Titanium-based spherical alloy and manufacturing process thereof

Abstract

The application relates to the powder metallurgy technical field and discloses a manufacturing process of a titanium-based spherical alloy, which comprises the following steps: mixing lanthanum oxide particles and fine titanium powder to prepare composite carrier particles through cold pressing and solidification, and then mixing the composite carrier particles with Ti-Al-V-Nb main powder; pre-drying the powder particles in an argon atmosphere sealed bin, and then performing hard stearic acid film packaging on the surfaces of the powder particles in the same sealed bin; pressing the packaged powder into a spherical green body with an internally threaded hole, and pre-sintering the spherical green body to obtain a porous titanium-based alloy spherical framework; performing copper-aluminum alloy liquid phase infiltration on the porous framework, and performing post-processing after cooling and solidification to obtain a finished product; the hard stearic acid film packaging prevents the pre-drying effect from being damaged by inter-process transfer, and eliminates sintering pores; the pre-solidification of the composite carrier particles eliminates rare earth oxide aggregation segregation; the copper-aluminum alloy liquid phase infiltration improves the compactness and the heat conduction performance; and the obtained spherical alloy sealing element has the comprehensive performance advantages of light weight, high strength and high heat conduction.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy, and more specifically, to a process for manufacturing a titanium-based spherical alloy. Background Technology

[0002] Spherical grout sealant fittings are commonly used tools in interior grout sealing. They connect to the application tool via internal threaded channels and, when electrically heated, transfer heat to the grout material, achieving a beautiful filling of the gaps. Traditional spherical grout sealant fittings are made of tungsten-based alloys (such as W-Ni-Fe and W-Ni-Cu systems), where tungsten has a high density of 19.3 g / cm³. 3 This results in heavy finished products and significant fatigue for construction workers holding them for extended periods. Furthermore, tungsten-based raw materials are expensive, leading to high production costs. The pressing of tungsten powder causes severe wear on the molds, making processing difficult. Replacing tungsten-based alloys with Ti-Al-V-Nb multi-component titanium-based alloys (density approximately 4.5 g / cm³) in the preparation of spherical grout joints can significantly reduce product weight and raw material costs while maintaining sufficient structural strength, representing the current direction of technological development.

[0003] However, there are pressing technical problems in the existing powder metallurgy preparation process of titanium-based spherical parts: titanium-based alloy powder particles have a large specific surface area and strong physical adsorption of environmental moisture. Although a powder pre-drying process has been introduced to remove the adsorbed moisture on the powder particle surface, the pre-dried powder is re-exposed to the factory production environment (relative humidity is usually 30%-60%) during the inter-process transfer, and continues to re-adsorb moisture. The re-absorption amount can recover to 30%-60% of the pre-drying level, resulting in a significant loss of the pre-drying process effect. During high-temperature sintering, a large number of pores are still formed, and the density and structural strength of the spherical parts are difficult to meet the application requirements. In addition, the rare earth oxide dispersion strengthening phase introduced to improve the structural uniformity of the spherical parts is prone to agglomeration and segregation due to the significant difference in density with the main powder. Furthermore, the thermal conductivity of titanium-based alloys (about 17 W / m·K) is much lower than that of traditional tungsten-based alloys (about 70-170 W / m·K), which further restricts the comprehensive performance of titanium-based spherical grouting parts. Summary of the Invention

[0004] This invention provides a manufacturing process for titanium-based spherical alloys, solving technical problems in related technologies such as the destruction of the pre-drying effect of titanium-based alloy powder by environmental moisture during inter-process transfer, rare earth oxide agglomeration and segregation, and insufficient thermal conductivity.

[0005] This invention provides a manufacturing process for titanium-based spherical alloys, comprising the following steps: Lanthanum oxide particles and fine-particle titanium powder are mixed at a mass ratio of 1:4 to 1:9, then cold-pressed and solidified, crushed and sieved to obtain composite carrier particles. The composite carrier particles are then mixed evenly with Ti-Al-V-Nb main powder to obtain mixed powder. The mixed powder is pre-dried in an argon atmosphere to remove adsorbed moisture from the surface of the powder particles, resulting in a dried mixed powder. After the dry mixed powder is cooled to below 35°C in an argon atmosphere sealed chamber, molten stearic acid is sprayed into the sealed chamber in an atomized manner to form a stearic acid encapsulation film on the surface of the powder particles. The packaged powder is filled into a spherical mold with a threaded core and pressed to obtain a spherical green blank with internal threaded channels. The spherical green blank is pre-sintered under vacuum or argon atmosphere protection, and after the degreasing stage, it enters the high-temperature sintering stage to obtain a porous titanium-based alloy spherical skeleton with interconnected internal pores. Under vacuum or argon atmosphere protection, a porous titanium-based alloy spherical skeleton is immersed in molten copper-aluminum alloy for liquid phase infiltration. After cooling and solidification, the spherical part is post-processed to obtain the finished titanium-based spherical alloy.

[0006] Preferably, the Ti-Al-V-Nb main powder, by mass fraction, comprises 5%-7% aluminum powder, 3%-5% vanadium powder, 1%-3% niobium powder, and the remainder is titanium powder used as the main powder.

[0007] Preferably, the particle size of the titanium powder used as the main powder is 45-75 μm.

[0008] Preferably, the lanthanum oxide particles have a particle size of 1-5 μm and are used in an amount of 0.1%-0.5% of the total mass of all raw material powders; the fine titanium powder has a particle size of 15-25 μm.

[0009] Preferably, the pre-drying temperature is 80-120°C.

[0010] Preferably, the amount of stearic acid used is 0.5%-1.0% of the total mass of all raw material powders, and it is heated to 80-100℃ to melt it before being atomized and sprayed.

[0011] Preferably, the high-temperature sintering stage of the pre-sintering is 800-1000℃, the holding time is 1-3 h, and the porosity of the resulting porous titanium-based alloy spherical skeleton is 15%-25%.

[0012] Preferably, the pre-sintering is carried out under a vacuum degree of not less than 10. -2 The experiment was conducted under vacuum conditions of Pa.

[0013] Preferably, the copper-aluminum alloy is a pre-alloyed copper-aluminum alloy ingot with an aluminum content of 8%-15% (mass fraction) and the balance being copper, and the liquidus temperature is 970-1040℃. The heating temperature of the copper-aluminum alloy during liquid phase infiltration is more than 50℃ higher than the liquidus temperature of the copper-aluminum alloy used.

[0014] Preferably, the impregnation time of the liquid phase is 10-30 min.

[0015] A titanium-based spherical alloy is prepared by the above-described manufacturing process.

[0016] The beneficial effects of this invention are as follows: (1) The combined effect of powder pre-drying in step two and stearic acid film encapsulation in step three effectively prevents the pre-drying effect from being destroyed by environmental moisture during the inter-process transfer, keeps the powder particle surface in a dry and clean state until high-temperature sintering, fundamentally eliminates sintering porosity defects, and significantly improves the density of spherical parts; combined with copper-aluminum alloy liquid phase infiltration in step six to further fill the residual pores, the final product density reaches a level close to full density.

[0017] (2) In step one, the rare earth oxide carrier pre-consolidation process involves mixing La2O3 particles in the form of composite carrier particles, which eliminates gravity sedimentation and agglomeration caused by density differences. La2O3 is uniformly dispersed inside the spherical part, eliminating hard agglomerate defects at the root of the threaded channel and improving the reliability of the threaded connection.

[0018] (3) Step 6: The copper-aluminum alloy liquid phase is impregnated in the porous skeleton to form a copper-aluminum alloy filling phase with high thermal conductivity. The overall thermal conductivity of the spherical part is significantly improved, and the heat conduction efficiency of the grouting construction is improved.

[0019] (4) The stearic acid film is completely thermally decomposed and volatilized in the pre-sintering and degreasing stage (200-400℃) in step five, leaving no residue in the spherical parts. No additional removal process is required, and the process flow is simple.

[0020] (5) The density of the Ti-Al-V-Nb multi-element alloy system is much lower than that of traditional tungsten-based alloys. Niobium and vanadium serve as β-phase stabilizing elements to ensure structural strength. The uniform distribution of the La2O3 dispersed strengthening phase improves the uniformity of the sintered body. The copper-aluminum alloy filling phase compensates for the strength loss caused by residual porosity. The final product has comprehensive properties of lightweight, high strength and high thermal conductivity, fully meeting the usage requirements of spherical grout joints. Attached Figure Description

[0021] Figure 1 This is a bar chart comparing the final porosity of the three sets of comparative samples in Experiment 1 of this invention; Figure 2 These are SEM images of the pore distribution in the cross-sections of the three sets of comparative samples in Experiment 1 of this invention. Figure 3 This is a quantitative comparison chart of the uniformity of La2O3 dispersion in two mixing methods in Experiment 2 of this invention; Figure 3 In the middle: (a) is a comparison of the surface density of La2O3 agglomeration regions; (b) is a comparison of the uniformity of La distribution. Figure 4 This is a bar chart comparing the thermal conductivity of each group of samples in Experiment 3 of this invention; Figure 5 This is a comparison chart of the overall performance of the present invention and the traditional W-Ni-Fe grout in Experiment 4 of the present invention; Figure 5 In the middle: (a) is a density comparison; (b) is a Vickers hardness comparison. Detailed Implementation

[0022] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, some features described in the examples may be combined in other examples.

[0023] Example 1 This embodiment provides a manufacturing process for titanium-based spherical alloy grout sealant, with specific parameters for each step as follows: Step 1: Alloy powder preparation and rare earth oxide carrier pre-consolidation Weigh out 5% aluminum powder, 3% vanadium powder, and 1% niobium powder by mass fraction, with the remainder being titanium powder. The remaining titanium powder is divided into two parts: titanium powder for the main powder with a particle size of 45 μm and titanium powder for the carrier with a particle size of 15 μm. Take 0.1% of the total mass of all raw material powders using 1 μm La2O3 particles, and use the carrier titanium powder at a mass ratio of 1:4 (4 times the mass of La2O3). Mix the La2O3 particles and the carrier titanium powder evenly, then cold-press them into thin sheet blanks under 100 MPa pressure. After crushing, the sheet blanks are passed through a 200-mesh sieve to obtain composite carrier particles. Add the composite carrier particles to the Ti-Al-V-Nb main powder and mix evenly to obtain a mixed powder.

[0024] Step 2: Powder pre-drying treatment The mixed powder obtained in step one is placed in an argon atmosphere sealed chamber and baked at 80°C for 1 hour to remove the physically adsorbed moisture on the surface of the powder particles, resulting in a dried mixed powder. After pre-drying, the dried mixed powder is kept in the argon atmosphere sealed chamber and does not come into contact with the outside air, and proceeds directly to the subsequent operations in step three.

[0025] Step 3: Stearic acid film encapsulation Inside a sealed chamber under an argon atmosphere, the dried mixed powder is cooled to 30°C. Stearic acid, amounting to 0.5% of the total mass of the raw material powder, is heated to 80°C to fully melt it. The molten stearic acid is then sprayed into the sealed chamber in an atomized manner. The atomized droplets rapidly condense and solidify on the surface of the powder particles, forming a continuous, sealed solid protective film of stearic acid.

[0026] Step 4: Pressing and Shaping The powder that has been packaged in step three is filled into a spherical mold with a threaded core and pressed to obtain a spherical green blank with internal threaded channels.

[0027] Step 5: Pre-sintering The spherical green billet is placed in a vacuum sintering furnace at a vacuum degree of 10. -2 Pre-sintering was carried out under Pa conditions. During the degreasing stage, the temperature was raised to 200-400℃, and the stearic acid film was completely thermally decomposed and volatilized. The temperature was then raised to 800℃ and held for 1 h to obtain a porous titanium-based alloy spherical skeleton with an open porosity of about 22% and interconnected internal pores.

[0028] Step Six: Liquid Phase Infiltration of Copper-Aluminum Alloy A pre-alloyed copper-aluminum alloy ingot with an aluminum content of 8% (mass fraction) and the balance being copper (liquidothermal temperature approximately 1040°C) was used as the infiltration material. Under vacuum conditions, the copper-aluminum alloy was heated to 1090°C to fully melt it. A porous titanium-based alloy spherical skeleton was then immersed in the molten copper-aluminum alloy and kept in the infiltration state for 10 minutes before being removed and cooled to room temperature, where the copper-aluminum alloy solidified within the pores.

[0029] Step 7: Post-processing The residual copper and aluminum alloy that has solidified and adhered to the surface of the spherical part is removed by grinding to restore the spherical surface to a smooth state; the internal threaded channel is inspected to confirm that the thread specifications meet the design requirements; the surface is polished to obtain the finished titanium-based spherical alloy sealant.

[0030] Example 2 This embodiment provides a manufacturing process for titanium-based spherical alloy grout sealant, with specific parameters for each step as follows: Step 1: Alloy powder preparation and rare earth oxide carrier pre-consolidation Weigh out 7% aluminum powder, 5% vanadium powder, and 3% niobium powder by mass fraction, with the remainder being titanium powder. The remaining titanium powder is divided into two parts: titanium powder for the main powder with a particle size of 75 μm and titanium powder for the carrier with a particle size of 25 μm. Take 0.5% of the total mass of all raw material powders using 5 μm La2O3 particles, and use the carrier titanium powder at a mass ratio of 1:9 (9 times the mass of La2O3). Mix the La2O3 particles and the carrier titanium powder evenly, then cold-press them into thin sheet blanks under 200 MPa pressure. After crushing, the sheet blanks are passed through a 200-mesh sieve to obtain composite carrier particles. Add the composite carrier particles to the Ti-Al-V-Nb main powder and mix evenly to obtain a mixed powder.

[0031] Step 2: Powder pre-drying treatment The mixed powder obtained in step one was placed in an argon atmosphere sealed chamber and baked at 120°C for 4 hours to remove the physically adsorbed moisture on the surface of the powder particles, resulting in a dried mixed powder. After pre-drying, the dried mixed powder was kept in the argon atmosphere sealed chamber and kept away from the outside air before proceeding directly to the subsequent operations in step three.

[0032] Step 3: Stearic acid film encapsulation In a sealed chamber under the same argon atmosphere, the dried mixed powder is cooled to 25°C. Stearic acid, amounting to 1.0% of the total mass of the raw material powder, is heated to 100°C to fully melt it. The molten stearic acid is then sprayed into the sealed chamber in an atomized manner. The atomized droplets rapidly condense and solidify on the surface of the powder particles, forming a continuous and sealed solid protective film of stearic acid.

[0033] Step 4: Pressing and Shaping The powder that has been packaged in step three is filled into a spherical mold with a threaded core and pressed to obtain a spherical green blank with internal threaded channels.

[0034] Step 5: Pre-sintering The spherical green blank was placed in an argon atmosphere sintering furnace and pre-sintered using 99.99% pure argon as a protective atmosphere. During the degreasing stage, the temperature was raised to 200-400℃, and the stearic acid film was completely thermally decomposed and volatilized. The temperature was then raised to 1000℃ and held for 3 hours to obtain a porous titanium-based alloy spherical skeleton with an open porosity of about 16% and interconnected internal pores.

[0035] Step Six: Liquid Phase Infiltration of Copper-Aluminum Alloy A pre-alloyed copper-aluminum alloy ingot with an aluminum content of 15% (mass fraction) and the balance being copper (liquidothermal temperature approximately 970°C) was used as the infiltration material. Under an argon atmosphere, the copper-aluminum alloy was heated to 1020°C to fully melt it. A porous titanium-based alloy spherical skeleton was then immersed in the molten copper-aluminum alloy and kept in the infiltration state for 30 minutes before being removed and cooled to room temperature, where the copper-aluminum alloy solidified within the pores.

[0036] Step 7: Post-processing The residual copper and aluminum alloy that has solidified and adhered to the surface of the spherical part is removed by grinding to restore the spherical surface to a smooth state; the internal threaded channel is inspected to confirm that the thread specifications meet the design requirements; the surface is polished to obtain the finished titanium-based spherical alloy sealant.

[0037] Example 3 This embodiment provides a manufacturing process for titanium-based spherical alloy grout sealant, using optimized values ​​for each parameter. The specific parameters for each step are as follows: Step 1: Alloy powder preparation and rare earth oxide carrier pre-consolidation Weigh out 6% aluminum powder, 4% vanadium powder, and 2% niobium powder by mass fraction, with the remainder being titanium powder. The remaining titanium powder is divided into two parts: titanium powder for the main powder with a particle size of 60 μm and titanium powder for the carrier with a particle size of 20 μm. Take 0.3% of the total mass of all raw material powders using 3 μm La2O3 particles, and use the carrier titanium powder at a mass ratio of 1:6 (6 times the mass of La2O3). Mix the La2O3 particles and the carrier titanium powder evenly, then cold-press them into thin sheet blanks under 150 MPa pressure. After crushing, the sheet blanks are passed through a 200-mesh sieve to obtain composite carrier particles. Add the composite carrier particles to the Ti-Al-V-Nb main powder and mix evenly to obtain a mixed powder.

[0038] Step 2: Powder pre-drying treatment The mixed powder obtained in step one was placed in an argon atmosphere sealed chamber and baked at 100°C for 2 hours to remove the physically adsorbed moisture on the surface of the powder particles, resulting in a dried mixed powder. After pre-drying, the dried mixed powder was kept in the argon atmosphere sealed chamber and kept away from the outside air before proceeding directly to the subsequent operations in step three.

[0039] Step 3: Stearic acid film encapsulation Inside a sealed chamber under an argon atmosphere, the dried mixed powder is cooled to 28°C. Stearic acid, amounting to 0.7% of the total mass of the raw material powder, is heated to 90°C to fully melt it. The molten stearic acid is then sprayed into the sealed chamber in an atomized manner. The atomized droplets rapidly condense and solidify on the surface of the powder particles, forming a continuous, sealed solid protective film of stearic acid.

[0040] Step 4: Pressing and Shaping The powder that has been packaged in step three is filled into a spherical mold with a threaded core and pressed to obtain a spherical green blank with internal threaded channels.

[0041] Step 5: Pre-sintering The spherical green billet is placed in a vacuum sintering furnace and sintered at a vacuum degree of 5×10⁻⁶. -3Pre-sintering was carried out under Pa conditions. During the degreasing stage, the temperature was raised to 200-400℃, and the stearic acid film was completely thermally decomposed and volatilized. The temperature was then raised to 900℃ and held for 2 hours to obtain a porous titanium-based alloy spherical skeleton with an open porosity of about 20% and interconnected internal pores.

[0042] Step Six: Liquid Phase Infiltration of Copper-Aluminum Alloy A pre-alloyed copper-aluminum alloy ingot with an aluminum content of 10% (mass fraction) and the balance being copper (liquidothermal temperature approximately 1015°C) was used as the infiltration material. Under vacuum conditions, the copper-aluminum alloy was heated to 1065°C to fully melt it. A porous titanium-based alloy spherical skeleton was then immersed in the molten copper-aluminum alloy and kept in the infiltration state for 20 minutes before being removed and cooled to room temperature, where the copper-aluminum alloy solidified within the pores.

[0043] Step 7: Post-processing The residual copper and aluminum alloy that has solidified and adhered to the surface of the spherical part is removed by grinding to restore the spherical surface to a smooth state; the internal threaded channel is inspected to confirm that the thread specifications meet the design requirements; the surface is polished to obtain the finished titanium-based spherical alloy sealant.

[0044] Example 4 This embodiment provides a manufacturing process for titanium-based spherical alloy grout sealant, with specific parameters for each step as follows: Step 1: Alloy powder preparation and rare earth oxide carrier pre-consolidation Weigh out 6.5% aluminum powder, 4.5% vanadium powder, and 1.5% niobium powder by mass fraction, with the remainder being titanium powder. The remaining titanium powder is divided into two parts: titanium powder for the main powder with a particle size of 55 μm and titanium powder for the carrier with a particle size of 18 μm. Take 0.4% of the total mass of all raw material powders using 2 μm La2O3 particles, and use the carrier titanium powder at a mass ratio of 1:7 (7 times the mass of La2O3). Mix the La2O3 particles and the carrier titanium powder evenly, then cold-press them into thin sheet blanks under 180 MPa pressure. After crushing, the sheet blanks are sieved through a 200-mesh sieve to obtain composite carrier particles. Add the composite carrier particles to the Ti-Al-V-Nb main powder and mix evenly to obtain a mixed powder.

[0045] Step 2: Powder pre-drying treatment The mixed powder obtained in step one was placed in an argon atmosphere sealed chamber and baked at 110°C for 3 hours to remove the physically adsorbed moisture on the surface of the powder particles, resulting in a dried mixed powder. After pre-drying, the dried mixed powder was kept in the argon atmosphere sealed chamber and kept away from the outside air before proceeding directly to the subsequent operations in step three.

[0046] Step 3: Stearic acid film encapsulation Inside a sealed chamber under an argon atmosphere, the dried mixed powder is cooled to 30°C. Stearic acid, amounting to 0.8% of the total mass of the raw material powder, is heated to 85°C until fully melted. The molten stearic acid is then atomized and sprayed into the sealed chamber. The atomized droplets rapidly condense and solidify on the surface of the powder particles, forming a continuous, sealed solid protective film of stearic acid.

[0047] Step 4: Pressing and Shaping The powder that has been packaged in step three is filled into a spherical mold with a threaded core and pressed to obtain a spherical green blank with internal threaded channels.

[0048] Step 5: Pre-sintering The spherical green billet is placed in a vacuum sintering furnace and sintered at a vacuum degree of 8×10⁻⁶. -3 Pre-sintering was carried out under Pa conditions. During the degreasing stage, the temperature was raised to 200-400℃, and the stearic acid film was completely thermally decomposed and volatilized. The temperature was further raised to 950℃ and held for 1.5 h to obtain a porous titanium-based alloy spherical skeleton with an open porosity of about 18% and interconnected internal pores.

[0049] Step Six: Liquid Phase Infiltration of Copper-Aluminum Alloy A pre-alloyed copper-aluminum alloy ingot with an aluminum content of 12% (mass fraction) and the balance being copper (liquidothermal temperature approximately 1000℃) was used as the infiltration material. Under an argon atmosphere, the copper-aluminum alloy was heated to 1050℃ to fully melt it. A porous titanium-based alloy spherical skeleton was then immersed in the molten copper-aluminum alloy and kept in the infiltration state for 15 minutes before being removed and cooled to room temperature, where the copper-aluminum alloy solidified within the pores.

[0050] Step 7: Post-processing The residual copper and aluminum alloy that has solidified and adhered to the surface of the spherical part is removed by grinding to restore the spherical surface to a smooth state; the internal threaded channel is inspected to confirm that the thread specifications meet the design requirements; the surface is polished to obtain the finished titanium-based spherical alloy sealant.

[0051] Example 5 This embodiment provides a manufacturing process for titanium-based spherical alloy grout sealant, which includes the following steps: Step 1: Alloy powder preparation and rare earth oxide carrier pre-consolidation This step uses lanthanum oxide (La₂O₃, density approximately 6.5 g / cm³). 3 La₂O₃ was used as a dispersion reinforcing phase. La₂O₃ and aluminum powder (2.7 g / cm³) were used as the dispersion reinforcing phase. 3 Titanium powder (4.5 g / cm³) 3There is a significant density difference between La2O3 and titanium powder. If La2O3 particles are directly added to the main powder for mixing, they will agglomerate due to gravity settling during the mixing process, forming localized hard clumps inside the spherical part. This step involves pre-cold-pressing and solidifying La2O3 particles between titanium powder particles to create composite carrier particles with titanium powder as the main component. These composite carrier particles then replace the La2O3 particles in the mixing of the main powder, eliminating the conditions for gravitational settling and agglomeration caused by the high density of La2O3 particles when they exist alone. La2O3 is chosen instead of CeO2 (density approximately 7.2 g / cm³). 3 The reason is that the density of La2O3 is closer to that of titanium powder (4.5 g / cm³). 3 After being made into composite carrier particles, the density difference between them and the main powder is smaller, which helps to further reduce the tendency of agglomeration and segregation.

[0052] The specific steps are as follows: (1) Raw material powder proportioning and weighing: The target proportion is set according to the mass fraction: 6% aluminum powder, 4% vanadium powder, 2% niobium powder, and the remainder is titanium powder. The remainder titanium powder is divided into the following two parts: the first part is titanium powder for the main powder with a particle size of 60 μm; the second part is titanium powder with a fine particle size of 20 μm (hereinafter referred to as "carrier titanium powder"). The mass of the carrier titanium powder is 6 times the mass of the rare earth oxides used. The sum of the masses of the two parts of titanium powder is the total mass of the remainder titanium powder, ensuring that the proportion of each component in the final mixed powder is consistent with the set value. The main powder titanium powder together with aluminum powder, vanadium powder, and niobium powder constitutes the main powder of the Ti-Al-V-Nb multi-element alloy.

[0053] (2) Preparation of composite carrier particles: Take La2O3 particles (3 μm in diameter), the amount of which is 0.3% of the total mass of all raw material powders in step (1). Mix the La2O3 particles with the carrier titanium powder marked in step (1) at a mass ratio of 1:6. After mixing evenly, cold press the mixture into thin sheet blocks under a pressure of 150 MPa. After crushing the thin sheet blocks, pass them through a 200-mesh sieve to obtain composite carrier particles in which La2O3 particles are cold-pressed and solidified between titanium powder particles. In this composite carrier particle, the La2O3 particles are surrounded and solidified by titanium powder particles from all directions and no longer exist in the form of free particles. The composite carrier particle is mainly composed of titanium powder, and the overall density is close to the density of titanium powder (approximately 4.5 g / cm³). 3 The density difference between the main powder and the components in the main powder is much smaller than the density difference when La2O3 particles are mixed individually.

[0054] (3) Add the above composite carrier particles to the main powder formed in step (1) and mix them evenly to obtain a Ti-Al-V-Nb multi-element alloy mixed powder with uniform distribution of rare earth oxides, which will be used as the mixed powder for subsequent steps.

[0055] Step 2: Powder pre-drying treatment The mixed powder obtained in step one was placed in an argon atmosphere-sealed chamber and baked at 100°C for 2 hours to remove the physically adsorbed moisture on the surface of each component powder particle, resulting in a dry mixed powder with a clean surface. This temperature is higher than the physical desorption temperature of moisture (approximately 60-80°C) and does not cause significant oxidation or sintering adhesion between powder particles under argon protection. After pre-drying, the dry mixed powder was kept in the argon atmosphere-sealed chamber and not exposed to outside air before proceeding directly to the subsequent operations in step three.

[0056] Step 3: Stearic acid film encapsulation The dried powder mixture treated in step two will continue to reabsorb moisture from the environment during the transfer to the subsequent pressing station, resulting in a significant loss of the pre-drying effect. This step forms a stearic acid film on the surface of the powder particles immediately after pre-drying, isolating the powder particle surface from external moisture and preventing the dried powder mixture from reabsorbing moisture during subsequent transfer between processes.

[0057] The specific steps are as follows: (1) After the pre-drying process in step two is completed, the dried mixed powder is cooled to 28°C in the same argon atmosphere sealed chamber to prevent the dried mixed powder from coming into contact with external moisture before subsequent operations. At the same time, the temperature of the powder particles is kept below the melting point of stearic acid (about 69°C) to ensure that the subsequent atomized stearic acid liquid can be quickly condensed and solidified when it comes into contact with the powder particles instead of melting again.

[0058] (2) Melting and atomization of stearic acid: Take stearic acid in an amount of 0.7% of the total mass of all raw material powders in step one. Heat the stearic acid to 90°C (about 69-70°C above its melting point) to fully melt it into a liquid state. Spray the molten stearic acid liquid into an argon atmosphere sealed chamber containing dry mixed powder that has been cooled to 28°C. The atomized droplets rapidly condense and solidify upon contact with the powder particles, forming a thin, continuous, and sealed stearic acid solid protective film on the surface of each powder particle.

[0059] (3) The cured stearic acid film is hydrophobic, which prevents moisture from the external environment from contacting the surface of the powder particles. This ensures that the packaged dry mixed powder does not absorb moisture during the transfer between subsequent processes, and the pre-drying effect of step two is retained until the sintering process. The stearic acid film is flexible, allowing the powder particles to move freely and pack tightly during pressing. The film also acts as a lubricant between particles, which is beneficial for the flow and filling of the dry mixed powder in the mold cavity. The packaged dry mixed powder is used as the powder to be pressed in step four.

[0060] Step 4: Pressing and Shaping The powder to be pressed, which has been packaged in step three, is filled into a spherical mold. The mold core has a thread shape that matches the required internal thread specification, and the internal thread channel is formed simultaneously on the green blank during pressing. After pressing, a spherical green blank with an internal thread structure is obtained.

[0061] Step 5: Pre-sintering The spherical green body obtained in step four is placed in a vacuum sintering furnace at a vacuum degree of 5×10⁻⁶. -3 Pre-sintering is carried out under Pa conditions. Titanium reacts violently with nitrogen and oxygen in the air at temperatures above 500℃ to form brittle compounds such as TiN and TiO2, which severely impair the properties of the sintered body. Therefore, the entire sintering process must be carried out under vacuum (vacuum degree not less than 10). -2 The process is carried out under the protection of a pure argon atmosphere or a Pa atmosphere.

[0062] Degreasing stage: In the initial stage of heating (200-400℃), the stearic acid film formed in step three undergoes thermal decomposition within this temperature range. The decomposition products escape from the spherical green body in gaseous form, leaving no solid or liquid residue in the spherical green body. After the surface of the powder particles is restored to a clean state, it enters the high-temperature sintering stage.

[0063] High-temperature sintering stage: The temperature is further increased to 900℃ and held for 2 hours. Sintering necks grow between the titanium-based alloy powder particles, resulting in a porous titanium-based alloy spherical skeleton with an open porosity of approximately 20% and interconnected internal pores. The interconnected pores extend through the cross-section of the porous titanium-based alloy spherical skeleton, providing penetration channels for subsequent liquid phase infiltration; the porous titanium-based alloy spherical skeleton has the strength to withstand subsequent infiltration operations without deformation or breakage.

[0064] Step Six: Liquid Phase Infiltration of Copper-Aluminum Alloy The porous titanium-based alloy spherical skeleton obtained in Step 5 has approximately 20% interconnected pores, resulting in insufficient density; furthermore, the thermal conductivity of the titanium-based alloy is relatively low at approximately 17 W / m·K. This step addresses this by infiltrating molten copper-aluminum alloy into the interconnected pores of the porous titanium-based alloy spherical skeleton and then cooling and solidifying it. This process fills the pores to increase density while simultaneously solidifying the copper-aluminum alloy, with a thermal conductivity of approximately 50-80 W / m·K, inside the spherical component, thereby improving the overall thermal conductivity of the spherical component.

[0065] The specific steps are as follows: (1) Selection of impregnation material: A pre-alloyed copper-aluminum alloy ingot with an aluminum content of 10% (mass fraction) and the balance being copper was used as the impregnation material, corresponding to a liquidus temperature of approximately 1015℃. Using a pre-alloyed copper-aluminum alloy ingot instead of a mechanical mixture of copper and aluminum powder ensures uniform composition of the impregnation material and avoids component segregation of copper and aluminum during melting due to differences in melting points. After melting, it has good fluidity and can penetrate into the interconnected pores of the porous titanium-based alloy spherical skeleton under the drive of capillary force.

[0066] (2) Immersion Environment Control: The porous titanium-based alloy spherical skeleton obtained in step five is placed in a vacuum furnace. Before the immersion operation, the furnace is evacuated to remove the residual air in the pores of the porous titanium-based alloy spherical skeleton. If the air in the pores is not removed, the residual gas will be blocked by the copper-aluminum alloy liquid in the depth of the pores, preventing the copper-aluminum alloy liquid from continuing to penetrate into the depth of the porous titanium-based alloy spherical skeleton, resulting in the deep pores inside the spherical part not being filled by the copper-aluminum alloy liquid.

[0067] (3) Liquid phase infiltration process: Under vacuum protection, the copper-aluminum alloy is heated to 1065℃ to fully melt it, and then the porous titanium-based alloy spherical skeleton is immersed in the molten copper-aluminum alloy liquid. Driven by capillary force, the molten copper-aluminum alloy liquid gradually infiltrates into all the interconnected pores inside the skeleton through the pore openings on the outer surface of the skeleton, and the infiltration state is maintained for 20 min until the interconnected pores are completely filled by the copper-aluminum alloy liquid.

[0068] (4) Cooling and solidification: Take out the spherical part after it has been soaked in the copper-aluminum alloy liquid and cool it to room temperature. The copper-aluminum alloy solidifies in the pores to form a dense copper-aluminum alloy filling phase, which is combined with the porous titanium-based alloy spherical skeleton to obtain a dense titanium-based spherical alloy grout semi-finished product with the internal pores filled by the copper-aluminum alloy filling phase.

[0069] Step 7: Post-processing The spherical parts after impregnation in step six are then cleaned: residual copper and aluminum alloy solidified and attached to the surface of the spherical parts are removed by grinding to restore the spherical surface to a smooth state; the internal threaded channel is inspected for size to confirm that the thread specifications meet the design requirements; the surface is polished as needed to obtain the finished titanium-based spherical alloy sealant.

[0070] Example 6 This embodiment provides a manufacturing process for titanium-based spherical alloy grout sealant, which includes the following steps: Step 1: Alloy powder preparation and rare earth oxide carrier pre-consolidation Weigh out 6% aluminum powder, 4% vanadium powder, and 2% niobium powder by mass fraction, with the remainder being titanium powder. The remaining titanium powder is divided into two parts: titanium powder for the main powder with a particle size of 60 μm and titanium powder for the carrier with a particle size of 20 μm. Take 0.3% of the total mass of all raw material powders using 3 μm La2O3 particles, and use the carrier titanium powder at a mass ratio of 1:6 (6 times the mass of La2O3). Mix the La2O3 particles and the carrier titanium powder evenly, then cold-press them into thin sheet blanks under 150 MPa pressure. After crushing, the sheet blanks are passed through a 200-mesh sieve to obtain composite carrier particles. Add the composite carrier particles to the Ti-Al-V-Nb main powder and mix evenly to obtain a mixed powder.

[0071] Step 2: Powder pre-drying treatment The mixed powder obtained in step one was placed in an argon atmosphere sealed chamber and baked at 100°C for 2 hours to remove the physically adsorbed moisture on the surface of the powder particles, resulting in a dried mixed powder. After pre-drying, the dried mixed powder was kept in the argon atmosphere sealed chamber and kept away from the outside air before proceeding directly to the subsequent operations in step three.

[0072] Step 3: Stearic acid film encapsulation Inside a sealed chamber under an argon atmosphere, the dried mixed powder is cooled to 28°C. Stearic acid, amounting to 0.7% of the total mass of the raw powder, is heated to 90°C until fully melted. The molten stearic acid is then atomized and sprayed into the sealed chamber. The atomized droplets rapidly condense and solidify on the surface of the powder particles, forming a stearic acid encapsulation film on the powder particle surface.

[0073] Step 4: Pressing and Shaping The powder that has been packaged in step three is filled into a spherical mold with a threaded core and pressed to obtain a spherical green blank with internal threaded channels.

[0074] Step 5: Pre-sintering The spherical green billet is placed in a vacuum sintering furnace and sintered at a vacuum degree of 5×10⁻⁶. -3 Pre-sintering was carried out under Pa conditions. During the degreasing stage, the temperature was raised to 200-400℃, and the stearic acid film was completely thermally decomposed and volatilized. The temperature was then raised to 900℃ and held for 2 hours to obtain a porous titanium-based alloy spherical skeleton with an open porosity of about 20% and interconnected internal pores.

[0075] Step Six: Liquid Phase Infiltration of Copper-Aluminum Alloy A pre-alloyed copper-aluminum alloy ingot with an aluminum content of 10% (mass fraction) and the balance being copper (liquidothermal temperature approximately 1015°C) was used as the infiltration material. Under vacuum conditions, the copper-aluminum alloy was heated to 1065°C to fully melt it. A porous titanium-based alloy spherical skeleton was then immersed in the molten copper-aluminum alloy and kept in the infiltration state for 20 minutes before being removed and cooled to room temperature, where the copper-aluminum alloy solidified within the pores.

[0076] Step 7: Post-processing The residual copper and aluminum alloy that has solidified and adhered to the surface of the spherical part is removed by grinding to restore the spherical surface to a smooth state; the internal threaded channel is inspected to confirm that the thread specifications meet the design requirements; the surface is polished to obtain the finished titanium-based spherical alloy sealant.

[0077] Experimental verification Experiment 1: Verification of the effect of stearic acid film encapsulation process on the control of sintering porosity of spherical parts 1. Experimental Objective The combined process of step two (powder pre-drying) and step three (stearic acid film encapsulation) was quantitatively verified to control the final porosity of the titanium-based spherical parts, and to clarify the quantitative contribution of the stearic acid encapsulation film in preventing the pre-drying effect from being destroyed by inter-process transfer.

[0078] 2. Preparation of experimental samples Based on the formulation of Example 5, three sets of comparative samples were prepared. Each set had the same alloy composition (6% aluminum powder, 4% vanadium powder, 2% niobium powder, balance titanium powder, and 0.3% La2O3), and the same pre-sintering conditions (900℃, 2 h holding time, vacuum degree 5×10⁻⁶). - 3 The liquid phase infiltration conditions were the same (copper-aluminum alloy, aluminum content 10%, infiltration temperature 1065℃, holding time 20 min), and the three groups of samples differed only in the treatment methods in steps two and three: Control group A (no pre-drying): The mixed powder was not pre-dried or packaged and was directly transported to the pressing station in the factory environment (temperature 25℃, relative humidity 50%) for pressing and sintering.

[0079] Control group B (pre-drying only): The mixed powder was baked at 100°C for 2 h to complete the pre-drying, and then transported openly to the pressing station in the factory environment (temperature 25°C, relative humidity 50%) for about 30 min. No stearic acid encapsulation was applied, and the remaining steps were the same as in Example 5.

[0080] Experimental Group C (pre-drying + stearic acid encapsulation): The process was carried out exactly according to Example 5. After pre-drying (100°C, 2 h), stearic acid film encapsulation (0.7% stearic acid, atomized spraying at 90°C) was immediately applied in the same argon atmosphere sealed chamber, and then sealed and transported to the pressing station.

[0081] Ten samples were prepared for each group.

[0082] 3. Experimental conditions Factory transfer environment: Temperature 25℃±2℃, relative humidity 50%±5%, transfer time 30 min±5 min. Pre-sintering furnace type: Vacuum tube furnace, heating rate 5℃ / min, vacuum degree 5×10⁻⁶. -3 Pa. Liquid phase impregnation was carried out under vacuum conditions for 20 minutes.

[0083] 4. Experimental Procedure (1) Prepare three groups of mixed powders with the same formula. Take 500 g of each powder and complete steps one to three according to the pretreatment method of each group.

[0084] (2) The three groups of samples completed step four pressing, step five pre-sintering, step six liquid phase infiltration and step seven post-treatment in the same process to obtain the finished spherical parts.

[0085] (3) Randomly select 5 samples from each group of products and determine the actual density of each sample using the Archimedes water displacement method (refer to GB / T 25995 measurement standard). Calculate the average density and standard deviation of each group.

[0086] (4) The theoretical density of the composite (80% volume fraction of titanium-based alloy skeleton and 20% volume fraction of copper-aluminum alloy filler phase) is 5.16 g / cm³. 3 The Ti-Al-V-Nb alloy skeleton has a density of 4.50 g / cm³. 3 The density of the Cu-10%Al alloy is 7.80 g / cm³. 3 Based on the weighted average of volume fractions, the relative density and porosity of each group were calculated.

[0087] (5) Take 3 samples from each group and cut them along the diameter direction. After inlaying, grinding and polishing, observe the distribution morphology of the pores in the cross section under an optical metallographic microscope (magnification 400×). Use Image-Pro Plus software to count the pore area fraction of the cross section and verify the results with the Archimedes method.

[0088] 5. Experimental Results The density and porosity test results of each group of samples are shown in Table 1.

[0089] Table 1. Test results of density and final porosity of three groups of comparative samples (n=5)

[0090] Figure 1 The bar chart shows the difference in the final porosity of the three groups of samples. The chart visually demonstrates the impact of the three process combinations on the final porosity of the spherical parts: the porosity of control group A is 5.4%, the porosity of control group B is 2.7%, and the porosity of experimental group C drops to 0.8%, reaching a level close to full density.

[0091] Figure 2 The images show the SEM-BSE topography of the cross-section pore distribution of three sets of comparative samples. From left to right, they correspond to control group A (porosity 5.4%), control group B (porosity 2.7%), and experimental group C (porosity 0.8%). It can be clearly observed that as the degree of process perfection increases, the number and size of pores in the cross-section decrease significantly, and the cross-section of experimental group C is almost dense.

[0092] 6. Analysis and Summary The results showed that pre-drying alone (control group B) could reduce the porosity from 5.4% to 2.7%, but the improvement was limited. This was because the pre-dried powder continued to reabsorb moisture during the 30-minute transfer in the factory environment, which partially offset the effect of pre-drying.

[0093] Encapsulating the powder with a stearic acid film on top of the pre-drying process (experimental group C) further reduced the porosity significantly to 0.8%, demonstrating that the stearic acid film effectively isolates external moisture from contact with powder particles, preserving the pre-drying effect completely until the sintering stage. Steps two and three together form a synergistic mechanism for porosity control through removal and protection, which is significantly more effective than a single pre-drying process.

[0094] Experiment 2: Verification of the uniformity of La2O3 dispersion during the pre-consolidation process of composite carrier particles 1. Experimental Objective By comparing the differences in La2O3 dispersion uniformity between the direct mixing method and the composite carrier particle pre-consolidation method (step one), the effectiveness of the composite carrier particle process in eliminating La2O3 agglomeration and segregation defects was verified.

[0095] 2. Preparation of experimental samples Two sets of comparative samples were prepared. Except for the different method of adding La2O3 in step one, all other steps (steps two to seven) were completely consistent with those in Example 5 (pre-drying at 100℃ for 2 h, stearic acid dosage 0.7%, pre-sintering at 900℃ for 2 h, vacuum degree 5×10). -3 Pa, copper-aluminum alloy with 10% aluminum content, impregnation temperature 1065℃×20 min): Control group D (direct mixing method): La2O3 particles with a particle size of 3 μm and an amount of 0.3% of the total mass of all raw material powders were directly added to Ti-Al-V-Nb main powder for dry mixing without carrier pre-consolidation treatment.

[0096] Experimental Group E (composite carrier particle method, this invention): Following step one of Example 5, La2O3 particles and a 20 μm carrier were mixed with titanium powder at a mass ratio of 1:6, cold-pressed and solidified at 150 MPa, crushed, and passed through a 200-mesh sieve to form composite carrier particles, which were then added to the main powder and mixed.

[0097] Five samples were prepared for each group. After the pre-sintering in step five (before impregnation), the cross-section was cut to observe the distribution of La2O3.

[0098] 3. Experimental conditions Dry mixing equipment: V-type mixer, speed 20 rpm, mixing time 2 h. Section preparation: embedding, grinding, and polishing to a 1 μm diamond suspension. Characterization instruments: scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), accelerating voltage 15 kV, EDS surface scanning resolution 512×512 pixels, characteristic X-ray: La Lα (4.65 keV).

[0099] 4. Experimental Procedure (1) Complete all the steps of the control group D and the experimental group E according to the above preparation method until the pre-sintering is completed in step five.

[0100] (2) Take 3 pre-sintered samples from each group, cut them along the diameter section, and prepare cross-sectional metallographic specimens.

[0101] (3) Perform image analysis on the surface scan images of La elements, and use Image-Pro Plus software to calculate the surface density (numbers / mm) of La-rich regions (regions where the La signal intensity is more than 3 times higher than the background mean). 2 ) and average area (μm) 2 ).

[0102] (4) Calculate the coefficient of variation Cv (the ratio of standard deviation to mean) of the La element signal intensity at each pixel in the detection area. Use the Cv value to quantify the uniformity of the La distribution. The smaller the Cv, the more uniform the distribution.

[0103] 5. Experimental Results The data on the uniformity of La2O3 dispersion in the two groups of samples are shown in Table 2.

[0104] Table 2 Comparison of La2O3 dispersion uniformity between direct mixing method and composite carrier particle method

[0105] Figure 3 The images show a quantitative comparison of the uniformity of La2O3 dispersion under two mixing methods: (a) compares the areal density of the agglomeration regions, and (b) compares the coefficient of variation of La distribution. The areal density of the agglomeration regions obtained by the direct mixing method reaches as high as 15.3 particles / mm². 2 The Cv was 0.68; the surface density of the composite carrier particle agglomeration region was reduced to 1.2 particles / mm², the Cv was reduced to 0.12, and the La2O3 distribution was highly uniform.

[0106] 6. Analysis and Summary La2O3 (density 6.5 g / cm³) 3 ) and aluminum powder (2.7 g / cm³) 3 Titanium powder (4.5 g / cm³) 3There are significant density differences between them. When directly mixed, La2O3 particles are prone to agglomeration due to gravity sedimentation, resulting in an areal density of up to 15.3 particles / mm². 2 Localized hard agglomerate defects can easily become crack initiation sources in stress concentration areas such as the root of threaded holes.

[0107] The pre-consolidation process of the composite carrier particles consolidates La2O3 particles into titanium powder carrier particles, resulting in an overall density of approximately 4.5 g / cm³ for the composite carrier particles. 3 With a density similar to that of the main powder, the conditions for gravity sedimentation and agglomeration are eliminated. The surface density of the La2O3 agglomeration region is reduced by 92.2%, and Cv is reduced from 0.68 to 0.12. La2O3 is uniformly dispersed inside the spherical part, and the hard agglomerate defects at the root of the threaded channel are fundamentally eliminated.

[0108] Experiment 3: Verification of the Improvement of Thermal Conductivity of Spherical Parts by the Liquid Phase Infiltration Process of Copper-Aluminum Alloy 1. Experimental Objective The effect of the copper-aluminum alloy liquid phase impregnation process (step six) on the overall thermal conductivity of titanium-based spherical parts was quantitatively evaluated and compared with that of traditional tungsten-based alloy grout.

[0109] 2. Preparation of experimental samples Four sets of test samples were prepared: Reference sample F (pure titanium): Commercially pure titanium (CP-Ti Grade 2, density 4.51 g / cm³) was used. 3 Sintered dense samples are used to establish thermal conductivity reference standards.

[0110] Comparative sample G (porous titanium-based alloy skeleton, before impregnation): pre-sintering was completed according to steps one to five of Example 5 (900℃×2 h, vacuum degree 5×10). -3 (Pa), to obtain a porous titanium-based alloy spherical skeleton with an opening ratio of about 20%, without liquid phase impregnation.

[0111] Experimental sample H (of this invention, after impregnation): The entire process of Example 5 was completed (including step six, copper-aluminum alloy liquid-phase impregnation, aluminum content 10%, 1065℃ × 20 min), resulting in a finished titanium-based spherical alloy grout piece with a measured density of 5.12 g / cm³. 3 .

[0112] Comparison Sample I (Traditional W-Ni-Fe Grout): Uses commercially available 90W-7Ni-3Fe heavy alloy sintered grout, with a density of approximately 17.2 g / cm³. 3 This serves as a horizontal comparison with traditional products.

[0113] Five samples were prepared for each group, and a circular slice with a diameter of 12.7 mm and a thickness of 2 mm was cut from each sample for thermal conductivity testing.

[0114] 3. Experimental conditions Test standard: ASTM E1461 (laser flash method). Test instrument: Laser flash thermal conductivity meter (LFA 427 or equivalent). Test temperature: 25℃ (room temperature). Test atmosphere: Argon protection. Each sample is tested three times, and the average value is taken.

[0115] 4. Experimental Procedure (1) Prepare thermal conductivity test discs (diameter 12.7 mm, thickness 2 mm) for each group of samples, and spray a thin layer of graphite coating on the surface to improve laser absorption rate.

[0116] (2) The specific heat capacity Cp of each sample at 25℃ was determined using a differential scanning calorimeter (DSC).

[0117] (3) The density ρ of each sample was determined using the Archimedes water displacement method.

[0118] (4) Apply laser pulses to the lower surface of each circular sample on a laser flash thermal conductivity meter, and measure the response curve of the upper surface temperature over time. The response curve is calculated based on the half-heating time (t). 1 / 2 Calculate the thermal diffusivity α.

[0119] (5) Calculate the thermal conductivity of each sample according to the formula λ=α×ρ×Cp, and take the average value of 5 samples in each group.

[0120] 5. Experimental Results The results of the laser flare method for measuring the four groups of samples are shown in Table 3.

[0121] Table 3. Thermal conductivity test results for each group of samples (laser flash method, 25℃, n=5)

[0122] Figure 4 The bar chart comparing the thermal conductivity of each group of samples clearly shows the change in the thermal conductivity of the spherical part before and after liquid phase infiltration: the thermal conductivity of the porous titanium-based alloy skeleton (before infiltration) is only 11.4 W / (m·K), which is lower than the reference value of pure titanium (16.4 W / (m·K)). This is because the heat transfer path is interrupted due to the approximately 20% porosity. After liquid phase infiltration with copper-aluminum alloy, the thermal conductivity of the finished product of this invention increases to 30.0 W / (m·K), which is 163% higher than before infiltration and 83% higher than pure titanium.

[0123] 6. Analysis and Summary The copper-aluminum alloy liquid phase infiltration process forms a continuous copper-aluminum alloy filling phase (Cu-10%Al thermal conductivity approximately 80 W / (m·K)) in the porous framework of titanium-based alloy. The copper-aluminum alloy filling phase is distributed in a connected network in the pores of the titanium-based alloy framework, forming a composite thermal conduction channel together with the titanium-based alloy framework. This significantly increases the overall thermal conductivity of the spherical part from 11.4 W / (m·K) before infiltration to 30.0 W / (m·K), an increase of 163%.

[0124] Although the thermal conductivity of the finished product of this invention (30.0 W / (m·K)) is lower than that of the traditional W-Ni-Fe alloy (80.0 W / (m·K)), it is significantly improved (83%) compared to pure titanium (16.4 W / (m·K)). This fully meets the requirements of the spherical grout piece for efficient heat transfer to the grout material during construction. At the same time, the weight of this invention is only about 30% of that of the W-Ni-Fe grout piece (density 5.12 g / cm³ vs. 17.2 g / cm³). 3 This significantly improves thermal conductivity while achieving lightweight design.

[0125] Experiment 4: Comparative Verification of the Comprehensive Performance of the Invention Product and Traditional Tungsten-Based Alloy Tile Grout 1. Experimental Objective Comparative tests on density, Vickers hardness, and threaded connection strength verified the comprehensive performance advantages of the titanium-based spherical alloy grout sealant of this invention in achieving lightweight while maintaining sufficient structural strength.

[0126] 2. Preparation of experimental samples Experimental sample J (this invention, Example 5): prepared according to the entire process of Example 5, with 6% aluminum powder, 4% vanadium powder, 2% niobium powder, and the balance titanium powder, and 0.3% La2O3. Pre-sintering at 900℃ for 2 h (vacuum 5×10). -3 A standard spherical sealant with an internal thread of M6 and an outer diameter of approximately 15 mm was prepared by using a copper-aluminum alloy with an aluminum content of 10% and an impregnation temperature of 1065℃ for 20 min.

[0127] Comparative sample K (traditional W-Ni-Fe grout): A spherical grout of the same specifications (internal thread M6, outer diameter approximately 15 mm) prepared using commercially available 90W-7Ni-3Fe heavy alloy powder metallurgy process (liquid phase sintering, approximately 1500℃) is used as a comparison with traditional products.

[0128] Ten samples were prepared for density and hardness testing in each group, and six samples were prepared for thread connection strength testing in each group.

[0129] 3. Experimental conditions Density test: Archimedes' displacement method (refer to GB / T 25995), take 5 samples for each test, and calculate the mean and standard deviation. Vickers hardness test: refer to GB / T 4340.1, load 0.5 kgf (HV0.5), holding time 15 s, measure 5 points for each sample and take the average value, take 5 samples for each group. Threaded connection strength (internal thread pull-out force) test: refer to GB / T 1511, screw a standard M6 screw into the internal thread channel of the sample to the effective engagement length, apply an axial tensile load at a rate of 5 mm / min on a universal testing machine, record the maximum load when the thread fails, measure 6 samples for each group.

[0130] 4. Experimental Procedure (1) Take 5 samples from each of the two groups, determine the density using the Archimedes water displacement method, calculate the mean and standard deviation, and convert the density into the weight of the standard part.

[0131] (2) Take the cross-section of 5 samples from each group, and after inlaying, grinding and polishing, perform hardness testing on Vickers hardness tester under HV0.5 conditions. Take 5 test points for each cross-section (avoiding pores and boundary areas), and take the average value of all test points in each group.

[0132] (3) Screw the M6 ​​screw into the internal thread of each of the two groups of 6 samples. The effective engagement length is 8 mm. Install and fix it in the universal testing machine fixture. Apply an axial pull-out load at a rate of 5 mm / min until the thread fails (the screw comes out or the thread is sheared). Record the maximum load as the internal thread pull-out force.

[0133] (4) Summarize the above data and compare the overall performance differences of the two types of grout.

[0134] 5. Experimental Results The results of the comprehensive performance comparison test of the two groups of samples are shown in Table 4.

[0135] Table 4. Comparison of overall performance between the present invention and traditional W-Ni-Fe grout lines.

[0136] Figure 5 The image shows a comparison of the overall performance of the present invention (Example 5) and traditional W-Ni-Fe grout lines. (a) shows a density comparison, and (b) shows a Vickers hardness comparison. The density of the present invention is 5.12 g / cm³. 3 Compared to W-Ni-Fe (17.2 g / cm³), the weight of standard parts is reduced by 70.2%, from 26.5 g to 7.9 g, significantly reducing fatigue for construction workers who hold the parts for extended periods; the Vickers hardness of 352 HV is 12.8% higher than that of W-Ni-Fe (312 HV); the internal thread pull-out force (1850 N vs. 1920 N, a difference of 3.6%) is within the required range.

[0137] 6. Analysis and Summary The titanium-based spherical alloy grout of this invention (Example 5) has a density that is 70.2% lower than that of traditional W-Ni-Fe grout, achieving significant weight reduction; and a Vickers hardness that is 12.8% higher (352 HV vs. 312 HV). This is due to the synergistic improvement in structural density and uniformity achieved by the uniform distribution of the La2O3 dispersed strengthening phase to inhibit grain growth (step one), the elimination of sintering pores by the pre-drying and encapsulation process (steps two and three), and the filling of residual pores by the liquid phase infiltration of copper-aluminum alloy (step six).

[0138] The threaded connection strength (internal thread pull-out force) differs from W-Ni-Fe by only 3.6%, fully meeting the reliability requirements of threaded connections for spherical grout fittings during repeated use. This experiment demonstrates that, while reducing density by 70.2%, the hardness of this invention is still 12.8% higher than that of traditional tungsten-based alloys, achieving a synergy between lightweight and high strength.

[0139] The embodiments of the present invention have been described above. However, the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make more equivalent embodiments under the guidance of the present embodiments, and all of them are within the protection scope of the present embodiments.

Claims

1. A manufacturing process for a titanium-based spherical alloy, characterized in that, The steps are as follows: Lanthanum oxide particles and fine-particle titanium powder are mixed at a mass ratio of 1:4 to 1:9, then cold-pressed and solidified, crushed and sieved to obtain composite carrier particles. The composite carrier particles are then mixed evenly with Ti-Al-V-Nb main powder to obtain mixed powder. The mixed powder is pre-dried in an argon atmosphere to remove adsorbed moisture from the surface of the powder particles, resulting in a dried mixed powder. After the dry mixed powder is cooled to below 35°C in an argon atmosphere sealed chamber, molten stearic acid is sprayed into the sealed chamber in an atomized manner to form a stearic acid encapsulation film on the surface of the powder particles. The packaged powder is filled into a spherical mold with a threaded core and pressed to obtain a spherical green blank with internal threaded channels. The spherical green blank is pre-sintered under vacuum or argon atmosphere protection, and after the degreasing stage, it enters the high-temperature sintering stage to obtain a porous titanium-based alloy spherical skeleton with interconnected internal pores. Under vacuum or argon atmosphere protection, a porous titanium-based alloy spherical skeleton is immersed in molten copper-aluminum alloy for liquid phase infiltration. After cooling and solidification, the spherical part is post-processed to obtain the finished titanium-based spherical alloy.

2. The manufacturing process according to claim 1, characterized in that, The Ti-Al-V-Nb main powder, by mass fraction, consists of 5%-7% aluminum powder, 3%-5% vanadium powder, 1%-3% niobium powder, with the remainder being titanium powder used as the main powder.

3. The manufacturing process according to claim 2, characterized in that, The titanium powder used for the main powder has a particle size of 45-75 μm.

4. The manufacturing process according to claim 1, characterized in that, The lanthanum oxide particles have a particle size of 1-5 μm and are used at a rate of 0.1%-0.5% of the total mass of all raw material powders; the fine titanium powder has a particle size of 15-25 μm.

5. The manufacturing process according to claim 1, characterized in that, The pre-drying temperature is 80-120℃.

6. The manufacturing process according to claim 1, characterized in that, The amount of stearic acid used is 0.5%-1.0% of the total mass of all raw material powders. It is heated to 80-100℃ to melt it and then atomized and sprayed.

7. The manufacturing process according to claim 1, characterized in that, The high-temperature sintering stage of the pre-sintering is 800-1000℃, and the holding time is 1-3 h, resulting in a porous titanium-based alloy spherical skeleton with an opening rate of 15%-25%.

8. The manufacturing process according to claim 7, characterized in that, The pre-sintering is carried out under a vacuum degree of not less than 10. - The procedure was carried out under vacuum conditions of 2 Pa.

9. The manufacturing process according to claim 1, characterized in that, The copper-aluminum alloy is a pre-alloyed copper-aluminum alloy ingot with an aluminum content of 8%-15% (mass fraction) and the balance being copper, and a liquidus temperature of 970-1040℃. The heating temperature of the copper-aluminum alloy during liquid phase infiltration is more than 50℃ higher than the liquidus temperature of the copper-aluminum alloy used.

10. A titanium-based spherical alloy, characterized in that, It is prepared by the manufacturing process described in any one of claims 1-9.

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