CN114888289B - Gradient titanium-based composite material and preparation method thereof - Google Patents

Abstract

The invention provides a gradient titanium-based composite material and a preparation method thereof, and relates to the technical field of composite materials, wherein the gradient titanium-based composite material comprises a surface layer, an intermediate layer and a core layer; the surface layer, the middle layer, the core layer, the middle layer and the surface layer are sequentially arranged along the thickness direction of the gradient titanium-based composite material; the surface layer is a titanium alloy layer; the middle layer and the core layer are titanium-based composite layers with reinforcing phases, and the volume fraction of the reinforcing phases in the middle layer is lower than that in the core layer; wherein the titanium-based composite layer is prepared from titanium alloy powder and ceramic powder. The gradient titanium-based composite material provided by the invention has excellent strength and plasticity and toughness, no obvious interface transition layer, and the preparation method is simple and stable and is suitable for preparing the large-size gradient layered titanium-based composite material.

Description

A gradient titanium-based composite material and its preparation method

Technical field

The invention relates to the technical field of composite materials, and in particular to a gradient titanium-based composite material and a preparation method thereof.

Background technique

As an engineering material, titanium alloy has the advantages of low density, high specific strength, and good high-temperature performance. It is widely used in aviation, aerospace, chemical industry, marine, biological and other fields. The titanium-based composite material obtained by introducing the reinforcing phase into the titanium alloy has a certain improvement in strength and wear resistance compared with the titanium alloy. However, the introduction of the reinforcing phase will lead to a decrease in the plasticity and toughness of the titanium-based composite material. Most of the titanium-based composite materials prepared in recent years are titanium-based composite materials with a single component. For example, the Chinese patent application number CN200810136852.8 discloses a single-component discontinuous fiber-reinforced titanium-based composite material. While its strength is improved, The plasticity will be significantly reduced. Therefore, it is difficult for a single homogeneous material to meet the requirements of high strength and high toughness at the same time.

Researchers have discovered that biological materials such as bamboo and shells in nature have excellent mechanical properties such as fracture toughness. Therefore, based on bionics ideas, they designed multi-component layered titanium-based composite materials to improve their toughness. However, most of the existing layered titanium-based composite materials adopt the stacking hot rolling method disclosed in the patent application number CN201210138430.0 or the welding diffusion method disclosed in the patent application number CN201310498988.4. The existing layer materials are combined to obtain a layer titanium-based composite materials. Each layer of material in the above method is obtained by wire cutting after preparing the block or directly purchased. However, the former method of obtaining each layer of material is costly and complicated to operate; the latter is purchased directly and it is difficult to adjust the thickness and composition of each layer, so the layer thickness is limited. It reduces the designability and controllability of shape-shaped materials and makes the material preparation process cumbersome. Moreover, the interfacial bonding strength of this kind of layered titanium-based composite materials prepared by combining layers is generally low, resulting in low overall plasticity of the material.

Contents of the invention

Embodiments of the present invention provide a gradient titanium-based composite material and a preparation method thereof. The gradient titanium-based composite material has excellent strength and plastic toughness. There is no obvious interface transition layer between layers. The preparation method is simple, stable and suitable for Preparation of large-scale gradient layered titanium-based composite materials.

In a first aspect, the present invention provides a gradient titanium-based composite material. The gradient titanium-based composite material includes a surface layer, an intermediate layer and a core layer; in the thickness direction of the gradient titanium-based composite material, the surface layer, the The middle layer, the core layer, the middle layer and the surface layer are arranged in order;

The surface layer is a titanium alloy layer;

The middle layer and the core layer are titanium-based composite layers with a reinforcing phase, and the volume fraction of the reinforcing phase in the middle layer is lower than the volume fraction of the reinforcing phase in the core layer; wherein, the titanium-based composite The layer is made of titanium alloy powder and ceramic powder.

Preferably, the intermediate layer is composed of at least two sub-intermediate layers; wherein the volume fraction of the reinforcement phase in different sub-intermediate layers is different.

Preferably, along the thickness direction from the surface layer to the core layer, the volume fraction of the reinforcement phase in the at least two sub-intermediate layers is distributed in a gradient increasing manner.

Preferably, the surface layer is made of TC4 powder.

Preferably, the titanium-based composite layer is made of TC4 powder and _TiB2 powder.

Preferably, the particle size of the TC4 powder is 80-120 μm;

The particle size of the TiB ₂ powder is 1 to 8 μm.

Preferably, the volume fraction of the reinforcing phase in the titanium-based composite layer is 3 to 20%.

Preferably, the volume fraction of the reinforcement phase in the intermediate layer is 3 to 10%;

The volume fraction of the reinforcement phase in the core layer is 9-20%.

More preferably, the volume fraction of the reinforcement phase in the core layer is 9-15%.

Preferably, the intermediate layer includes a first sub-intermediate layer and a second sub-intermediate layer;

The volume fraction of the reinforcement phase in the first sub-intermediate layer is 3-5%, and the volume fraction of the reinforcement phase in the second sub-intermediate layer is 5-10%;

The first sub-intermediate layer is adjacent to the surface layer; the second sub-intermediate layer is adjacent to the core layer.

Preferably, the thicknesses of the sub-middle layer, the surface layer and the core layer are all the same.

In a second aspect, the present invention provides a method for preparing the gradient titanium-based composite material described in the first aspect. The preparation method includes:

(1) Ball mill titanium alloy powder and ceramic powder to obtain mixed powder for preparing the intermediate layer and core layer;

(2) Place titanium alloy powder, mixed powder for preparing the intermediate layer, mixed powder for preparing the core layer, mixed powder for preparing the intermediate layer, and titanium alloy powder in sequence in the mold, and then proceed Hot pressing and sintering to obtain the gradient titanium-based composite material including a surface layer, an intermediate layer and a core layer;

Wherein, the intermediate layer and the core layer are titanium-based composite layers with a reinforcing phase, and the volume fraction of the reinforcing phase in the intermediate layer is lower than the volume fraction of the reinforcing phase in the core layer.

Preferably, in step (1):

The ball milling speed of the ball milling treatment is 180-220rpm, preferably 200rpm;

The ball milling time is preferably 5 hours, and the ball-to-material ratio is preferably 5:1.

Preferably, in step (2):

The vacuum degree of the hot pressing sintering is not higher than 1×10 ^-2 Pa, the sintering temperature is 1300°C, the pressure is 25MPa, and the heat preservation time is 1.5h.

Compared with the prior art, the present invention at least has the following beneficial effects:

The invention combines a titanium-based composite layer with a higher reinforcing phase content and a titanium-based composite layer with a lower reinforcing phase content. On the basis of ensuring the interface strength, it can effectively alleviate the deformation process by virtue of its gradient layered structure. The strain localization in the material allows the structural advantages of the material to be fully utilized, and the deformation is more stable and uniform, thereby improving the problem of inversion of strength and plastic toughness of a single titanium-based composite material, and the prepared gradient titanium-based composite material has good comprehensive properties.

The present invention adopts the method of spreading powder to realize gradient layered structural design, and the gradient components and layer thickness are controllable. At the same time, the hot-pressing sintering technology is used, and the preparation method is simple. The interface of the prepared gradient titanium-based composite material is metallurgical bonding. The interface between the layers is straight and well bonded. There is no obvious interface transition layer, which solves the problem of other existing problems. The problem of poor interfacial bonding strength of layered materials prepared by this method.

Description of drawings

Figure 1 is a flow chart of a method for preparing a gradient titanium-based composite material according to an embodiment of the present invention;

Figure 2 is a comparison curve of the three-point bending properties of the gradient titanium-based composite material prepared in Example 1 of the present invention and the titanium-based composite material prepared in Comparative Example 1;

Figure 3 is a scanning electron microscope image of the gradient titanium-based composite material prepared in Example 1 of the present invention;

Figure 4 is a schematic diagram of a powder spreading method according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the present invention. Embodiments are not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

The embodiment of the present invention provides a gradient titanium-based composite material. The gradient titanium-based composite material includes a surface layer, an intermediate layer and a core layer; in the thickness direction of the gradient titanium-based composite material, the surface layer, the intermediate layer, the core layer, the intermediate layer and The surface layers are arranged in sequence;

The surface layer is titanium alloy layer;

The middle layer and the core layer are titanium-based composite layers with a reinforcing phase, and the volume fraction of the reinforcing phase in the middle layer is lower than the volume fraction of the reinforcing phase in the core layer; wherein, the titanium-based composite layer is made of titanium alloy powder and ceramic powder. .

In the present invention, the layered structure of the gradient titanium-based composite material is as follows in the thickness direction: surface layer-middle layer-core layer-middle layer-surface layer; that is, the outermost layer is a titanium alloy layer with good plasticity and low strength (i.e., the volume of the reinforcement phase Fraction is 0%), the core layer is a titanium-based composite layer with the highest reinforcing phase content among the three layers, and the core layer has the highest compressive strength and poor tensile and bending properties among the three layers, and the reinforcing phase in the middle layer The content is between the surface layer and the core layer, thus forming a gradient structure in which the reinforcing phase content increases from both sides to the center. This gradient structure can effectively alleviate the strain localization during the deformation process, allowing the structural advantages of the material to be fully utilized and the deformation to be more stable and uniform, thus improving the problem of inversion of the strength and plastic toughness of a single titanium-based composite material, and the prepared Gradient titanium-based composite materials have good comprehensive mechanical properties.

According to some preferred embodiments, the intermediate layer is composed of at least two sub-intermediate layers; wherein the volume fraction of the reinforcement phase in different sub-intermediate layers is different.

According to some preferred embodiments, along the thickness direction from the surface layer to the core layer, the volume fraction of the reinforcement phase in at least two sub-intermediate layers is distributed in a gradient increasing manner.

In the present invention, by arranging at least two sub-intermediate layers in the intermediate layer, the gradient layered structure of the gradient titanium-based composite material can be flexibly designed, and by adding sub-intermediate layers, the gradient from the surface layer to the core layer can be The transition is refined, thereby more stably and uniformly relieving strain localization during deformation, resulting in gradient titanium-based composite materials with high strength and high toughness.

Traditional titanium-based composite materials are mainly uniform composites with uniform components and density, so their properties are also single. However, the gradient titanium-based composite material of the present invention can be optimized in composition and structure in appropriate areas according to actual application conditions, so that the local characteristics of the material can adapt to its specific needs, so that it has multiple performance advantages and is beneficial to Give full play to the performance of each layer.

According to some preferred embodiments, the surface layer is made of TC4 powder.

According to some preferred embodiments, the titanium-based composite layer is made of TC4 powder and _TiB2 powder.

According to some preferred embodiments, the particle size of TC4 powder is 80-120 μm (for example, it can be 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm or 120 μm);

The particle size of TiB ₂ powder is 1 to 8 μm (for example, it can be 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm or 8μm).

In the present invention, TC4 powder and _TiB2 powder generate TiBw after an in-situ autogenic reaction to obtain a titanium-based composite layer. In the titanium-based composite layer, TiBw is the reinforcing phase and TC4 is the matrix phase.

It should be noted that the thickness of the surface layer and the titanium-based composite layer is specifically limited according to the powder particle size and the requirements for the gradient titanium-based composite material. In the present invention, the thickness of the surface layer and the titanium-based composite layer is not less than 100 μm, for example, it can be 100 μm, 150 μm, 200 μm, 400 μm, 500 μm, 600 μm, 800 μm, 1 mm, 1.5 mm, etc.

According to some preferred embodiments, the volume fraction of the reinforcing phase in the titanium-based composite layer is 3 to 20% (for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% , 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%).

According to some preferred embodiments, the volume fraction of the reinforcing phase in the intermediate layer is 3 to 10% (for example, it can be 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7 %, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%);

The volume fraction of the reinforcement phase in the core layer is 9 to 20% (for example, it can be 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14% , 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5% or 20%).

According to some more preferred embodiments, the volume fraction of the reinforcing phase in the core layer is 9 to 15% (for example, it can be 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5% or 15%).

According to some more preferred embodiments, the intermediate layer includes a first sub-intermediate layer and a second sub-intermediate layer;

The volume fraction of the reinforcement phase in the first sub-intermediate layer is 3 to 5% (for example, it can be 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8% or 5%). The volume fraction of the reinforcement phase in the two sub-intermediate layers is 5 to 10% (for example, it can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%);

The first sub-intermediate layer is adjacent to the surface layer; the second sub-intermediate layer is adjacent to the core layer.

Specifically, in one embodiment of the present invention, the layered structure of the gradient titanium-based composite material can be as follows in the thickness direction: surface layer - first sub-intermediate layer - second sub-intermediate layer - core layer - second sub-intermediate layer - The first sub-middle layer - the surface layer.

According to some preferred embodiments, the thicknesses of the sub-middle layer, the surface layer and the core layer are all the same.

The invention also provides a method for preparing gradient titanium-based composite materials. The preparation method is used to obtain the gradient titanium-based composite materials provided by the invention. As shown in Figure 1, the preparation method includes:

(1) Ball mill titanium alloy powder and ceramic powder to obtain mixed powder for preparing the intermediate layer and core layer;

(2) Place titanium alloy powder, mixed powder for preparing the intermediate layer, mixed powder for preparing the core layer, mixed powder for preparing the intermediate layer, and titanium alloy powder in sequence in the mold, and then proceed Hot-press sintering to obtain a gradient titanium-based composite material including a surface layer, an intermediate layer and a core layer;

Wherein, the middle layer and the core layer are titanium-based composite layers with a reinforcing phase, and the volume fraction of the reinforcing phase in the middle layer is lower than the volume fraction of the reinforcing phase in the core layer.

In the present invention, mixed powders with different contents of ceramic powders are prepared according to the preset ratio of ceramic powders and titanium alloy powders. By spreading the powder layer by layer and then hot pressing and sintering, a gradient layer is prepared. The titanium-based composite material with a similar structure has a simple preparation method. The interface of the prepared gradient titanium-based composite material is metallurgical bonding, the overall structure is intact, and there are no obvious defects such as holes and cracks. The interface between the layers is straight and well bonded. There is no obvious interface transition layer, which solves the problem of poor bonding at the interface of layered materials prepared by other existing methods.

Specifically, since the volume fraction of the reinforcing phase is affected by the ceramic powder content in the mixed powder, the ceramic powder content in the mixed powder used to prepare the intermediate layer is lower than that in the mixed powder used to prepare the core layer. content.

It should be noted that the present invention can use the cooperation of the graphite mold and the gear screw to control the thickness of each layer, thereby achieving flexible design and control of the thickness of each layer.

According to some preferred embodiments, in step (1):

The ball milling speed of the ball milling treatment is 180-220rpm (for example, it can be 180rpm, 190rpm, 200rpm, 210rpm or 220rpm);

The ball milling time is 5h, and the ball-to-material ratio is 5:1.

It should be noted that the present invention uses a planetary ball mill.

In the present invention, small-sized ceramic powder is adhered to the surface of large-sized titanium alloy powder through low-energy ball milling.

According to some preferred embodiments, the ball milling speed of the ball milling treatment is 200 rpm.

According to some preferred embodiments, in step (2):

The vacuum degree of hot pressing sintering is not higher than 1×10 ^-2 Pa (for example, it can be 1×10 ^-2 Pa, 5×10 ^-3 Pa, 1×10 ^{-3 Pa} , 5×10 ^-4 Pa or 1 ×10 ^-4 Pa, etc.), the sintering temperature is 1300°C, the pressure is 25MPa, and the holding time is 1.5h.

In order to more clearly illustrate the technical solutions and advantages of the present invention, a gradient titanium-based composite material and its preparation method will be described in detail below through several examples.

Example 1

The layered structure of the gradient titanium-based composite material along the thickness direction is: surface layer (TC4 layer) - first sub-intermediate layer (reinforcement phase volume fraction is 4%) - second sub-intermediate layer (reinforcement phase volume fraction is 8%) - Core layer (reinforcement phase volume fraction is 12%) - second sub-intermediate layer (reinforcement phase volume fraction is 8%) - first sub-intermediate layer (reinforcement phase volume fraction is 4%) - surface layer (TC4 layer);

Preparation method for preparing the above-mentioned gradient titanium-based composite material:

(1) Ball mill TC4 powder (particle size: 80-100 μm) and _TiB2 powder (particle size: 5-8 μm) in a certain ratio to obtain the above-mentioned first sub-intermediate layer and second sub-intermediate layer respectively. Mixed powder of layer and core layer;

Among them, the ball milling speed in the ball milling process is 200rpm, the ball milling time is 5h, and the ball-to-material ratio is 5:1;

(2) Mix TC4 powder, the mixed powder used to prepare the first sub-intermediate layer, the mixed powder used to prepare the second sub-intermediate layer, the mixed powder used to prepare the core layer, and the mixed powder used to prepare the second sub-intermediate layer. The mixed powder of the first layer, the mixed powder used to prepare the first sub-intermediate layer, and the TC4 powder are placed in the graphite mold in sequence. The lower pressure head of the graphite mold can change the height of the lower pressure head through the gear screw, as shown in the figure. As shown in 4, the thickness of each layer is controlled by the gear screw to be 1mm;

After the laying is completed, the mold is placed in the hot-pressing sintering furnace, evacuated, so that the vacuum degree of the hot-pressing sintering furnace reaches 10 ^-2 Pa, and kept at a sintering temperature of 1300°C and a pressure of 25MPa for 1.5 After 1 hour, it is cooled in the furnace to obtain a gradient titanium-based composite material.

Example 2

Embodiment 2 is basically the same as Embodiment 1, except that:

The layered structure of the gradient titanium-based composite material along the thickness direction is: surface layer (TC4 layer) - first sub-intermediate layer (reinforcement phase volume fraction is 5%) - second sub-intermediate layer (reinforcement phase volume fraction is 10%) - Core layer (reinforcement phase volume fraction is 15%) - second sub-intermediate layer (reinforcement phase volume fraction is 10%) - first sub-intermediate layer (reinforcement phase volume fraction is 5%) - surface layer (TC4 layer).

Example 3

Embodiment 3 is basically the same as Embodiment 1, except that:

The layered structure of the gradient titanium-based composite material along the thickness direction is: surface layer (TC4 layer) - first sub-intermediate layer (reinforcement phase volume fraction is 3%) - second sub-intermediate layer (reinforcement phase volume fraction is 6%) - Core layer (reinforcement phase volume fraction is 9%) - second sub-intermediate layer (reinforcement phase volume fraction is 6%) - first sub-intermediate layer (reinforcement phase volume fraction is 3%) - surface layer (TC4 layer).

Example 4

Embodiment 4 is basically the same as Embodiment 1, except that:

The layered structure of the gradient titanium-based composite material is as follows in the thickness direction: surface layer (TC4 layer) - first sub-middle layer (reinforcement phase volume fraction is 6%) - core layer (reinforcement phase volume fraction is 12%) - second sub-layer Middle layer (reinforcement phase volume fraction is 6%) - surface layer (TC4 layer).

Example 5

Embodiment 5 is basically the same as Embodiment 1, except that:

Surface layer (TC4 layer) - first sub-intermediate layer (volume fraction of enhanced phase is 3%) - second sub-intermediate layer (volume fraction of enhanced phase is 6%) - third sub-intermediate layer (volume fraction of enhanced phase is 9%) - Core layer (reinforcement phase volume fraction is 12%) - third sub-intermediate layer (reinforcement phase volume fraction is 9%) - second sub-intermediate layer (reinforcement phase volume fraction is 6%) - first sub-intermediate layer (reinforcement phase volume fraction is 6%) Phase volume fraction is 3%) - surface layer (TC4 layer).

Example 6

Embodiment 6 is basically the same as Embodiment 1, except that:

The particle size of TC4 powder is 100~120μm, and the particle size of _TiB2 powder is 1~5μm;

The thickness of each layer is controlled by the gear screw to be 1.5mm.

Comparative example 1

The volume fraction of the reinforcement phase in traditional uniformly compounded titanium-based composite materials is 5.1%.

Preparation method for preparing the titanium-based composite material:

TC4 powder (particle size is 80-100 μm) and _TiB2 powder (particle size is 5-8 μm) are ball-milled in a certain ratio to obtain mixed powder for preparing the titanium-based composite material;

The mixed powder is placed in a graphite mold with a thickness of 7 mm. After the placement is completed, the mold is placed in a hot-pressing sintering furnace and evacuated until the vacuum degree of the hot-pressing sintering furnace reaches 10 ^-2 Pa, and after being kept for 1.5 hours at a sintering temperature of 1300°C and a pressure of 25 MPa, the titanium-based composite material was obtained by cooling with the furnace.

Comparative example 2

Comparative Example 2 is basically the same as Example 1, except that:

The layered structure of the gradient titanium-based composite material along the thickness direction is: surface layer (TC4 layer) - first sub-intermediate layer (reinforcement phase volume fraction is 4%) - second sub-intermediate layer (reinforcement phase volume fraction is 8%) - Core layer (reinforcement phase volume fraction is 12%).

Comparative example 3

Comparative Example 3 is basically the same as Example 1, except that:

The layered structure of the titanium-based composite material along the thickness direction is: surface layer (TC4 layer) - core layer (reinforcement phase volume fraction is 12%) - surface layer (TC4 layer) - core layer (reinforcement phase volume fraction is 12%) - surface layer (TC4 layer) - core layer (reinforcement phase volume fraction is 12%) - surface layer (TC4 layer).

It should be noted that because the densities of the reinforcement phase and TC4 are almost equal, the theoretical densities of the surface layer, middle layer and core layer are basically the same, and the error is negligible. Therefore, for Example 1, when the thickness of each layer is the same, the average content of the reinforcing phase in the gradient titanium matrix composite material is about 5.1%, that is, 5.1%=(4%+8%+12%+8%+4 %)/7; for Comparative Example 3, when the thickness of each layer is the same, the average content of the reinforcing phase in the titanium-based composite material is about 5.1%, that is, 5.1%=(12%+12%+12%)/7 .

In the present invention, the gradient titanium-based composite material prepared in Example 1 and the titanium-based composite material prepared in Comparative Example 1 were subjected to a three-point bending test at room temperature, and the room temperature stress-strain curve was obtained as shown in Figure 2.

In Example 1, the outermost TC4 layer of the prepared gradient titanium-based composite material has the lowest strength but good plasticity; while the titanium-based composite layer with a reinforcing phase content of 4 vol.% has high plasticity but good strength. Lower; the titanium-based composite layer with a reinforcing phase content of 8vol.% has higher strength, but poor plasticity; the titanium-based composite layer with a reinforcing phase content of 12vol.% has the highest reinforcing phase content and the highest compressive strength , but the tensile and bending properties are poor. After mechanical property testing, the three-point bending strength of the gradient titanium-based composite material reaches more than 1800MPa, and the fracture strain can reach about 5%; compared with the single titanium-based composite with a reinforcing phase content of 5.1 vol.% obtained in Comparative Example 1 Compared with other materials, gradient layered materials exhibit higher fracture strains without losing flexural strength. At the same time, as shown in Figure 3, the overall structure of the gradient layered titanium-based composite material is intact, with no obvious defects such as holes and cracks. The material shows the designed gradient of increasing and decreasing reinforcement phase content in the direction of the powder layer. In addition, by estimating the toughness of the material based on the area under the load-displacement curve in the bending test, it can be found that the bending toughness of the gradient titanium-based composite material of Example 1 is more than 2 times higher than that of the titanium-based composite material of Comparative Example 1. The overall performance Better comprehensive mechanical properties (the load-displacement curve can be obtained by processing the curve in Figure 2). The gradient titanium-based composite material prepared in Comparative Example 2 does not adopt a symmetrical design, so the mechanical properties of the material are greatly affected by the loading direction; the titanium-based composite material prepared in Comparative Example 3 only uses powders of two components The titanium-based composite material formed by alternating layers does not form a gradient distribution in the structure, and the layered titanium-based composite material has limited improvement in toughness.

It should be noted that in Figure 3, TC4 is used to characterize the surface layer in the gradient titanium-based composite material, 4vol.% TiB is used to characterize the first sub-intermediate layer in the gradient titanium-based composite material, and 8vol.% TiB is used to characterize the gradient The second sub-intermediate layer in titanium-based composites, 12vol.% TiB, is used to characterize the core layer in gradient titanium-based composites.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be used Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent substitutions are made to some of the technical features; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. The parts of the present invention that are not described in detail are well known to those skilled in the art.

Claims (13)

1. The gradient titanium-based composite material is characterized by comprising a surface layer, an intermediate layer and a core layer; the surface layer, the middle layer, the core layer, the middle layer and the surface layer are sequentially arranged along the thickness direction of the gradient titanium-based composite material;

the surface layer is a titanium alloy layer;

the middle layer and the core layer are titanium-based composite layers with reinforcing phases, and the volume fraction of the reinforcing phases in the middle layer is lower than that in the core layer; wherein the titanium-based composite layer is prepared from titanium alloy powder and ceramic powder; the volume fraction of the reinforcing phase in the intermediate layer is 3-10%; the volume fraction of the reinforcing phase in the core layer is 9-20%.

2. The gradient titanium-based composite of claim 1, wherein:

the middle layer consists of at least two sub middle layers; wherein the volume fraction of the reinforcing phase in the different sub-interlayers is different.

3. The gradient titanium-based composite of claim 2, wherein:

the volume fraction of the reinforcing phase in the at least two sub-intermediate layers is distributed in a gradient increasing manner along the thickness direction from the surface layer to the core layer.

4. The gradient titanium-based composite of claim 1, wherein:

the surface layer is prepared from TC4 powder;

the titanium-based composite layer is formed by TC4 powder and TiB ₂ And (5) preparing powder.

5. The gradient titanium matrix composite of claim 4, wherein:

the grain diameter of the TC4 powder is 80-120 mu m;

the TiB is ₂ The particle size of the powder is 1-8 mu m.

6. The gradient titanium-based composite of claim 1, wherein:

the volume fraction of the reinforcing phase in the titanium-based composite layer is 3-20%.

7. The gradient titanium-based composite of claim 1, wherein:

the volume fraction of the reinforcing phase in the core layer is 9-15%.

8. The gradient titanium-based composite of claim 2, wherein:

the intermediate layer comprises a first sub-intermediate layer and a second sub-intermediate layer;

the volume fraction of the reinforcing phase in the first sub-intermediate layer is 3-5%, and the volume fraction of the reinforcing phase in the second sub-intermediate layer is 5-10%;

the first sub-interlayer is adjacent to the skin layer; the second sub-interlayer is adjacent to the core layer.

9. The gradient titanium-based composite of claim 2, wherein:

the thicknesses of the sub-intermediate layer, the surface layer and the core layer are all the same.

10. A method of preparing a gradient titanium matrix composite material according to any one of claims 1 to 9, characterized in that the method of preparing comprises:

(1) Ball milling is carried out on the titanium alloy powder and the ceramic powder to obtain mixed powder for preparing the intermediate layer and the core layer;

(2) Sequentially laying titanium alloy powder, mixed powder for preparing an intermediate layer, mixed powder for preparing a core layer, mixed powder for preparing an intermediate layer and titanium alloy powder in a mould, and then performing hot-pressing sintering to obtain the gradient titanium-based composite material comprising a surface layer, the intermediate layer and the core layer;

wherein the intermediate layer and the core layer are titanium-based composite layers having a reinforcing phase, and the volume fraction of the reinforcing phase in the intermediate layer is lower than the volume fraction of the reinforcing phase in the core layer.

11. The method of claim 10, wherein in step (1):

the ball milling rotating speed of the ball milling treatment is 180-220 rpm.

12. The method of claim 10, wherein in step (1):

the ball milling rotating speed of the ball milling treatment is 200rpm;

ball milling time is 5h, and ball-material ratio is 5:1.

13. The preparation method according to any one of claims 11 to 12, wherein in step (2):

the vacuum degree of the hot pressed sintering is not higher than 1 multiplied by 10 ^-2 Pa, sintering temperature 1300 ℃, pressure 25MPa and heat preservation time 1.5h.