CN117966052A - Preparation method of titanium-based composite material with high strength and toughness and service performance at 700 DEG C - Google Patents

Abstract

The invention discloses a preparation method of a titanium-based composite material with high strength and toughness and 700 ℃ service performance, which comprises the following steps: step 1, calculating the content of each reinforced powder in the externally added powder M in the raw material powder according to the designed content of the reinforced phase to determine the mass ratio of TC25G alloy powder to each reinforced powder; step 2, weighing TC25G alloy powder and external powder according to a designed mass ratio, and performing ball milling and mixing to uniformly mix the powder to obtain composite powder; step 3, carrying out hot-pressing sintering on the obtained composite powder, and carrying out in-situ autogenous reaction to prepare a block composite material; and step 4, performing hot extrusion on the obtained block composite material to obtain the titanium-based composite material with room temperature strong plasticity and service performance. The titanium-based composite material disclosed by the invention has the advantages of ensuring excellent room temperature strength-plastic/toughness matching and obviously improving the high-temperature performance of the titanium-based composite material above 700 ℃. The titanium-based composite material provided by the invention can be used for aerospace vehicles.

Description

A method for preparing a titanium-based composite material with high strength and toughness and 700°C service performance

Technical Field

The invention relates to a method for preparing a titanium-based composite material with high strength and toughness and 700°C service performance, belonging to the technical field of titanium alloys and composite materials thereof.

Background technique

In order to meet the dual needs of future aerospace vehicles for structural weight reduction and performance improvement, especially the urgent need for high toughness and high-temperature service performance of key lightweight structural components at room temperature and high temperature conditions. As a key material for modern aircraft engines, high-temperature titanium alloys are widely used in aircraft engine blades, disks, casings and other components to reduce engine weight and improve the thrust-to-weight ratio of aircraft, thereby significantly improving the service performance of aircraft engines. However, with the increase in the operating temperature of aircraft, higher requirements are placed on the service performance of high-temperature titanium alloys. At the same time, the service conditions of aircraft have become more complex, and the service performance requirements of high-temperature titanium alloys are no longer limited to a single performance indicator, but are expected to have excellent comprehensive performance at room temperature and high temperature conditions.

In order to further improve the comprehensive performance of titanium alloys, the current research focus is mainly on improving the high-temperature strength of materials through composite methods. However, there are some problems with titanium-based composite materials in the past, such as the single type of reinforcing phase and the neglect of the design and regulation of the microstructure of the matrix titanium alloy. Therefore, the commercial high-temperature titanium alloys currently developed on the market are relatively insufficient in terms of room temperature strength, and there is still an inversion problem of room temperature strength-plasticity/toughness. More importantly, these materials have insufficient performance under high temperature conditions above 650°C. There is an urgent need to develop a new type of titanium alloy and its composite materials with a service temperature above 700°C and excellent room temperature strength and plasticity.

Summary of the invention

The present invention aims to solve the bottleneck problem that it is difficult to achieve both room temperature strength and plasticity matching and high temperature strength improvement in existing high temperature titanium-based composite material research, and further proposes a method for preparing a titanium-based composite material with both high strength and toughness and 700°C service performance.

The technical solution adopted by the present invention to solve the above-mentioned problem is: the present invention comprises the following steps:

Step 1: Calculate the content of each strengthening powder in the added powder M in the raw material powder according to the designed strengthening phase content, so as to determine the mass ratio of the TC25G alloy powder and each strengthening powder;

Step 2, weighing TC25G alloy powder and external powder according to the designed mass ratio, and mixing them by ball milling to make the powders evenly mixed to obtain composite powder;

Step 3, hot pressing and sintering the obtained composite powder, and performing an in-situ autogenous reaction to prepare a bulk composite material;

Step 4: hot-extrude the obtained block composite material to obtain a titanium-based composite material with both room temperature strength and plasticity and serviceability.

Furthermore, the added powder in step 1 includes original β grain boundary strengthening powder, α/β phase boundary strengthening powder and matrix strengthening powder.

Furthermore, the mass fraction of the original β grain boundary strengthening powder in the composite powder is 0.05-5%, the original β grain boundary strengthening powder includes at least one of B powder, _TiB2 powder, Y powder and La powder, and the particle size of the original β grain boundary strengthening powder is 0.05-10μm.

Furthermore, in step 3, at least one reinforcing phase of TiB, Y ₂ O ₃ and La ₂ O ₃ is generated at the original β grain boundary through the in-situ autogenous reaction.

Furthermore, the mass fraction of the α/β phase boundary strengthening powder in the composite powder is 0.05-3%; the α/β phase boundary strengthening powder includes Si powder, and the particle size of the α/β phase boundary strengthening powder is 0.05-5 μm.

Furthermore, in step 3, at least one reinforcing phase of (Ti, Zr) ₅ Si ₃ and (Ti, Zr) ₆ Si ₃ is generated at the α/β phase interface through the in-situ autogenous reaction, and the size of the reinforcing phase is 0.01-5 μm.

Furthermore, the mass fraction of the matrix strengthening powder in the composite powder is 0.05-5%, the matrix strengthening powder includes at least one of Ta powder, Mo powder and W powder, and the particle size of the matrix strengthening powder is 0.01-5 μm.

Further, in step 2, the nominal composition of the TC25G alloy powder is

Ti-6.5Al-4Zr-2Sn-4Mo-1W-0.2Si, and the particle size of the TC25G alloy spherical powder is 10-300 μm.

Furthermore, the matrix structure of the titanium-based composite material obtained by step 4 is a basket-like structure composed of α phase and β phase; wherein the α phase is lamellar, including micron-sized primary α phase and nanometer-sized secondary α phase; and the β phase is separated by the interwoven α phase. The primary α phase lamella length is 1-50 μm and the width is 0.5-3 μm; the secondary α phase lamella length is 0.05-2 μm and the width is 10-200 nm.

Furthermore, the titanium-based composite material obtained by step 4 has a tensile strength σ _b greater than 1300 MPa and an elongation δ greater than 7% at room temperature; a tensile strength σ _b greater than 650 MPa and an elongation δ greater than 20% at 700°C.

The beneficial effects of the present invention are:

1. The matrix selected in the present invention is TC25G dual-phase titanium alloy, which has multiple advantages, including high temperature resistance, high strength, high toughness, and heat treatment strengthening. Compared with near-α-type high-temperature titanium alloys, TC25G has greater potential in organizational regulation and performance improvement due to its high content of β-stabilizing elements. The alloy can be used for a long time at a temperature of up to 550°C, providing a reliable performance foundation for applications in high-temperature environments.

2. The present invention is based on the concept of "multi-effect response". It introduces reinforcements of different sizes into the material and places them at different positions of the material to bear the load, so as to achieve multi-level and multi-effect material response. Specific measures include the introduction _of TiB whiskers, which effectively limits the size of the original grains; _the introduction of rare earth oxides _Y2O3 or _La2O3 , which effectively reduces the oxygen content in the powder metallurgy process; the introduction of fast eutectoid Si elements, which effectively strengthens the matrix phase interface; the introduction of high melting point Ta, Mo or W elements, which play a role in solid solution strengthening and improve the heat resistance of the matrix. These elements jointly promote the improvement of the strength and plasticity of the composite material through the coupling effect of multiple elements. This design concept comprehensively improves the performance of the composite material through the synergistic effects of multiple effects, and achieves an optimized response to material properties at different levels.

3. The preparation method adopted by the present invention is simple, stable and highly controllable, and the type and content of the reinforcing phase are regulated by powder metallurgy technology. At the same time, by introducing the second phase at the high-temperature weak zone-phase interface in the alloy, a multi-level and multi-scale reinforcing phase distribution is formed, thereby improving the high-temperature strength of the interface.

4. The present invention realizes a multi-level and multi-scale basket-like structure by regulating the matrix organization. This organizational structure shows excellent strength-plasticity matching at room temperature and high temperature conditions, and realizes a complex and orderly weaving of the internal structure of the material, so that it can take into account both strength and plasticity at room temperature and high temperature environments, and at the same time has high fracture resistance and creep resistance, so that it meets the design requirements for room temperature strength-plasticity matching and high temperature resistance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of a method for preparing a titanium-based composite material having both high strength and toughness and 700° C. service performance according to the present invention;

FIG2 is a scanning electron microscope image of the titanium-based composite material prepared in Example 1;

FIG3 is a graph showing the tensile properties of the titanium-based composite material prepared in Example 1 at room temperature and 700° C.;

FIG4 is a scanning electron microscope image of the titanium-based composite material prepared in Example 2;

FIG5 is a graph showing the tensile properties of the titanium-based composite material prepared in Example 2 at room temperature and 700° C.;

FIG6 is a scanning electron microscope image of the titanium-based composite material prepared in Example 3;

FIG. 7 is a graph showing the tensile properties of the titanium-based composite material prepared in Example 3 at room temperature and 700° C.

FIG8 is a comparison diagram of the tensile property curves of the titanium-based composite materials prepared in Examples 1 to 3 at room temperature and at 700° C.

Specific embodiments

The present invention can be further understood by the following specific examples of the present invention, but they are not intended to limit the present invention.

Embodiment 1:

As shown in FIG. 1 , in a specific embodiment of the present invention, a method for preparing a titanium-based composite material having both high strength and toughness and 700° C. service performance comprises the following specific steps:

Step 1. According to the designed content of reinforcing phase or reinforcing element, the calculated mass ratio of TC25G alloy powder and additional powder M is as follows. The additional powder M is classified into original β grain boundary strengthening powder, α/β phase boundary strengthening powder and matrix strengthening powder according to the role played.

The original β grain boundary strengthening powder includes _TiB2 powder and Y powder (ie, yttrium powder), and the mass fraction of the original β grain boundary strengthening powder in the composite powder is 5%; the particle size of the original β grain boundary strengthening powder is 0.05-10 μm;

The α/β phase boundary strengthening powder includes Si powder, and the mass fraction of the α/β phase boundary strengthening powder in the composite powder is 1%; the particle size of the α/β phase boundary strengthening powder is 0.05-5 μm;

The matrix reinforcement powder includes W powder, and the mass fraction of the matrix reinforcement powder in the composite powder is 0.05%; the particle size of the matrix reinforcement powder is 0.01-5 μm.

Step 2: Weigh TC25G alloy (also the matrix alloy) powder and the added powder M according to the designed mass ratio, and mix them by ball milling to make the powders evenly mixed to obtain composite powder.

Among them, the nominal composition of the TC25G titanium alloy powder used is Ti-6.5Al-4Zr-2Sn-4Mo-1W-0.2Si, and the particle size of the TC25G alloy spherical powder is 10-300μm.

During the ball milling mixing, the rotation speed of the ball mill is 250 r/min, the ball milling time is 5 h, the ball-to-material ratio is 4:1, and the ball milling atmosphere is Ar gas.

Step 3: hot-pressing and sintering the obtained composite powder in a vacuum-sealed container, and performing an in-situ autogenous reaction to prepare a bulk composite material. The original β grain boundary, α/β phase interface, matrix composition and organization of the matrix alloy are enhanced by the in-situ autogenous reaction.

The added _TiB2 powder generates TiB whiskers at the original β grain boundaries through an in-situ autogenous reaction. The TiB whiskers generated by the reaction are short rod-shaped or needle-shaped, with a length of 1-50 μm and a width of 0.1-5 μm. The TiB whiskers play a role in bearing loads and improve the strength of the material at room temperature and high temperature. At the same time, TiB, as a nucleation site for the α phase, can significantly refine the matrix grains, avoid the appearance of coarse Widmanstatten structure, and improve the strength and plasticity of the material.

The added Y powder reacts with O at the original β grain boundary to generate a stable high melting point compound Y ₂ O _3. The Y ₂ O ₃ generated by the reaction is in granular form with a size of 0.05-10μm. Y ₂ O ₃ is dispersed in the matrix alloy, playing a role of dispersion strengthening, which is beneficial to improving the high temperature instantaneous strength and endurance strength of the matrix alloy. In addition, the reduction of O content in the matrix and the interface solves the problem of powder metallurgy brittleness and improves the plasticity of the material.

The added Si powder generates at least one of the reinforcing phases (Ti,Zr) ₅ Si ₃ and (Ti,Zr) ₆ Si ₃ at the α/β phase interface through an in-situ autogenous reaction and is distributed at the α and β phase interfaces. The reinforcement generated by the reaction is in the form of submicron particles with a size of 0.01-5μm. The dispersed silicide can bear the load and effectively hinder the dislocation movement, thereby improving the high temperature strength and creep resistance of the titanium alloy.

The strengthening of the matrix mainly comes from the effect of the added element W (i.e., strengthening element) on the material composition and organization. The added element W is dissolved in the matrix crystal at the atomic scale to exert a strengthening and toughening effect, thereby improving the high-temperature softening resistance of the matrix titanium alloy. The effect on composition refers to the high-melting-point W element being dissolved in the lattice, which, on the one hand, exerts a solid solution strengthening effect, and on the other hand, improves the stability of the material at high temperatures. Organizational strengthening refers to the control of the matrix with a multi-scale microstructure through thermal deformation.

In the hot pressing sintering, the hot pressing sintering temperature is 1300° C., the hot pressing sintering pressure is 30 MPa, and the sintering time is 1 hour.

Step 4: hot-extrude the obtained bulk composite material to regulate the matrix structure, further refine the grains, and obtain a titanium-based composite material (also a multi-scale matrix structure) with excellent room temperature strength and plasticity and service performance above 700°C.

As shown in FIG2 , the matrix structure is a basket-like structure formed by the α phase and the β phase. The α phase is lamellar, including a micron-sized primary α phase and a nanometer-sized secondary α phase, and the β phase is separated by the interwoven α phases. The primary α phase lamellae are 1-50 μm long and 0.5-3 μm wide; the secondary α phase lamellae are 0.05-2 μm long and 10-200 nm wide.

_TiB whiskers are arranged linearly along the extrusion direction at the interface of the original matrix ball after deformation (i.e. after hot extrusion treatment), and are distributed in a network shape perpendicular to the extrusion direction. _Y2O3 particles are distributed at the interface of the original matrix ball after deformation (i.e. after hot extrusion treatment).

During hot extrusion, the block material is kept warm in a box-type heat treatment furnace for 30 minutes, the holding temperature is 1000°C, the extrusion die is kept warm at 300°C, and the extrusion ratio is 13:1.

As shown in FIG3 , the titanium-based composite material having both room temperature strong plasticity and serviceability prepared by the above steps has a room temperature tensile strength σ _b of 1310 MPa and an elongation δ of 8.8%; a tensile strength σ _b of 712 MPa and an elongation δ of 22% at 700° C.

Embodiment 2:

As shown in FIG. 1 , in a specific embodiment of the present invention, a method for preparing a titanium-based composite material having both high strength and toughness and 700° C. service performance comprises the following specific steps:

Step 1: According to the content of the designed reinforcing phase or reinforcing element, the calculated mass ratio of the TC25G alloy powder and the additional powder M is as follows. The additional powder M is classified into original β grain boundary strengthening powder, α/β phase boundary strengthening powder and matrix strengthening powder according to the role played.

The original β grain boundary strengthening powder includes _TiB2 powder and La powder (i.e. lanthanum powder), and the mass fraction of the original β grain boundary strengthening powder in the composite powder is 2.5%; the particle size of the original β grain boundary strengthening powder is 0.05-10 μm;

The α/β phase boundary strengthening powder includes Si powder, and the mass fraction of the α/β phase boundary strengthening powder in the composite powder is 0.05%; the particle size of the α/β phase boundary strengthening powder is 0.05-5 μm;

The matrix strengthening powder includes Mo powder, and the mass fraction of the matrix strengthening powder in the composite powder is 5%; the particle size of the matrix strengthening powder is 0.01-5 μm.

Step 2: Weigh TC25G alloy (also matrix alloy) powder and external powder M according to the designed mass ratio, and mix them by ball milling to make the powders evenly mixed to obtain composite powder.

Among them, the nominal composition of the TC25G titanium alloy powder used is Ti-6.5Al-4Zr-2Sn-4Mo-1W-0.2Si, and the particle size of the TC25G alloy spherical powder is 10-300μm.

During the ball milling mixing, the rotation speed of the ball mill is 180 r/min, the ball milling time is 5 h, the ball-to-material ratio is 3:1, and the ball milling atmosphere is Ar gas.

Step 3: hot-pressing and sintering the obtained composite powder in a vacuum-sealed container, and performing an in-situ autogenous reaction to prepare a bulk composite material. The original β grain boundary, α/β phase interface, matrix composition and organization of the matrix alloy are enhanced by the in-situ autogenous reaction.

The added _TiB2 powder generates TiB whiskers at the original β grain boundaries through an in-situ autogenous reaction. The TiB whiskers generated by the reaction are short rod-shaped or needle-shaped, with a length of 1-50 μm and a width of 0.1-5 μm. The TiB whiskers play a role in bearing loads and improve the strength of the material at room temperature and high temperature. At the same time, TiB, as a nucleation site for the α phase, can significantly refine the matrix grains, avoid the appearance of coarse Widmanstatten structure, and improve the strength and plasticity of the material.

The added La powder reacts with O at the original β grain boundary to generate a stable high melting point compound La ₂ O _3. The La ₂ O ₃ generated by the reaction is in granular form with a size of 0.05-10μm. La ₂ O ₃ is dispersed in the matrix alloy, playing a role of dispersion strengthening, which is beneficial to improving the high temperature instantaneous strength and endurance strength of the matrix alloy. In addition, the reduction of O content in the matrix and the interface solves the problem of powder metallurgy brittleness and improves the plasticity of the material.

The added Si powder generates at least one of the reinforcing phases (Ti,Zr) ₅ Si ₃ and (Ti,Zr) ₆ Si ₃ at the α/β phase interface through an in-situ autogenous reaction and is distributed at the α and β phase interfaces. The reinforcement generated by the reaction is in the form of submicron particles with a size of 0.01-5μm. The dispersed silicide can bear the load and effectively hinder the dislocation movement, thereby improving the high temperature strength and creep resistance of the titanium alloy.

The strengthening of the matrix mainly comes from the effect of the added element Mo (i.e. strengthening element) on the material composition and structure. The added element Mo is dissolved in the matrix crystal at the atomic scale to exert a strengthening and toughening effect. This in turn improves the high-temperature softening resistance of the matrix titanium alloy. The effect on the composition refers to the high-melting-point Mo element being dissolved in the lattice, which on the one hand exerts a solid solution strengthening effect, and on the other hand improves the stability of the material at high temperatures. The strengthening of the structure refers to the matrix with a multi-scale microstructure that is regulated by thermal deformation.

In the hot pressing sintering, the hot pressing sintering temperature is 1200° C., the hot pressing sintering pressure is 30 MPa, and the sintering time is 1 hour.

Step 4: hot-extrude the obtained bulk composite material to regulate the matrix structure, further refine the grains, and obtain a titanium-based composite material (also a multi-scale matrix structure) with excellent room temperature strength and plasticity and service performance above 700°C.

As shown in FIG4 , the matrix structure is a basket-like structure formed by the α phase and the β phase. The α phase is lamellar, including a micron-sized primary α phase and a nanometer-sized secondary α phase, and the β phase is separated by the interwoven α phases. The primary α phase lamellae are 1-50 μm long and 0.5-3 μm wide; the secondary α phase lamellae are 0.05-2 μm long and 10-200 nm wide.

TiB whiskers are arranged linearly along the extrusion direction at the interface of the original matrix ball after deformation (i.e. after hot extrusion treatment), and are distributed in a network shape perpendicular to the extrusion direction. _{La 2} O ₃ particles are distributed at the interface of the original matrix ball after deformation (i.e. after hot extrusion treatment).

During hot extrusion, the block material is kept warm in a box-type heat treatment furnace for 30 minutes, the holding temperature is 1100°C, the extrusion die is kept warm at 400°C, and the extrusion ratio is 13:1.

As shown in FIG5 , the titanium-based composite material having both room temperature strong plasticity and serviceability prepared by the above steps has a room temperature tensile strength σ _b of 1402 MPa and an elongation δ of 10.6%, and a tensile strength σ _b of 720 MPa and an elongation δ of 27% at 700°C.

Embodiment three:

As shown in FIG. 1 , in a specific embodiment of the present invention, a method for preparing a titanium-based composite material having both high strength and toughness and 700° C. service performance comprises the following specific steps:

Step 1. According to the designed content of reinforcing phase or reinforcing element, the calculated mass ratio of TC25G alloy powder and additional powder M is as follows. The additional powder M is classified into original β grain boundary strengthening powder, α/β phase boundary strengthening powder and matrix strengthening powder according to the role played.

The original β grain boundary strengthening powder includes B powder (i.e., boron powder) and Y powder, and the mass fraction of the original β grain boundary strengthening powder in the composite powder is 0.05%; the particle size of the original β grain boundary strengthening powder is 0.05-10 μm;

The α/β phase boundary strengthening powder includes Si powder, and the mass fraction of the α/β phase boundary strengthening powder in the composite powder is 3%; the particle size of the α/β phase boundary strengthening powder is 0.05-5 μm;

The matrix strengthening powder includes Ta powder, and the mass fraction of the matrix strengthening powder in the composite powder is 2%; the particle size of the matrix strengthening powder is 0.01-5 μm.

Step 2: Weigh TC25G alloy (also matrix alloy) powder and external powder M according to the designed mass ratio, and mix them by ball milling to make the powders evenly mixed to obtain composite powder.

Among them, the nominal composition of the TC25G titanium alloy powder used is Ti-6.5Al-4Zr-2Sn-4Mo-1W-0.2Si, and the particle size of the TC25G alloy spherical powder is 10-300μm.

During the ball milling mixing, the rotation speed of the ball mill is 250 r/min, the ball milling time is 5 h, the ball-to-material ratio is 4:1, and the ball milling atmosphere is Ar gas.

Step 3: hot-pressing and sintering the obtained composite powder in a vacuum-sealed container, and performing an in-situ autogenous reaction to prepare a bulk composite material. The original β grain boundary, α/β phase interface, matrix composition and organization of the matrix alloy are enhanced by the in-situ autogenous reaction.

The added B powder generates TiB whiskers at the original β grain boundaries through an in-situ autogenous reaction. The TiB whiskers generated by the reaction are short rod-shaped or needle-shaped, with a length of 1-50 μm and a width of 0.1-5 μm. The TiB whiskers play a role in bearing loads and improve the strength of the material at room temperature and high temperature. At the same time, TiB, as a nucleation site for the α phase, can significantly refine the matrix grains, avoid the appearance of coarse Widmanstatten structure, and improve the strength and plasticity of the material.

The added Y powder reacts with O at the original β grain boundary to generate a stable high melting point compound Y ₂ O _3. The Y ₂ O ₃ generated by the reaction is in granular form with a size of 0.05-10μm. Y ₂ O ₃ is dispersed in the matrix alloy, playing a role of dispersion strengthening, which is beneficial to improving the high temperature instantaneous strength and endurance strength of the matrix alloy. In addition, the reduction of O content in the matrix and the interface solves the problem of powder metallurgy brittleness and improves the plasticity of the material.

The added Si powder generates at least one of the reinforcing phases (Ti,Zr) ₅ Si ₃ and (Ti,Zr) ₆ Si ₃ at the α/β phase interface through an in-situ autogenous reaction and is distributed at the α and β phase interfaces. The reinforcement generated by the reaction is in the form of submicron particles with a size of 0.01-5μm. The dispersed silicide can bear the load and effectively hinder the dislocation movement, thereby improving the high temperature strength and creep resistance of the titanium alloy.

The strengthening of the matrix mainly comes from the effect of the added element Ta (i.e., strengthening element) on the material composition and organization. The added element Ta is solid-dissolved in the matrix crystal at the atomic scale to exert a strengthening and toughening effect, thereby improving the high-temperature softening resistance of the matrix titanium alloy. The effect on composition refers to the solid solution of the high-melting-point Ta element in the lattice, which, on the one hand, exerts a solid solution strengthening effect, and on the other hand, improves the stability of the material at high temperatures. Organizational strengthening refers to the control of the matrix with a multi-scale microstructure through thermal deformation.

In the hot pressing sintering, the hot pressing sintering temperature is 1300° C., the hot pressing sintering pressure is 30 MPa, and the sintering time is 1 hour.

Step 4: hot-extrude the obtained bulk composite material to regulate the matrix structure, further refine the grains, and obtain a titanium-based composite material (also a multi-scale matrix structure) with excellent room temperature strength and plasticity and service performance above 700°C.

As shown in FIG6 , the matrix structure is a basket-like structure formed by the α phase and the β phase. The α phase is lamellar, including a micron-sized primary α phase and a nanometer-sized secondary α phase, and the β phase is separated by the interwoven α phases. The primary α phase lamellae are 1-50 μm long and 0.5-3 μm wide; the secondary α phase lamellae are 0.05-2 μm long and 10-200 nm wide.

_TiB whiskers are arranged linearly along the extrusion direction at the interface of the original matrix ball after deformation (i.e. after hot extrusion treatment), and are distributed in a network shape perpendicular to the extrusion direction. _Y2O3 particles are distributed at the interface of the original matrix ball after deformation (i.e. after hot extrusion treatment).

During hot extrusion, the block material is kept warm in a box-type heat treatment furnace for 30 minutes, the holding temperature is 1000°C, the extrusion die is kept warm at 300°C, and the extrusion ratio is 17:1.

As shown in FIG7 , the titanium-based composite material with both room temperature ductility and serviceability prepared by the above steps has a room temperature tensile strength σ _b of 1449 MPa and an elongation δ of 9.8%; a tensile strength σ _b of 744 MPa and an elongation δ of 31% at 700° C.

Table 1 below shows the mass fraction of the additional powder M (eg, original β grain boundary strengthening powder, α/β phase boundary strengthening powder and matrix strengthening powder) used in the preparation methods of Examples 1-3 in the composite powder.

Table 1

The following Table 2 lists the additional powders M (eg, original β grain boundary strengthening powder, α/β phase boundary strengthening powder, and matrix strengthening powder) used in the preparation methods of Examples 1-3.

Table 2

Table 3 below lists the performance parameters of the titanium-based composite materials having both high strength and toughness and 700° C. service performance prepared by the preparation methods of Examples 1-3 at room temperature and 700° C.

table 3

As shown in FIG8 , the results of three examples show that the excellent comprehensive performance is that the room temperature tensile strength σ _b is greater than 1300 MPa, the elongation δ is greater than 8%, the tensile strength σ _b is greater than 650 MPa at 700° C., and the elongation δ is greater than 20%.

The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims (10)

1. A preparation method of a titanium-based composite material with high strength and toughness and 700 ℃ service performance is characterized by comprising the following steps: the preparation method of the titanium-based composite material with high strength and toughness and 700 ℃ service performance comprises the following steps:

step 1, calculating the content of each reinforced powder in the externally added powder M in the raw material powder according to the designed content of the reinforced phase to determine the mass ratio of TC25G alloy powder to each reinforced powder;

step 2, weighing TC25G alloy powder and external powder according to a designed mass ratio, and performing ball milling and mixing to uniformly mix the powder to obtain composite powder;

step 3, carrying out hot-pressing sintering on the obtained composite powder, and carrying out in-situ autogenous reaction to prepare a block composite material;

And step 4, performing hot extrusion on the obtained block composite material to obtain the titanium-based composite material with room temperature strong plasticity and service performance.

2. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, which is characterized in that: the additional powder in the step 1 comprises original beta grain boundary reinforced powder, alpha/beta phase boundary reinforced powder and matrix reinforced powder.

3. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, according to claim 2, which is characterized in that: the mass fraction of the original beta grain boundary strengthening powder in the composite powder is 0.05-5%, the original beta grain boundary strengthening powder comprises at least one of B powder, tiB ₂ powder, Y powder and La powder, and the grain diameter of the original beta grain boundary strengthening powder is 0.05-10 mu m.

4. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, according to claim 3, which is characterized in that: in step 3, at least one reinforcing phase of TiB, Y ₂O₃ and La ₂O₃ is generated at the original beta grain boundary by the in situ autogenous reaction.

5. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, according to claim 2, which is characterized in that: the alpha/beta phase boundary strengthening powder accounts for 0.05-3% of the composite powder by mass; the alpha/beta phase boundary strengthening powder comprises Si powder, and the particle size of the alpha/beta phase boundary strengthening powder is 0.05-5 mu m.

6. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, according to claim 5, which is characterized in that: in step 3, at least one reinforcing phase of (Ti, zr) ₅Si₃ and (Ti, zr) ₆Si₃ is generated at the alpha/beta phase interface by the in-situ autogenous reaction, and the size of the reinforcing phase is 0.01-5 μm.

7. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, according to claim 2, which is characterized in that: the matrix reinforced powder accounts for 0.05-5% of the composite powder by mass, the matrix reinforced powder comprises at least one of Ta powder, mo powder and W powder, and the particle size of the matrix reinforced powder is 0.01-5 mu m.

8. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, which is characterized in that: in the step 2, the nominal composition of the TC25G alloy powder is as follows

Ti-6.5Al-4Zr-2Sn-4Mo-1W-0.2Si, and the grain size of the TC25G alloy spherical powder is 10-300 mu m.

9. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, which is characterized in that: the organism tissue of the titanium-based composite material obtained in the step 4 is of a net-like basket structure consisting of an alpha phase and a beta phase; wherein the alpha phase is lamellar and comprises a micron-sized primary alpha phase and a nanometer-sized secondary alpha phase; the beta phases are separated by inter-interleaved alpha phases. The length of the primary alpha photo layer is 1-50 mu m, and the width is 0.5-3 mu m; the length of the secondary alpha photo layer is 0.05-2 mu m, and the width is 10-200nm.

10. The method for preparing the titanium-based composite material with high strength and toughness and 700 ℃ service performance, which is characterized in that: the tensile strength sigma _b of the titanium-based composite material obtained in the step 4 is more than 1300Mpa, and the elongation delta is more than 8%; the tensile strength sigma _b at 700 ℃ is more than 650MPa, and the elongation delta is more than 20%.