Electron beam additive spherical tantalum-titanium alloy powder and preparation method and application thereof

Abstract

The invention relates to electron beam additive spherical tantalum-titanium alloy powder and a preparation method and application thereof. The powder is tantalum-titanium alloy powder composed of two refractory elements of Ta and Ti and the balance unavoidable impurities, the Ta content is 56-58%, and preferably, the alloy powder has one or more of the following items: the particle size is 20-200 [mu] m, preferably 45-105 [mu] m; o is less than 4000 ppm, preferably 1t; and 2500 ppm, and 2500 ppm; h is less than 100 ppm, preferably lt; 50 ppm; n is less than 350ppm, preferably 1t; 200 ppm of the total weight; c is less than 300 ppm, preferably 1t; the particle size is 45 to 105 [mu] m.

Description

Technical Field

[0001] The present invention relates to a tantalum-titanium alloy powder, and more particularly to a tantalum-titanium alloy powder for electron beam additive manufacturing. Background Art

[0002] Tantalum-titanium alloys possess excellent high-temperature strength and high-temperature oxidation resistance, offering promising applications in numerous demanding fields, including defense, military, and nuclear industries. However, due to the significant difference in melting points between tantalum and titanium, the production of tantalum-titanium alloys using traditional smelting and pressure processing techniques presents significant challenges and high production costs. Furthermore, conventional machining methods are unable to meet the requirements for complex, irregularly shaped parts.

[0003] In recent years, the rapid development of additive manufacturing technology has provided new solutions for the fabrication of complex structural components. This technology can produce geometrically complex components through a layer-by-layer deposition process, avoiding the limitations of traditional machining methods. However, existing additive manufacturing techniques still present some challenges when applied to tantalum-titanium alloys, such as irregular shapes, which hinder their widespread application in additive manufacturing.

[0004] The prior art has the following disadvantages in particular:

[0005] 1. The traditional smelting and pressure processing technology is difficult to prepare tantalum-titanium alloys, and the preparation process is complex and costly.

[0006] 2. For complex and irregular parts, neither traditional machining methods nor 3D printing (also known as additive manufacturing) can meet the high production requirements (one reason may be the low elongation).

[0007] 3. It is difficult to obtain powder materials that meet the requirements of additive manufacturing applications.

[0008] In particular, 3D printing with existing tantalum-titanium alloy powders cannot produce materials with ideal comprehensive mechanical properties, especially the comprehensive properties of tensile strength, yield strength and elongation.

[0009] In order to promote the engineering application of tantalum-titanium alloys in the fields of national defense, military industry, nuclear industry, etc., it is urgent to overcome the need to provide a tantalum-titanium alloy powder, whose components after 3D printing meet the following requirements: tensile strength ≥815MPa, yield strength ≥680MPa, and elongation ≥14.5%.

[0010] Through extensive research, the inventors have developed a spherical tantalum-titanium alloy powder suitable for additive manufacturing (e.g., electron beam additive manufacturing) and a method for preparing the powder. Components obtained by 3D printing from the powder meet the following requirements: tensile strength ≥815 MPa, yield strength ≥680 MPa, and elongation ≥14.5%. Summary of the Invention

[0011] According to one aspect of the present invention, a tantalum-titanium alloy powder is provided.

[0012] Preferably, the tantalum-titanium alloy powder of the present invention has one or more of the following characteristics:

[0013] Particle size 20-200 μm, preferably 45-105 μm;

[0014] O<4000ppm, preferably <2500ppm;

[0015] H < 100 ppm, preferably < 50 ppm;

[0016] N < 350 ppm, preferably < 200 ppm;

[0017] C < 300 ppm, preferably < 150 ppm.

[0018] More preferably, the Nb content of the powder is ≤0.01%, and / or C ≤0.006%, and / or Si ≤0.01%, and / or Fe ≤0.02% (eg ≤0.016%).

[0019] After extensive research, the inventors discovered that tantalum-titanium alloy powder with a particle size of 45-105 μm is particularly suitable for electron beam additive manufacturing (additive manufacturing is also known as 3D printing).

[0020] The alloy powder is basically composed of two refractory elements, Ta and Ti, and inevitable impurities as the balance, with the Ta content being 56-58%.

[0021] Through extensive research, the applicant discovered that titanium alloys with this composition combine the extreme corrosion resistance of tantalum and the lightweight properties of titanium, and perform excellently in high-temperature, severe corrosion and biomedical fields.

[0022] Considering its application scenarios, tantalum-titanium alloys with a Ta content of 56-58% exhibit both good elongation and strength. Furthermore, the extremely low impurity content ensures excellent performance of the alloy powder and the components 3D-printed from it.

[0023] Preferably, the tantalum-titanium alloy powder of the present invention is in a spherical form (sphericity is preferably ≥95%).

[0024] Advantageously, tantalum-titanium alloy products printed using this powder have good high-temperature strength and high-temperature oxidation resistance, and can be widely used in the nuclear industry and other fields.

[0025] According to another aspect of the present invention, a method for preparing tantalum-titanium alloy powder is provided, which can realize the preparation of personalized and complex structural parts. Specifically, the method includes the following steps:

[0026] Step 1: providing tantalum powder and titanium powder as raw materials;

[0027] Step 2: Tantalum powder and titanium powder are mixed in a mass ratio of 56-58% tantalum and 42-44% titanium;

[0028] Step 3: isostatically pressing the mixed tantalum and titanium powders to obtain a rod. Preferably, the pressure range is 100-300 MPa, preferably 210±20 MPa, and the holding time is preferably 3-30 minutes, more preferably 10-15 minutes. Preferably, the diameter of the rod is 52-53 mm.

[0029] Step 4: Sinter the isostatically pressed tantalum-titanium rod to obtain a sintered green body. Sintering can improve the densification of the rod. Sintering is preferably performed at a temperature of 1400-1800°C, more preferably 1600-1650°C, with a holding time of 2-8 hours, preferably 4-6 hours. Sintering does not substantially change the rod's external dimensions.

[0030] Step 5, spheroidized powder preparation: spherical tantalum-titanium alloy powder is prepared from the sintered green body by using a gas atomization (eg, electrode induction melting gas atomization) powder making process, and sieved to obtain a powder with a particle size of 20-200 μm, preferably 45-105 μm.

[0031] Step 6: Degas the tantalum-titanium alloy powder.

[0032] Preferably, pickling is performed after degassing. Preferably, the pickling solution is HCl (preferably 36%-38% by mass): water = 1:2 (volume ratio). After pickling, rinse with pure water, preferably until the conductivity is less than 0.5 uS / cm, preferably less than 0.3 uS / cm;

[0033] Preferably, the step 1 includes:

[0034] Step 101: Prepare tantalum powder with a purity greater than 99.95%. Preferably, the tantalum powder has an N content less than 50 ppm and a particle size of -325 mesh.

[0035] Step 102: Prepare titanium powder with a purity greater than 99%, preferably with a particle size of -325 mesh.

[0036] The tantalum powder described in step 101 is readily commercially available. Preferably, tantalum powder obtained by reduction with potassium fluorotantalate is selected as the raw material. The titanium powder used in step 102 can be purchased, for example, from Tiantilong (Tianjin) Metal Materials Co., Ltd. On the one hand, high-purity raw materials ensure that the resulting alloy powder has an extremely low impurity content. On the other hand, the unique process of the present invention avoids the introduction of other impurities, which also contributes to the extremely low impurity content of the resulting alloy powder.

[0037] Preferably, the step 5 includes:

[0038] Step 501: placing a tantalum-titanium sintered body (e.g., with a diameter of 52-53 mm) in an electrode induction melting gas atomization powder making device;

[0039] Step 502: introducing an inert gas to form a protective atmosphere;

[0040] Step 503: Induction heating the tantalum-titanium alloy rod until it is molten;

[0041] Step 504: using high-pressure inert gas to atomize the molten tantalum-titanium alloy into droplets;

[0042] Step 505: The droplets solidify rapidly during flight to form spherical powder particles.

[0043] Preferably, the step 6 includes preliminary degassing and secondary degassing. More preferably, the step 6 includes preliminary degassing, secondary degassing and final degassing. Most preferably, the step 6 specifically includes:

[0044] Step 601: preliminarily degas the spherical powder obtained in step 5 by keeping it at 500±20°C (e.g., for 60-150 minutes);

[0045] Step 602: The tantalum-titanium alloy powder after the initial degassing is kept at 750±20° C. (e.g., for 120-250 minutes) for secondary degassing;

[0046] Step 603 : The tantalum-titanium alloy powder after the secondary degassing is kept at 900±30° C. (eg, for 600-1200 minutes) for final degassing.

[0047] This method can produce spherical tantalum-titanium alloy powders that meet the requirements of electron beam additive manufacturing and are well-suited for a variety of demanding applications (especially high-temperature strength). By carefully optimizing various process parameters, this method ensures that the produced tantalum-titanium alloy powders have an optimized tantalum-titanium ratio, a suitable particle size distribution (e.g., a particle size of 20-200μm, preferably 45-105μm), and low impurity content (such as the aforementioned low levels of O, H, N, and / or C), thus meeting the requirements of additive manufacturing processes.

[0048] According to another aspect of the present invention, a spherical tantalum-titanium alloy powder (sphericity ≥ 95%, powder for additive manufacturing) is used in additive manufacturing (e.g., electron beam additive manufacturing and / or laser additive manufacturing), as well as in the nuclear industry, aerospace, and biomedical fields. This spherical alloy powder is obtained, for example, by the aforementioned method.

[0049] The tantalum-titanium alloy spherical powder produced by the present invention can be used to produce components with complex shapes. Moreover, the produced components have good mechanical properties, such as strength and elongation. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 FIG1 is an electron microscope photograph of a spherical powder according to an embodiment of the present invention, which clearly shows that the powder has an ideal sphericity. DETAILED DESCRIPTION

[0051] To further illustrate the present invention, preferred embodiments of the present invention are described below in conjunction with the examples, and the objects, features, and advantages of the present invention are clearly shown. However, these descriptions are intended to further illustrate the features and advantages of the present invention and are not intended to limit the present invention. Where specific conditions are not specified in the examples, conventional conditions were used. Where the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional products.

[0052] For the purposes of this specification, all numbers representing the amounts of ingredients, reaction conditions, etc. in the specification and claims are to be understood as being modified by the term "about" in all cases, unless otherwise specified. Accordingly, the numerical parameters given in the following specification and the appended claims are approximate values, which may vary depending on the desired properties sought to be obtained by the present invention, unless otherwise indicated. At a minimum, and without intending to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be interpreted according to the number of reported significant figures and according to conventional rounding techniques.

[0053] Regarding the tests in the examples and comparative examples, the particle size distribution was tested according to GB / T 19077 "Particle size analysis - laser diffraction method"; the O content was tested according to GB / T 15076.14 "Tantalum and niobium chemical analysis methods - determination of oxygen content"; the H hydrogen content was tested according to GB / T 15076.15 "Tantalum and niobium chemical analysis methods - determination of hydrogen content"; and the C content was tested according to GB / T 15076.8 "Tantalum and niobium chemical analysis methods - determination of carbon content".

[0054] Example 1:

[0055] Step 1: Prepare raw materials:

[0056] Step 101: Prepare tantalum powder raw material, the purity of tantalum is not less than 99.9%;

[0057] Step 102: Prepare titanium powder raw material, the purity of titanium is not less than 99.5%;

[0058] Step 2, powder mixing: Tantalum and titanium powder raw materials are mixed in a mass ratio of 58% tantalum and 42% titanium, and mixed in a V-type mixer for 4 hours.

[0059] Step 3: Isostatic Pressing: The mixed tantalum and titanium powders are isostatically pressed to obtain rods with a diameter of 52-53 mm. The pressure used is 210 MPa and the holding time is 12 minutes.

[0060] Step 4, sintering: the isostatically pressed tantalum-titanium rod is placed in a vacuum furnace for sintering at a temperature of 1625° C. for 5 hours. The sintered green body is obtained after the furnace is cooled to room temperature.

[0061] Step 5: Gas atomization and screening: The sintered green body is pulverized by gas atomization and screened to obtain a powder with a particle size of 45-105 μm.

[0062] Step 6: Powder degassing treatment, as follows:

[0063] Step 601: Preliminary degassing of the sieved tantalum-titanium alloy powder is performed by keeping the temperature at 500° C. for 90 minutes in a vacuum furnace;

[0064] Step 602: The tantalum-titanium alloy powder after the initial degassing is kept at 750° C. in a vacuum furnace for 150 minutes for secondary degassing;

[0065] Step 603: The tantalum-titanium alloy powder after secondary degassing is placed in a vacuum furnace at 900° C. for 900 minutes for final degassing;

[0066] Then, the tantalum-titanium alloy powder after the ultimate degassing is pickled with a pickling solution of HCl (mass concentration 37%): water = 1:2 (volume ratio), and then the pickled tantalum-titanium alloy powder is rinsed and filtered with deionized water until the conductivity is less than 0.3uS / cm.

[0067] Step 7: Performing composition analysis and particle size distribution analysis on the prepared spherical tantalum-titanium alloy powder. The analysis shows that the particle size range is 45-105 μm, the O content is less than 2200 ppm, the H content is less than 50 ppm, the N content is less than 200 ppm, and the C content is less than 150 ppm.

[0068] Example 2:

[0069] Step 1 is the same as in Example 1.

[0070] Step 2, powder mixing: Tantalum and titanium powder raw materials are mixed in a mass ratio of 57% tantalum to 43% titanium, and mixed for 6 hours using a three-dimensional motion mixer.

[0071] Step 3 is basically the same as in Example 1, but the holding time is 15 minutes.

[0072] Step 4, sintering: the isostatically pressed tantalum-titanium powder is placed in a vacuum induction melting furnace for sintering at a temperature of 1650° C. for 6 hours. The sintered green body is obtained after the furnace is cooled to room temperature.

[0073] Step 5 is the same as in Example 1.

[0074] Step 6: Powder degassing:

[0075] Step 601: Preliminary degassing of the sieved tantalum-titanium alloy powder is performed by keeping the temperature at 500° C. for 120 minutes in a vacuum furnace;

[0076] Step 602: The tantalum-titanium alloy powder after the initial degassing is kept at 750° C. in a vacuum furnace for 180 minutes for secondary degassing;

[0077] Step 603: The tantalum-titanium alloy powder after secondary degassing is placed in a vacuum furnace at 900° C. for 1000 minutes for final degassing;

[0078] The degassed tantalum-titanium alloy powder was then pickled using a 1:2 volume ratio of HCl (38%) to water. The pickled tantalum-titanium alloy powder was then rinsed and filtered with deionized water until the conductivity was less than 0.3 μS / cm.

[0079] Step 7: Testing: The prepared spherical tantalum-titanium alloy powder was subjected to composition analysis and particle size distribution analysis. The impurity content is shown in Table 1 below.

[0080] In addition, the test results of the spherical powder prepared in Example 2 are as follows:

[0081] Table 1: Chemical composition of tantalum-titanium alloy spherical powder (wt%)

[0082] The morphology of the prepared spherical powder was detected by scanning electron microscopy, showing good sphericity. Figure 1 .

[0083] Example 3:

[0084] Step 1: Prepare raw materials:

[0085] Step 101: Prepare tantalum powder raw material, the purity of tantalum is 99.98%;

[0086] Step 102: Prepare titanium powder raw material, the purity of titanium is 99.8%;

[0087] Step 2, powder mixing: Tantalum and titanium powder raw materials are mixed in a mass ratio of 56% tantalum to 44% titanium, and ball milled in a planetary ball mill for 8 hours.

[0088] Step 3, isostatic pressing: the mixed tantalum-titanium powder is subjected to isostatic pressing at a pressure of 210 MPa and a holding time of 10 minutes.

[0089] Step 4, sintering: the isostatically pressed tantalum-titanium powder is placed in a vacuum arc melting furnace for sintering at a temperature of 1600° C. for 4 hours. The sintered green body is obtained after the furnace is cooled to room temperature.

[0090] Step 5: Gas atomization and screening: The sintered tantalum-titanium alloy rod is powdered by gas atomization and screened to obtain a powder with a particle size of 45-105 μm.

[0091] Step 6: Powder degassing:

[0092] Step 601: Preliminary degassing of the sieved tantalum-titanium alloy powder is performed by keeping the temperature at 500° C. for 60 minutes in a vacuum furnace;

[0093] Step 602: The tantalum-titanium alloy powder after the initial degassing is kept at 750° C. in a vacuum furnace for 150 minutes for secondary degassing;

[0094] Step 603: The tantalum-titanium alloy powder after secondary degassing is placed in a vacuum furnace at 900° C. for 800 minutes for final degassing;

[0095] The degassed tantalum-titanium alloy powder was then pickled using a 36% HCl:water ratio of 1:2 (volume ratio). The pickled tantalum-titanium alloy powder was then rinsed and filtered with deionized water until the conductivity was less than 0.3 μS / cm.

[0096] Step 7, testing: The prepared spherical tantalum-titanium alloy powder is subjected to composition analysis and particle size distribution analysis. The particle size range is 45-105 μm. The analysis shows that the O content is less than 2400 ppm, the H content is less than 30 ppm, the N content is less than 150 ppm, and the C content is less than 100 ppm.

[0097] Comparative Example 1:

[0098] Example 3 was essentially repeated, but the mass ratio of tantalum to titanium was 59% tantalum and 41% titanium.

[0099] Comparative Example 2:

[0100] Example 3 was essentially repeated, but the mass ratio of tantalum to titanium was 55% tantalum and 45% titanium.

[0101] The powders obtained in the examples and comparative examples were 3D printed using electron beam 3D printing to produce standard test specimens for mechanical properties (room temperature tensile test standard GB / T 228.1-2010).

[0102] The performance comparison of the powder printing products prepared in Example 2, Comparative Example 1 and Comparative Example 2 is as follows:

[0103] From the above comparison, it can be seen that when the tantalum content is in the range of 56-58%, the tantalum-titanium alloy powder has the following characteristics: tensile strength ≥815MPa, yield strength ≥680MPa, and elongation ≥14.5%, which meets the actual industrial requirements.

Claims

1. A tantalum-titanium alloy powder composed of two refractory elements, Ta and Ti, and inevitable impurities as the balance, wherein the Ta content is 56-58%. Preferably, the alloy powder has one or more of the following: Particle size 20-200 μm, preferably 45-105 μm; O<4000ppm, preferably <2500ppm; H < 100 ppm, preferably < 50 ppm; N < 350 ppm, preferably < 200 ppm; C < 300ppm, preferably < 150ppm, Particle size 45-105μm.

2. The powder according to claim 1, wherein the Nb content is ≤0.01%, and / or the C content is ≤0.006%, and / or the Si content is ≤0.01%, and / or the Fe content is ≤0.02% (e.g., ≤0.016%).

3. A method for preparing tantalum-titanium alloy powder, comprising the following steps: Step 1: providing tantalum powder and titanium powder as raw materials; Step 2: Tantalum powder and titanium powder are mixed in a mass ratio of 56-58% tantalum and 42-44% titanium; Step 3: isostatically pressing the mixed tantalum-titanium powder to obtain a rod (preferably, the rod has a diameter of 52-53 mm). Preferably, the pressure range is 100-300 MPa, preferably the pressure is 210±20 MPa, and the holding time is preferably 3-30 minutes, more preferably 10-15 minutes. Step 4: Sintering the isostatically pressed tantalum-titanium rod to obtain a sintered green body, preferably at a temperature of 1400-1800° C., more preferably 1600-1650° C., with a holding time of 2-8 hours, preferably 4-6 hours; Step 5, preparing spheroidized powder: using a gas atomization (e.g., electrode induction melting gas atomization) powder making process to prepare spherical tantalum-titanium alloy powder from the sintered green body, and sieving to obtain a powder with a particle size of 20-200 μm, preferably 45-105 μm; Step 6: Degas the tantalum-titanium alloy powder.

4. The method according to claim 3, further comprising pickling after degassing, wherein the pickling solution is preferably HCl (preferably 36%-38% by mass concentration): water = 1:2 (volume ratio). Optionally, after pickling, the product is rinsed with pure water, preferably until the conductivity is less than 0.5 uS / cm, preferably less than 0.3 uS / cm.

5. The method according to claim 3 or 4, wherein step 1 comprises: Step 101: Prepare tantalum powder with a purity greater than 99.95%, preferably, the N content of the tantalum powder is less than 50 ppm, and the particle size is -325 mesh; Step 102: Titanium powder with a purity greater than 99%, preferably having a particle size of -325 mesh.

6. The method according to claim 3, 4 or 6, wherein step 5 comprises: Step 501: placing a tantalum-titanium sintered body (e.g., with a diameter of 52-53 mm) in an electrode induction melting gas atomization powder making device; Step 502: introducing an inert gas to form a protective atmosphere; Step 503: Induction heating the tantalum-titanium alloy rod to a molten state; Step 504: using high-pressure inert gas to atomize the molten tantalum-titanium alloy into droplets; Step 505: The droplets solidify rapidly during flight to form spherical powder particles.

7. The method according to claim 3, 4 or 6, wherein step 6 comprises primary degassing, secondary degassing and optionally final degassing.

8. The method according to claim 3, 4 or 6, wherein step 6 comprises: Step 601: preliminarily degas the spherical powder obtained in step 5 by keeping it at 500±20°C (e.g., for 60-150 minutes); Step 602: The tantalum-titanium alloy powder after the initial degassing is kept at 750±20° C. (e.g., for 120-250 minutes) for secondary degassing; Step 603 : The tantalum-titanium alloy powder after the secondary degassing is kept at 900±30° C. (eg, for 600-1200 minutes) for final degassing.

9. A powder obtained according to the method of any one of claims 3 to 8 and a component obtained by 3D printing the powder.

10. Use of the powder according to claim 1, 2 or 9 in additive manufacturing (such as electron beam additive manufacturing and / or laser additive manufacturing) and the nuclear industry, aerospace, and biomedical fields.

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