Method for producing a powder for a titanium-based composite material and use thereof

Abstract

The application belongs to the technical field of metal matrix composite material preparation, and particularly relates to a preparation method and application of a powder for a titanium-based composite material. The powder prepared through a pre-homogenization-solidification-second powdering composite powder preparation route is highly uniform in composition, controllable in oxygen content, and good in interface bonding. The TMCs made of the powder are high in density, excellent and stable in mechanical properties. Through raw material combination and process innovation, the performance close to that of pre-alloyed spherical powder is realized at a lower cost, and the high-cost industrialization obstacle is broken. Further, the process flow of the application is stable, the yield of finished products is high, and the powder produced can be simultaneously applied to two mainstream processes of powder metallurgy and additive manufacturing, realizing "one powder for two uses", and greatly improving production flexibility and efficiency. The problems of poor uniformity and interface pollution of mechanically mixed powder, and high cost and difficult process of pre-alloyed powder are fundamentally solved.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composite material preparation technology, specifically relating to a method for preparing powder for titanium matrix composite materials and its application. Background Technology

[0002] Titanium matrix composites (TMCs) have significant applications in aerospace, biomedicine, and other fields due to their high specific strength, excellent high-temperature performance, and corrosion resistance. Based on the distribution of the reinforcing phase in the matrix, TMCs can be classified into continuous fiber-reinforced TMCs and particulate-reinforced TMCs. There are also two methods for preparing particulate-reinforced TMCs: the additive method, which directly adds the reinforcing phase to the matrix, and the in-situ synthesis method, where the reinforcing phase is generated through a reaction during sample forming. The core performance of TMCs depends on the distribution and interfacial bonding quality of the reinforcing components (such as TiB and TiC) in the titanium matrix. Powder, as the initial raw material, directly affects the final material's performance. Currently, in-situ synthesis of TMCs mainly relies on powder metallurgy (PM) and additive manufacturing (AM). These two processes have significantly different requirements for powder properties, and existing powder systems all face technical bottlenecks.

[0003] TMCs are prepared by powder metallurgy (PM) through a powder mixing-pressing-sintering process. The powder systems are divided into two categories: (1) Non-spherical powder prepared by hydrogenation dehydrogenation is mechanically mixed with ceramic reinforcing phase by ball milling or V-type powder mixer. Advantages: simple process, low cost, and flexible adjustment of reinforcing phase ratio. Disadvantages: poor mixing uniformity, density difference leads to reinforcing phase agglomeration, forming local enrichment areas after sintering; interface contamination, mechanical mixing introduces oxygen increment, aggravating the generation of brittle phase at the interface; pressing defects, hard reinforcing phase reduces powder compressibility, green density decreases, resulting in high sintering porosity. (2) The reinforcing phase is pre-dispersed in titanium melt and titanium rods are made, and spherical composite powder containing reinforcing body is prepared by atomization. Advantages: uniform composition and low oxygen content. Disadvantages: high process cost, complex process, long production process, and low yield.

[0004] Additive manufacturing (AM) uses high-energy beams to melt and solidify TMCs layer by layer. The main processes are selective laser melting (SLM) and electron beam melting (EBM). (1) Powder for SLM process: high sphericity, particle size distribution of 20~53μm, flowability ≤40s / 50g (Hall flow meter), oxygen content <0.1wt%. Existing powder types and existing problems: mechanical mixing powder density difference leads to powder layering (ρtitanium powder ≠ ρTiB2); laser absorption rate difference (titanium powder α≈35% < ceramic α>80%), causing unmelted ceramic clusters; typical defects: cracks initiation at the ceramic / titanium molten pool boundary, large thermal stress. The advantage of pre-alloyed composite powder is that the composition is uniform and it can achieve near-fully dense forming. Its disadvantage is that the production cost is high. (2) Powder for EBM process: low powder resistivity, prevents charge accumulation, particle size 53~106μm, high vacuum stability. Existing powder types and their problems: Mechanically mixed powders can cause electron beam deflection; reinforcing phases can lead to local electric field distortion and scanning path deviation; the volatilization of reinforcing phases and the decomposition of SiC, B4C, etc., under vacuum conditions can result in uncontrolled composition. Pre-alloyed composite powders have the advantage of good compositional stability, but the disadvantage is high cost.

[0005] In view of this, the present invention proposes a method for preparing powder for titanium-based composite materials. The powder prepared solves the problems of existing mechanically mixed powders and pre-alloyed powders, and can meet the multiple requirements of TMCs powders such as uniform composition, excellent performance, good adaptability to forming process, and low cost. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing titanium-based composite powder and its application. By optimizing the powder morphology, composition uniformity and reinforcement distribution characteristics, the invention solves the problems of interfacial reaction, insufficient densification and discrete mechanical properties that exist in the forming process of traditional titanium-based composite powder.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] On one hand, the present invention provides a method for preparing powder for titanium-based composite materials, comprising the following steps:

[0009] Step 1: The spherical titanium alloy powder prepared by the PREP method is subjected to HDH (hydrogenation-dehydrogenation process) treatment to obtain non-spherical titanium alloy powder with a particle size ≤106μm and an oxygen content of 0.10~0.15wt%; wherein, the spherical titanium alloy powder prepared by the PREP method has a particle size of 106~300μm and an oxygen content of 0.05~0.07wt%.

[0010] Step 2: The titanium alloy spherical powder prepared by the EIGA method and the non-spherical titanium alloy powder are mixed using a double cone mixer to obtain a mixed powder; wherein, the titanium alloy spherical powder prepared by the EIGA method has a particle size of 53~250μm and an oxygen content of 0.05~0.08wt%; during mixing, the weight ratio of the non-spherical titanium alloy powder to the titanium alloy spherical powder is 1:(1~3), the mixing weight is 100~500kg, the mixing time is 2~5h, and the mixing process is protected by inert gas;

[0011] Step 3: The mixed powder and reinforcing phase particles are fed into an air jet mill and homogenized in an argon atmosphere to obtain a composite powder; wherein the particle size of the reinforcing phase particles is 0.040~10μm, and the weight percentage is 0.5~1.5wt%; the single feed rate of the air jet mill is 10~15kg, the single processing time is 10~15min, the outlet pressure is 5~10MPa, and the argon purity is ≥99.999%;

[0012] Step 4: The composite powder is loaded into a cylindrical rubber sleeve and subjected to cold isostatic pressing to obtain a green blank; wherein, the cylindrical rubber sleeve has a specification of φ (100~150)×(1000~1500)mm; the parameters of the cold isostatic pressing are: pressure of 250~350MPa and time of 5~10min;

[0013] Step 5: After hot isostatic pressing of the green billet, a bar billet is obtained; wherein the parameters of the hot isostatic pressing are as follows: heating to 550-650℃ at 3-5℃ / min and holding for 1-3 hours, then heating to 920-1080℃ at 2-3℃ / min and holding for 4-6 hours; while heating, pressurizing to 150-200MPa at 20-30MPa / h and holding for 4-6 hours; after holding for the predetermined time, cooling to room temperature at 4-6℃ / min and 40-60MPa / h.

[0014] Step 6: After removing the cladding by machining the billet, the powder is prepared by atomization (PREP / EIGA) and then sieved to obtain titanium-based composite material powder.

[0015] In another aspect, the present invention provides the application of the powder prepared by the method for preparing titanium-based composite material powder as described above in powder metallurgy (PM) and additive manufacturing (AM).

[0016] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0017] The core innovation of this invention lies in the ingenious design of a composite powder preparation route of "pre-homogenization-consolidation-secondary powdering". It is not a simple improvement on existing single technologies, but rather an integrated and combined innovation that successfully achieves an excellent balance between component uniformity, process adaptability, production cost and final material properties, and solves the inherent technical bottlenecks of the two mainstream powder systems (mechanically mixed powder & pre-alloyed spherical powder).

[0018] (1) Performance: Significantly improves the overall mechanical properties of the final titanium-based composite material.

[0019] This invention solves the problem of uniform distribution of the reinforcing phase: Compared with mechanically mixed powders, traditional ball milling or V-type mixing cannot resolve the density difference between ceramic phases such as TiB2 and titanium powder, which easily leads to agglomeration during transportation and powder spreading. This invention first uses an air jet mill for efficient homogenization, and then utilizes cold isostatic pressing (CIP) and hot isostatic pressing (HIP) for thorough consolidation. The HIP process allows the reinforcing phase to react in situ with the titanium matrix under high temperature and pressure (e.g., Ti + TiB2 → 2TiB), generating TiB whiskers that are smaller, more uniformly distributed, and have stronger interfacial bonding. This fundamentally eliminates "local enrichment areas" and "unmelted ceramic clusters," avoiding the problem of reinforcing phase agglomeration becoming crack initiation points, significantly improving the material's density, strength, toughness, and fatigue performance, and reducing the dispersion of mechanical properties.

[0020] The powder interface state was optimized, and the oxygen content was controlled: Compared with mechanically mixed powders, prolonged mechanical mixing introduces a large increase in oxygen (oxygen content can rise from 0.1wt% to over 0.3wt%), severely deteriorating interfacial bonding and forming a brittle phase. This invention employs an air jet mill (under ultra-high purity Ar gas protection) for short-time (10-15 min) efficient mixing, greatly reducing oxidation contamination. Furthermore, HDH-treated non-spherical powder (0.10-0.15wt% oxygen) and low-oxygen EIGA spherical powder (0.05-0.08wt% oxygen) were intentionally mixed. The slightly higher oxygen content of the HDH-treated non-spherical powder may help form fine oxide dispersion reinforcing phases during subsequent sintering, while the EIGA-prepared spherical powder ensures that the overall oxygen content does not become uncontrollable. Finally, through HIP consolidation and secondary atomization, the oxygen content of the finished powder can be stabilized at a low and controllable level. This results in a clean, well-bonded interface, reducing interfacial brittleness and improving the ductility and high-temperature performance of the composite material.

[0021] Improved adaptability of powder forming processes: For powder metallurgy (PM), the final composite powder is a pre-sintered "semi-alloyed" powder with better compressibility than purely mechanically mixed powder (because the hard ceramic phase is already encapsulated in the matrix), higher green density, easier densification during subsequent sintering, and lower porosity in the final product. For additive manufacturing (AM): Selective laser melting (SLM) produces spherical powders after secondary atomization, with good flowability and uniform powder distribution. More importantly, the composition is highly uniform, solving the problem of uneven melting caused by differences in laser absorption rate in mechanically mixed powders, avoiding the generation of unmelted TiB2 and voids, and enabling near-fully dense forming. Electron beam melting (EBM) produces highly conductive titanium-based spherical powders, which do not suffer from electron beam deflection or electric field distortion due to the insulating ceramic phase, as is the case with mixed powders; the reinforcing phase is pre-dissolved in the matrix, avoiding the volatilization and compositional runaway of the reinforcing phase (such as B4C) under vacuum conditions.

[0022] (2) Efficiency and cost: Cost reduction and efficiency improvement of high-performance powder have been achieved.

[0023] Significantly reduced production costs: Compared to pre-alloyed spherical powders, directly preparing pre-alloyed composite powders using EIGA or PREP processes is technically extremely difficult, has a low yield, and is very expensive. This invention cleverly avoids this technical challenge. The cost strategy of this invention optimizes raw material costs by mixing relatively inexpensive HDH powder with high-quality but expensive EIGA spherical powder, reducing raw material costs while ensuring performance. Large-scale production is possible because the double-cone mixer in step 2 produces large batches (100-500 kg), and although the air jet mill in step 3 has a small single-batch feed (10-15 kg), it is a midstream processing stage with a short processing time (10-15 min / batch), resulting in considerable overall efficiency. Most importantly, the final atomization powder preparation step (PREP / EIGA) is for already homogenized and solidified HIP rod blanks. At this point, the rod blank composition is absolutely uniform, and the yield and efficiency of atomization powder preparation are far higher than those of directly atomizing non-uniform titanium melts (containing ceramic phases). Ultimately, at a cost far lower than that of pure pre-alloyed spherical powder, a powder with compositional uniformity comparable to or even better was obtained.

[0024] Improved production efficiency and flexibility: The powder has dual uses, and the final powder meets both PM and AM process requirements, achieving product standardization, reducing production line changeovers and inventory types, and improving production flexibility. High process stability: The core homogenization step is completed by an air jet mill, ensuring good repeatability and easy control; the subsequent CIP / HIP processes are very mature, with stable quality and high yield.

[0025] (3) Flexibility in phase selection: This method is applicable not only to TiB2 but also to other ceramic reinforcing phases (such as B4C, La2O3, etc.), and has excellent platform technology characteristics. Controllable powder properties: By adjusting the ratio of HDH powder to EIGA powder, air jet milling parameters, HIP regime, and secondary atomization process, the particle size distribution, morphology, oxygen content, and microstructure of the final powder can be precisely controlled to meet the specific needs of different application scenarios.

[0026] In summary, the powder prepared by this invention exhibits highly uniform composition, controllable oxygen content, and excellent interfacial bonding, resulting in TMCs with high density, excellent and stable mechanical properties. Through raw material combination and process innovation, near-pre-alloyed spherical powder performance is achieved at a lower cost, overcoming the high cost barrier to industrialization. Furthermore, the process of this invention is stable, with a high yield, and the produced powder is applicable to both powder metallurgy and additive manufacturing, achieving "dual-purpose powder" and significantly improving production flexibility and efficiency. It fundamentally solves the problems of poor uniformity and interfacial contamination in mechanically mixed powders, as well as the high cost and difficult processing of pre-alloyed powders, making it an excellent solution with both scientific and engineering practical value. Attached Figure Description

[0027] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of the preparation method of the present invention;

[0030] Figure 2 Microscopic optical image of the mixed powder in Example 1;

[0031] Figure 3 Photograph of the bar blank prepared in Example 1;

[0032] Figure 4 The image shows the powder morphology of the titanium-based composite material (TMCs) obtained in Example 1.

[0033] Figure 5 This is a schematic diagram of the internal structure of the titanium-based composite material (TMCs) powder obtained in Example 1. Detailed Implementation

[0034] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0035] 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 with reference to the accompanying drawings and embodiments.

[0036] This invention provides a method for preparing powder for titanium-based composite materials, comprising the following steps:

[0037] Step 1: The spherical titanium alloy powder prepared by the PREP method is subjected to HDH (hydrogenation-dehydrogenation process) treatment to obtain non-spherical titanium alloy powder with a particle size ≤106μm and an oxygen content of 0.10~0.15wt%; wherein, the spherical titanium alloy powder prepared by the PREP method has a particle size of 106~300μm and an oxygen content of 0.05~0.07wt%.

[0038] Step 2: The titanium alloy spherical powder prepared by the EIGA method and the non-spherical titanium alloy powder are mixed using a double cone mixer to obtain a mixed powder; wherein, the titanium alloy spherical powder prepared by the EIGA method has a particle size of 53~250μm and an oxygen content of 0.05~0.08wt%; during mixing, the weight ratio of the non-spherical titanium alloy powder to the titanium alloy spherical powder is 1:(1~3), the mixing weight is 100~500kg, the mixing time is 2~5h, and the mixing process is protected by inert gas;

[0039] Step 3: The mixed powder and reinforcing phase particles are fed into an air jet mill and homogenized in an argon atmosphere to obtain a composite powder; wherein the particle size of the reinforcing phase particles is 0.040~10μm, and the weight percentage is 0.5~1.5wt%; the single feed rate of the air jet mill is 10~15kg, the single processing time is 10~15min, the outlet pressure is 5~10MPa, and the argon purity is ≥99.999%;

[0040] Step 4: The composite powder is loaded into a cylindrical rubber sleeve and subjected to cold isostatic pressing to obtain a green blank; wherein, the cylindrical rubber sleeve has a specification of φ (100~150)×(1000~1500)mm; the parameters of the cold isostatic pressing are: pressure of 250~350MPa and time of 5~10min;

[0041] Step 5: After hot isostatic pressing of the green billet, a bar billet is obtained; wherein the parameters of the hot isostatic pressing are as follows: heating to 550-650℃ at 3-5℃ / min and holding for 1-3 hours, then heating to 920-1080℃ at 2-3℃ / min and holding for 4-6 hours; while heating, pressurizing to 150-200MPa at 20-30MPa / h and holding for 4-6 hours; after holding for the predetermined time, cooling to room temperature at 4-6℃ / min and 40-60MPa / h.

[0042] Step 6: After removing the cladding by machining the billet, the powder is prepared by atomization (PREP / EIGA) and then sieved to obtain titanium-based composite material powder.

[0043] To demonstrate the effectiveness of the present invention, the following embodiments and comparative examples are provided for verification.

[0044] Example 1

[0045] See Figure 1-5 As shown in the figure, this embodiment provides a method for preparing powder for titanium-based composite materials, and the specific steps are as follows:

[0046] Step 1: The spherical TC4 titanium alloy powder prepared by the PREP method is subjected to HDH treatment to obtain non-spherical TC4 titanium alloy powder with a particle size of 53~106μm and an oxygen content of 0.10wt%. Specifically, the spherical TC4 titanium alloy powder prepared by the PREP method has a particle size of 106~150μm and an oxygen content of 0.05wt%.

[0047] Step 2: The spherical TC4 titanium alloy powder prepared by the EIGA method is mixed with the non-spherical TC4 titanium alloy powder using a double cone mixer to obtain a mixed powder. See [link to relevant documentation]. Figure 2 As shown; wherein, the TC4 titanium alloy spherical powder prepared by the EIGA method has a particle size of 53~106μm and an oxygen content of 0.08wt%; during mixing, the weight ratio of the non-spherical TC4 titanium alloy powder to the TC4 titanium alloy spherical powder is 1:1, the mixing weight is 100kg, the mixing time is 2h, and the mixing process is protected by Ar gas.

[0048] Step 3: The mixed powder and reinforcing phase particles TiB2 are fed into an air jet mill and homogenized in an Ar atmosphere to obtain a composite powder; wherein the particle size of the reinforcing phase particles is 10 μm and the weight percentage is 1.5 wt%; the single feed rate of the air jet mill is 15 kg, the single processing time is 15 min, the outlet pressure is 15 MPa, and the argon purity is 99.999%;

[0049] Step 4: The composite powder is loaded into a cylindrical rubber sleeve and subjected to cold isostatic pressing to obtain a green compact; wherein the cylindrical rubber sleeve has a specification of φ100×1000mm; the parameters of the cold isostatic pressing are: pressure of 350Mpa and time of 5min.

[0050] Step 5: After hot isostatic pressing of the green billet, a bar billet is obtained. (See attached image) Figure 3 As shown; wherein, the parameters of the hot isostatic pressing are as follows: heating to 650℃ at 3℃ / min and holding for 1 hour, then heating to 920℃ at 2℃ / min and holding for 6 hours, while simultaneously increasing the pressure to 150MPa at 20MPa / h and holding for 6 hours; after holding for the predetermined time, cooling to room temperature pressure at 4℃ / min and 60MPa / h.

[0051] Step 6: After removing the cladding from the TC4 billet by machining, it is powdered using PREP and sieved to obtain titanium-based composite material powder. See [link to relevant documentation]. Figure 4 , Figure 5 As shown.

[0052] Example 2

[0053] This embodiment provides a method for preparing powder for titanium-based composite materials, the specific steps of which are as follows:

[0054] Step 1: The spherical TC4 titanium alloy powder prepared by the PREP method is subjected to HDH (hydrogenation-dehydrogenation process) treatment to obtain non-spherical TC4 titanium alloy powder with a particle size of 38~75μm and an oxygen content of 0.12wt%. Specifically, the spherical TC4 titanium alloy powder prepared by the PREP method has a particle size of 150~212μm and an oxygen content of 0.06wt%.

[0055] Step 2: The spherical TC4 titanium alloy powder prepared by the EIGA method and the non-spherical TC4 titanium alloy powder are mixed using a double cone mixer to obtain a mixed powder. The spherical TC4 titanium alloy powder prepared by the EIGA method has a particle size of 106~180μm and an oxygen content of 0.065wt%. During mixing, the weight ratio of the non-spherical TC4 titanium alloy powder to the spherical TC4 titanium alloy powder is 1:2, the mixing weight is 300kg, the mixing time is 3h, and the mixing process is protected by N2 gas.

[0056] Step 3: The mixed powder and reinforcing phase particles TiB2 are fed into an air jet mill and homogenized in an Ar atmosphere to obtain a composite powder; wherein the particle size of the reinforcing phase particles is 5 μm and the weight percentage is 1.0 wt%; the single feed rate of the air jet mill is 12 kg, the single processing time is 12 min, the outlet pressure is 8 MPa, and the argon purity is 99.999%;

[0057] Step 4: The composite powder is loaded into a cylindrical rubber sleeve and subjected to cold isostatic pressing to obtain a green blank; wherein, the cylindrical rubber sleeve has a specification of φ125×1250mm; the parameters of the cold isostatic pressing are: pressure of 300MPa and time of 7min.

[0058] Step 5: After hot isostatic pressing of the green billet, a bar billet is obtained. (See attached image) Figure 3 As shown; wherein, the parameters of the hot isostatic pressing are as follows: the temperature is increased to 600℃ at 4℃ / min and held for 2h, then increased to 1000℃ at 2.5℃ / min and held for 5h. At the same time as the temperature is increased, the pressure is increased to 175MPa at 25MPa / h and held for 5h. After the temperature and pressure are held for the predetermined time, the pressure is reduced to room temperature at 5℃ / min and 50MPa / h.

[0059] Step 6: After removing the cladding from the TC4 billet by machining, the powder is prepared by EIGA method and then sieved to obtain titanium-based composite material powder.

[0060] Example 3

[0061] This embodiment provides a method for preparing powder for titanium-based composite materials, the specific steps of which are as follows:

[0062] Step 1: The spherical TC4 titanium alloy powder prepared by the PREP method is subjected to HDH (hydrogenation-dehydrogenation process) treatment to obtain non-spherical TC4 titanium alloy powder with a particle size of 0~53μm and an oxygen content of 0.15wt%; wherein, the spherical TC4 titanium alloy powder prepared by the PREP method has a particle size of 212~300μm and an oxygen content of 0.07wt%.

[0063] Step 2: The spherical TC4 titanium alloy powder prepared by the EIGA method and the non-spherical TC4 titanium alloy powder are mixed using a double cone mixer to obtain a mixed powder; wherein, the particle size of the titanium alloy spherical powder prepared by the EIGA method is 180~250μm and the oxygen content is 0.05wt%; during mixing, the weight ratio of the non-spherical TC4 titanium alloy powder to the spherical TC4 titanium alloy powder is 1:3, the mixing weight is 500kg, the mixing time is 5h, and the mixing process is protected by Ar gas;

[0064] Step 3: The mixed powder and reinforcing phase particles TiB2 are fed into an air jet mill and homogenized in an Ar atmosphere to obtain a composite powder; wherein the particle size of the reinforcing phase particles is 0.04 μm and the weight percentage is 0.5 wt%; the single feed rate of the air jet mill is 10 kg, the single processing time is 10 min, the outlet pressure is 5 MPa, and the argon purity is 99.999%;

[0065] Step 4: The composite powder is loaded into a cylindrical rubber sleeve and subjected to cold isostatic pressing to obtain a green blank; wherein, the cylindrical rubber sleeve has a specification of φ150×1500mm; the parameters of the cold isostatic pressing are: pressure of 250MPa and time of 10min.

[0066] Step 5: After hot isostatic pressing of the green billet, a bar billet is obtained. (See attached image) Figure 3 As shown; wherein, the parameters of the hot isostatic pressing are as follows: the temperature is increased to 550℃ at 5℃ / min and held for 3h, then increased to 1080℃ at 3℃ / min and held for 4h. At the same time as the temperature is increased, the pressure is increased to 200MPa at 30MPa / h and held for 4h. After the temperature and pressure are held for the predetermined time, the pressure is decreased to room temperature at 6℃ / min and 40MPa / h.

[0067] Step 6: After removing the cladding from the TC4 billet by machining, the powder is prepared by PREP method and then sieved to obtain titanium-based composite material powder.

[0068] Comparative Example 1

[0069] This comparative example provides a method for preparing a powder, the preparation process of which is as follows:

[0070] Step 1: Powdering and sieving are carried out using HDH (hydrogenation-dehydrogenation process) to obtain non-spherical TC4 titanium alloy powder with a particle size of 106~250μm and an oxygen content of 0.18wt%.

[0071] Step 2: The prepared powder and reinforcing phase particles are fed into a ball mill for homogenization. The ball-to-powder ratio is 10:1, the mixing time is 2 hours, and the weight of each mixing cycle is 20 kg, to obtain a composite powder. The reinforcing phase particles have a particle size of 10 μm and a weight percentage of 1.5 wt%.

[0072] Step 3: The composite powder is loaded into a steel bladder and subjected to hot isostatic pressing (HIP). The holding temperature during HIP is 920°C and the pressure is 150 MPa. After exiting the furnace, TC4 titanium-based composite material is obtained.

[0073] Comparative Example 2

[0074] This comparative example provides a method for preparing a powder, the preparation process of which is as follows:

[0075] Step 1: Vacuum induction melting is used. Titanium raw materials and reinforcing phase particles are placed into the furnace, and the furnace cavity is evacuated to a high vacuum of 1.0 × 10⁻⁶. -2 Pa below. Preheating at a low current of 1200A for initial melting, followed by refining at a high current of 4000A, wherein the reinforcing phase particles have a powder particle size of 0.04μm and a weight percentage of 1.0wt%.

[0076] Step 2: The homogenized composite melt is poured into a copper mold of a specific shape and rapidly solidified to form a composite electrode rod with a diameter of φ60mm and an O content of 0.01wt%.

[0077] Step 3: The above-mentioned rod blanks are pulverized and sieved using EIGA to obtain TC4 titanium-based composite material powder.

[0078] Comparative Example 3

[0079] This comparative example provides a method for preparing a powder, the preparation process of which is as follows:

[0080] Step 1: Powdering and sieving are carried out using HDH to obtain non-spherical TC4 titanium alloy powder with a particle size of 0~106μm and an oxygen content of 0.20wt%.

[0081] Step 2: The prepared powder and reinforcing phase particles are fed into a V-type mechanical mixer for homogenization. The mixing time is 5 hours, and the weight of each mixing is 200 kg, to obtain a composite powder. The reinforcing phase particles have a particle size of 5 μm and a weight percentage of 1.0 wt%.

[0082] Step 3: The composite powder is loaded into a cylindrical rubber sleeve and subjected to cold isostatic pressing to obtain a green blank; wherein, the cylindrical rubber sleeve has a specification of φ150×1500mm; the parameters of the cold isostatic pressing are: pressure of 250MPa and time of 10min.

[0083] Step 4: Sinter the green blank to obtain TC4 titanium-based composite material; wherein the sintering parameters are: temperature 1050℃, holding time 5h.

[0084] To verify the performance of the titanium-based composite powders prepared in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3, the performance of the titanium-based composite materials (TMCs) prepared from the above powders was tested, and the following data were obtained, as shown in Table 1.

[0085] Table 1

[0086]

[0087] As shown in Table 1, the TC4 titanium-based composite materials prepared using the powders from Examples 1, 2, and 3, through precise selection and mixing of powder raw materials, effectively controlled the oxygen content, fundamentally solving the fatal damage to the plasticity of TMCs caused by high oxygen content, and achieving an optimal combination of high strength and good ductility and toughness. Customized material designs can be implemented for different application requirements, such as prioritizing reshaping toughness or strength, successfully solving the industry problem of balancing strength and ductility and toughness in traditional TMCs.

[0088] Based on the performance data in Table 1, the TC4 titanium-based composite materials prepared using the powders of Examples 1, 2, and 3 were compared and analyzed with those of Comparative Examples 1, 2, and 3. Examples 1, 2, and 3 employed the method of the present invention, while Comparative Examples 1, 2, and 3 represent the preparation processes of conventional mechanically mixed powders (Comparative Examples 1 and 3) and pre-alloyed powders (Comparative Example 2), respectively.

[0089] In terms of density, the density of Examples 1, 2, and 3 is higher than that of Comparative Examples 1, 2, and 3, indicating that the method of the present invention can significantly improve the density of the material. This is due to the thorough consolidation of cold isostatic pressing (CIP) and hot isostatic pressing (HIP), which reduces porosity.

[0090] In terms of mechanical properties, the tensile strength and yield strength of the examples were generally higher than those of the comparative examples. For example, the tensile strength of Example 2 reached 1354 MPa and the yield strength reached 1205 MPa, which was much higher than that of Comparative Example 1 (978 MPa and 902 MPa) and Comparative Example 3 (1086 MPa and 965 MPa). Although Comparative Example 2 (pre-alloyed powder) had higher strength (tensile strength 1200 MPa), its fracture toughness (70 MPa·m) was lower. ¹ / ² The low elongation after fracture and impact toughness (45 J / cm²) indicate a deficiency in toughness in the pre-alloyed powder. The elongation after fracture and reduction of area of ​​the examples are comparable to or slightly lower than those of the comparative examples, but they achieve a good balance between strength and toughness by combining high strength and toughness. For example, Example 1 has an elongation after fracture of 15%, a reduction of area of ​​46%, an impact toughness of 62 J / cm², and a fracture toughness of 95 MPa·m. ¹ / ² This is better than Comparative Example 2.

[0091] Comparative Examples 1 and 3 exhibited high plasticity and toughness, but low strength, due to localized defects caused by uneven distribution of the reinforcing phase and interface contamination. In contrast, the present invention achieves uniform distribution of the reinforcing phase and interface optimization through air jet milling and HIP treatment, avoiding performance dispersion.

[0092] Conclusion: The powder prepared in this invention significantly improves the overall performance of TC4 titanium-based composite materials, achieving an optimal balance between density, strength, and toughness. It solves the problems of poor uniformity and interface contamination inherent in traditional mechanically mixed powders, as well as the bottlenecks of high cost and insufficient toughness in pre-alloyed powders. Example 2 is particularly suitable for high-strength applications, while Examples 1 and 3 demonstrate a balanced performance in both strength and toughness, meeting the needs of different scenarios.

[0093] Figure 4Typical SEM microstructures of the titanium-based composite powders prepared in Examples 1, 2, and 3 are shown. From a macroscopic perspective, the powder particles are highly spherical with smooth surfaces and uniform particle size distribution, without obvious satellite spheres, agglomerates, or irregularly shaped particles. This demonstrates that the subsequent PREP or EIGA secondary atomization powder preparation process parameters were properly controlled, ensuring excellent powder flowability and spreading characteristics, fully meeting the basic requirements of additive manufacturing processes for powder raw materials.

[0094] Further high-magnification observations revealed a finer microstructure on the particle surface:

[0095] Unique rapid solidification microstructure: A mixed solidification morphology consisting of fine cellular crystals and dendrites can be clearly observed on the surface of individual powder particles. This structure is a typical characteristic of rapid solidification of molten metal droplets under extremely high cooling rates during secondary atomization. The cellular structure indicates a relatively stable local solidification interface, while the appearance of dendrites reflects rapid growth in a specific crystallographic orientation. This fine cellular / dendritic structure directly reflects the refinement of the grains within the powder, which contributes to improving the strength and toughness of the final material.

[0096] Dispersed distribution and interface characteristics of the reinforcing phase: Dispersed reinforcing phase particles (such as TiB2 or its reaction products) can be observed between cells / dendritic layers on the particle surface. These reinforcing phases are small in size and uniformly distributed, without large-scale agglomeration. They clearly delineate the boundaries of the original grains, making the micro-interfaces on the particle surface clearly visible. This phenomenon proves the effectiveness of the present invention: it ensures a highly uniform distribution of the reinforcing phase in the titanium matrix, avoiding segregation caused by density differences or uneven mixing during subsequent remelting and atomization.

[0097] Excellent interfacial bonding: The interface between the reinforcing phase and the metal matrix is ​​clear and tightly bonded, with no obvious pores or cracks observed. This indicates that during the hot isostatic pressing process, a good interfacial reaction may have occurred between the reinforcing phase and the titanium matrix, forming a strongly bonded interface, rather than a simple mechanical embedding.

[0098] Figure 5 Schematic diagrams of the microstructure of the TC4 titanium-based composite materials prepared in Examples 1, 2, and 3 are shown. As can be seen from the figures, the reinforcing phase (such as TiB whiskers) is uniformly distributed in the titanium matrix in a fine and dispersed form, without obvious aggregation or segregation. The reinforcing phase is tightly bonded to the matrix interface, without pores or cracks, forming a continuous network structure. This microstructure originates from the in-situ reaction during the HIP process (such as Ti + TiB₂ → 2TiB), which generates fine-sized TiB whiskers under high temperature and pressure, enhancing the interfacial bonding force. The uniformly distributed reinforcing phase effectively hinders dislocation movement, improving the strength and hardness of the material, while the fine whiskers prevent stress concentration, improving toughness and fatigue performance. Figure 5The schematic diagram illustrates the reason for the high performance of the embodiments: the uniform distribution of the reinforcing phase and the optimization of the interface eliminate "local enrichment regions" and crack initiation sites, resulting in high density and stable mechanical properties. Compared with the comparative examples, the present invention achieves precise control of the microstructure by controlling the oxygen content and the HIP process, providing a reliable foundation for the application of TMCs.

[0099] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0100] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing powder for titanium-based composite materials, characterized in that, Includes the following steps: Step 1: Perform HDH treatment on some of the titanium alloy spherical powders prepared by the atomization method to obtain non-spherical titanium alloy powders; Step 2: Mix the spherical titanium alloy powder and the non-spherical titanium alloy powder evenly in a specific ratio to obtain a mixed powder; Step 3: After homogenizing the mixed powder with the reinforcing phase particles, a composite powder is obtained; the homogenization treatment time is 10-15 min, the outlet pressure is 5-10 MPa, and the argon purity is ≥99.999%. Step 4: The composite powder is loaded into a sleeve and subjected to cold isostatic pressing to obtain a green body; the parameters of the cold isostatic pressing are: pressure 250~350MPa, time 5~10min. Step 5: After hot isostatic pressing of the green billet, a bar billet is obtained; the parameters of the hot isostatic pressing are as follows: the temperature is increased to 550-650℃ at 3-5℃ / min and held for 1-3 hours, then the temperature is increased to 920-1080℃ at 2-3℃ / min and held for 4-6 hours; while heating, the pressure is increased to 150-200MPa at 20-30MPa / h and held for 4-6 hours; after holding for the predetermined time, the temperature is decreased to room temperature pressure at 4-6℃ / min and 40-60MPa / h. Step 6: After removing the cladding from the billet by machining, the billet is powdered and sieved to obtain titanium-based composite material powder.

2. The method for preparing titanium-based composite material powder according to claim 1, characterized in that, In step 1, titanium alloy spherical powder is prepared by PREP method, with a particle size of 106~300μm and an oxygen content of 0.05~0.07wt%.

3. The method for preparing titanium-based composite material powder according to claim 1, characterized in that, In step 1, the particle size of the non-spherical titanium alloy powder is ≤106μm and the oxygen content is 0.10~0.15wt%.

4. The method for preparing titanium-based composite material powder according to claim 1, characterized in that, In step 2, the titanium alloy spherical powder prepared by the EIGA method has a particle size of 53~250μm and an oxygen content of 0.05~0.08wt%.

5. The method for preparing titanium-based composite powder according to claim 1, characterized in that, In step 2, a double cone mixer is used for mixing, wherein the weight ratio of the non-spherical titanium alloy powder to the spherical titanium alloy powder is 1:(1~3), the mixing weight is 100~500kg, the mixing time is 2~5h, and the mixing process is protected by inert gas.

6. The method for preparing titanium-based composite powder according to claim 1, characterized in that, In step 3, the particle size of the reinforcing phase particles is 0.040~10μm, and the weight percentage is 0.5~1.5wt%.

7. The method for preparing titanium-based composite powder according to claim 1, characterized in that, In step 3, under an argon atmosphere, the mixed powder and reinforcing phase particles are homogenized in an air jet mill, with a single feed rate of 10-15 kg.

8. The method for preparing titanium-based composite powder according to claim 1, characterized in that, In step 4, the composite powder is loaded into a cylindrical rubber sleeve and subjected to cold isostatic pressing.

9. The application of powder prepared by the method for preparing titanium-based composite material powder according to any one of claims 1 to 8 in powder metallurgy and additive manufacturing.

Images