A low cost short process manufacturing technique for powder metallurgy titanium alloys

Abstract

This invention provides a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, relating to the technical field of titanium alloy manufacturing. The technology uses titanium scrap as raw material and integrates powder preparation, forming, and sintering / hot deformation processes to produce high-performance powder metallurgy titanium alloy products. This invention proposes a core "sintering-pressing integration" process, simultaneously completing densification and microstructure refinement in a single thermal cycle. This avoids grain coarsening caused by secondary heating and completely eliminates post-densification processes such as hot isostatic pressing, significantly shortening the process, reducing energy consumption and costs. The prepared titanium alloy products have a density ≥99.9% and a grain size ≤20μm, exhibiting a tensile strength increase of over 15% compared to titanium alloy forgings of the same grade in national standards, and a cost reduction of over 30%. This technology is suitable for low-cost, high-efficiency preparation of titanium alloys and has broad application prospects in aerospace, weaponry, and other fields.

Description

Technical Field

[0001] This invention relates to the technical field of titanium alloy manufacturing, and in particular to a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys. Background Technology

[0002] Titanium and titanium alloys hold an irreplaceable position in aerospace, biomedical, and chemical industries due to their high specific strength, excellent corrosion resistance, and good biocompatibility. However, the widespread application of titanium materials has always been constrained by their high production costs. Traditional casting-forging methods for titanium alloys suffer from inherent problems such as long process flows, low material utilization, and high costs, severely limiting their wider application. The traditional "Kroll" method for producing sponge titanium—multiple vacuum melting processes—and its large-scale forging process are lengthy, energy-intensive, and have low material utilization, resulting in persistently high final product costs, with market prices reaching tens of times that of steel. Therefore, reducing production costs has become a core challenge and key approach to promoting the wider application of titanium alloys and fostering the development of the titanium industry.

[0003] Currently, the traditional powder metallurgy titanium alloy process flow is "powder preparation-forming-sintering-hot working," which has inherent performance bottlenecks that restrict its application in high-performance structural components. Specifically, titanium alloys prepared by traditional powder metallurgy processes have porosity, oxide inclusions, and coarse microstructure within the sintered body, making it difficult for their density and mechanical properties to reach the level of forgings. To improve performance, subsequent densification processes such as hot isostatic pressing or powder forging are often required. However, the former is expensive, time-consuming, and cannot refine grains, while the latter is difficult to balance economy and efficiency due to high mold costs and discrete processes. Although there are short-process technologies such as hot pressing sintering and spark plasma sintering, their equipment investment is large, size is limited, or, like conventional hot extrusion, defects cannot be completely eliminated due to insufficient extrusion ratio. It has always been difficult to achieve an effective balance between low cost and high performance.

[0004] Chinese patent CN119101817A discloses a powder metallurgy titanium alloy preparation process. The method involves extruding, drying, pulverizing, and sieving titanium composite powder, aluminum powder, molybdenum powder, additives, auxiliary agents, and binders, followed by cold isostatic pressing, and then hot isostatic sintering and heat treatment. Obviously, this method has the disadvantages of high raw material costs, complex composition control, lengthy process flow, low production efficiency, reliance on expensive hot isostatic pressing equipment, and failure to fully utilize interstitial elements in the raw materials.

[0005] Chinese patent CN115821140A discloses a titanium-containing alloy for metallurgy and its low-cost production method. The method involves first pre-forming the reactant raw materials into reaction blocks, then adding them into a closed track kiln heating device to gradually carry out carbothermic and nitriding reactions, finally producing a titanium-containing alloy. However, this method suffers from the following drawbacks: the raw material system is complex and the composition is difficult to control; the process is intermittent and inefficient; the product is a ceramic matrix composite material, a non-dense metallic titanium alloy; its application fields are limited; and it fails to achieve the preparation of high-performance structural materials.

[0006] Chinese patent CN111763841A discloses powder metallurgy titanium or titanium alloy products and their short-process preparation method. This method has the following drawbacks: the sintering temperature is too high and the holding time is long, which can easily lead to grain coarsening. The process flow has a cooling-heating step, resulting in low thermal cycling efficiency. The amount of hot extrusion deformation is limited, the densification driving force is insufficient, and the process control is complex with many segmented sintering parameters that are difficult to match precisely.

[0007] Chinese patent CN110791682A discloses a method for preparing powder metallurgy titanium alloys. This method suffers from problems such as excessively high sintering temperature leading to grain coarsening, the presence of a cooling-reheating step in the process flow resulting in low thermal cycling efficiency, the need for secondary heating before hot processing, high equipment investment and energy consumption, and strict requirements on the oxygen content of raw materials, making it impossible to utilize high-oxygen titanium powder.

[0008] Chinese patent CN106191493A discloses a method for preparing powder metallurgy titanium alloys. This method has safety hazards in the sintering atmosphere and is prone to hydrogen embrittlement. The process involves cooling-dehydrogenation-recooling steps, resulting in low thermal efficiency. It does not involve hot deformation processing, has limited densification, and has complex raw material composition that requires the addition of pure Ti powder, thus limiting cost control.

[0009] Therefore, there is an urgent need in this field to develop a novel short-process powder metallurgy titanium alloy manufacturing technology that combines low-cost raw materials, low-cost forming, and high-efficiency densification technology. This technology can significantly reduce production costs while stably producing high-quality titanium alloy products that are fully dense, have fine microstructure, and excellent mechanical properties, thus opening up a technological path from titanium waste recycling to the manufacture of high-value products. Summary of the Invention

[0010] The main objective of this invention is to address the technical problems in existing titanium alloy preparation technologies, such as long process flows, high costs, and insufficient density and mechanical properties of the finished products. Therefore, a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys is proposed, capable of solving the aforementioned problems.

[0011] The technical solution is as follows:

[0012] A low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, comprising the following steps:

[0013] S1. Titanium waste treatment: The commercially available titanium scrap is ultrasonically cleaned with water using an automatic conveyor cleaning machine to remove surface oil and attachments. After that, it is directly conveyed to the water area for rinsing with water, and then conveyed to the drying area for hot air drying, finally obtaining clean titanium waste.

[0014] S2. Powder preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, vacuumed, and then heated. Hydrogen gas is then introduced to spontaneously hydrogenate the material. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling and then vibrated and sieved. The sieved powder is then heated to the vacuum dehydrogenation temperature and held to dehydrogenate the material to obtain hydrogenated dehydrogenated titanium alloy powder.

[0015] S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold isostatic pressing cavity while vibrating, then vacuumed and sealed, the sealed cold isostatic pressing is placed in a stainless steel mesh basket, and then the stainless steel mesh basket is placed in a cold isostatic press for cold isostatic pressing. After demolding, the titanium alloy billet is obtained.

[0016] S4. Surface coating: A commercially available antioxidant is uniformly coated onto the surface of the titanium alloy blank in S3 to obtain a titanium alloy coated blank.

[0017] S5, Sintering and Pressing Integrated Forming: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering, and then the red-hot compact is directly placed into a preheated mold for hot deformation processing to obtain high-performance titanium alloy material.

[0018] S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment, and then cooled; then, depending on the requirements of the target product, whether to perform aging treatment is selected, followed by furnace cooling, and finally high-performance powder metallurgy titanium and titanium alloy products are obtained.

[0019] Optionally, the automatic conveying cleaning machine in S1 includes three parts: an ultrasonic zone, a clean water zone, and a drying zone. The titanium waste is continuously and automatically conveyed in each part by an automatic conveyor belt. The titanium waste includes scraps and titanium chips generated during titanium processing, as well as residual materials generated during ingot or sponge titanium production. Except for impurity elements, its main alloy element composition meets the requirements of commercially available titanium alloy grades, and the oxygen content is <0.4wt.%.

[0020] Optionally, in S1, the ultrasonic frequency for ultrasonic water cleaning is 20-40 kHz, the temperature is controlled at 40-85℃, and the time is 60-150 min; the temperature for water rinsing is controlled at 20-50℃, and the time is 10-30 min; the temperature for hot air drying is controlled at 80-120℃, and the time is 20-90 min.

[0021] Optionally, in S2, a vacuum is drawn to below 1 Pa, and then heated to 300-450℃; the ball milling speed for high-energy ball milling is 150-350 rpm, and the time is 8-18 h; the mesh size of the vibrating sieve is 300 mesh, the temperature of vacuum dehydrogenation is 600-780℃, the holding time for dehydrogenation is 2-10 h, and the vacuum degree is controlled below 0.1 Pa; the particle size of the powder under sieve is D50≤30μm, D90≤60μm, and the hydrogen content of the powder after dehydrogenation is <0.1wt.% and the oxygen content is <0.45wt.%.

[0022] Optionally, the diameter of the S3 cold isostatic pressing sleeve is 20-80mm smaller than that of the stainless steel basket. The sleeve length is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous, with a hole diameter of 5-20mm and a distance of 3-10mm between holes. The cold isostatic pressing pressure is 150-300MPa, and the holding time is 2-5min. After cold isostatic pressing, the relative density of the titanium alloy billet is 75-85%, and the oxygen content is <0.45wt.%.

[0023] Optionally, the shape of the titanium alloy blank in S3 can be flexibly selected according to the target product, and can be a square blank, bar blank, tube blank, plate blank or irregular shape blank.

[0024] Optionally, the thickness of the commercially available antioxidant layer in S4 is 0.2-0.4 mm, the main components of the antioxidant are SiO2, Al2O3 and CaO, and the oxidation temperature is 1100-1200℃.

[0025] Optionally, the sintering atmosphere in S5 is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1000-1200℃, and the holding time is 2-3h; the hot deformation processing in S5 includes extrusion, rotary forging, die forging, or wire rolling, which can be flexibly selected according to the target product, the die preheating temperature is 400-500℃, the die surface is sprayed with graphite emulsion or glass lubricant, and the hot deformation amount is ≥70%.

[0026] Optionally, the titanium alloy material in S5 has a density ≥99.9%, an average grain size ≤20μm, an oxygen content <0.5wt.%, and a hydrogen content <0.015wt.%.

[0027] Optionally, the heat treatment temperature in S6 is 710-960℃, held for 0.5-5 hours and then cooled. Subsequently, depending on the requirements of the target product, an aging treatment is performed at a temperature of 480-650℃, held for 2-8 hours and then furnace cooled.

[0028] Optionally, the cooling method in S6 is water cooling, air cooling, or furnace cooling; when the heat treatment temperature is ≥850℃, the cooling method is water cooling; when the heat treatment temperature is <850℃, the cooling method is air cooling or furnace cooling.

[0029] Optionally, the tensile strength of S6 titanium and titanium alloy products is increased by more than 15% compared with the same grade of titanium alloy forgings in the national standard.

[0030] Optionally, the titanium alloy product in S6 is TC4 titanium alloy with tensile strength > 1000MPa, yield strength ≥ 880MPa, and elongation > 10%; the titanium product is pure titanium with tensile strength ≥ 600MPa, yield strength ≥ 480MPa, and elongation ≥ 15%; the manufacturing cost is reduced by more than 30%.

[0031] Optionally, S2-S6 in the low-cost, short-process manufacturing technology for powder metallurgy titanium alloys are not only applicable to titanium waste, but also applicable to the preparation of α, α+β, near-β and β-series titanium alloys using sponge titanium, master alloys and elemental metals as raw materials.

[0032] Technical principle of the invention:

[0033] This invention utilizes titanium scrap as raw material and employs a systematic process including ultrasonic cleaning of titanium scrap, hydrogenation and dehydrogenation powdering, cold isostatic pressing of billets, antioxidant surface coating, integrated sintering and hot deformation forming, and heat treatment control to achieve efficient and low-cost preparation of titanium alloys. The core of this technology lies in the continuous integration of sintering and hot deformation processes, simultaneously completing densification and microstructure refinement within a single thermal cycle. This significantly shortens the process, reduces energy consumption, and ultimately yields fully dense, fine-grained, high-strength and high-toughness titanium alloy products. Their comprehensive mechanical properties reach or exceed those of traditional forgings, making them suitable for near-net-shape integrated low-cost manufacturing of various titanium alloys, with significant resource recycling and cost advantages.

[0034] The core innovation of this invention lies in integrating the sintering and hot deformation processes into a single, continuous operation. The sintered billet is directly transferred to a preheating mold while still red-hot for hot deformation. This single thermal cycle simultaneously achieves both sintering densification and plastic deformation densification, completely eliminating the expensive and time-consuming post-densification processes required in traditional powder metallurgy, such as hot isostatic pressing or multiple forging. This significantly shortens the production cycle and reduces equipment investment and energy consumption. Furthermore, by selecting the appropriate hot deformation mold, complex target components can be manufactured directly. Compared to the traditional two- to three-step process of sintering and hot deformation, this method offers higher manufacturing efficiency, a shorter process, and lower costs.

[0035] The method of this invention applies an anti-oxidation coating to the surface of the titanium alloy blank before the sintering process. This protective coating is mainly composed of SiO2, Al2O3, and CaO, and can form a dense oxygen barrier at a high temperature of 1100-1200℃, effectively preventing oxygen in the atmosphere from diffusing into the blank.

[0036] The structural design of the stainless steel mesh basket of this invention, along with the annular gap between it and the inner sheath, combined with the regular porous structure of its sidewalls and bottom, ensures the uniform and isotropic transmission of hydrostatic pressure, thereby obtaining a pressed billet with a regular shape and uniform density. The top handle design significantly improves the efficiency and safety of filling, transferring, and removing the billet.

[0037] The shortened process proposed in this invention is not a simple reduction of the original steps, but rather a fundamental reconstruction of the thermal circulation path through an integrated continuous forming process of "sintering-hot deformation". This design actively cuts off the "slow cooling-reheating" link that is difficult to avoid in traditional step-by-step processes, thereby effectively suppressing the tendency of grain growth caused by long-term heat preservation or repeated heating in the critical temperature range.

[0038] The above technical solution has at least the following advantages compared with the existing technology:

[0039] The above-mentioned solution proposes a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, which can solve the technical problems of long process flow, high cost, and insufficient density and mechanical properties of products in existing titanium alloy preparation technologies.

[0040] This invention uses titanium scrap as raw material, which is purified through a process and then hydrogenated and dehydrogenated to produce titanium alloy powder. This route completely eliminates the reliance on expensive spherical titanium alloy powder or sponge titanium raw materials, reducing raw material costs to 20-70% of traditional processes from the source. At the same time, it realizes the resource recycling of residual titanium waste, turning waste into treasure, resulting in extremely significant economic and environmental benefits.

[0041] The stainless steel wire mesh basket designed by the method of the present invention, along with its annular gap, sidewalls, and bottom regular porous structure, together ensure that high-quality pressed blanks with a relative density of 75-85% and an oxygen content of <0.45wt.% can be stably produced, laying an important foundation for subsequent sintering densification.

[0042] The surface anti-oxidation coating treatment performed before the sintering process in this invention reduces the stringent requirements on the purity of raw materials, greatly reduces the inherent oxygen sensitivity and oxygen embrittlement of the titanium matrix, significantly improves the strength and specific strength of titanium alloys, has strong industrial applicability, expands the range of usable raw materials, and improves the overall fault tolerance and economy of the process.

[0043] This invention utilizes the aforementioned "sintered pressing" process, combined with large deformation processing, to generate intense triaxial compressive stress and plastic deformation. This not only completely eliminates residual porosity at powder particle boundaries and within the product, achieving full densification, but also significantly refines the grain structure. Coupled with a flexible subsequent heat treatment process, the final product maintains good plasticity while possessing high strength, with performance improvements exceeding 15% compared to the same grade of material meeting national standards, and cost reductions exceeding 30%.

[0044] This process significantly compresses the process flow while preserving and fully utilizing the fine-grained structure. The final sample exhibits excellent strength (>1000MPa) and good plasticity (elongation >10%). Its performance is mainly due to the fine-grained strengthening mechanism successfully achieved and preserved by this process.

[0045] This invention is not an improvement on a single technology, but rather a system of interconnected and mutually reinforcing processes. While the irregular shape and high oxygen content of lower-cost HDH titanium powder are inherently performance limitations, this invention effectively prevents grain growth through subsequent sintering and pressing techniques. It also breaks down the original particle boundaries, homogenizes oxygen distribution, and achieves full densification. Furthermore, the homogenized compact produced by cold isostatic pressing with a stainless steel basket provides ample deformation space for subsequent sintering and pressing, thus refining the grains. This closed-loop design, where "preceding processes create conditions for subsequent processes, and subsequent processes compensate for the deficiencies of preceding processes," constitutes a robust technological barrier, making it difficult for competitors to achieve equivalent results by imitating a single step.

[0046] The technical approach of this invention is not only applicable to common titanium and titanium alloy scraps such as TA1 and TC4, but can also be extended to the preparation of various titanium alloys, including α, α+β, near-β, and β-series titanium alloys, using sponge titanium, master alloys, or elemental titanium as raw materials. Through flexible design of cold-formed isocladding cavities and hot-deformation dies, bars, tubes, slabs, and various profiles can be efficiently produced, greatly expanding its application potential in aerospace, biomedical, and chemical equipment fields, and demonstrating significant economic benefits and industrial promotion value.

[0047] In summary, the core innovation of this invention compared to traditional methods lies in constructing a short-process titanium alloy preparation technology that uses titanium scrap as raw material and integrates sintering and pressing as the key innovation. This process continuously combines sintering and hot deformation, simultaneously achieving material densification, microstructure refinement, and performance control within a single thermal cycle. It completely avoids the grain coarsening and energy waste caused by cooling and reheating in traditional step-by-step processes. It offers high flexibility, simple operation, and wide applicability, making it suitable for the low-cost, high-efficiency industrial production and promotion of titanium alloys. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a process flow diagram of a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to the present invention. Detailed Implementation

[0050] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0051] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0052] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0053] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0054] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0055] A low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, wherein the low-cost, short-process manufacturing technology for powder metallurgy titanium alloys combines Figure 1 Includes the following steps:

[0056] S1. Titanium waste treatment: The commercially available titanium scrap is ultrasonically cleaned with water using an automatic conveyor cleaning machine to remove surface oil and attachments. After that, it is directly conveyed to the water area for rinsing with water, and then conveyed to the drying area for hot air drying, finally obtaining clean titanium waste.

[0057] S2. Powder preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, vacuumed, and then heated. Hydrogen gas is then introduced to spontaneously hydrogenate the material. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling and then vibrated and sieved. The sieved powder is then heated to the vacuum dehydrogenation temperature and held to dehydrogenate the material to obtain hydrogenated dehydrogenated titanium alloy powder.

[0058] S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold isostatic pressing cavity while vibrating, then vacuumed and sealed, the sealed cold isostatic pressing is placed in a stainless steel mesh basket, and then the stainless steel mesh basket is placed in a cold isostatic press for cold isostatic pressing. After demolding, the titanium alloy billet is obtained.

[0059] S4. Surface coating: A commercially available antioxidant is uniformly coated onto the surface of the titanium alloy blank in S3 to obtain a titanium alloy coated blank.

[0060] S5, Sintering and Pressing Integrated Forming: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering, and then the red-hot compact is directly placed into a preheated mold for hot deformation processing to obtain high-performance titanium alloy material.

[0061] S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment, and then cooled; then, depending on the requirements of the target product, whether to perform aging treatment is selected, followed by furnace cooling, and finally high-performance powder metallurgy titanium and titanium alloy products are obtained.

[0062] Specifically, the automatic conveyor cleaning machine in S1 consists of three parts: an ultrasonic zone, a clean water zone, and a drying zone. The automatic conveyor belt enables continuous automatic conveying of titanium scrap in each part. The titanium scrap includes scraps and titanium chips generated during titanium processing, as well as residual materials generated during ingot casting or sponge titanium production. Except for impurity elements, its main alloy element composition meets the requirements of commercially available titanium alloy grades, and the oxygen content is <0.4wt.%.

[0063] Specifically, in S1, the ultrasonic frequency of ultrasonic water cleaning is 20-40kHz, the temperature is controlled at 40-85℃, and the time is 60-150min; the temperature of water rinsing is controlled at 20-50℃, and the time is 10-30min; the temperature of hot air drying is controlled at 80-120℃, and the time is 20-90min.

[0064] Specifically, in S2, a vacuum is drawn to below 1 Pa, and then heated to 300-450℃; the ball milling speed for high-energy ball milling is 150-350 rpm, and the time is 8-18 h; the mesh size of the vibrating sieve is 300 mesh; the temperature for vacuum dehydrogenation is 600-780℃; the holding time for dehydrogenation is 2-10 h; and the vacuum degree is controlled below 0.1 Pa; the particle size of the powder under sieve is D50≤30μm, D90≤60μm, and the hydrogen content of the powder after dehydrogenation is <0.1wt.% and the oxygen content is <0.45wt.%.

[0065] Specifically, the diameter of the S3 cold isostatic pressing sleeve is 20-80mm smaller than that of the stainless steel basket. The sleeve length is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous, with a hole diameter of 5-20mm and a distance of 3-10mm between holes. The cold isostatic pressing pressure is 150-300MPa, and the holding time is 2-5min. The relative density of the titanium alloy billet after cold isostatic pressing is 75-85%, and the oxygen content is <0.45wt.%.

[0066] In particular, the shape of the titanium alloy blank in S3 can be flexibly selected according to the target product, and can be a square blank, bar blank, tube blank, plate blank or irregular shape blank.

[0067] Specifically, the thickness of the commercially available antioxidant layer in S4 is 0.2-0.4 mm, and the main components of the antioxidant are SiO2, Al2O3, and CaO. The antioxidant temperature is 1100-1200℃.

[0068] Specifically, the sintering atmosphere in S5 is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1000-1200℃, and the holding time is 2-3 hours; the hot deformation processing in S5 includes extrusion, rotary forging, die forging, or wire rolling, which can be flexibly selected according to the target product. The die preheating temperature is 400-500℃, and the die surface is sprayed with graphite emulsion or glass lubricant. The hot deformation amount is ≥70%.

[0069] Specifically, the titanium alloy material in S5 has a density ≥99.9%, an average grain size ≤20μm, an oxygen content <0.5wt.%, and a hydrogen content <0.015wt.%.

[0070] Specifically, in S6, the heat treatment temperature is 710-960℃, and the temperature is held for 0.5-5 hours before cooling. Then, depending on the requirements of the target product, an aging treatment is performed at a temperature of 480-650℃, and the temperature is held for 2-8 hours before furnace cooling.

[0071] Specifically, the cooling method in S6 is water cooling, air cooling, or furnace cooling; when the heat treatment temperature is ≥850℃, the cooling method is water cooling; when the heat treatment temperature is <850℃, the cooling method is air cooling or furnace cooling.

[0072] In particular, the tensile strength of S6 titanium and titanium alloy products is increased by more than 15% compared with the same grade of titanium alloy forgings in the national standard.

[0073] Specifically, the titanium alloy products in S6 are TC4 titanium alloys with tensile strength > 1000MPa, yield strength ≥ 880MPa, and elongation > 10%; the titanium products are pure titanium with tensile strength ≥ 600MPa, yield strength ≥ 480MPa, and elongation ≥ 15%; manufacturing costs are reduced by more than 30%.

[0074] In particular, S2-S6 in the aforementioned low-cost, short-process manufacturing technology for powder metallurgy titanium alloys are not only applicable to titanium waste, but also applicable to the preparation of α, α+β, near-β, and β-series titanium alloys using sponge titanium, master alloys, and elemental metals as raw materials.

[0075] Example 1

[0076] This embodiment presents a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, which combines... Figure 1 Includes the following steps:

[0077] S1. Titanium waste treatment: Commercially available TC4 titanium scrap is ultrasonically cleaned with water using an automatic conveyor cleaning machine. The ultrasonic frequency is 20kHz, the temperature is controlled at 50℃, and the time is 90 minutes. After removing surface oil and adhering substances, it is directly conveyed to the clean water area for rinsing with water at a temperature controlled at 30℃ for 20 minutes. Then it is conveyed to the drying area for hot air drying at a temperature controlled at 100℃ for 60 minutes, finally obtaining titanium waste with a clean surface.

[0078] The automatic conveyor cleaning machine comprises three parts: an ultrasonic zone, a clean water zone, and a drying zone. An automatic conveyor belt enables continuous and automatic transport of titanium scrap in each part. The titanium scrap includes offcuts and shavings generated during titanium processing, as well as residual materials from ingot casting or sponge titanium production. Except for impurities, its main alloying element composition meets the requirements of commercially available TC4 titanium alloy grades, with an oxygen content <0.4 wt.%.

[0079] S2. Powder Preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, evacuated to a vacuum level below 1 Pa, and then heated to 350°C. Hydrogen gas is then introduced for spontaneous hydrogenation. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling at 200 rpm for 10 hours. It is then vibrated and sieved at a mesh size of 300. The sieved powder is then heated to the vacuum dehydrogenation temperature of 720°C and held for 8 hours, with the vacuum level controlled below 0.1 Pa, to obtain hydrogenated dehydrogenated titanium alloy powder.

[0080] The powder passing through the sieve has a particle size of D50≤30μm and D90≤60μm, and after dehydrogenation, the hydrogen content of the powder is 0.03wt.% and the oxygen content is 0.40wt.%.

[0081] S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold-pressed blank cavity while vibrating, followed by vacuum extraction and sealing. The sealed cold-pressed blank is then placed in a stainless steel basket. The diameter of the cold-pressed blank is 40mm smaller than that of the stainless steel basket. The length of the blank is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous structures with a hole diameter of 10mm and a distance of 6mm between the holes.

[0082] The stainless steel wire mesh basket is then placed in a cold isostatic press for cold isostatic pressing. The cold isostatic pressing pressure is 150 MPa and the holding time is 3 min. After demolding, a titanium alloy blank is obtained. The relative density of the titanium alloy blank after cold isostatic pressing is 75% and the oxygen content is 0.40 wt.%. The shape of the titanium alloy blank is a bar.

[0083] S4. Surface coating: A commercially available antioxidant is uniformly coated on the surface of the titanium alloy blank in S3. The thickness of the commercially available antioxidant layer is 0.2 mm. The main components of the antioxidant are SiO2, Al2O3 and CaO. The oxidation temperature is 1200℃ to obtain a titanium alloy coated blank.

[0084] S5. Sintering and Pressing Integrated Forming: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering. The sintering atmosphere is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1200℃, and the holding time is 2h. Then, the red-hot compact is directly placed into a preheated mold for extrusion. The mold preheating temperature is 420℃, and the mold surface is sprayed with graphite emulsion or glass lubricant. The hot deformation amount is 82%, and high-performance titanium alloy material is obtained.

[0085] The high-performance titanium alloy material has a density ≥99.9%, an average grain size of approximately 14 μm, an oxygen content of 0.42 wt.%, and a hydrogen content of 0.025 wt.%.

[0086] S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment at a temperature of 920℃. After holding at this temperature for 1 hour, it is water-cooled. Then, depending on the requirements of the target product, an aging treatment is performed at a temperature of 550℃. After holding at this temperature for 4 hours, it is furnace-cooled to obtain a high-performance powder metallurgy TC4 titanium alloy product.

[0087] In this embodiment S6, the tensile strength of the TC4 titanium alloy product is increased by more than 15% compared with that of the same grade of titanium alloy forgings in the national standard.

[0088] The TC4 titanium alloy has a tensile strength of approximately 1200 MPa, a yield strength of approximately 1050 MPa, a yield ratio of approximately 0.875, an elongation of approximately 13%, and a strength-ductility product of approximately 15.6 GPa. The manufacturing cost is reduced by 35% compared to the traditional "sponge titanium-smelting-forging" process. It has a uniform microstructure, dense structure, and fine grains.

[0089] Example 2

[0090] This embodiment presents a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, which combines... Figure 1 Includes the following steps:

[0091] S1. Titanium waste treatment: Commercially available TA1 titanium scrap is ultrasonically cleaned with water using an automatic conveyor cleaning machine. The ultrasonic frequency is 25kHz, the temperature is controlled at 70℃, and the time is 120 minutes. After removing surface oil and adhering substances, it is directly conveyed to the clean water area for rinsing with water at a temperature controlled at 30℃ for 20 minutes. Then it is conveyed to the drying area for hot air drying at a temperature controlled at 100℃ for 70 minutes, finally obtaining titanium waste with a clean surface.

[0092] The automatic conveyor cleaning machine comprises three parts: an ultrasonic zone, a clean water zone, and a drying zone. An automatic conveyor belt enables continuous and automatic transport of titanium scrap in each part. The titanium scrap includes offcuts and shavings generated during titanium processing, as well as residual materials from ingot casting or sponge titanium production. Except for impurities, its main alloying element composition meets the requirements of commercially available TA1 titanium alloy grades, with an oxygen content <0.4 wt.%.

[0093] S2. Powder Preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, evacuated to a vacuum level below 1 Pa, and then heated to 400°C. Hydrogen gas is then introduced for spontaneous hydrogenation. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling at 270 rpm for 12 hours. It is then vibrated and sieved at a mesh size of 300. The sieved powder is then heated to the vacuum dehydrogenation temperature of 720°C and held for 4 hours, with the vacuum level controlled below 0.1 Pa, to obtain hydrogenated dehydrogenated titanium alloy powder.

[0094] The powder passing through the sieve has a particle size of D50≤30μm and D90≤60μm, and after dehydrogenation, the powder has a hydrogen content of 0.08wt.% and an oxygen content of 0.25wt.%.

[0095] S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold-pressed blank cavity while vibrating, followed by vacuum extraction and sealing. The sealed cold-pressed blank is then placed in a stainless steel basket. The diameter of the cold-pressed blank is 60mm smaller than that of the stainless steel basket. The length of the blank is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous with a hole diameter of 8mm and a distance of 5mm between the holes.

[0096] The stainless steel mesh basket is then placed in a cold isostatic press for cold isostatic pressing. The cold isostatic pressing pressure is 280 MPa and the holding time is 3 min. After demolding, a titanium alloy blank is obtained. The relative density of the titanium alloy blank after cold isostatic pressing is 80% and the oxygen content is 0.30 wt.%. The shape of the titanium alloy blank is a bar.

[0097] S4. Surface coating: A commercially available antioxidant is uniformly coated on the surface of the titanium alloy blank in S3. The thickness of the commercially available antioxidant layer is 0.3 mm. The main components of the antioxidant are SiO2, Al2O3 and CaO. The oxidation temperature is 1200℃ to obtain the titanium alloy coated blank.

[0098] S5. Sintering and Pressing Integrated Forming: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering. The sintering atmosphere is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1100℃, and the holding time is 2-3 hours. Then, the red-hot compact is directly placed into a preheated mold for extrusion. The mold preheating temperature is 450℃, and the mold surface is sprayed with graphite emulsion or glass lubricant. The hot deformation amount is 80%, and high-performance titanium alloy material is obtained.

[0099] The high-performance titanium alloy material has a density ≥99.9%, an average grain size of approximately 15 μm, an oxygen content of 0.35 wt.%, and a hydrogen content of 0.01 wt.%.

[0100] S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment at a temperature of 880℃. After holding at this temperature for 2 hours, it is air-cooled. Then, according to the requirements of the target product, no aging treatment is performed. Finally, a high-performance powder metallurgy TA1 titanium alloy product is obtained.

[0101] In this embodiment S6, the tensile strength of the TA1 titanium alloy product is increased by 20% compared with that of the same grade titanium alloy forgings in the national standard.

[0102] The TA1 titanium alloy has a tensile strength of approximately 650 MPa, a yield strength of approximately 550 MPa, a yield ratio of approximately 0.846, an elongation of approximately 18%, and a strength-ductility product of approximately 11.7 GPa. The manufacturing cost is reduced by 40% compared to the traditional "sponge titanium-smelting-rolling" process. It has a uniform microstructure, dense structure, and fine grains.

[0103] Example 3

[0104] This embodiment presents a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, which combines... Figure 1 Includes the following steps:

[0105] S1. Titanium waste treatment: Commercially available TA15 titanium scrap is ultrasonically cleaned with water using an automatic conveyor cleaning machine. The ultrasonic frequency is 30kHz, the temperature is controlled at 70℃, and the time is 150min. After removing surface oil and adhering substances, it is directly conveyed to the clean water area for rinsing with water at a temperature controlled at 35℃ for 30min. Then it is conveyed to the drying area for hot air drying at a temperature controlled at 110℃ for 70min, finally obtaining titanium waste with a clean surface.

[0106] The automatic conveyor cleaning machine comprises three parts: an ultrasonic zone, a clean water zone, and a drying zone. An automatic conveyor belt enables continuous and automatic transport of titanium scrap in each part. The titanium scrap includes offcuts and shavings generated during titanium processing, as well as residual materials from ingot casting or sponge titanium production. Except for impurities, its main alloying element composition meets the requirements of commercially available TA15 titanium alloy grades, with an oxygen content <0.4 wt.%.

[0107] S2. Powder Preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, evacuated to a vacuum level below 1 Pa, and then heated to 400°C. Hydrogen gas is then introduced for spontaneous hydrogenation. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling at 300 rpm for 12 hours. It is then vibrated and sieved at a mesh size of 300 mesh. The sieved powder is then heated to the vacuum dehydrogenation temperature of 700°C and held for 8 hours, with the vacuum level controlled below 0.1 Pa, to obtain hydrogenated dehydrogenated titanium alloy powder.

[0108] The powder passing through the sieve has a particle size of D50≤30μm and D90≤60μm, and after dehydrogenation, the powder has a hydrogen content of 0.04wt.% and an oxygen content of 0.30wt.%.

[0109] S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold-pressed blank cavity while vibrating, followed by vacuum extraction and sealing. The sealed cold-pressed blank is then placed in a stainless steel basket. The diameter of the cold-pressed blank is 48mm smaller than that of the stainless steel basket. The length of the blank is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous structures with a hole diameter of 15mm and a distance of 5mm between the holes.

[0110] The stainless steel wire mesh basket is then placed in a cold isostatic press for cold isostatic pressing. The cold isostatic pressing pressure is 300 MPa and the holding time is 4 min. After demolding, a titanium alloy blank is obtained. The relative density of the titanium alloy blank after cold isostatic pressing is 81% and the oxygen content is 0.33 wt.%. The shape of the titanium alloy blank is a square blank.

[0111] S4. Surface coating: A commercially available antioxidant is uniformly coated on the surface of the titanium alloy blank in S3. The thickness of the commercially available antioxidant layer is 0.4 mm. The main components of the antioxidant are SiO2, Al2O3 and CaO. The oxidation temperature is 1100-1200℃ to obtain a titanium alloy coated blank.

[0112] S5. Sintering and Pressing: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering. The sintering atmosphere is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1200℃, and the holding time is 3h. Then, the red-hot compact is directly placed into a preheated mold for die forging. The mold preheating temperature is 500℃, and the mold surface is sprayed with graphite emulsion or glass lubricant. The hot deformation amount is 75%, and high-performance titanium alloy material is obtained.

[0113] The high-performance titanium alloy material has a density ≥99.9%, an average grain size of approximately 15 μm, an oxygen content of 0.4 wt.%, and a hydrogen content of 0.035 wt.%.

[0114] S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment at a temperature of 830℃. After holding at this temperature for 3 hours, it is cooled. Then, according to the requirements of the target product, an aging treatment is performed at a temperature of 550℃. After holding at this temperature for 8 hours, it is furnace cooled to obtain a high-performance powder metallurgy TA15 titanium alloy product.

[0115] In this embodiment S6, the tensile strength of the TA15 titanium alloy product is increased by more than 25% compared with the same grade of titanium alloy forgings in the national standard.

[0116] The TA15 titanium alloy has a tensile strength of approximately 1100 MPa, a yield strength of approximately 1000 MPa, a yield-to-tensile ratio of approximately 0.909, an elongation of approximately 14%, and a strength-ductility product of approximately 15.4 GPa. The manufacturing cost is reduced by 35% compared to the traditional "sponge titanium-smelting-rolling" process. It has a uniform microstructure, dense structure, and fine grains.

[0117] Example 4

[0118] This embodiment presents a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, which combines... Figure 1 Includes the following steps:

[0119] S1. Titanium waste treatment: Commercially available TC4 scrap waste is ultrasonically cleaned with water using an automatic conveyor cleaning machine. The ultrasonic frequency of the ultrasonic water cleaning is 20kHz, the temperature is controlled at 50℃, and the time is 90min. After removing surface oil and attachments, it is directly conveyed to the clean water area for rinsing with water at a temperature controlled at 20℃ for 20min. Then it is conveyed to the drying area for hot air drying at a temperature controlled at 80℃ for 100min, finally obtaining titanium waste with a clean surface.

[0120] The automatic conveyor cleaning machine comprises three parts: an ultrasonic zone, a clean water zone, and a drying zone. An automatic conveyor belt enables continuous and automatic transport of titanium scrap in each part. The titanium scrap includes offcuts and shavings generated during titanium processing, as well as residual materials from ingot casting or sponge titanium production. Except for impurities, its main alloying element composition meets the requirements of commercially available TC4 titanium alloy grades, with an oxygen content <0.4 wt.%.

[0121] S2. Powder Preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, evacuated to a vacuum level below 1 Pa, and then heated to 350°C. Hydrogen gas is then introduced for spontaneous hydrogenation. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling at 250 rpm for 12 hours. Subsequently, it is vibrated and sieved at a mesh size of 300 mesh. The sieved powder is then heated to the vacuum dehydrogenation temperature of 680°C and held for 6 hours, with the vacuum level controlled below 0.1 Pa, to obtain hydrogenated dehydrogenated titanium alloy powder.

[0122] The powder passing through the sieve has a particle size of D50≤30μm and D90≤60μm, and after dehydrogenation, the powder has a hydrogen content of 0.08wt.% and an oxygen content of 0.20wt.%.

[0123] S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold-pressed blank cavity while vibrating, followed by vacuum extraction and sealing. The sealed cold-pressed blank is then placed in a stainless steel basket. The diameter of the cold-pressed blank is 50mm smaller than that of the stainless steel basket. The length of the blank is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous with a hole diameter of 10mm and a distance of 6mm between the holes.

[0124] The stainless steel wire mesh basket is then placed in a cold isostatic press for cold isostatic pressing. The cold isostatic pressing pressure is 220 MPa and the holding time is 4 min. After demolding, a titanium alloy blank is obtained. The relative density of the titanium alloy blank after cold isostatic pressing is 81% and the oxygen content is 0.25 wt.%. The shape of the titanium alloy blank is a square billet.

[0125] S4. Surface coating: A commercially available antioxidant is uniformly coated on the surface of the titanium alloy blank in S3. The thickness of the commercially available antioxidant layer is 0.4 mm. The main components of the antioxidant are SiO2, Al2O3 and CaO. The oxidation temperature is 1200℃ to obtain a titanium alloy coated blank.

[0126] S5. Sintering and Pressing: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering. The sintering atmosphere is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1200℃, and the holding time is 2h. Then, the red-hot compact is directly placed into a preheated mold for die forging. The mold preheating temperature is 500℃, and the mold surface is sprayed with graphite emulsion or glass lubricant. The hot deformation amount is 75%, and high-performance titanium alloy material is obtained.

[0127] The high-performance titanium alloy material has a density ≥99.9%, an average grain size of approximately 15 μm, an oxygen content of 0.28 wt.%, and a hydrogen content of 0.006 wt.%.

[0128] S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment at a temperature of 920℃. After holding at this temperature for 1 hour, it is cooled. Then, depending on the requirements of the target product, an aging treatment is performed at a temperature of 550℃. After holding at this temperature for 4 hours, it is cooled in the furnace to finally obtain a high-performance powder metallurgy TC4 alloy product.

[0129] In this embodiment S6, the tensile strength of the TC4 titanium alloy product is increased by more than 15% compared with that of the same grade of titanium alloy forgings in the national standard.

[0130] The TC4 alloy has a tensile strength of approximately 1100 MPa, a yield strength of approximately 960 MPa, a yield ratio of approximately 0.876, an elongation of approximately 13%, and a strength-ductility product of approximately 14.30 GPa. The manufacturing cost is reduced by 40% compared to the traditional "sponge titanium-smelting-forging" process. It has a uniform microstructure, dense structure, and fine grains.

[0131] Example 5

[0132] This embodiment presents a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, which combines... Figure 1 Includes the following steps:

[0133] S1. Titanium waste treatment: Commercially available Ti-6242 titanium scrap is ultrasonically cleaned with water using an automatic conveyor cleaning machine. The ultrasonic frequency is 30kHz, the temperature is controlled at 50℃, and the time is 90 minutes. After removing surface oil and adhering substances, it is directly conveyed to the clean water area for rinsing with water at a temperature controlled at 25℃ for 15 minutes. Then it is conveyed to the drying area for hot air drying at a temperature controlled at 100℃ for 60 minutes, finally obtaining titanium waste with a clean surface.

[0134] The automatic conveyor cleaning machine comprises three parts: an ultrasonic zone, a clean water zone, and a drying zone. An automatic conveyor belt enables continuous and automatic transport of titanium scrap in each part. The titanium scrap includes offcuts and shavings generated during titanium processing, as well as residual materials from ingot casting or sponge titanium production. Except for impurities, its main alloying element composition meets the requirements of commercially available Ti-6242 titanium alloy grades, with an oxygen content <0.4 wt.%.

[0135] S2. Powder Preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, evacuated to a vacuum level below 1 Pa, and then heated to 380°C. Hydrogen is then introduced for spontaneous hydrogenation. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling at 260 rpm for 12 hours. It is then vibrated and sieved at a mesh size of 300 mesh. The sieved powder is then heated to the vacuum dehydrogenation temperature of 650°C and held for 10 hours, with the vacuum level controlled below 0.1 Pa, to obtain hydrogenated dehydrogenated titanium alloy powder.

[0136] The powder passing through the sieve has a particle size of D50≤30μm and D90≤60μm, and after dehydrogenation, the powder has a hydrogen content of 0.07wt.% and an oxygen content of 0.20wt.%.

[0137] S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold-pressed blank cavity while vibrating, followed by vacuum extraction and sealing. The sealed cold-pressed blank is then placed in a stainless steel basket. The diameter of the cold-pressed blank is 50mm smaller than that of the stainless steel basket. The length of the blank is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous with a hole diameter of 12mm and a distance of 8mm between the holes.

[0138] The stainless steel wire mesh basket is then placed in a cold isostatic press for cold isostatic pressing. The cold isostatic pressing pressure is 220 MPa and the holding time is 3 min. After demolding, a titanium alloy blank is obtained. The relative density of the titanium alloy blank after cold isostatic pressing is 80% and the oxygen content is 0.25 wt.%. The shape of the titanium alloy blank is a bar.

[0139] S4. Surface coating: A commercially available antioxidant is uniformly coated on the surface of the titanium alloy blank in S3. The thickness of the commercially available antioxidant layer is 0.3 mm. The main components of the antioxidant are SiO2, Al2O3 and CaO. The oxidation temperature is 1150℃ to obtain the titanium alloy coated blank.

[0140] S5. Sintering and Pressing Integrated Forming: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering. The sintering atmosphere is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1150℃, and the holding time is 2.5h. Then, the red-hot compact is directly placed into a preheated mold for extrusion processing. The mold preheating temperature is 450℃, and the mold surface is sprayed with graphite emulsion or glass lubricant. The hot deformation amount is 80%, and high-performance titanium alloy material is obtained.

[0141] The high-performance titanium alloy material has a density ≥99.9%, an average grain size of approximately 15 μm, an oxygen content of 0.30 wt.%, and a hydrogen content of 0.009 wt.%.

[0142] S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment at a temperature of 940℃. After holding at this temperature for 1 hour, it is cooled. Then, depending on the requirements of the target product, an aging treatment is performed at a temperature of 590℃. After holding at this temperature for 5 hours, it is furnace cooled to obtain a high-performance powder metallurgy Ti-6242 titanium alloy product.

[0143] In this embodiment S6, the tensile strength of the Ti-6242 titanium alloy product is increased by more than 15% compared with the same grade of titanium alloy forgings in the national standard.

[0144] The Ti-6242 titanium alloy has a tensile strength of approximately 1100 MPa, a yield strength of approximately 980 MPa, a yield-to-tensile ratio of approximately 0.89, an elongation of approximately 13%, and a strength-ductility product of approximately 14.3 GPa. Its manufacturing cost is 42% lower than that of the traditional "sponge titanium-smelting-forging" process. It also has a uniform microstructure, dense structure, and fine grains.

[0145] Example 6

[0146] This embodiment presents a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, which combines... Figure 1 Includes the following steps:

[0147] S1. Titanium waste treatment: Commercially available TA7 titanium scrap is ultrasonically cleaned with water using an automatic conveyor cleaning machine. The ultrasonic frequency is 25kHz, the temperature is controlled at 50℃, and the time is 90 minutes. After removing surface oil and adhering substances, it is directly conveyed to the clean water area for rinsing with water at a temperature controlled at 25℃ for 15 minutes. Then it is conveyed to the drying area for hot air drying at a temperature controlled at 110℃ for 60 minutes, finally obtaining titanium waste with a clean surface.

[0148] The automatic conveyor cleaning machine comprises three parts: an ultrasonic zone, a clean water zone, and a drying zone. An automatic conveyor belt enables continuous and automatic transport of titanium scrap in each part. The titanium scrap includes offcuts and shavings generated during titanium processing, as well as residual materials from ingot casting or sponge titanium production. Except for impurities, its main alloying element composition meets the requirements of commercially available TA7 titanium alloy grades, with an oxygen content <0.4 wt.%.

[0149] S2. Powder Preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, evacuated to a vacuum level below 1 Pa, and then heated to 350°C. Hydrogen is then introduced for spontaneous hydrogenation. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling at 200 rpm for 12 hours. It is then vibrated and sieved at a mesh size of 300 mesh. The sieved powder is then heated to the vacuum dehydrogenation temperature of 750°C and held for 6 hours, with the vacuum level controlled below 0.1 Pa, to obtain hydrogenated dehydrogenated titanium alloy powder.

[0150] The powder passing through the sieve has a particle size of D50≤30μm and D90≤60μm, and after dehydrogenation, the powder has a hydrogen content of 0.03wt.% and an oxygen content of 0.25wt.%.

[0151] S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold-pressed blank cavity while vibrating, followed by vacuum extraction and sealing. The sealed cold-pressed blank is then placed in a stainless steel basket. The diameter of the cold-pressed blank is 45mm smaller than that of the stainless steel basket. The length of the blank is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous with a hole diameter of 10mm and a distance of 5mm between the holes.

[0152] The stainless steel wire mesh basket is then placed in a cold isostatic press for cold isostatic pressing. The cold isostatic pressing pressure is 200 MPa and the holding time is 4 min. After demolding, a titanium alloy blank is obtained. The relative density of the titanium alloy blank after cold isostatic pressing is 78% and the oxygen content is 0.30 wt.%. The shape of the titanium alloy blank is a square billet.

[0153] S4. Surface coating: A commercially available antioxidant is uniformly coated on the surface of the titanium alloy blank in S3. The thickness of the commercially available antioxidant layer is 0.2 mm. The main components of the antioxidant are SiO2, Al2O3 and CaO. The oxidation temperature is 1150℃ to obtain the titanium alloy coated blank.

[0154] S5. Sintering and Pressing Integrated Forming: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering. The sintering atmosphere is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1150℃, and the holding time is 3h. Then, the red-hot compact is directly placed into a preheated mold for extrusion processing. The mold preheating temperature is 450℃, and the mold surface is sprayed with graphite emulsion or glass lubricant. The hot deformation amount is 90%, and high-performance titanium alloy material is obtained.

[0155] The high-performance titanium alloy material has a density ≥99.9%, an average grain size of approximately 12 μm, an oxygen content of 0.40 wt.%, and a hydrogen content of 0.008 wt.%.

[0156] S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment at a temperature of 850℃. After holding at this temperature for 2 hours, it is air-cooled to obtain a high-performance powder metallurgy TA7 titanium alloy product.

[0157] In this embodiment S6, the tensile strength of the TA7 alloy titanium alloy product is increased by more than 20% compared with the same grade of titanium alloy forgings in the national standard.

[0158] The TA7 titanium alloy has a tensile strength of approximately 1010 MPa, a yield strength of approximately 880 MPa, a yield ratio of approximately 0.87, an elongation of approximately 13%, and a strength-ductility product of approximately 12.35 GPa. The manufacturing cost is reduced by 40% compared to the traditional "sponge titanium-smelting-forging" process. It has a uniform microstructure, dense structure, and fine grains.

[0159] The above-mentioned solution proposes a low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, which can solve the technical problems of long process flow, high cost, and insufficient density and mechanical properties of products in existing titanium alloy preparation technologies.

[0160] This invention uses titanium scrap as raw material, which is purified through a process and then hydrogenated and dehydrogenated to produce titanium alloy powder. This route completely eliminates the reliance on expensive spherical titanium alloy powder or sponge titanium raw materials, reducing raw material costs to 20-70% of traditional processes from the source. At the same time, it realizes the resource recycling of residual titanium waste, turning waste into treasure, resulting in extremely significant economic and environmental benefits.

[0161] The stainless steel wire mesh basket designed by the method of the present invention, along with its annular gap, sidewalls, and bottom regular porous structure, together ensure that high-quality pressed blanks with a relative density of 75-85% and an oxygen content of <0.45wt.% can be stably produced, laying an important foundation for subsequent sintering densification.

[0162] The surface anti-oxidation coating treatment performed before the sintering process in this invention reduces the stringent requirements on the purity of raw materials, greatly reduces the inherent oxygen sensitivity and oxygen embrittlement of the titanium matrix, significantly improves the strength and specific strength of titanium alloys, has strong industrial applicability, expands the range of usable raw materials, and improves the overall fault tolerance and economy of the process.

[0163] This invention utilizes the aforementioned "sintered pressing" process, combined with large deformation processing, to generate intense triaxial compressive stress and plastic deformation. This not only completely eliminates residual porosity at powder particle boundaries and within the product, achieving full densification, but also significantly refines the grain structure. Coupled with a flexible subsequent heat treatment process, the final product maintains good plasticity while possessing high strength, with performance improvements exceeding 15% compared to the same grade of material meeting national standards, and cost reductions exceeding 30%.

[0164] This process significantly compresses the process flow while preserving and fully utilizing the fine-grained structure. The final sample exhibits excellent strength (>1000MPa) and good plasticity (elongation >10%). Its performance is mainly due to the fine-grained strengthening mechanism successfully achieved and preserved by this process.

[0165] This invention is not an improvement on a single technology, but rather a system of interconnected and mutually reinforcing processes. While the irregular shape and high oxygen content of lower-cost HDH titanium powder are inherently performance limitations, this invention effectively prevents grain growth through subsequent sintering and pressing techniques. It also breaks down the original particle boundaries, homogenizes oxygen distribution, and achieves full densification. Furthermore, the homogenized compact produced by cold isostatic pressing with a stainless steel basket provides ample deformation space for subsequent sintering and pressing, thus refining the grains. This closed-loop design, where "preceding processes create conditions for subsequent processes, and subsequent processes compensate for the deficiencies of preceding processes," constitutes a robust technological barrier, making it difficult for competitors to achieve equivalent results by imitating a single step.

[0166] The technical approach of this invention is not only applicable to common titanium and titanium alloy scraps such as TA1 and TC4, but can also be extended to the preparation of various titanium alloys, including α, α+β, near-β, and β-series titanium alloys, using sponge titanium, master alloys, or elemental titanium as raw materials. Through flexible design of cold-formed isocladding cavities and hot-deformation dies, bars, tubes, slabs, and various profiles can be efficiently produced, greatly expanding its application potential in aerospace, biomedical, and chemical equipment fields, and demonstrating significant economic benefits and industrial promotion value.

[0167] In summary, the core innovation of this invention compared to traditional methods lies in constructing a short-process titanium alloy preparation technology that uses titanium scrap as raw material and integrates sintering and pressing as the key innovation. This process continuously combines sintering and hot deformation, simultaneously achieving material densification, microstructure refinement, and performance control within a single thermal cycle. It completely avoids the grain coarsening and energy waste caused by cooling and reheating in traditional step-by-step processes. It offers high flexibility, simple operation, and wide applicability, making it suitable for the low-cost, high-efficiency industrial production and promotion of titanium alloys.

[0168] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0169] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0170] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0171] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A low-cost, short-process manufacturing technology for powder metallurgy titanium alloys, characterized in that, The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys includes the following steps: S1. Titanium waste treatment: The commercially available titanium scrap is ultrasonically cleaned with water using an automatic conveyor cleaning machine to remove surface oil and attachments. After that, it is directly conveyed to the water area for rinsing with water, and then conveyed to the drying area for hot air drying, finally obtaining clean titanium waste. S2. Powder preparation: The titanium waste from S1 is placed in a vacuum hydrogenation furnace, vacuumed, and then heated. Hydrogen gas is then introduced to spontaneously hydrogenate the material. When the hydrogen absorption reaches 3 wt.% or more, the hydrogen valve is closed. After cooling, the hydrogenated material is crushed by high-energy ball milling and then vibrated and sieved. The sieved powder is then heated to the vacuum dehydrogenation temperature and held to dehydrogenate the material to obtain hydrogenated dehydrogenated titanium alloy powder. S3, Cold-pressed billet: The titanium alloy powder in S2 is loaded into the cold isostatic pressing cavity while vibrating, then vacuumed and sealed, the sealed cold isostatic pressing is placed in a stainless steel mesh basket, and then the stainless steel mesh basket is placed in a cold isostatic press for cold isostatic pressing. After demolding, the titanium alloy billet is obtained. S4. Surface coating: A commercially available antioxidant is uniformly coated onto the surface of the titanium alloy blank in S3 to obtain a titanium alloy coated blank. S5, Sintering and Pressing Integrated Forming: The titanium alloy coated compact from S4 is placed in a sintering furnace for atmosphere sintering, and then the red-hot compact is directly placed into a preheated mold for hot deformation processing to obtain high-performance titanium alloy material. S6. Heat treatment control: The S5 titanium alloy material is placed in a heat treatment furnace for heat treatment, and then cooled; then, depending on the requirements of the target product, whether to perform aging treatment is selected, followed by furnace cooling, and finally high-performance powder metallurgy titanium and titanium alloy products are obtained.

2. The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to claim 1, characterized in that, The S1 automatic conveyor cleaning machine consists of three parts: an ultrasonic zone, a clean water zone, and a drying zone. The automatic conveyor belt enables continuous automatic transport of titanium scrap in each part. The titanium scrap includes scraps and titanium chips generated during titanium processing, as well as residual materials generated during ingot or sponge titanium production. Except for impurity elements, its main alloy element composition meets the requirements of commercially available titanium alloy grades, and the oxygen content is <0.4wt.%.

3. The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to claim 1, characterized in that, In S1, the ultrasonic frequency for ultrasonic water cleaning is 20-40kHz, the temperature is controlled at 40-85℃, and the time is 60-150min; the temperature for water rinsing is controlled at 20-50℃, and the time is 10-30min; the temperature for hot air drying is controlled at 80-120℃, and the time is 20-90min.

4. The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to claim 1, characterized in that, In S2, a vacuum is drawn to below 1 Pa, and then heated to 300-450℃; the ball milling speed for high-energy ball milling is 150-350 rpm, and the time is 8-18 h; the mesh size of the vibrating sieve is 300 mesh, the temperature of vacuum dehydrogenation is 600-780℃, the holding time for dehydrogenation is 2-10 h, and the vacuum degree is controlled below 0.1 Pa; the particle size of the powder under sieve is D50≤30μm, D90≤60μm, and the hydrogen content of the powder after dehydrogenation is <0.1wt.% and the oxygen content is <0.45wt.%.

5. The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to claim 1, characterized in that, The S3 cold isostatic pressing sleeve is 20-80mm smaller in diameter than the stainless steel basket. The sleeve length is determined by the length of the target product. The stainless steel basket is square or round, with a handle on the top. Except for the top, the other side walls and bottom are porous, with a hole diameter of 5-20mm and a distance of 3-10mm between holes. The cold isostatic pressing pressure is 150-300MPa, and the holding time is 2-5min. After cold isostatic pressing, the relative density of the titanium alloy billet is 75-85%, and the oxygen content is <0.45wt.%.

6. The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to claim 1, characterized in that, The thickness of the commercially available antioxidant layer in S4 is 0.2-0.4 mm. The main components of the antioxidant are SiO2, Al2O3, and CaO. The antioxidant temperature is 1100-1200℃.

7. The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to claim 1, characterized in that, The sintering atmosphere in S5 is high-purity argon gas with a purity of ≥99.9%, the sintering temperature is 1000-1200℃, and the holding time is 2-3 hours. The hot deformation processing in S5 includes extrusion, rotary forging, die forging, or wire rolling, which can be flexibly selected according to the target product. The die preheating temperature is 400-500℃, and the die surface is sprayed with graphite emulsion or glass lubricant. The hot deformation amount is ≥70%.

8. The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to claim 1, characterized in that, In S6, the heat treatment temperature is 710-960℃, and the temperature is held for 0.5-5 hours before cooling. Then, depending on the requirements of the target product, an aging treatment is performed at a temperature of 480-650℃, and the temperature is held for 2-8 hours before furnace cooling.

9. The low-cost, short-process manufacturing technology for powder metallurgy titanium alloys according to claim 1, characterized in that, Compared with the same grade of titanium alloy forgings in the national standard, the tensile strength of S6 titanium and titanium alloy products is increased by more than 15%.

Images