part. See Figure 1 as shown below. The specific steps are as follows:

[0053] Step 1: Atomize the AlCoCrFeNi master alloy bar by gas atomization method. After sieving by air flow, AlCoCrFeNi powder with a particle size of 10 μm to 50 μm is obtained. Among them, the diameter of the AlCoCrFeNi master alloy bar is 50 mm, the length is 600 mm, the power efficiency during powder making is 60%, the feeding speed is 70 mm / min, and the gas flow rate during air flow sieving is 1000 Nm 3 / h;

[0054] Step 2: Prepare TC4 (Ti-6Al-4V) alloy powder by plasma rotating electrode method and sieve it by a vibrating screen under argon protection to obtain TC4 alloy powder with a particle size of 10 μm to 150 μm.

[0055] The parameters for preparing TC4 alloy powder by the plasma rotating electrode method are as follows: the diameter of the TC4 master alloy bar is 50 mm, the length is 700 mm, the rotation speed is 32000 r / min, the feeding value is 25 mm / min, the distance between the TC4 master alloy bar and the plasma arc (PV value) is 35 mm, the current is 1200 A, and the voltage is 80 V. In addition, before powder making, 3 TC4 master alloy bars are required for furnace washing to consume the residual gas components in the atomization chamber. The purity of the argon is 99.999%;

[0056] Step 3: Mix the TC4 alloy powder and AlCoCrFeNi powder in a double-cone mixer to obtain titanium-based mixed powder with a particle size of 10 μm to 150 μm. Among them, the introduction ratio of AlCoCrFeNi powder is 0.2 wt.%, the rotation speed of the double-cone mixer is 30 r / min, and the mixing duration is 120 min. See Figure 2 as shown Figure 2 in the SEM image of the titanium-based mixed powder. The highlighted part in the figure is the AlCoCrFeNi powder;

[0057] Step 4: First, load the titanium-based mixed powder into a first steel jacket made of 20 steel. After mechanical compaction, degas it at 400 °C to 8.9×10 -4 Pa, then degas it at 500 °C to 8.3×10 -5 Pa, then use micro-beam plasma sealing welding, then keep it at 850 °C and 150 MPa for 180 min, and then cool it to room temperature with the furnace and machine-process to remove the first steel jacket to obtain a titanium-based composite master alloy bar;

[0058] Step 5: The titanium-based composite master alloy bar is processed by plasma rotating electrode process to produce powder. After vibration screening, titanium-based composite powder with a particle size of 10 μm to 150 μm is obtained. The parameters for preparing the titanium-based composite powder by the plasma rotating electrode process are as follows: the rotation speed of the titanium-based composite master alloy bar is 20,000 r / min, the feeding speed is 50 mm / min, the arc distance is 30 mm, the current is 1,400 A, the voltage is 80 V, and the vacuum degree is < 5×10 -3 Pa;

[0059] Step 6: First, the titanium-based composite powder is filled into a second steel jacket made of 20 steel. After mechanical compaction, it is degassed at 400 °C to 8.9×10 -4 Pa, and then degassed at 500 °C to 8.3×10 -5 Pa. Then, it is sealed by micro-plasma welding. Then, it is heat-insulated at a temperature of 850 °C and a pressure of 150 MPa for 180 min, and then cooled to room temperature with the furnace. Finally, the second steel jacket is removed by machining to obtain the titanium-based composite part A;

[0060] Specifically, in Step 4 and Step 6, the parameters of the micro-plasma sealing welding are as follows: the welding current is 20 A, the arc voltage is 15 V, and the welding speed is 2.5 mm / s.

[0061] The obtained titanium-based composite part A is observed for its microstructure. Refer to Figure 3 As shown, it can be seen that the high-entropy alloy particles, as the second phase, precipitate at the grain boundaries. The precipitated phase can effectively hinder the movement of dislocations. That is, when the titanium alloy matrix is stressed, the high-entropy alloy particles play a pinning role on the dislocations, making the deformation more uniform; the presence of the high-entropy alloy particles introduces a strain gradient, promotes the multi-system slip of dislocations, improves the uniform deformation ability of the part, and thus delays fracture. Example 2

[0062] This example provides a method for preparing a titanium-based composite part. Refer to Figure 1 As shown, the specific steps are as follows:

[0063] Step 1: The AlCrCoNiCu master alloy bar is processed by gas atomization to produce powder. After air screening, AlCrCoNiCu powder with a particle size of 10 μm to 50 μm is obtained. Among them, the diameter of the AlCrCoNiCu master alloy bar is 60 mm, the length is 600 mm, the power efficiency during powder making is 50%, the feeding speed is 50 mm / min, and the gas flow rate during air screening is 900 Nm 3 / h;

[0064] Step 2: Prepare TA15 (Ti-6.5Al-1Mo-1V-2Zr) alloy powder with a particle size of 10 μm to 150 μm by the plasma rotating electrode process and screen it using a rotary vibrating sieve under argon protection;

[0065] The parameters for preparing TA15 alloy powder by the plasma rotating electrode process are as follows: the diameter of the TA15 master alloy rod is 60 mm, the length is 700 mm, the rotation speed is 25000 r / min, the feed value is 30 mm / min, the distance between the TA15 master alloy rod and the plasma arc (PV value) is 35 mm, the current is 1300 A, and the voltage is 82 V; in addition, before powder making, 3 TA15 master alloy rods are required for furnace washing to consume the residual gas components in the atomization chamber; the purity of the argon is 99.999%;

[0066] Step 3: Mix the TA15 alloy powder and AlCrCoNiCu powder in a double-cone mixer to obtain a titanium-based mixed powder with a particle size of 10 μm to 150 μm; among them, the introduction ratio of AlCrCoNiCu powder is 1.0 wt.%, the rotation speed of the double-cone mixer is 30 r / min, and the mixing duration is 80 min; see Figure 4 as shown, Figure 4 is the scanning electron microscope image of the titanium-based mixed powder, and the highlighted part in the figure is the AlCrCoNiCu powder;

[0067] Step 4: First, load the titanium-based mixed powder into a first steel jacket made of 20 steel. After mechanical compaction, degas it at 400 °C to 5.3×10 -4 Pa, and then degas it at 500 °C to 9.2×10 -5 Pa. Then, use microbeam plasma sealing welding, and then keep it at a temperature of 880 °C and a pressure of 130 MPa for 150 min. After that, cool it to room temperature with the furnace and then machine-process to remove the first steel jacket to obtain a titanium-based composite master alloy rod;

[0068] Step 5: Powder the titanium-based composite master alloy rod by the plasma rotating electrode process. After vibrating and screening, obtain a titanium-based composite powder with a particle size of 10 μm to 150 μm; the parameters for preparing the titanium-based composite powder by the plasma rotating electrode process are as follows: the rotation speed of the titanium-based composite master alloy rod is 25000 r / min, the feed speed is 35 mm / min, the arc distance is 40 mm, the current is 1200 A, the voltage is 85 V, and the vacuum degree < 5×10 -3 Pa;

[0069] Step 6: First, load the titanium-based composite powder into a second steel jacket made of 20 steel. After mechanical compaction, degas it at 400 °C to 5.3×10 -4 Pa, and then degas it at 500 °C to 9.2×10-5 After the pressure reaches 1 Pa, micro-plasma sealing welding is adopted, and then it is heat-insulated for 150 min at a temperature of 880 °C and a pressure of 130 MPa. After furnace cooling to room temperature, the second steel ladle sleeve is removed by machining, and finally the titanium-based composite part B is obtained;

[0070] Specifically, in steps 4 and 6, the parameters of the micro-plasma sealing welding are as follows: the welding current is 15 A, the arc voltage is 22 V, and the welding speed is 1.5 mm / s.

[0071] The microstructure of the prepared titanium-based composite part B is observed, as shown in Figure 5 It can be seen that the high-entropy alloy particles, as the second phase, precipitate at the grain boundaries. The precipitated phase can effectively hinder the movement of dislocations. That is, when the titanium alloy matrix is stressed, the high-entropy alloy particles play a pinning role on the dislocations, making the deformation more uniform; the existence of the high-entropy alloy particles introduces a strain gradient, promotes the multi-system slip of dislocations, improves the uniform deformation ability of the part, and thus delays fracture. Example 3

[0072] This example provides a preparation method for a titanium-based composite part, as shown in Figure 1 The specific steps are as follows:

[0073] Step 1: The AlCoCrFeNi master alloy bar is atomized by gas atomization to obtain AlCoCrFeNi powder with a particle size of 10 μm to 50 μm after vibration screening; among them, the diameter of the AlCoCrFeNi master alloy bar is 80 mm, the length is 400 mm, the power efficiency during powder making is 80%, and the feeding speed is 90 mm / min;

[0074] Step 2: Use the plasma rotating electrode method to prepare and obtain TB6 (Ti-10V-2Fe-3Al) alloy powder with a particle size of 10 μm to 150 μm by vibration screening under argon protection;

[0075] The parameters for preparing TB6 alloy powder by the plasma rotating electrode method are as follows: the diameter of the TB6 master alloy bar is 80 mm, the length is 700 mm, the rotation speed is 20000 r / min, the feeding value is 45 mm / min, the distance (PV value) between the TB6 master alloy bar and the plasma arc is 45 mm, the current is 1000 A, and the voltage is 88 V; in addition, before powder making, 3 TB6 master alloy bars are required to wash the furnace to consume the residual gas components in the atomization chamber; the purity of the argon is 99.999%;

[0076] Step 3: Mix the TB6 alloy powder and AlCoCrFeNi powder in a double-cone mixer to obtain a titanium-based mixed powder with a particle size of 10 μm to 150 μm. Among them, the introduction ratio of AlCoCrFeNi powder is 7.0 wt.%, the rotation speed of the double-cone mixer is 15 r / min, and the mixing duration is 180 min; see Figure 6 as shown in Figure 6 Figure Figure 6 is the scanning electron microscope image of the titanium-based mixed powder, and the highlighted part in the figure is the AlCoCrFeNi powder;

[0077] Step 4: First, load the titanium-based mixed powder into a first steel jacket made of 20 steel, mechanically vibrate and compact it, degas at 300 °C to 6.5×10 -4 Pa, then degas at 400 °C to 7.5×10 -5 Pa, then use microbeam plasma sealing welding, then keep it at 950 °C and 100 MPa for 120 min, and then cool it to room temperature in the furnace and machine-process to remove the first steel jacket to obtain a titanium-based composite master alloy bar;

[0078] Step 5: Prepare powder from the titanium-based composite master alloy bar by the plasma rotating electrode process. After vibrating and screening, obtain a titanium-based composite powder with a particle size of 10 μm to 150 μm. The parameters for preparing the titanium-based composite powder by the plasma rotating electrode process are as follows: the rotation speed of the titanium-based composite master alloy bar is 32000 r / min, the feeding speed is 20 mm / min, the arc distance is 50 mm, the current is 1000 A, the voltage is 90 V, and the vacuum degree < 5×10 -3 Pa;

[0079] Step 6: First, load the titanium-based composite powder into a second steel jacket made of 20 steel, mechanically vibrate and compact it, degas at 300 °C to 6.5×10 -4 Pa, then degas at 400 °C to 7.5×10 -5 Pa, then use microbeam plasma sealing welding, then keep it at 950 °C and 100 MPa for 120 min, and then cool it to room temperature in the furnace and machine-process to remove the second steel jacket to finally obtain a titanium-based composite part C;

[0080] Specifically, in Step 4 and Step 6, the parameters of the microbeam plasma sealing welding are as follows: the welding current is 10 A, the arc voltage is 30 V, and the welding speed is 0.5 mm / s.

[0081] Observe the microstructure of the prepared titanium-based composite part C, see Figure 7As shown, it can be seen that the high-entropy alloy particles, as the second phase, precipitate at the grain boundaries. The precipitated phase can effectively hinder the movement of dislocations. That is, when the titanium alloy matrix is stressed, the high-entropy alloy particles play a pinning role on the dislocations, making the deformation more uniform. The presence of the high-entropy alloy particles introduces a strain gradient, promotes the multi-system slip of dislocations, improves the uniform deformation ability of the workpiece, and thus delays fracture.

[0082] To verify the mechanical properties of the titanium-based composite workpieces A, B, and C prepared in the embodiments of the present invention, tensile tests were carried out at room temperature, and the test results are shown in Table 1:

[0083] Table 1

[0084] Tensile strength MPa Yield strength MPa Elongation % Reduction of area % Example 1 980 875 19 45 Example 2 1050 950 15 43 Example 3 1180 1010 12 42

[0085] As shown in Table 1, for the titanium-based composite workpieces prepared by the preparation method of the present invention, after tensile tests, their tensile strength is ≥980 MPa, yield strength is ≥875 MPa, elongation is ≥15%, and reduction of area is >40%. They have both good strength and plasticity, meeting the actual use requirements of aeroengine turbine blades and high-pressure compressor disks.

[0086] It should also be noted that for the titanium-based composite workpieces prepared by the preparation method of the present invention, compared with traditional titanium-based composite workpieces, the introduction of high-entropy alloys significantly increases the lattice distortion, and the high-entropy alloy particles themselves, as the second phase, can effectively hinder the movement of dislocations. That is, when the titanium alloy matrix is stressed, the high-entropy alloy particles play a certain pinning role on the dislocations. The increase in the precipitated phase on the grain boundaries also hinders the movement of dislocations, and its interface effect also makes the stress distribution more uniform, reduces stress concentration, and delays crack propagation, which further improves the yield strength and tensile strength of the composite workpiece. In addition, when a variety of elements are mixed in an almost equal proportion at the microscale with the introduction of high-entropy alloy particles, it is usually easy to form simple crystal configurations such as face-centered cubic (FCC) or body-centered cubic (BCC), and at the same time, a multi-phase structure such as trace metal intermetallic compounds or amorphous phases will be accompanied. This multi-phase structure can have a synergistic deformation effect, making the workpiece show higher plasticity macroscopically. As the second phase, the high-entropy alloy particles can effectively hinder the propagation of cracks. That is, when the crack encounters the high-entropy alloy particles during propagation, more energy is required to continue to propagate. When the dislocations bypass or cut through the high-entropy alloy particles, more dislocation multiplication and interaction will be triggered, making the deformation more uniform. Further, the presence of the high-entropy alloy particles introduces a strain gradient, promotes the multi-system slip of dislocations, improves the uniform deformation ability of the workpiece, and thus delays fracture. Further, the interfacial bonding strength between the high-entropy alloy particles and the titanium alloy matrix is relatively high, which can effectively transfer stress, avoid local stress concentration, make the stress distribution near the interface more uniform, and delay local plastic instability.

[0087] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0088] It should be understood that the present invention is not limited to the above-described content and can be modified and changed without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A preparation method of a titanium-based composite part, characterized in that, It includes the following steps: Step 1: Prepare high-entropy alloy powder with a specific particle size by gas atomization method; Step 2: Prepare titanium alloy powder with a specific particle size by plasma rotating electrode method; Step 3: Mix the high-entropy alloy powder and titanium alloy powder in a specific ratio to obtain titanium-based mixed powder; Step 4: First, load the titanium-based mixed powder into the first sheath, then perform compaction, degassing, and sealing welding treatments on the first sheath in sequence, and then perform hot isostatic pressing. After cooling, remove the first sheath to obtain a titanium-based composite master alloy bar; Step 5: Use the plasma rotating electrode method to powder the titanium-based composite master alloy bar to obtain titanium-based composite powder with a specific particle size; Step 6: First, load the titanium-based composite powder into the second sheath, then perform compaction, degassing, and sealing welding treatments on the second sheath in sequence, and then perform hot isostatic pressing. After cooling, remove the second sheath to finally obtain the required titanium-based composite part.

2. The preparation method of the titanium-based composite part according to claim 1, wherein In Step 1, the parameters for preparing high-entropy alloy powder by gas atomization method: the power efficiency is 50% - 80%, and the feeding speed is 50 mm / min - 100 mm / min.

3. The preparation method of the titanium-based composite part according to claim 1, characterized in that, In Step 2, the parameters for preparing titanium alloy powder by the plasma rotating electrode process are as follows: the rotational speed is 20,000 r / min to 32,000 r / min, the feed rate is 20 mm / min to 50 mm / min, the arc distance is 30 mm to 50 mm, the current is 1,000 A to 1,400 A, the voltage is 80 V to 90 V, and the vacuum degree is < 5×10 - 3 Pa.

4. The preparation method of the titanium-based composite part according to claim 1, characterized in that, In Step 2, the titanium alloy powder is one of α-type titanium alloy, α + β-type titanium alloy, and β-type titanium alloy.

5. The preparation method of the titanium-based composite part according to claim 1, characterized in that, In Step 3, the mass fraction of high-entropy alloy powder in the titanium-based mixed powder is 0.1% - 8.0%.

6. The preparation method of the titanium-based composite part according to claim 1, wherein, The high-entropy alloy powder is one of AlCoCrFeNi, AlCrCoNiCu, CuCrFeTiNi, CoCrMoNbTi, FeCoNiTaAl.

7. The preparation method of the titanium-based composite part according to claim 1, characterized in that In Step 4 and Step 6, the degassing process is in two steps: in the first step, heat up to 300°C to 400°C and degas until the vacuum degree ≤ 1.0×10 -3 Pa; in the second step, heat up to 400°C to 500°C and degas until the vacuum degree ≤ 1.0×10 -4 Pa.

8. The preparation method of the titanium-based composite part according to claim 1, characterized in that, In Step 4 and Step 6, the parameters of the hot isostatic pressing: the temperature is 850°C - 950°C, the heating rate is 2°C / min - 20°C / min, the pressure is 100 MPa - 150 MPa, and the holding time is 120 min - 180 min.

9. A titanium-based composite component, characterized in that, Prepared by the preparation method described in any one of claims 1 - 8.

10. Use of the titanium-based composite part according to claim 9, characterized in that, Applications in aeroengine turbine blades and high-pressure compressor disks.

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