High machinability MIM titanium alloy material and preparation method thereof

Abstract

This invention relates to a method for preparing a high-machinability MIM titanium alloy material, belonging to the field of MIM, and includes the following steps: S1, feedstock preparation: mixing a mixed powder with a feedstock to prepare a feedstock; wherein the mixed powder includes titanium alloy spherical powder and a cutting aid; S2, placing the feedstock in an injection molding machine and injecting to form a green compact; S3, debinding the green compact to form a debinded compact; S4, sintering the debinded compact to obtain a sintered compact. This invention improves the machinability of titanium alloy materials by adding a cutting aid based on powder injection molding, which helps to reduce the subsequent machining costs of titanium alloy materials.

Description

Technical Field

[0001] This invention relates to the field of MIM titanium alloy material preparation, and particularly to a method for preparing a high-machinability MIM titanium alloy material. Background Technology

[0002] Titanium alloys possess advantages such as low density, high specific strength, low coefficient of thermal expansion, good corrosion resistance, high biocompatibility, easy welding, non-magnetic properties, and good creep resistance, leading to their widespread application in aerospace, chemical, medical, and smart wearable fields. However, titanium alloys also exhibit poor thermal conductivity, are prone to oxidation, have low plasticity and high hardness, and low elastic modulus. This results in heat concentration, high cutting edge stress, and significant springback during machining, causing severe tool wear. Metal injection molding, a molding technology combining the advantages of plastic injection molding and powder metallurgy, offers high production efficiency, high flexibility in material composition, and the ability to produce complex parts.

[0003] However, injection molding cannot meet all product requirements regarding structure, size, precision, and surface quality; most still require machining to ensure these specifications. The characteristics of metal injection molding mean that the resulting titanium alloy material is not completely dense, containing numerous micropores. These micropores easily lead to intermittent cutting during machining, increasing tool vibration and impact frequency. Poor thermal conductivity, high stress, and high springback, coupled with intermittent cutting, exacerbate tool wear, increasing machining costs and reducing production efficiency. Therefore, optimizing titanium alloy injection molding technology to prepare a highly machinable MIM titanium alloy material is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a high-machinability titanium alloy material. This method is based on powder injection molding technology and utilizes the addition of cutting aids to improve the machinability of the titanium alloy material.

[0005] The technical solution to achieve the objective of this invention is as follows: This invention includes the following steps:

[0006] S1. Feed preparation: The mixed powder and binder are mixed to prepare the feed; wherein the mixed powder includes titanium alloy spherical powder and cutting aid, wherein the cutting aid is sphericalized; the titanium alloy spherical powder has a particle size of 1-20 μm; the cutting aid is MnS or CaF2 or a mixture of the two, with a particle size of 1-10 μm; the mass percentage of the cutting aid in the mixed powder is 0.01%-2.00%;

[0007] S2. Place the feed material into the injection molding machine and inject to form a green body;

[0008] S3. Degrease the green body to form a degreased green body;

[0009] S4. Sinter the degreased blank to obtain a sintered blank.

[0010] This invention selects MnS and CaF2 as raw materials for cutting aids because they do not decompose at the sintering temperature of titanium alloys and are distributed in the micropores or grains and grain boundaries of MIM titanium alloys after sintering. The cutting aids distributed in the micropores can significantly compensate for the impact of the pores, reduce the probability of intermittent cutting to a certain extent, and reduce tool vibration and wear. MIM titanium alloys have high sintering density and high interparticle fusion. During the sintering process, some of the cutting aids are distributed in the grain boundaries or inside the grains along with particle adhesion and grain boundary migration. This part of the cutting aids can play a role in chip breaking and reduce the probability of tool sticking.

[0011] The mass ratio of MnS and CaF2 in the cutting aid is 1:1 because the inventors found that although both MnS and CaF2 can be used as cutting aids, the effect of using them together is greater than using them alone, and the sintered blanks obtained by using them together have better dimensional stability.

[0012] Cutting aids in their natural state are in the form of flakes, such as Figure 1 In (a), after grinding by a specialized titanium alloy feeding preparation equipment, under the action of a high-speed rotating hammer, the scales are bent, broken, and spherical by intense friction, shearing, and collision, ultimately forming a spherical or near-spherical shape, such as... Figure 1 (b), (c), and (d) are shown in the diagram. The particle size of the spheroidized cutting aid will also decrease slightly, reaching approximately 1–6 μm. Both the spheroidization treatment and feed preparation of the cutting aid must be carried out in an argon atmosphere below 1000 ppm to prevent the cutting aid and titanium alloy powder from becoming damp or oxidized.

[0013] To ensure good powder flowability and sintering activity, the titanium alloy powder used in injection molding is typically spherical powder with a diameter of 1–20 μm. After spheroidization, the cutting aid has a shape more similar to the titanium alloy powder, making uniform mixing easier. Simultaneously, the reduction in the particle size of the cutting aid through spheroidization results in smaller heterogeneous "defects" formed in the sintered blank due to the presence of the cutting aid, thus minimizing the impact of these "defects" on the material's mechanical properties. See details... Figure 2 and Figure 3 The porosity of the sintered blanks after spheroidization and non-spheroidization with cutting aids is shown.

[0014] Furthermore, the preparation of feed in step S1 above includes the following steps:

[0015] A. MnS and CaF2 are mixed at a mass ratio of 1:1 and spheroidized by mechanical grinding. The spheroidization process is carried out in argon gas with an oxygen content of less than 1000 ppm. The stirring speed is 60-80 r / min and the stirring time is 1-2 hours to prepare a cutting aid.

[0016] B. Mix the titanium alloy spherical powder with the cutting aid evenly. The mixing process is carried out in an argon atmosphere with an oxygen content of less than 1000 ppm. The stirring speed is 40 r / min and the stirring time is 0.5 to 1 hour to obtain the mixed powder.

[0017] C. Add binder and mix to prepare feed.

[0018] Furthermore, the chemical composition of the above-mentioned titanium alloy spherical powder is as follows: Al: 5.5%~6.75%; V: 3.5%~4.5%; Fe: ≤0.3%; impurities: ≤1.0%; the remainder is Ti.

[0019] Furthermore, the ratio of the mixed powder to the binder in the above feed is 0.5≤V1 / V2≤1.9, where V1 is the volume of the mixed powder and V2 is the volume of the binder.

[0020] The volume ratio of the mixed powder to the binder is related to the actual tap density of the selected mixed powder. Choosing a reasonable volume ratio based on the actual tap density of the powder helps the binder to completely coat the powder particles, avoiding both excessive powder particles leading to poor feed flowability and excessive binder content leading to poor shape retention of the injection molded product.

[0021] As an optimized design, the volume percentage of the mixed powder in the above feed is 58% to 63%, with the remainder being a binder; the binder comprises, by mass percentage, 60% to 70% polyoxymethylene, 12% to 15% polyethylene, 15% to 20% polypropylene, and 3% to 5% stearic acid; the loading range of the feed is 53% to 73%.

[0022] Furthermore, in step S2 above, the mold temperature during injection is 80-120℃, the feeding heating temperature is 160-220℃, the injection pressure is 80-120MPa, and the holding time is 1-2.5s.

[0023] Furthermore, in step S3, the injection preform is degreased to obtain a degreased preform; the specific technical parameters for degreasing are: degreasing is carried out using oxalic acid as a medium for catalytic degreasing, and the degreasing time is t≥(60+60*h)min, where h is the maximum thickness of the injection preform in mm;

[0024] Furthermore, in step S4 above, the sintering temperature T satisfies the following condition: 0.6TL≤T≤0.95TL, where TL is the theoretical melting point temperature of the mixed powder.

[0025] Furthermore, in step S5 above, the method for verifying machinability is to roughen the inner hole of a part using a CNC machine tool at a speed of 9000 rpm, a feed rate of 2000 mm / min, and a cutting time of 108 seconds. The tool life is determined based on the abrupt changes in product size and surface roughness, and the material machinability is judged based on the tool life.

[0026] The present invention has positive effects: (1) The present invention improves the problem of poor cutting performance of titanium alloy by adding a certain amount of cutting aid to titanium alloy spherical powder.

[0027] (2) The method of the present invention is simple and feasible, and can be implemented on conventional MIM equipment without the need for additional equipment and processes. The product of the present invention has excellent machinability, which can significantly improve the machinability of MIM titanium alloy materials, reduce production costs, and improve production efficiency. Attached Figure Description

[0028] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0029] Figure 1 This is a schematic diagram of the spheroidization process of the cutting aid in this invention;

[0030] Figure 2 The pore morphology of the sintered blank prepared after spheroidization of the cutting aid in this invention is shown.

[0031] Figure 3 Pore ​​morphology of sintered blanks prepared without spheroidization of cutting aids. Detailed Implementation

[0032] (Comparative Example)

[0033] This invention includes the following steps:

[0034] S1. Feed Preparation: Prepare titanium alloy spherical powder with a particle size range of 1-20 μm (D50: 10-13 μm) and mix it with a binder. The chemical composition of the titanium alloy spherical powder is: Al: 5.5%-6.75%; V: 3.5%-4.5%; Fe: ≤0.3%; impurities: ≤1.0%; the remainder is Ti. The titanium alloy spherical powder and binder are mixed to prepare the feed; the volume ratio of titanium alloy spherical powder to binder is 1.7; the titanium alloy spherical powder accounts for 63% of the feed by volume, and the remainder is binder; the binder components, by mass percentage, include 60%-70% polyoxymethylene, 12%-15% polyethylene, 15%-20% polypropylene, and 3%-5% stearic acid.

[0035] S2. Place the feed material into the injection molding machine and inject it into the mold to form an injection preform; the injection parameters are: mold temperature 80~120℃, feed material heating temperature 160~220℃, injection pressure 80~120MPa; holding time 1~2.5s;

[0036] S3. Degrease the injection preform to obtain a degreased preform; the specific technical parameters for degreasing are: degreasing is carried out using oxalic acid as a medium for catalytic degreasing, and the degreasing time is t≥(60+60*h)min, where h is the maximum thickness of the injection preform in mm;

[0037] S4. The degreased blank is subjected to high-vacuum sintering to obtain a sintered blank; the specific technical parameters for sintering are: high-vacuum sintering is performed using a metal cavity sintering furnace, and the pressure inside the furnace is ≤1.0×10⁻⁶. -3 Pa, sintering temperature T satisfies 0.65TL≤T≤0.95TL.

[0038] Finally, the machinability of the sintered billet was verified. The inner hole of a part was roughened using a CNC machine tool at a speed of 9000 rpm, a feed rate of 2000 mm / min, and a cutting time of 108 seconds. The tool life was determined based on the abrupt changes in product size and surface roughness, and the machinability of the material was judged based on the tool life.

[0039] The density of the sintered part is 4.38 g / cm³. 3 The yield strength reached 930 MPa, and the elongation was around 11%. Machinability was tested using a cutting tool on 80 parts.

[0040] (Example 1)

[0041] This invention includes the following steps:

[0042] S1. Feed Preparation: MnS and CaF2 are mixed at a mass ratio of 1:1 and then spheroidized to prepare a cutting aid; wherein the particle size of MnS and CaF2 is 1-10 μm. The cutting aid is mixed with titanium alloy spherical powder, and the mass percentage of the cutting aid is 0.10-0.30%; a binder is added to prepare the feed. The chemical composition of the titanium alloy powder is: Al: 5.5%-6.75%; V: 3.5%-4.5%; Fe: ≤0.3%; impurities: ≤1.0%; the remainder is Ti, and the particle size range is 1-20 μm (D50: 10-13 μm). The titanium alloy mixed powder accounts for 63% of the volume of the feed, and the remainder is the binder; the components of the polymer binder include, by mass percentage, 60%-70% polyoxymethylene, 12%-15% polyethylene, 15%-20% polypropylene, and 3%-5% stearic acid;

[0043] S2. Place the feed material into the injection molding machine and inject it into the mold to form an injection preform; the injection parameters are: mold temperature 80~120℃, feed material heating temperature 160~220℃, injection pressure 80~120MPa; holding time 1~2.5s;

[0044] S3. Degrease the injection preform to obtain a degreased preform; the specific technical parameters for degreasing are: degreasing is carried out using oxalic acid as a medium for catalytic degreasing, and the degreasing time is t≥(60+60*h)min, where h is the maximum thickness of the injection preform in mm;

[0045] S4. The degreased blank is subjected to high-vacuum sintering to obtain a sintered blank; the specific technical parameters for sintering are: high-vacuum sintering is performed using a metal cavity sintering furnace, and the pressure inside the furnace is ≤1.0×10⁻⁶. -3 Pa, sintering temperature T satisfies 0.65TL≤T≤0.95TL.

[0046] The preparation of feed in step S1 above includes the following steps:

[0047] A. MnS and CaF2 are mixed at a mass ratio of 1:1 and spheroidized by mechanical grinding. The spheroidization process is carried out in argon gas with an oxygen content of less than 1000 ppm. The stirring speed is 60-80 r / min and the stirring time is 1-2 hours to prepare a cutting aid.

[0048] B. Mix the titanium alloy spherical powder with the cutting aid evenly. The mixing process is carried out in an argon atmosphere with an oxygen content of less than 1000 ppm. The stirring speed is 40 r / min and the stirring time is 0.5 to 1 hour to obtain the mixed powder.

[0049] C. Add binder and mix to prepare feed.

[0050] This invention selects MnS and CaF2 as raw materials for cutting aids because they do not decompose at the sintering temperature of titanium alloys and are distributed in the micropores or grains and grain boundaries of MIM titanium alloys after sintering. The cutting aids distributed in the micropores can significantly compensate for the impact of the pores, reduce the probability of intermittent cutting to a certain extent, and reduce tool vibration and wear. MIM titanium alloys have high sintering density and high interparticle fusion. During the sintering process, some of the cutting aids are distributed in the grain boundaries or inside the grains along with particle adhesion and grain boundary migration. This part of the cutting aids can play a role in chip breaking and reduce the probability of tool sticking.

[0051] The mass ratio of MnS and CaF2 in the cutting aid is 1:1 because the inventors found that although both MnS and CaF2 can be used as cutting aids, the effect of using them together is greater than using them alone, and the sintered blanks obtained by using them together have better dimensional stability.

[0052] Cutting aids in their natural state are in the form of flakes, such as Figure 1 In (a), after being ground in an internal mixer, under the action of a high-speed rotating hammer, and undergoing intense friction, shearing, and collision, the scale-like structure is bent, broken, and spherical, ultimately forming a spherical or near-spherical shape, such as... Figure 1 (b), (c), and (d) are shown in the diagram. The particle size of the spheroidized cutting aid will also decrease slightly, reaching approximately 1–6 μm. Both the spheroidization treatment and feed preparation of the cutting aid must be carried out in an argon atmosphere below 1000 ppm to prevent the cutting aid and titanium alloy powder from becoming damp or oxidized.

[0053] To ensure good powder flowability and sintering activity, the titanium alloy powder used in injection molding is typically spherical powder with a diameter of 1–20 μm. After spheroidization, the cutting aid has a shape more similar to the titanium alloy powder, making uniform mixing easier. Simultaneously, the reduction in the particle size of the cutting aid through spheroidization results in smaller heterogeneous "defects" formed in the sintered blank due to the presence of the cutting aid, thus minimizing the impact of these "defects" on the material's mechanical properties. See details... Figure 2 and Figure 3 The porosity of the sintered blanks after spheroidization and non-spheroidization with cutting aids is shown.

[0054] Finally, the machinability of the sintered billet was verified. The inner hole of a part was roughened using a CNC machine tool at a speed of 9000 rpm, a feed rate of 2000 mm / min, and a cutting time of 108 seconds. The tool life was determined based on the abrupt changes in product size and surface roughness, and the machinability of the material was judged based on the tool life.

[0055] The density of the sintered part is 4.38 g / cm³. 3The yield strength reached 930 MPa, and the elongation was around 11%. Machinability was demonstrated through a cutting test on a certain part, with a result of 160 pieces per tool.

[0056] (Example 2)

[0057] This invention includes the following steps:

[0058] S1. Feed Preparation: MnS and CaF2 are mixed at a mass ratio of 1:1 and then spheroidized to prepare a cutting aid; wherein the particle size of MnS and CaF2 is 1-10 μm. The cutting aid is mixed with titanium alloy spherical powder, and the mass percentage of the cutting aid is 0.30-0.60%; a binder is added to prepare the feed. The chemical composition of the titanium alloy powder is: Al: 5.5%-6.75%; V: 3.5%-4.5%; Fe: ≤0.3%; impurities: ≤1.0%; the remainder is Ti, and the particle size range is 1-20 μm (D50: 10-13 μm). The titanium alloy mixed powder accounts for 63% of the volume of the feed, and the remainder is the binder; the components of the polymer binder include, by mass percentage, 60%-70% polyoxymethylene, 12%-15% polyethylene, 15%-20% polypropylene, and 3%-5% stearic acid;

[0059] S2. Place the feed material into the injection molding machine and inject it into the mold to form an injection preform; the injection parameters are: mold temperature 80~120℃, feed material heating temperature 160~220℃, injection pressure 80~120MPa; holding time 1~2.5s;

[0060] S3. Degrease the injection preform to obtain a degreased preform; the specific technical parameters for degreasing are: degreasing is carried out using oxalic acid as a medium for catalytic degreasing, and the degreasing time is t≥(60+60*h)min, where h is the maximum thickness of the injection preform in mm;

[0061] S4. The degreased blank is subjected to high-vacuum sintering to obtain a sintered blank; the specific technical parameters for sintering are: high-vacuum sintering is performed using a metal cavity sintering furnace, and the pressure inside the furnace is ≤1.0×10⁻⁶. -3 Pa, sintering temperature T satisfies 0.65TL≤T≤0.95TL.

[0062] Finally, the machinability of the sintered billet was verified. The inner hole of a part was roughened using a CNC machine tool at a speed of 9000 rpm, a feed rate of 2000 mm / min, and a cutting time of 108 seconds. The tool life was determined based on the abrupt changes in product size and surface roughness, and the machinability of the material was judged based on the tool life.

[0063] The density of the sintered part is 4.36 g / cm³. 3The yield strength reached 900 MPa, and the elongation was around 8%. Machinability was tested on a certain part using a turning tool, achieving a result of 170 pieces per tool.

[0064] (Example 3)

[0065] This invention includes the following steps:

[0066] S1. Feed Preparation: Titanium alloy spherical powder with a particle size range of 1-20 μm (D50: 10-13 μm) is mixed with a cutting aid under an argon atmosphere. The chemical composition of the titanium alloy spherical powder is: Al: 5.5%-6.75%; V: 3.5%-4.5%; Fe: ≤0.3%; impurities: ≤1.0%; the remainder is Ti. The cutting aid is spheroidized MnS, added at a ratio of 0.3%. After uniform mixing, a mixed powder is obtained. The mixed powder is then mixed with a binder to prepare a feed. The ratio of the mixed powder to the binder is 1.7. The titanium alloy mixed powder accounts for 63% of the feed by volume, with the remainder being the binder. The binder comprises, by mass percentage, 60%-70% polyoxymethylene, 12%-15% polyethylene, 15%-20% polypropylene, and 3%-5% stearic acid.

[0067] S2. Place the feed material into the injection molding machine and inject it into the mold to form an injection preform; the injection parameters are: mold temperature 80~120℃, feed material heating temperature 160~220℃, injection pressure 80~120MPa; holding time 1~2.5s;

[0068] S3. Degrease the injection preform to obtain a degreased preform; the specific technical parameters for degreasing are: degreasing is carried out using oxalic acid as a medium for catalytic degreasing, and the degreasing time is t≥(60+60*h)min, where h is the maximum thickness of the injection preform in mm;

[0069] S4. The degreased blank is subjected to high-vacuum sintering to obtain a sintered blank; the specific technical parameters for sintering are: high-vacuum sintering is performed using a metal cavity sintering furnace, and the pressure inside the furnace is ≤1.0×10⁻⁶. -3 Pa, sintering temperature T satisfies 0.65TL≤T≤0.95TL.

[0070] Finally, the machinability of the sintered billet was verified. The inner hole of a part was roughened using a CNC machine tool at a speed of 9000 rpm, a feed rate of 2000 mm / min, and a cutting time of 108 seconds. The tool life was determined based on the abrupt changes in product size and surface roughness, and the machinability of the material was judged based on the tool life.

[0071] The density of the sintered part is 4.38 g / cm³. 3The yield strength reached 930 MPa, and the elongation was around 10%. Machinability was tested on a certain part using a turning tool, achieving a result of 155 pieces per tool.

[0072] (Example 4)

[0073] This invention includes the following steps:

[0074] S1. Feed Preparation: Titanium alloy spherical powder with a particle size range of 1-20 μm (D50: 10-13 μm) is mixed with a cutting aid under an argon atmosphere. The chemical composition of the titanium alloy spherical powder is: Al: 5.5%-6.75%; V: 3.5%-4.5%; Fe: ≤0.3%; impurities: ≤1.0%; the remainder is Ti. The cutting aid is spheroidized CaF2, with an addition ratio of 0.3%. After uniform mixing, a mixed powder is obtained. The mixed powder is then mixed with a binder to prepare a feed. The ratio of the mixed powder to the binder is 1.7. The titanium alloy mixed powder accounts for 63% of the volume of the feed, with the remainder being the binder. The binder comprises, by mass percentage, 60%-70% polyoxymethylene, 12%-15% polyethylene, 15%-20% polypropylene, and 3%-5% stearic acid.

[0075] S2. Place the feed material into the injection molding machine and inject it into the mold to form an injection preform; the injection parameters are: mold temperature 80~120℃, feed material heating temperature 160~220℃, injection pressure 80~120MPa; holding time 1~2.5s;

[0076] S3. Degrease the injection preform to obtain a degreased preform; the specific technical parameters for degreasing are: degreasing is carried out using oxalic acid as a medium for catalytic degreasing, and the degreasing time is t≥(60+60*h)min, where h is the maximum thickness of the injection preform in mm;

[0077] S4. The degreased blank is subjected to high-vacuum sintering to obtain a sintered blank; the specific technical parameters for sintering are: high-vacuum sintering is performed using a metal cavity sintering furnace, and the pressure inside the furnace is ≤1.0×10⁻⁶. -3 Pa, sintering temperature T satisfies 0.65TL≤T≤0.85TL.

[0078] Finally, the machinability of the sintered billet was verified. The inner hole of a part was roughened using a CNC machine tool at a speed of 9000 rpm, a feed rate of 2000 mm / min, and a cutting time of 108 seconds. The tool life was determined based on the abrupt changes in product size and surface roughness, and the machinability of the material was judged based on the tool life.

[0079] The density of the sintered part is 4.38 g / cm³. 3The yield strength reached 930 MPa, and the elongation was around 10%. Machinability was tested on a certain part using a turning tool, achieving a result of 156 pieces per tool.

[0080] By comparing the technical parameters of the sintered parts in the comparative examples with those in Examples 1, 2, 3, and 4, it can be seen that the addition of cutting aids can significantly improve the cutting performance of MIM titanium alloy materials.

[0081] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-machinability MIM titanium alloy material, characterized in that... Includes the following steps: S1. Feed Preparation: A feed is prepared by mixing the mixed powder with a binder; wherein the mixed powder includes titanium alloy spherical powder and a cutting aid, wherein the cutting aid is sphericalized; the titanium alloy spherical powder has a particle size of 1~20μm; the cutting aid is MnS or CaF2 or a mixture of the two, with a particle size of 1~10μm; the mass percentage of the cutting aid in the mixed powder is 0.01%~2.00%; S2. Place the feed material into the injection molding machine and inject to form a green body; S3. Degrease the green body to form a degreased green body; S4. Sinter the degreased blank to obtain a sintered blank; The chemical composition of the titanium alloy spherical powder is as follows: Al: 5.5%~6.75%; V: 3.5%~4.5%; Fe: ≤0.3%; impurities: ≤1.0%; the remainder is Ti. The mixed powder in the feed accounts for 58% to 63% of the volume, with the remainder being binder.

2. The method of claim 1, wherein the high machinability MIM titanium alloy material is prepared by the following steps. When the cutting aid is a mixture of MnS and CaF2, the mass ratio of MnS to CaF2 is 1:

1.

3. The method of claim 2, wherein the high machinability MIM titanium alloy material is prepared by the following steps. The preparation of feed in step S1 includes the following steps: A. Mix MnS and CaF2 at a mass ratio of 1:1 and spheroidize them by mechanical grinding. The spheroidizing process is carried out in argon gas with an oxygen content of less than 1000 ppm. The stirring speed is 60-80 r / min and the stirring time is 1-2 hours to prepare a cutting aid. B. Mix the titanium alloy spherical powder with the cutting aid evenly. The mixing process is carried out in an argon atmosphere with an oxygen content of less than 1000 ppm. The stirring speed is 40 r / min and the stirring time is 0.5~1H to obtain the mixed powder. C. Add binder and mix to prepare feed.

4. The method of claim 3, wherein the high machinability MIM titanium alloy material is prepared by the following steps. The adhesive comprises, by weight percentage, 60% to 70% polyoxymethylene, 12% to 15% polyethylene, 15% to 20% polypropylene, and 3% to 5% stearic acid.

5. The method of claim 1, wherein the high machinability MIM titanium alloy material is prepared by the following steps. In step S2, the mold temperature during injection is 80~120℃, the feeding heating temperature is 160~220℃, the injection pressure is 80~120MPa, and the holding time is 1~2.5s.

6. The method for preparing a high-machinability MIM titanium alloy material according to claim 1, characterized in that: In step S3, the injection preform is degreased to obtain a degreased preform. The specific technical parameters for degreasing are: oxalic acid medium is used for catalytic degreasing, and the degreasing time is t≥(60+60*h)min, where h is the maximum thickness of the injection preform in mm.

7. The method for preparing a high-machinability MIM titanium alloy material according to claim 1, characterized in that: In step S4, the sintering temperature T satisfies the following condition: 0.6TL≤T≤0.95TL, where TL is the theoretical melting point temperature of the mixed powder.

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