TC4 titanium alloy powder for EBSM and preparation method and forming method of TC4 titanium alloy powder

Abstract

The invention relates to a preparation method of TC4 titanium alloy powder for EBSM, which comprises the following steps: S1, pulverizing a TC4 titanium alloy bar through plasma rotating electrode pulverizing equipment to obtain first through powder and a material head; s2, the first passing powder is screened, and X powder is obtained; s3, the material head obtained in the step S1 is subjected to friction welding splicing, a spliced bar is obtained, electrode induction melting gas atomization equipment is adopted, the spliced bar is subjected to powder making, and second through powder is obtained; s4, the second passing powder is screened, and Y powder is obtained; s5, the X powder and the Y powder are mixed according to the mass ratio of 2: 1-4: 1, and TC4 titanium alloy powder is obtained; after the TC4 titanium alloy powder prepared through the method is formed through the EBSM technology, an obtained workpiece is high in density and low in surface roughness, and the strength and plasticity are obviously improved.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy powder metallurgy, and in particular to TC4 titanium alloy powder for EBSM (Electron Beam Selective Melting) and a preparation method and a molding method thereof. Background Art

[0002] Metal 3D printing is widely used in aerospace, biomedicine and other fields. As a common raw material for 3D printing, the quality of TC4 titanium alloy powder and its molding performance are crucial. The preparation method of TC4 titanium alloy powder generally uses the PREP (Plasma Rotating Electrode Process) method or the EIGA (Electrode Induction Melting Gas Atomization) method, and the molding method of TC4 titanium alloy powder generally uses the EBSM method.

[0003] The principle of EBSM process is: first spread a layer of powder on the bottom plate, and the electron beam selectively melts according to the information of the cross-sectional profile under the control of the computer. The metal powder is melted together under the bombardment of the electron beam and bonded to the formed part below, stacked layer by layer until the entire part is formed. The EBSM process has high energy density and high energy absorption rate. It can use coarse powder for printing and has high forming efficiency, which is about 2 to 3 times that of the SLM (Selective Laser Melting) method; the forming temperature is high, the thermal stress is small, and the material plasticity is good; the high vacuum environment, the impurity pollution is low, and there is almost no oxygen addition, but because this process uses coarse-grained powder for forming, the surface accuracy is low; elements with high vapor pressure (such as Al) are easily volatilized and lost in a vacuum and high temperature environment, resulting in insufficient strength of TC4 titanium alloy; the deposited metallurgical quality is poor, and the parts have microcracks or pore defects.

[0004] The principle of PREP process is: one end of the high-speed rotating metal rod faces the high-temperature plasma heat source, and is heated and melted into liquid. The liquid film is crushed into droplets by centrifugal force and thrown out. The tiny droplets fly and solidify in the inert gas and spheroidize to form powder under the action of surface tension. The advantages of PREP powder in EBSM molding: high powder sphericity, good powder spreading uniformity; no hollow powder, no inherited pore defects in the sedimentation state; high purity, small increase in impurity elements. The disadvantages of PREP powder in EBSM molding: good powder fluidity, the powder bed will be collapsed by the impact of the electron beam.

[0005] The principle of the EIGA process is: through a high-speed inert gas flow, the liquid metal flow generated by the bottom of the bar in the induction coil is crushed into small droplets and quickly cooled and condensed to obtain spherical metal powder. The advantages of EIGA powder in EBSM molding: high purity, small increase in impurity elements; low bar size requirements, low production cost; a small amount of satellite powder on the surface of the particles, the powder bed has high hardness after preheating, is not easy to collapse, and has less splashing; the disadvantages of EIGA powder in EBSM molding: coarse powder (particle size ≥ 75μm) has many hollow powder defects, there are inherited pore defects in the sedimentation state, and the density is low. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention proposes a preparation method of TC4 titanium alloy powder for EBSM and a molding method thereof. The TC4 titanium alloy powder has high strength, good surface accuracy, is not easy to collapse, and has high density while ensuring low cost, good powder spreading uniformity, high purity, high molding efficiency, and good plasticity.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for preparing TC4 titanium alloy powder for EBSM, comprising the following steps:

[0009] S1, grinding TC4 titanium alloy rods by plasma rotating electrode grinding equipment to obtain first-pass powder and slugs;

[0010] S2, sieving the first powder to obtain X powder;

[0011] S3, performing friction welding splicing on the material heads obtained in S1 to obtain spliced ​​bar materials, and using electrode induction melting gas atomization equipment to grind the spliced ​​bar materials to obtain a second pass of powder;

[0012] S4, sieving the second powder to obtain Y powder;

[0013] S5. Mix the X powder and the Y powder in a mass ratio of 2:1 to 4:1 to obtain TC4 titanium alloy powder.

[0014] Preferably, in S1, the chemical composition of the TC4 titanium alloy rod is as follows by mass percentage: Al: 6.45-6.75%, V: 3.50%-4.50%, Fe: 0.15-0.25%, C: ≤0.08%, N: ≤0.03%, H: ≤0.012%, O: 0.09-0.12%, and Ti as a remainder.

[0015] Preferably, when the first pass powder is prepared by the plasma rotating electrode powder making equipment, the rotation speed is 28000-32000 rpm, the feed speed is 20-50 mm / min, the power is 100-150 kw, and the oxygen content is ≤1 ppm.

[0016] Preferably, in S2, an ultrasonic vibration screening machine is used to screen the first powder according to the particle size distribution of D10=58±5μm, D50=80±5μm, and D90=101±5μm, and the mesh numbers of the ultrasonic vibration screening machine are 270 mesh and 140 mesh.

[0017] Preferably, the particle size of the X powder is 53-106 μm, the sphericity is ≥97%, and the hollow powder rate is ≤0.03%.

[0018] Preferably, the specifications of TC4 titanium alloy rods are: diameter 55-60mm, length 700mm, straightness ≤0.05mm, surface roughness ≤3.2μm; the specifications of spliced ​​rods are: diameter 55-60mm, length 200-500mm, straightness ≤1mm.

[0019] Preferably, when the second powder is prepared by electrode induction melting gas atomization equipment, the atomization pressure is 3.0-5.0 MPa, the feed speed is 20-70 mm / min, the power is 30-60 kw, and the oxygen content is ≤1 ppm.

[0020] Preferably, an airflow classification device and an ultrasonic vibration screening machine are used successively, and the second powder is subjected to airflow classification and vibration screening according to the particle size distribution D10=50±5μm, D50=60±5μm, D90=70±5μm. The mesh numbers of the ultrasonic vibration screening machine are 325 mesh and 200 mesh, the particle size of the Y powder is 45-75μm, the sphericity is ≥94%, and the hollow powder rate is ≤0.30%.

[0021] The present invention also provides a TC4 titanium alloy powder prepared by the above preparation method.

[0022] The present invention also provides a molding method for the TC4 titanium alloy powder prepared by the above-mentioned preparation method, wherein the TC4 titanium alloy powder is put into an EBSM device, and the powder layer thickness is 0.09-0.11 mm, the preheating temperature is 500-750° C., and the energy density is 3.0-4.5 J / mm 2 The molding is carried out with the parameters of scanning spacing of 0.08 to 0.12 mm and scanning speed of 1.0 to 3.0 m / s.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention uses the characteristics of high reduction degree of raw material components in two powder making processes when preparing alloy powder, and selects the chemical composition of the powdered TC4 titanium alloy rod as follows: Al: 6.45-6.75%, V: 3.50%-4.50%, Fe: 0.15-0.25%, C: ≤0.08%, N: ≤0.03%, H: ≤0.012%, O: 0.09-0.12%, Ti balance; the mass percentage of Al in the TC4 titanium alloy rod is 6.45-6.75%, so that the prepared TC4 titanium alloy powder has a high The Al content is relatively high, ensuring that the Al content of the parts after EBSM forming is ≥6.0%, reducing the impact of insufficient strength caused by the reduction of α phase content due to the volatilization of Al elements during EBSM forming; the mass percentage of Fe in TC4 titanium alloy bars is 0.15-0.25%, which can improve the strength of the alloy to a certain extent without causing a decrease in the toughness of the alloy; the mass percentage of O in TC4 titanium alloy bars is 0.09-0.12%, which not only avoids the problem of insufficient strength of the formed parts caused by low O content, but also avoids the risk of high O content reducing the toughness and plasticity of the alloy;

[0025] (2) The present invention uses the PREP method and the EIGA method in series, which not only makes full use of waste materials to save costs, but also achieves the goal of consistent powder composition in different processes and eliminates the difference in composition of raw material batches;

[0026] (3) The present invention processes the powder through two processes, vibrating screening and airflow classification, to achieve the effect of limiting the powder particle size and improving the particle sphericity; both coarse-grained PREP powder with no hollow powder and high sphericity and fine-grained EIGA powder with a small amount of hollow powder and satellite powder are obtained;

[0027] (4) By mixing coarse-grained PREP powder and fine-grained EIGA powder in a certain proportion and introducing a small amount of satellite powder, the problem of easy collapse of PREP powder during molding is solved, ensuring the stability of the molding process; the advantage of almost no hollow powder is also brought into play, solving the problem of many metallurgical defects in EIGA powder molding, and significantly improving the density of the deposited state; at the same time, the powder particle size is reduced by mixing the powders, thereby reducing the surface roughness of the molded parts and improving the surface quality;

[0028] (5) The present invention provides a better raw material of TC4 alloy powder for EBSM and develops the process parameters for its forming. The surface roughness of the obtained product is ≤20μm, the density is ≥99.5%, the room temperature tensile strength is ≥1020MPa, the yield strength is ≥950MPa, the elongation after fracture is ≥14%, the cross-sectional shrinkage is ≥40%, the bending strength is ≥2000Mpa, and the fracture toughness is ≥90Mpa·m 1 / 2 , fatigue strength ≥500Mpa, with excellent comprehensive mechanical properties, higher than the existing technical level. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 (a) is a SEM image of X powder in Example 1 of the present invention, Figure 1 (b) is a SEM image of Y powder in Example 1 of the present invention, Figure 1 (c) is a SEM image of the TC4 titanium alloy powder in Example 1 of the present invention;

[0030] Figure 2 This is a photo of EBSM molding of TC4 titanium alloy powder in Example 1 of the present invention;

[0031] Figure 3 This is a metallographic photograph of the TC4 titanium alloy powder in the EBSM molding deposition state in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] A molding method of TC4 titanium alloy powder for EBSM, comprising: putting the TC4 titanium alloy powder into an EBSM device, and heating the powder layer to a thickness of 0.11 mm, a preheating temperature of 750° C., and an energy density of 4.5 J / mm 2 , the parameters of scanning spacing 0.12mm and scanning speed 3.0m / s were used for molding;

[0035] The preparation method of TC4 titanium alloy powder in this embodiment includes the following steps:

[0036] S1. Powdering TC4 titanium alloy rods by plasma rotating electrode powder making equipment to obtain first powder and material head; wherein the chemical composition of TC4 titanium alloy rods is as follows by mass percentage: Al: 6.75%, V: 4%, Fe: 0.25%, C: 0.01%, N: 0.01%, H: 0.005%, O: 0.09%, Ti balance, and the specifications of TC4 titanium alloy rods are Straightness ≤ 0.05mm, surface roughness ≤ 3.2μm; During the first pass of powder preparation, the key parameters were set to speed 32000rpm, feed speed 50mm / min, power 150kw, oxygen content ≤ 1ppm;

[0037] S2, using an ultrasonic vibration screening machine, according to the particle size distribution D10 = 58 ± 5 μm, D50 = 80 ± 5 μm, D90 = 101 ± 5 μm, the first powder is screened to obtain X powder with a particle size of 53 to 106 μm, a sphericity of 97.5%, and a hollow powder rate of 0.02%; wherein the mesh number of the ultrasonic vibration screening machine is 270 mesh and 140 mesh;

[0038] S3, friction welding the material heads obtained in S1 to obtain spliced ​​bars, and using electrode induction melting gas atomization equipment to grind the spliced ​​bars to obtain the second powder, wherein the specifications of the spliced ​​bars are Straightness ≤1mm; when preparing the second pass powder, the key parameters are atomization pressure 5.0Mpa, feed speed 70mm / min, power 60kw, oxygen content ≤1ppm;

[0039] S4, successively using airflow classification equipment and ultrasonic vibration screening machine, according to the particle size distribution D10 = 50 ± 5 μm, D50 = 60 ± 5 μm, D90 = 70 ± 5 μm, the second powder was airflow classified and vibration screened to obtain Y powder with a particle size of 45-75 μm, a sphericity of 94.5%, and a hollow powder rate of 0.20%; the key parameters for airflow classification are set as feed frequency 20 Hz, classification frequency 20 Hz, air supply pressure 0.5 MPa, and oxygen content ≤ 50 ppm; the mesh number of the ultrasonic vibration screening machine during vibration screening is 325 mesh and 200 mesh;

[0040] S5. Using a cone mixer, mix the X powder and the Y powder in a mass ratio of 2:1 to obtain a TC4 titanium alloy powder with a particle size distribution of D10 = 53 ± 5 μm, D50 = 75 ± 5 μm, D90 = 95 ± 5 μm, a sphericity of 96.5%, and a hollow powder rate of 0.08%. During the mixing process of the X powder and the Y powder, the single mixing weight is 500 kg, the rotation speed is 15 rpm, and the mixing time is 5 h.

[0041] refer to Figure 1 It can be seen that the X powder prepared by the PREP process of the present invention has a coarse particle size, extremely high sphericity, smooth surface, and no satellite powder and hollow powder; the Y powder prepared by the EIGA process has a fine particle size, and there is a small amount of satellite powder and hollow powder; and the morphology of the mixed powder TC4 titanium alloy powder inherits the characteristics of the powders of the two powder making processes, with no hollow powder and high sphericity. The powder particles have a high content, a small amount of fine-grained powder can make the filling property better during powder spreading, and the introduced satellite powder can improve the hardness of the powder bed.

[0042] Example 2

[0043] A molding method of TC4 titanium alloy powder for EBSM, comprising: putting the TC4 titanium alloy powder into an EBSM device, and heating the powder layer to a thickness of 0.09 mm, a preheating temperature of 500° C., and an energy density of 3.0 J / mm 2 , the parameters of scanning spacing 0.08mm and scanning speed 1.0m / s were used for molding;

[0044] The preparation method of TC4 titanium alloy powder in this embodiment includes the following steps:

[0045] S1. Powdering TC4 titanium alloy rods by plasma rotating electrode powder making equipment to obtain first powder and material heads; wherein the chemical composition of TC4 titanium alloy rods is as follows by mass percentage: Al: 6.45%, V: 4.50%, Fe: 0.15%, C: 0.01%, N: 0.01%, H: 0.005%, O: 0.10%, Ti balance, and the specifications of TC4 titanium alloy rods are Straightness ≤ 0.05mm, surface roughness ≤ 3.2μm; During the first pass of powder preparation, the key parameters were set as rotation speed 28000rpm, feed speed 20mm / min, power 100kw, oxygen content ≤ 1ppm;

[0046] S2, using an ultrasonic vibration screening machine, according to the particle size distribution D10 = 58 ± 5 μm, D50 = 80 ± 5 μm, D90 = 101 ± 5 μm, the first powder is screened to obtain X powder with a particle size of 53 to 106 μm, a sphericity of 97.3%, and a hollow powder rate of 0.01%; wherein the mesh numbers of the ultrasonic vibration screening machine are 270 mesh and 140 mesh;

[0047] S3, friction welding the material heads obtained in S1 to obtain spliced ​​bars, and using electrode induction melting gas atomization equipment to grind the spliced ​​bars to obtain the second powder; wherein the spliced ​​bars are of specifications: Straightness ≤1mm; when preparing the second pass powder, the key parameters are atomization pressure 3.0Mpa, feed speed 20mm / min, power 30kw, oxygen content ≤1ppm;

[0048] S4, successively using airflow classification equipment and ultrasonic vibration screening machine, according to the particle size distribution D10 = 50 ± 5 μm, D50 = 60 ± 5 μm, D90 = 70 ± 5 μm, the second powder was airflow classified and vibration screened to obtain Y powder with a particle size of 45-75 μm, a sphericity of 94.2%, and a hollow powder rate of 0.25%; the key parameters for airflow classification were set as feed frequency 10 Hz, classification frequency 10 Hz, air supply pressure 0.5 MPa, and oxygen content ≤ 50 ppm; the mesh size of the ultrasonic vibration screening machine during vibration screening was 325 mesh and 200 mesh;

[0049] S5. Using a cone mixer, mix the X powder and the Y powder in a mass ratio of 2:1 to obtain a TC4 titanium alloy powder with a particle size distribution of D10 = 53 ± 5 μm, D50 = 75 ± 5 μm, D90 = 95 ± 5 μm, a sphericity of 96.5%, and a hollow powder rate of 0.07%. During the mixing process of the X powder and the Y powder, the single mixing weight is 50 kg, the rotation speed is 5 rpm, and the mixing time is 1 hour.

[0050] Example 3

[0051] A molding method of TC4 titanium alloy powder for EBSM, comprising: putting the TC4 titanium alloy powder into an EBSM device, and heating the powder layer with a thickness of 0.10 mm, a preheating temperature of 625° C., and an energy density of 3.7 J / mm 2 , the parameters of scanning spacing 0.10mm and scanning speed 2.0m / s were used for molding;

[0052] The preparation method of TC4 titanium alloy powder in this embodiment includes the following steps:

[0053] S1. Powdering TC4 titanium alloy rods by plasma rotating electrode powder making equipment to obtain first powder and material head; wherein the chemical composition of TC4 titanium alloy rods is as follows by mass percentage: Al: 6.60%, V: 3.5%, Fe: 0.20%, C: 0.01%, N: 0.01%, H: 0.005%, O: 0.12%, Ti balance, and the specifications of TC4 titanium alloy rods are Straightness ≤ 0.05mm, surface roughness ≤ 3.2μm; During the first pass of powder preparation, the key parameters were set as rotation speed 30000rpm, feed speed 35mm / min, power 125kw, oxygen content ≤ 1ppm;

[0054] S2, using an ultrasonic vibration screening machine, according to the particle size distribution D10 = 58 ± 5 μm, D50 = 80 ± 5 μm, D90 = 101 ± 5 μm, the first powder is screened to obtain X powder with a particle size of 53 to 106 μm, a sphericity of 97.4%, and a hollow powder rate of 0.02%; wherein the mesh number of the ultrasonic vibration screening machine is 270 mesh and 140 mesh;

[0055] S3, friction welding the material heads obtained in S1 to obtain spliced ​​bars, and using electrode induction melting gas atomization equipment to grind the spliced ​​bars to obtain the second powder; wherein the spliced ​​bars are of specifications: Straightness ≤1mm; when preparing the second pass powder, the key parameters are atomization pressure 4.0Mpa, feed speed 45mm / min, power 45kw, oxygen content ≤1ppm;

[0056] S4, successively using airflow classification equipment and ultrasonic vibration screening machine, according to the particle size distribution D10 = 50 ± 5 μm, D50 = 60 ± 5 μm, D90 = 70 ± 5 μm, the second powder was airflow classified and vibration screened to obtain Y powder with a particle size of 45-75 μm, a sphericity of 94.1%, and a hollow powder rate of 0.22%; the key parameters for airflow classification were set as feed frequency 15 Hz, classification frequency 15 Hz, air supply pressure 0.7 MPa, and oxygen content ≤ 50 ppm; the mesh size of the ultrasonic vibration screening machine during vibration screening was 325 mesh and 200 mesh;

[0057] S5. Using a cone mixer, mix the X powder and the Y powder in a mass ratio of 4:1 to obtain a TC4 titanium alloy powder with a particle size distribution of D10 = 53 ± 5 μm, D50 = 75 ± 5 μm, D90 = 95 ± 5 μm, a sphericity of 96.7%, and a hollow powder rate of 0.06%. During the mixing process of the X powder and the Y powder, the single mixing weight is 250 kg, the rotation speed is 10 rpm, and the mixing time is 3 h.

[0058] Comparative Example 1

[0059] A molding method for TC4 titanium alloy powder comprises the following steps: putting the TC4 titanium alloy powder into an EBSM device and molding the powder according to the following parameters: a powder layer thickness of 0.12 mm, a preheating temperature of 800° C., an energy density of 2.8 J / mm2, a scanning interval of 0.07 mm, and a scanning speed of 0.9 m / s.

[0060] In this embodiment, the preparation method of TC4 titanium alloy powder includes the following steps:

[0061] S1: PREP powder making: The TC4 titanium alloy bar is powdered by ultra-high speed plasma rotating electrode powder making equipment. The chemical composition of the TC4 titanium alloy bar is as follows: Al: 5.95%, V: 4.00%, Fe: 0.10%, C: 0.01%, N: 0.01%, H: 0.005%, O: 0.06%, Ti balance; the specification of the TC4 titanium alloy bar is Straightness ≤ 0.05mm, surface roughness ≤ 3.2μm; key parameters for preparing masa flour are: rotation speed 30000rpm, feed speed 35mm / min, power 125kw, oxygen content ≤ 1ppm;

[0062] S2: Using an ultrasonic vibration screening machine, the powder obtained in S1 was screened according to the particle size distribution of D10=58±5μm, D50=80±5μm, and D90=101±5μm to obtain TC4 titanium alloy powder with a particle size of 53-106μm, a sphericity of 97.4%, and a hollow powder rate of 0.02%; the mesh numbers of the ultrasonic vibration screening machine are 270 mesh and 140 mesh.

[0063] Comparative Example 2

[0064] A molding method for TC4 titanium alloy powder comprises the following steps: putting the TC4 titanium alloy powder into an EBSM device and molding the powder according to the parameters of a powder layer thickness of 0.08 mm, a preheating temperature of 450° C., an energy density of 4.6 J / mm2, a scanning interval of 0.13 mm, and a scanning speed of 3.2 m / s.

[0065] In this embodiment, the preparation method of TC4 titanium alloy powder includes the following steps:

[0066] S1: EIGA powder making: TC4 titanium alloy rods are powdered by electrode induction melting gas atomization equipment to obtain pure powder; the chemical composition of the TC4 titanium alloy rods is as follows by mass percentage: Al: 6.25%, V: 4.00%, Fe: 0.30%, C: 0.01%, N: 0.01%, H: 0.005%, O: 0.14%, Ti balance; the specifications of the TC4 titanium alloy rods are Straightness ≤1mm; when preparing puree, the key parameters are atomization pressure 5.5Mpa, feed speed 45mm / min, power 45kw, oxygen content ≤1ppm;

[0067] S2: The airflow classification equipment and ultrasonic vibration screening machine are used successively to perform airflow classification and vibration screening on the powder obtained in S1 according to the particle size distribution of D10=53±5μm, D50=75±5μm, and D90=95±5μm, so as to obtain TC4 titanium alloy powder with a particle size of 53-106μm, a sphericity of 93.5%, and a hollow powder rate of 0.35%; the key parameters of the airflow classification are a feed frequency of 15Hz, a classification frequency of 15Hz, an air supply pressure of 0.8Mpa, and an oxygen content of ≤50ppm; the mesh sizes of the ultrasonic vibration screening machine are 270 mesh and 140 mesh.

[0068] The EBSM forming properties corresponding to the above-mentioned Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2 are shown in Table 1:

[0069] Table 1 TC4 titanium alloy performance test results

[0070] performance Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Surface roughness μm 17 18 19 24 23 Density% 99.5 99.7 99.8 98.5 96.4 Tensile strengthMpa 1025 1033 1040 988 956 Yield StrengthMpa 953 968 970 935 910 Elongation after break % 15.3 15.6 14.3 14.2 13.5 Sectional shrinkage% 44.5 45.1 43.8 39.1 38.3 Bending strengthMpa 2041 2032 2020 1980 1965 <![CDATA[Fracture toughness Mpa·m 1 / 2 > 95.4 93.1 91.5 83.3 79.2 Fatigue strengthMpa 532 528 512 483 445

[0071] It can be seen from the data in Table 1 that the present invention can significantly improve the density of EBSM-formed TC4 titanium alloy, reduce surface roughness, and significantly improve the strength and plasticity of the material, which has very good promotion value.

[0072] The specific embodiments of the present invention enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0073] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing TC4 titanium alloy powder for EBSM, characterized in that: The following steps are involved: S1, grinding TC4 titanium alloy rods by plasma rotating electrode grinding equipment to obtain first-pass powder and slugs; S2, sieving the first powder to obtain X powder; S3, performing friction welding splicing on the material heads obtained in S1 to obtain spliced ​​bar materials, and using electrode induction melting gas atomization equipment to grind the spliced ​​bar materials to obtain a second pass of powder; S4, sieving the second powder to obtain Y powder; S5. Mix the X powder and the Y powder in a mass ratio of 2:1 to 4:1 to obtain TC4 titanium alloy powder.

2. The method for preparing TC4 titanium alloy powder for EBSM according to claim 1, characterized in that: In S1, the chemical composition of the TC4 titanium alloy rod is as follows by mass percentage: Al: 6.45-6.75%, V: 3.50%-4.50%, Fe: 0.15-0.25%, C: ≤0.08%, N: ≤0.03%, H: ≤0.012%, O: 0.09-0.12%, and Ti balance.

3. The method for preparing TC4 titanium alloy powder for EBSM according to claim 1, characterized in that: When the first pass powder is prepared by the plasma rotating electrode powder making equipment, the rotation speed is 28000-32000rpm, the feed speed is 20-50mm / min, the power is 100-150kw, and the oxygen content is ≤1ppm.

4. The method for preparing TC4 titanium alloy powder for EBSM according to claim 1, characterized in that: In S2, an ultrasonic vibration screening machine is used to screen the first powder according to the particle size distribution of D10=58±5μm, D50=80±5μm, and D90=101±5μm.

5. The method for preparing TC4 titanium alloy powder for EBSM according to claim 1, characterized in that: The particle size of X powder is 53-106 μm, the sphericity is ≥97%, and the hollow powder rate is ≤0.03%.

6. The method for preparing TC4 titanium alloy powder for EBSM according to claim 1, characterized in that: The specifications of TC4 titanium alloy bars are: diameter 55-60mm, length 700mm, straightness ≤0.05mm, surface roughness ≤3.2μm; the specifications of spliced ​​bars are: diameter 55-60mm, length 200-500mm, straightness ≤1mm.

7. The method for preparing TC4 titanium alloy powder for EBSM according to claim 1, characterized in that: When the second pass powder is prepared by electrode induction melting gas atomization equipment, the atomization pressure is 3.0-5.0Mpa, the feed speed is 20-70mm / min, the power is 30-60kw, and the oxygen content is ≤1ppm.

8. The method for preparing TC4 titanium alloy powder for EBSM according to claim 1, characterized in that: The second powder was subjected to airflow classification and vibration screening by using airflow classification equipment and ultrasonic vibration screening machine successively according to the particle size distribution of D10=50±5μm, D50=60±5μm, D90=70±5μm. The particle size of Y powder was 45-75μm, the sphericity was ≥94%, and the hollow powder rate was ≤0.30%.

9. A TC4 titanium alloy powder for EBSM, characterized in that: The TC4 titanium alloy powder is prepared by the preparation method according to any one of claims 1 to 8.

10. A method for forming TC4 titanium alloy powder for EBSM, characterized in that: Put TC4 titanium alloy powder into EBSM equipment, according to the powder layer thickness of 0.09-0.11mm, preheating temperature of 500-750℃, energy density of 3.0-4.5J / mm 2 , scanning spacing of 0.08 to 0.12 mm, and scanning speed of 1.0 to 3.0 m / s for molding, and the TC4 titanium alloy powder is prepared by the preparation method according to any one of claims 1 to 8.

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