阅读说明：本技术 一种陶瓷基复合材料基体膨胀系数测量方法和系统 (Method and system for measuring expansion coefficient of ceramic matrix composite substrate ) 是由 宋迎东 张盛 高希光 于 2020-04-20 设计创作，主要内容包括：本发明公开了一种陶瓷基复合材料基体膨胀系数测量方法,包括：S1,制备小复合材料,所述小复合材料由纤维束、包裹在纤维束外侧的待测量膨胀系数的基体以及粘接在纤维束和基体之间可氧化消除的界面层组成；S2,对所述小复合材料进行高温氧化,消除界面层,在氩气氛围中测量小复合材料在不同温度下的应变,计算得到基体的热膨胀系数。本发明无需制备纯陶瓷基体,采用易于制备的小复合材料来测量基体的热膨胀系数；另外,通过非接触方法测量小复合材料在高温下的热变形,继而计算得到基体的热膨胀系数,成功解决了测量陶瓷基复合材料的基体热膨胀系数这一技术难题,且方法易于实现。(The invention discloses a method for measuring the expansion coefficient of a ceramic matrix composite substrate, which comprises the following steps: s1, preparing a small composite material, wherein the small composite material consists of a fiber bundle, a matrix which is wrapped outside the fiber bundle and has an expansion coefficient to be measured, and an interfacial layer which is bonded between the fiber bundle and the matrix and can be oxidized and eliminated; and S2, carrying out high-temperature oxidation on the small composite material, eliminating an interface layer, measuring the strain of the small composite material at different temperatures in an argon atmosphere, and calculating to obtain the thermal expansion coefficient of the base body. According to the invention, a pure ceramic matrix does not need to be prepared, and a small composite material which is easy to prepare is adopted to measure the thermal expansion coefficient of the matrix; in addition, the thermal deformation of the small composite material at high temperature is measured by a non-contact method, and then the thermal expansion coefficient of the matrix is calculated, so that the technical problem of measuring the thermal expansion coefficient of the matrix of the ceramic matrix composite material is successfully solved, and the method is easy to realize.)

1. A method for measuring the expansion coefficient of a ceramic matrix composite substrate is characterized by comprising the following steps:

s1, preparing a small composite material, wherein the small composite material consists of a fiber bundle, a matrix which is wrapped outside the fiber bundle and has an expansion coefficient to be measured, and an interfacial layer which is bonded between the fiber bundle and the matrix and can be oxidized and eliminated;

and S2, carrying out high-temperature oxidation on the small composite material, eliminating an interface layer, measuring the strain of the small composite material at different temperatures in an argon atmosphere, and calculating to obtain the thermal expansion coefficient of the base body.

2. The method of measuring the coefficient of expansion of a ceramic matrix composite substrate of claim 1, wherein the interfacial layer comprises a pyrolytic carbon interfacial layer.

3. The method for measuring the coefficient of expansion of a ceramic matrix composite according to claim 1 or 2, wherein in step S1, the process for preparing a small composite comprises the following steps:

putting the fiber bundle into a high-temperature furnace;

depositing an interface layer on the surface of the fiber bundle;

depositing a substrate on the surface of the interface layer;

wherein, the process of depositing the matrix is completely equivalent to the ceramic matrix composite material to be measured, so that the matrix performance of the prepared small composite material and the ceramic matrix composite material to be measured is the same.

4. The method for measuring the expansion coefficient of the ceramic matrix composite substrate according to claim 1 or 2, wherein in step S2, the small composite material is oxidized at high temperature, the interface layer is eliminated, the strain of the small composite material at different temperatures is measured in argon atmosphere, and the process of calculating the expansion coefficient of the substrate comprises the following steps:

s21, clamping the small composite material in a high-temperature vacuum box to enable the small composite material to keep a state that one end is fixed and the other end is free;

s22, keeping the high-temperature vacuum box communicated with the outside air, enabling the small composite material to be in the air atmosphere, and heating the small composite material to enable the interface layer to be completely oxidized and disappear;

s23, cooling the temperature of the high-temperature vacuum box to room temperature, vacuumizing the high-temperature vacuum box, and introducing argon to finally enable the small composite material to be in an argon atmosphere;

s24, heating the small composite materials to the temperature T₁And T₂Measuring the strain of small composites at two temperatures₁And₂；

s25, calculating the matrix at T₁And T₂Coefficient of thermal expansion α;

5. the method for measuring the expansion coefficient of the ceramic matrix composite substrate according to claim 4, wherein in step S25, the expansion coefficient of the substrate is calculated by the following formula:

6. the method of claim 4, wherein the strain of the small composite material at two temperatures is measured in a non-contact manner in step S24₁And₂。

7. the method for measuring the coefficient of expansion of a ceramic matrix composite according to claim 4, wherein the non-contact measurement of the strain of the small composite at two temperatures is performed in step S24₁And₂comprises the following steps:

collecting deformation photos of the small composite material at different temperatures by using an industrial camera;

and comparing the deformation pictures at different temperatures by adopting a non-contact measurement algorithm, and calculating to obtain the strain of the small composite material at different temperatures.

8. The method for measuring the coefficient of expansion of the ceramic matrix composite substrate according to claim 4, wherein in step S22, the step of heating the small composite material to completely oxidize and eliminate the interface layer is performed by continuously oxidizing the interface layer at a temperature of not less than 800 ℃ for 1 hour or more when the interface layer is a pyrolytic carbon interface layer.

9. A system for measuring the coefficient of expansion of a ceramic matrix composite substrate, the system comprising:

the deposition equipment is used for preparing a small composite material, and the small composite material consists of a fiber bundle, a matrix which is wrapped outside the fiber bundle and is used for measuring the expansion coefficient, and an interfacial layer which is bonded between the fiber bundle and the matrix and can be oxidized and eliminated;

the high-temperature vacuum box is internally provided with a clamping mechanism, a heating unit and a vacuum unit, the clamping mechanism is used for clamping the small composite material in the high-temperature vacuum box to enable the small composite material to keep a state that one end of the small composite material is fixed and the other end of the small composite material is free, the heating unit is used for heating air in the high-temperature vacuum box to enable the small composite material to be oxidized at high temperature and eliminate an interface layer, and the vacuum unit is used for extracting air in the high-temperature vacuum box to enable the small composite material without the interface layer to be in a vacuum state;

the argon filling equipment is connected with the high-temperature vacuum box and is used for filling argon into the high-temperature vacuum box so that the small composite material for eliminating the interface layer is in an argon atmosphere;

the industrial camera is used for acquiring deformation photos of the small composite material at different temperatures;

and the processing device is used for comparing the deformation pictures at different temperatures by adopting a non-contact measurement algorithm, calculating the strain of the small composite material at different temperatures and then calculating the thermal expansion coefficient of the matrix.

Technical Field

The invention relates to the technical field of composite material mechanical property measurement, in particular to a method and a system for measuring the expansion coefficient of a ceramic matrix composite material matrix.

Background

Ceramic matrix composites are a class of materials that are compounded from fibers, a ceramic matrix, and interfacial layers between fibers/matrices. The ceramic matrix composite is an ideal material for the next generation of aeroengine high-temperature components because of the advantages of good high-temperature performance, high specific strength, high specific modulus, low density, insensitivity to gaps and the like. Because the preparation process comprises the heating and cooling processes, the internal stress distribution of the ceramic matrix composite is greatly influenced by the thermal expansion coefficient of the matrix, and the thermal expansion coefficient of the matrix is an essential parameter for predicting the macroscopic performance of the ceramic matrix composite by the component performance.

For resin-based and metal-based composite materials, the thermal expansion coefficient of the matrix [ Heluoxin, Zhanli, Yaohao, etc.. research on the influence of thermoplastic on the thermal expansion coefficient of epoxy resin. novel chemical materials 2012(03): 121-. However, this method is not suitable for ceramic matrix composites because of the difficulty in preparing pure ceramic matrices.

Currently, how to measure the thermal expansion coefficient of the matrix of the ceramic matrix composite material is an important and difficult technical problem in the technical field.

Disclosure of Invention

The invention aims to provide a method and a system for measuring the expansion coefficient of a ceramic matrix composite substrate, wherein the method does not need to prepare a pure ceramic substrate, and adopts a small composite material which is easy to prepare to measure the expansion coefficient of the substrate; in addition, the thermal deformation of the small composite material at high temperature is measured by a non-contact method, and then the thermal expansion coefficient of the matrix is calculated, so that the technical problem of measuring the thermal expansion coefficient of the matrix of the ceramic matrix composite material is successfully solved, and the method is easy to realize.

In order to achieve the above object, with reference to fig. 1, the present invention provides a method for measuring an expansion coefficient of a ceramic matrix composite substrate, the method comprising:

s1, preparing a small composite material, wherein the small composite material consists of a fiber bundle, a matrix which is wrapped outside the fiber bundle and has an expansion coefficient to be measured, and an interfacial layer which is bonded between the fiber bundle and the matrix and can be oxidized and eliminated;

and S2, carrying out high-temperature oxidation on the small composite material, eliminating an interface layer, measuring the strain of the small composite material at different temperatures in an argon atmosphere, and calculating to obtain the thermal expansion coefficient of the base body.

As a preferable example thereof, the interface layer includes a pyrolytic carbon interface layer.

As a preferred example, in step S1, the process of preparing the small composite material includes the following steps:

putting the fiber bundle into a high-temperature furnace;

depositing an interface layer on the surface of the fiber bundle;

depositing a substrate on the surface of the interface layer;

wherein, the process of depositing the matrix is completely equivalent to the ceramic matrix composite material to be measured, so that the matrix performance of the prepared small composite material and the ceramic matrix composite material to be measured is the same.

As a preferred example, in step S2, the process of performing high-temperature oxidation on the small composite material, eliminating the interface layer, measuring the strain of the small composite material at different temperatures in an argon atmosphere, and calculating the thermal expansion coefficient of the matrix includes the following steps:

s21, clamping the small composite material in a high-temperature vacuum box to enable the small composite material to keep a state that one end is fixed and the other end is free;

s22, keeping the high-temperature vacuum box communicated with the outside air, enabling the small composite material to be in the air atmosphere, and heating the small composite material to enable the interface layer to be completely oxidized and disappear;

s23, cooling the temperature of the high-temperature vacuum box to room temperature, vacuumizing the high-temperature vacuum box, and introducing argon to finally enable the small composite material to be in an argon atmosphere;

s24, heating the small composite materials to the temperature T₁And T₂Measuring the strain of small composites at two temperatures₁And₂；

s25, calculating the matrix at T₁And T₂Coefficient of thermal expansion α;

as a preferred example, in step S25, the thermal expansion coefficient of the base is calculated by using the following formula:

as a preferred example thereof, the stepsIn S24, strain of the small composite material at two temperatures is measured by a non-contact method₁And₂。

as a preferred example, in step S24, the strain of the small composite material at two temperatures is measured by a non-contact method₁And₂comprises the following steps:

collecting deformation photos of the small composite material at different temperatures by using an industrial camera;

and comparing the deformation pictures at different temperatures by adopting a non-contact measurement algorithm, and calculating to obtain the strain of the small composite material at different temperatures.

As a preferable example of this, in step S22, the heating of the small composite material to completely oxidize and disappear the interface layer means that, when the interface layer is a pyrolytic carbon interface layer, the oxidation is continued for 1 hour or more at a temperature of not less than 800 ℃.

Based on the method, the invention provides a measurement system for expansion coefficient of ceramic matrix composite material matrix, which comprises the following steps:

(1) the deposition equipment is used for preparing a small composite material, and the small composite material consists of a fiber bundle, a matrix which is wrapped outside the fiber bundle and is used for measuring the expansion coefficient, and an interfacial layer which is bonded between the fiber bundle and the matrix and can be oxidized and eliminated;

(2) the high-temperature vacuum box is internally provided with a clamping mechanism, a heating unit and a vacuum unit, the clamping mechanism is used for clamping the small composite material in the high-temperature vacuum box to enable the small composite material to keep a state that one end of the small composite material is fixed and the other end of the small composite material is free, the heating unit is used for heating air in the high-temperature vacuum box to enable the small composite material to be oxidized at high temperature and eliminate an interface layer, and the vacuum unit is used for extracting air in the high-temperature vacuum box to enable the small composite material without the interface layer to be in a vacuum state;

(3) the argon filling equipment is connected with the high-temperature vacuum box and is used for filling argon into the high-temperature vacuum box so that the small composite material for eliminating the interface layer is in an argon atmosphere;

(4) the industrial camera is used for acquiring deformation photos of the small composite material at different temperatures;

(5) and the processing device is used for comparing the deformation pictures at different temperatures by adopting a non-contact measurement algorithm, calculating the strain of the small composite material at different temperatures and then calculating the thermal expansion coefficient of the matrix.

Compared with the prior art, the technical scheme of the invention has the following remarkable beneficial effects:

(1) the method does not need to prepare a pure ceramic matrix, adopts a small composite material which is easy to prepare to measure the thermal expansion coefficient of the matrix, and is easy to realize.

(2) And measuring the thermal deformation of the small composite material at high temperature by a non-contact method, and then calculating to obtain the thermal expansion coefficient of the matrix.

(3) The process of depositing the matrix adopted in the preparation of the small composite material is completely equivalent to that of the ceramic matrix composite material to be measured, so that the matrix performance of the prepared small composite material and the matrix performance of the ceramic matrix composite material to be measured are the same, and the practice proves that the precision of the measurement result is extremely high.

It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be considered as part of the inventive subject matter of this disclosure unless such concepts are mutually inconsistent. In addition, all combinations of claimed subject matter are considered a part of the presently disclosed subject matter.

The foregoing and other aspects, embodiments and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. Additional aspects of the present invention, such as features and/or advantages of exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of specific embodiments in accordance with the teachings of the present invention.

Drawings

The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a flow chart of the method for measuring the expansion coefficient of the ceramic matrix composite according to the present invention.

Figure 2 is a schematic of a small composite of the present invention.

FIG. 3 is a schematic diagram of the present invention for measuring the coefficient of thermal expansion of a substrate.

FIG. 4 is a schematic representation of a small composite of the present invention after the disappearance of the oxidation of the interfacial layer of the pyrolytic carbon.

In the figure: 1-fiber, 2-matrix, 3-interface layer, 4-small composite material, 5-high temperature furnace, 6-vacuum box, and 7-industrial camera.

Detailed Description

In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings.

With reference to fig. 1, the present invention provides a method for measuring an expansion coefficient of a ceramic matrix composite substrate, wherein the method comprises:

s1, preparing a small composite material which consists of the fiber bundle, the matrix which is wrapped outside the fiber bundle and is used for measuring the expansion coefficient, and an interfacial layer which is bonded between the fiber bundle and the matrix and can be oxidized and eliminated.

And S2, carrying out high-temperature oxidation on the small composite material, eliminating an interface layer, measuring the strain of the small composite material at different temperatures in an argon atmosphere, and calculating to obtain the thermal expansion coefficient of the base body.

In the measurement method mentioned in the present invention, a pure ceramic matrix is not required to be prepared, but a small composite material which is easy to prepare is used to measure the thermal expansion coefficient of the matrix. The interface layer between the fiber and the matrix is oxidized and eliminated by carrying out high-temperature oxidation on the small composite material, so that the matrix in the small composite material can freely expand at high temperature. The thermal expansion coefficient of the matrix was calculated by measuring the thermal deformation of the small composite material at high temperature by a non-contact method (since the matrix is free to expand at this time, the measured thermal deformation of the matrix is also the thermal deformation of the matrix). Therefore, the invention solves the technical problem of measuring the thermal expansion coefficient of the matrix of the ceramic matrix composite material, and the method is easy to realize.

The invention provides a method for measuring the thermal expansion coefficient of a ceramic matrix composite substrate, which comprises the following steps:

step 1: preparing the small composite material. As shown in fig. 2, the small composite consists of a bundle of fibers 1, a matrix 2 surrounding the fibers, and an interfacial layer 3 between the fibers/matrix. During preparation, the fiber bundle is put into a high-temperature furnace, a pyrolytic carbon interface layer is deposited firstly, and then a matrix is deposited. The process of depositing the matrix of the small composite material is completely equivalent to that of the ceramic matrix composite material, so that the matrix performance of the small composite material and the ceramic matrix composite material obtained by preparation is the same. In addition, the interface layer between the small composite fiber/matrix in the present invention is a pyrolytic carbon interface layer, considering that pyrolytic carbon is easily oxidized.

Step 2: as shown in fig. 3, the small composite 4 is clamped in a high temperature vacuum box, which is composed of a vacuum box 6 and a high temperature furnace 5 in the box, so that the small composite 4 is kept in a state that one end is fixed and the other end is free.

And step 3: the vacuum box 6 is kept in communication with the outside air, leaving the small composite 4 in an air atmosphere. And heating the high-temperature furnace 5 to ensure that the temperature of the small composite material 4 is not lower than 800 ℃, and keeping the temperature for not less than 1 hour to ensure that the pyrolytic carbon interface layer 3 between the fiber and the matrix is completely oxidized and disappears. As shown in fig. 4, after the interface layer 3 has been oxidized and disappeared, the small composite material has no interaction between the fibers/matrix, and the matrix 2 is free to expand.

And 4, step 4: and (3) cooling the temperature of the high-temperature furnace 5 to room temperature, vacuumizing the vacuum box 6, and introducing argon to finally enable the small composite material 4 to be in an argon atmosphere.

And 5: the high temperature furnace 5 is heated to heat the small composite materials 4 to the temperature T in sequence₁And T₂Measuring the strain of the small composite 4 at two temperatures by a non-contact method₁And₂. As shown in fig. 3, deformation photographs of the small composite material 4 at different temperatures are acquired by the industrial camera 7, and the strain of the small composite material 4 at different temperatures can be calculated by comparing the deformation photographs at different temperatures by the non-contact measurement algorithm.

Step 6: miningCalculation of base 2 at T using the formula₁And T₂And a coefficient of thermal expansion α.

In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily defined to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any one implementation. In addition, some aspects of the present disclosure may be used alone, or in any suitable combination with other aspects of the present disclosure.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.