A high wear-resistant injection-molded titanium-based composite material and preparation method thereof

Abstract

The invention discloses an injection-molded titanium-based composite material, which is composed of titanium alloy and boron carbide composite particles. The preparation method is a metal powder injection molding method, and the binder used for injection molding is an easily removable aldehyde-based binder. The boron carbide composite particles are prepared by coating a TiB2 coating on the surface of boron carbide particles. The titanium-based composite material of the invention has high strength, high hardness and high wear resistance, and excellent comprehensive mechanical properties.

Description

Technical Field

[0001] The invention relates to the field of titanium-based composite materials, in particular to an injection-molded titanium-based composite material with high wear resistance. Background Art

[0002] Titanium alloys have the characteristics of low density, high specific strength, good corrosion resistance, and good biocompatibility, and can play an important role in the fields of petroleum, aerospace, biomedicine, etc. Low density is in line with the current trend of lightweight materials, which can reduce energy consumption, and its excellent comprehensive performance makes its application prospects broad. Therefore, titanium alloys are considered to be the most important metal materials in the 21st century. However, compared with steel, the hardness of the titanium alloy matrix is ​​low, the wear resistance is poor, and its processing formability is poor. Traditional processing methods are inefficient and costly. These shortcomings will limit the application of titanium alloys.

[0003] Adding a reinforcing phase to the titanium alloy matrix to prepare a titanium-based composite material can greatly improve the comprehensive mechanical properties of the titanium alloy, and is therefore considered one of the effective methods to improve the performance defects of traditional titanium alloys. The choice of reinforcing phase is usually hard ceramic particles with high hardness, high elastic modulus and low density. These particles not only have high hardness themselves, but also produce a second phase dispersion strengthening effect in the titanium alloy matrix, improving the hardness and strength of the composite material without losing the plasticity of the material.

[0004] Titanium alloys have high strength and low plasticity. Traditional machining methods are not only expensive, but also have simple machining structures, which limits the application of titanium alloys. The metal powder injection molding process has the advantages of high raw material utilization and low production cost. It can also achieve one-time forming of complex shapes and high product dimensional accuracy. It is the most popular component forming technology today. It overcomes the problem of poor processability of titanium alloys and has good applications in the field of titanium alloys and titanium-based composite materials. Summary of the invention

[0005] Technical problem to be solved: The technical problem to be solved by the present invention is to provide an injection-molded titanium-based composite material with high wear resistance.

[0006] Technical solution: A method for preparing a titanium-based composite material based on powder injection molding technology, the powder injection molding technology comprising the following steps:

[0007] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 160-200° C. for 1-3 hours to obtain a uniformly mixed feed;

[0008] S2, injecting the feed material through an injection molding machine, with an injection mold temperature of 80-120° C., a feed heating temperature of 160-200° C., an injection pressure of 100-140 MPa, and a holding time of 5-15 s to obtain a green body of a titanium-based composite material;

[0009] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 110-130° C., the degreasing time is 3-5 h, and a degreasing body is obtained;

[0010] S4. Sinter the debinded blank at a heating rate of 5-15°C / min, a sintering temperature of 1200-1400°C, and a holding time of 2-4h to obtain a sintered part.

[0011] Preferably, the titanium-based composite material comprises the following components in weight ratio:

[0012] Titanium alloy powder: 80-85 parts; boron carbide composite particles: 5-10 parts; binder: 40-45 parts.

[0013] Preferably, the titanium alloy is composed of the following components by weight:

[0014] Al: 5.5~6.5wt%, V: 3.6~4.4wt%; Fe: ≤0.3wt%, C: ≤0.1wt%; the balance is Ti.

[0015] Preferably, the particle size of the titanium alloy powder is in the range of 20 to 40 μm.

[0016] Preferably, the titanium alloy powder is prepared by a gas atomization method.

[0017] Preferably, the binder is the following components in weight ratio:

[0018] Polyoxymethylene: 80-90 parts; Polypropylene: 5-9 parts; Ethylene-vinyl acetate copolymer: 2-4 parts; Vinyl bisstearamide: 3-5 parts; Polyethylene glycol: 0-2 parts.

[0019] Preferably, the boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 2-10:1, the particle size range of the boron carbide particles is 1-20 μm, and the coating thickness range is 0.1-5 μm.

[0020] Preferably, the method for preparing the boron carbide composite particles comprises the following steps:

[0021] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring, the stirring power is 300-500 r / min, and the stirring time is 1-3 h to obtain a mixed solution;

[0022] S22, drying the mixed solution at a temperature of 120-160° C. for a drying time of 10-40 h to obtain a precursor;

[0023] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1200-1800°C for a time of 2-5 hours to obtain composite particles.

[0024] Preferably, in the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 20-60:4-10:1.

[0025] Preferably, in the mixed solution for preparing boron carbide composite particles, the carbon thermal reaction equation for generating TiB2 is TiO2+B4C+C=TiB2+CO, wherein the titanyl sulfate solution provides the titanium source, the boron carbide particles provide the boron source, and the starch or sucrose solution provides the carbon source.

[0026] Beneficial effects: Compared with the prior art, the present invention has the following characteristics:

[0027] The injection-molded titanium-based composite material of the present invention adopts boron carbide particles coated with TiB2 as the reinforcing phase of the titanium alloy. As a high-hardness ceramic phase, the Mohs hardness of boron carbide is between 9.3 and 9.5, and the elastic modulus reaches 450GPa. Its hardness is second only to diamond and cubic boron nitride, and its density is lower than that of diamond and cubic boron nitride, which can better take into account the high strength and lightweight of the alloy. And boron carbide is easy to prepare and has low cost, so it is preferred as a reinforcing phase. The hard phase of small particles is evenly dispersed in the titanium alloy matrix, which can not only play the role of second phase dispersion strengthening, but also promote fine grain strengthening, and further improve the comprehensive mechanical properties of the material. However, boron carbide is prone to agglomeration during the mixing process, especially the smaller the particle size, the more obvious the agglomeration phenomenon, and coating the TiB2 coating on the surface of the boron carbide particles can effectively improve the agglomeration phenomenon and make the mixing more uniform.

[0028] Moreover, the thermal expansion coefficient and density of TiB2 are very close to those of Ti. Choosing TiB2 as a coating can make the reinforcing phase more closely integrated with the titanium alloy matrix and better realize the composite strengthening of the material.

[0029] The present invention adopts the method of metal powder injection molding to prepare titanium-based composite materials, which absorbs the advantages of powder metallurgy and plastic injection molding. It can not only realize the sintering of metals in a relatively low temperature range below the melting point, but also realize the one-time forming and batch production of complex structural parts. The finished product has high dimensional accuracy, and only requires micro-machining or even no processing in the subsequent process, which overcomes the shortcomings of titanium alloys and titanium-based composite materials that are difficult to process and can effectively expand the application range of titanium-based materials. Secondly, the metal powder injection molding process has a high material utilization rate, and can achieve net forming when the process is mature, which significantly reduces the preparation cost of titanium-based materials.

[0030] The key to the metal powder injection molding process lies in the binder. The main function of the binder is to increase the fluidity of the feed and maintain the shape and strength of the green body after forming. It is required to have good fluidity, good curing properties, and easy removal. Aldehyde-based binders are mainly composed of polyoxymethylene, which is usually mixed with acid-resistant polymers and activators. They have good fluidity, high strength of the injected green body, are not easy to deform, have high product dimensional accuracy, and high strength of the formed parts. As a binder, they have good comprehensive performance. Compared with traditional wax-based binders and emerging water-based binders, aldehyde-based binders can use catalytic degreasing, the process is simple and easy to control, and the degreasing speed is fast, which is conducive to large-scale and efficient production. And the formaldehyde generated during the degreasing catalytic process can be directly ignited without burdening the environment.

[0031] Compared with the prior art, the present invention has the following advantages and positive effects:

[0032] The present invention uses TiB2-coated boron carbide composite particles as a reinforcing phase, which improves the strength and hardness of the composite material while ensuring tightness of bonding with the titanium alloy matrix, and has excellent comprehensive mechanical properties.

[0033] The present invention uses a metal powder injection molding process to prepare a titanium-based composite material, which can achieve one-time molding and batch production of complex structures, overcomes the difficulty of titanium alloy processing, and expands the application range of titanium-based materials.

[0034] The present invention uses an aldehyde-based binder, which has good fluidity, high injection green body strength, high product dimensional accuracy, can be quickly removed by a catalytic degreasing method, has a simple and easy-to-control process, and can be used for industrial-scale continuous production. DETAILED DESCRIPTION

[0035] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples.

[0036] Specific preferred examples are as follows:

[0037] Example 1

[0038] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0039] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 160° C. for 3 h to obtain a uniformly mixed feed;

[0040] S2, the feed is injected into an injection molding machine, the injection mold temperature is 80°C, the feed heating temperature is 160°C, the injection pressure is 100MPa, and the holding time is 15s to obtain a green body of the titanium-based composite material;

[0041] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 110° C., the degreasing time is 5 h, and a degreasing body is obtained;

[0042] S4, sintering the degreased blank at a heating rate of 5°C / min, a sintering temperature of 1200°C, and a holding time of 2h to obtain a sintered part; the titanium-based composite material comprises the following components in weight ratio:

[0043] Titanium alloy powder: 85 parts; boron carbide composite particles: 5 parts; binder: 40 parts;

[0044] The titanium alloy comprises the following components by weight:

[0045] Al: 6.5wt%, V: 3.6wt%; Fe: 0.05wt%, C: 0.1wt%; the balance is Ti;

[0046] The particle size of the titanium alloy powder is in the range of 30 to 40 μm;

[0047] The binder is the following components by weight:

[0048] Polyoxymethylene: 90 parts; Polypropylene: 5 parts; Ethylene-vinyl acetate copolymer: 2 parts; Ethylene bisstearamide: 3 parts; Polyethylene glycol: 0 parts;

[0049] The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 10:1, the particle size of the boron carbide particles ranges from 15 to 20 μm, and the coating thickness ranges from 0.1 to 5 μm;

[0050] The method for preparing the boron carbide composite particles comprises the following steps:

[0051] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring, the stirring power is 300r / min, and the stirring time is 3h to obtain a mixed solution;

[0052] S22, drying the mixed solution at a temperature of 160° C. for a drying time of 10 h to obtain a precursor;

[0053] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1200° C. for 5 hours to obtain composite particles; in the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 60:10:1.

[0054] Example 2

[0055] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0056] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 200° C. for 1 h to obtain a uniformly mixed feed;

[0057] S2, injecting the feed material through an injection molding machine, with an injection mold temperature of 120° C., a feed heating temperature of 200° C., an injection pressure of 140 MPa, and a holding time of 5 s to obtain a green body of a titanium-based composite material;

[0058] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 130° C., the degreasing time is 3 h, and a degreasing body is obtained;

[0059] S4, sintering the degreased blank at a heating rate of 15°C / min, a sintering temperature of 1400°C, and a holding time of 4h to obtain a sintered part; the titanium-based composite material comprises the following components in weight ratio:

[0060] Titanium alloy powder: 80 parts; boron carbide composite particles: 10 parts; binder: 45 parts;

[0061] The titanium alloy comprises the following components by weight:

[0062] Al: 5.5wt%, V: 4.4wt%; Fe: 0.28wt%, C: 0.03wt%; the balance is Ti;

[0063] The particle size of the titanium alloy powder is in the range of 20 to 30 μm;

[0064] The binder is the following components by weight:

[0065] Polyoxymethylene: 80 parts; Polypropylene: 9 parts; Ethylene-vinyl acetate copolymer: 4 parts; Ethylene bisstearamide: 5 parts; Polyethylene glycol: 2 parts;

[0066] The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 2:1, the particle size of the boron carbide particles ranges from 1 to 5 μm, and the coating thickness ranges from 0.1 to 5 μm;

[0067] The method for preparing the boron carbide composite particles comprises the following steps:

[0068] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring at a stirring power of 500 r / min and a stirring time of 1 h to obtain a mixed solution;

[0069] S22, drying the mixed solution at a temperature of 120° C. for a drying time of 40 h to obtain a precursor;

[0070] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1800° C. for 2 hours to obtain composite particles; in the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 20:4:1.

[0071] Example 3

[0072] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0073] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 170° C. for 1.5 h to obtain a uniformly mixed feed;

[0074] S2, the feed material is injection molded by an injection machine, the injection mold temperature is 100° C., the feed material heating temperature is 190° C., the injection pressure is 130 MPa, and the holding time is 12 s to obtain a green body of the titanium-based composite material;

[0075] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 115° C., the degreasing time is 3.5 h, and a degreasing body is obtained;

[0076] S4, sintering the degreased blank at a heating rate of 10°C / min, a sintering temperature of 1250°C, and a holding time of 3h to obtain a sintered part; the titanium-based composite material comprises the following components in weight ratio:

[0077] Titanium alloy powder: 83 parts; boron carbide composite particles: 7 parts; binder: 42 parts;

[0078] The titanium alloy comprises the following components by weight:

[0079] Al: 5.8wt%, V: 3.7wt%; Fe: 0.15wt%, C: 0.06wt%; the balance is Ti;

[0080] The particle size of the titanium alloy powder is in the range of 25 to 35 μm;

[0081] The binder is the following components by weight:

[0082] Polyoxymethylene: 83 parts; Polypropylene: 8 parts; Ethylene-vinyl acetate copolymer: 4 parts; Ethylene bisstearamide: 3 parts; Polyethylene glycol: 2 parts;

[0083] The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 5:1, the particle size of the boron carbide particles ranges from 5 to 10 μm, and the coating thickness ranges from 0.1 to 5 μm;

[0084] The method for preparing the boron carbide composite particles comprises the following steps:

[0085] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring, the stirring power is 450r / min, and the stirring time is 2h to obtain a mixed solution;

[0086] S22, drying the mixed solution at a temperature of 130° C. for a drying time of 25 h to obtain a precursor;

[0087] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1500° C. for 4 hours to obtain composite particles; in the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 30:7:1.

[0088] Example 4

[0089] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0090] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 190° C. for 2 h to obtain a uniformly mixed feed;

[0091] S2, the feed material is injection molded by an injection machine, the injection mold temperature is 90° C., the feed material heating temperature is 170° C., the injection pressure is 110 MPa, and the holding time is 10 s to obtain a green body of the titanium-based composite material;

[0092] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 125° C., the degreasing time is 4 h, and a degreasing body is obtained;

[0093] S4, sintering the debinded blank at a heating rate of 12°C / min, a sintering temperature of 1300°C, and a holding time of 2.5h to obtain a sintered part;

[0094] The titanium-based composite material comprises the following components by weight:

[0095] Titanium alloy powder: 81 parts; boron carbide composite particles: 9 parts; binder: 45 parts;

[0096] The titanium alloy comprises the following components by weight:

[0097] Al: 6.1wt%, V: 4.0wt%, Fe: 0.09wt%, C: 0.03wt%, the balance is Ti;

[0098] The particle size of the titanium alloy powder is in the range of 20 to 30 μm;

[0099] The binder is the following components by weight:

[0100] Polyoxymethylene: 84 parts; Polypropylene: 7 parts; Ethylene-vinyl acetate copolymer: 3 parts; Ethylene bisstearamide: 5 parts; Polyethylene glycol: 1 part;

[0101] The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 8:1, the particle size of the boron carbide particles ranges from 10 to 15 μm, and the coating thickness ranges from 0.1 to 5 μm;

[0102] The method for preparing the boron carbide composite particles comprises the following steps:

[0103] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring at a stirring power of 350 r / min and a stirring time of 2.5 h to obtain a mixed solution;

[0104] S22, drying the mixed solution at a temperature of 150° C. for a drying time of 20 h to obtain a precursor;

[0105] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1700° C. for 3 hours to obtain composite particles; in the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 40:6:1.

[0106] Example 5

[0107] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0108] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 180° C. for 2.5 h to obtain a uniformly mixed feed;

[0109] S2, the feed material is injection molded by an injection machine, the injection mold temperature is 110° C., the feed material heating temperature is 180° C., the injection pressure is 130 MPa, and the holding time is 8 s to obtain a green body of the titanium-based composite material;

[0110] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 130° C., the degreasing time is 4.5 h, and a degreasing body is obtained;

[0111] S4, sintering the degreased blank at a heating rate of 7°C / min, a sintering temperature of 1350°C, and a holding time of 3h to obtain a sintered part; the titanium-based composite material comprises the following components in weight ratio:

[0112] Titanium alloy powder: 84 parts; boron carbide composite particles: 6 parts; binder: 40 parts;

[0113] The titanium alloy comprises the following components by weight:

[0114] Al: 6.3wt%, V: 4.2wt%; Fe: 0.11wt%, C: 0.07wt%; the balance is Ti;

[0115] The particle size of the titanium alloy powder is in the range of 30 to 40 μm;

[0116] The binder is the following components by weight:

[0117] Polyoxymethylene: 88 parts; Polypropylene: 6 parts; Ethylene-vinyl acetate copolymer: 2 parts; Ethylene bisstearamide: 3 parts; Polyethylene glycol: 1 part;

[0118] The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 4:1, the particle size of the boron carbide particles ranges from 1 to 5 μm, and the coating thickness ranges from 0.1 to 5 μm;

[0119] The method for preparing the boron carbide composite particles comprises the following steps:

[0120] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring at a stirring power of 400 r / min and a stirring time of 1.5 h to obtain a mixed solution;

[0121] S22, drying the mixed solution at a temperature of 130° C. for a drying time of 35 h to obtain a precursor;

[0122] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1300° C. for a heating time of 4 h to obtain composite particles;

[0123] In the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 30:9:1.

[0124] Comparative Example 1:

[0125] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0126] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 170° C. for 2 h to obtain a uniformly mixed feed;

[0127] S2, the feed material is injection molded by an injection machine, the injection mold temperature is 90° C., the feed material heating temperature is 180° C., the injection pressure is 120 MPa, and the holding time is 10 s to obtain a green body of the titanium-based composite material;

[0128] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 120° C., the degreasing time is 4 h, and a degreasing body is obtained;

[0129] S4, sintering the debinded blank at a heating rate of 8°C / min, a sintering temperature of 1300°C, and a holding time of 3.5h to obtain a sintered part;

[0130] The titanium-based composite material comprises the following components by weight:

[0131] Titanium alloy powder: 88 parts; boron carbide composite particles: 2 parts; binder: 43 parts;

[0132] The titanium alloy comprises the following components by weight:

[0133] Al: 6.0wt%, V: 3.9wt%; Fe: 0.25wt%, C: 0.04wt%; the balance is Ti;

[0134] The particle size of the titanium alloy powder is in the range of 25 to 35 μm;

[0135] The binder is the following components by weight:

[0136] Polyoxymethylene: 85 parts; Polypropylene: 7 parts; Ethylene-vinyl acetate copolymer: 3 parts; Ethylene bisstearamide: 3 parts; Polyethylene glycol: 2 parts;

[0137] The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 6:1, the particle size of the boron carbide particles ranges from 5 to 10 μm, and the coating thickness ranges from 0.1 to 5 μm;

[0138] The method for preparing the boron carbide composite particles comprises the following steps:

[0139] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring, the stirring power is 450r / min, and the stirring time is 1.5h to obtain a mixed solution;

[0140] S22, drying the mixed solution at a temperature of 140° C. for a drying time of 15 h to obtain a precursor;

[0141] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1600° C. for 2 hours to obtain composite particles; in the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 20:5:1.

[0142] Comparative Example 2:

[0143] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0144] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 200° C. for 3 h to obtain a uniformly mixed feed;

[0145] S2, the feed material is injection molded by an injection machine, the injection mold temperature is 100° C., the feed material heating temperature is 160° C., the injection pressure is 110 MPa, and the holding time is 13 s to obtain a green body of the titanium-based composite material;

[0146] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 125° C., the degreasing time is 3.5 h, and a degreasing body is obtained;

[0147] S4, sintering the debinded blank at a heating rate of 13°C / min, a sintering temperature of 1350°C, and a holding time of 3.5h to obtain a sintered part;

[0148] The titanium-based composite material comprises the following components by weight:

[0149] Titanium alloy powder: 81 parts; boron carbide composite particles: 9 parts; binder: 44 parts;

[0150] The titanium alloy comprises the following components by weight:

[0151] Al: 5.5wt%, V: 4.4wt%; Fe: 0.28wt%, C: 0.03wt%; the balance is Ti;

[0152] The particle size of the titanium alloy powder is in the range of 20 to 30 μm;

[0153] The binder is the following components by weight:

[0154] Polyoxymethylene: 90 parts; Polypropylene: 10 parts;

[0155] The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 9:1, the particle size of the boron carbide particles ranges from 15 to 20 μm, and the coating thickness ranges from 0.1 to 5 μm;

[0156] The method for preparing the boron carbide composite particles comprises the following steps:

[0157] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring at a stirring power of 400 r / min and a stirring time of 2 h to obtain a mixed solution;

[0158] S22, drying the mixed solution at a temperature of 140° C. for a drying time of 35 h to obtain a precursor;

[0159] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1700° C. for 3 hours to obtain composite particles; in the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 50:8:1.

[0160] Comparative Example 3:

[0161] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0162] S1, mixing titanium alloy powder, boron carbide particles and a binder at a mixing temperature of 160° C. for 2.5 h to obtain a uniformly mixed feed;

[0163] S2, the feed material is injection molded by an injection machine, the injection mold temperature is 110° C., the feed material heating temperature is 190° C., the injection pressure is 140 MPa, and the holding time is 9 s to obtain a green body of the titanium-based composite material;

[0164] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 120° C., the degreasing time is 3 h, and a degreasing body is obtained;

[0165] S4, sintering the debinded blank at a heating rate of 9°C / min, a sintering temperature of 1250°C, and a holding time of 2.5h to obtain a sintered part;

[0166] The titanium-based composite material comprises the following components by weight:

[0167] Titanium alloy powder: 84 parts; boron carbide particles: 6 parts; binder: 41 parts;

[0168] The titanium alloy comprises the following components by weight:

[0169] Al: 5.7wt%, V: 3.9wt%; Fe: 0.23wt%, C: 0.09wt%; the balance is Ti;

[0170] The particle size of the titanium alloy powder is in the range of 25 to 35 μm;

[0171] The particle size of the boron carbide powder is in the range of 5 to 10 μm;

[0172] The binder is the following components by weight:

[0173] Polyoxymethylene: 85 parts; Polypropylene: 7 parts; Ethylene-vinyl acetate copolymer: 3 parts; Ethylene bisstearamide: 4 parts; Polyethylene glycol: 1 part.

[0174] Comparative Example 4:

[0175] A method for preparing a titanium-based composite material based on a powder injection molding technology, the powder injection molding technology comprising the following steps:

[0176] S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 190° C. for 1.5 h to obtain a uniformly mixed feed;

[0177] S2, the feed material is injection molded by an injection machine, the injection mold temperature is 80° C., the feed material heating temperature is 170° C., the injection pressure is 120 MPa, and the holding time is 11 s to obtain a green body of the titanium-based composite material;

[0178] S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 115° C., the degreasing time is 5 h, and a degreasing body is obtained;

[0179] S4, sintering the debinded blank at a heating rate of 11°C / min, a sintering temperature of 1400°C, and a holding time of 2.5h to obtain a sintered part;

[0180] The titanium-based composite material comprises the following components by weight:

[0181] Titanium alloy powder: 82 parts; boron carbide composite particles: 8 parts; binder: 44 parts;

[0182] The titanium alloy comprises the following components by weight:

[0183] Al: 6.0wt%, V: 4.0wt%; Fe: 0.13wt%, C: 0.05wt%; the balance is Ti;

[0184] The particle size of the titanium alloy powder is in the range of 20 to 30 μm;

[0185] The binder is the following components by weight:

[0186] Polyoxymethylene: 84 parts; Polypropylene: 6 parts; Ethylene-vinyl acetate copolymer: 3 parts; Ethylene bisstearamide: 5 parts; Polyethylene glycol: 2 parts;

[0187] The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 10:1, the particle size of the boron carbide particles ranges from 20 to 25 μm, and the coating thickness ranges from 0.1 to 5 μm;

[0188] The method for preparing the boron carbide composite particles comprises the following steps:

[0189] S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring, the stirring power is 300r / min, and the stirring time is 2.5h to obtain a mixed solution;

[0190] S22, drying the mixed solution at a temperature of 150° C. for a drying time of 25 h to obtain a precursor;

[0191] S33, heating the precursor in a nitrogen atmosphere at a temperature of 1600° C. for 3 hours to obtain composite particles; in the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 50:6:1.

[0192] name Yield strength / MPa Hardness / HV Friction coefficient Relative density / % Example 1 1088 835 0.3 96.7 Example 2 1159 859 0.2 96.5 Example 3 1092 844 0.3 97.6 Example 4 1056 850 0.3 97.2 Example 5 1130 841 0.2 96.9 Comparative Example 1 997 780 0.4 96.2 Comparative Example 2 984 812 0.4 94.8 Comparative Example 3 935 805 0.4 95.2 Comparative Example 4 947 793 0.4 95.5

[0193] In summary, compared with the comparative example, the titanium-based composite material prepared by the present invention has significantly improved strength, hardness and wear resistance, and has excellent comprehensive mechanical properties. In addition, the preparation process is simple, the time consumption is relatively short, the processability of the titanium-based composite material is improved, and the application range of the titanium-based composite material can be effectively expanded.

Claims

1. A method for preparing a titanium-based composite material based on powder injection molding technology, characterized in that: The preparation method comprises the following steps: S1, mixing titanium alloy powder, boron carbide composite particles and a binder at a mixing temperature of 160-200° C. for 1-3 hours to obtain a uniformly mixed feed; S2, injecting the feed material through an injection molding machine, with an injection mold temperature of 80-120° C., a feed heating temperature of 160-200° C., an injection pressure of 100-140 MPa, and a holding time of 5-15 s to obtain a green body of a titanium-based composite material; S3, degreasing the green body, using HNO3 as a catalytic degreasing method, the degreasing temperature is 110-130° C., the degreasing time is 3-5 h, and a degreasing body is obtained; S4, sintering the debinded blank at a heating rate of 5-15°C / min, a sintering temperature of 1200-1400°C, and a holding time of 2-4h to obtain a sintered part; The titanium-based composite material comprises the following components by weight: titanium alloy powder: 80-85 parts; boron carbide composite particles: 5-10 parts; binder: 40-45 parts; The boron carbide composite particles are boron carbide particles coated with a TiB2 coating, the molar ratio of the boron carbide particles to the TiB2 coating is 2-10:1, the particle size of the boron carbide particles is in the range of 1-20 μm, and the coating thickness is in the range of 0.1-5 μm; The binder comprises the following components in weight ratio: polyoxymethylene: 80-90 parts; polypropylene: 5-9 parts; ethylene-vinyl acetate copolymer: 2-4 parts; vinyl bisstearamide: 3-5 parts; polyethylene glycol: 0-2 parts.

2. The method for preparing a titanium-based composite material based on powder injection molding technology according to claim 1, characterized in that: The titanium alloy comprises the following components by weight: Al: 5.5~6.5wt%, V: 3.6~4.4wt%; Fe: ≤0.3wt%, C: ≤0.1wt%; the balance is Ti.

3. The method for preparing a titanium-based composite material based on powder injection molding technology according to claim 1, characterized in that: The particle size of the titanium alloy powder is in the range of 20 to 40 μm.

4. The method for preparing a titanium-based composite material based on powder injection molding technology according to claim 1, characterized in that: The titanium alloy powder is prepared by gas atomization.

5. The method for preparing a titanium-based composite material based on powder injection molding technology according to claim 1, characterized in that: The method for preparing the boron carbide composite particles comprises the following steps: S11, mixing the boron carbide particles with the titanyl sulfate solution, the starch or sucrose solution and the solvent anhydrous ethanol, using magnetic stirring, the stirring power is 300-500 r / min, and the stirring time is 1-3 h to obtain a mixed solution; S22, drying the mixed solution at a temperature of 120-160° C. for a drying time of 10-40 h to obtain a precursor; S33, heating the precursor in a nitrogen atmosphere at a temperature of 1200-1800°C for a time of 2-5 hours to obtain composite particles.

6. The method for preparing a titanium-based composite material based on powder injection molding technology according to claim 5, characterized in that: In the mixed solution of step S11, the molar ratio of boron carbide, starch or sucrose to titanyl sulfate is 20-60:4-10:1.