A method for preparing a SiC braided fiber reinforced titanium matrix composite plate

Abstract

The application relates to a preparation method of a SiC braided fiber reinforced titanium-based composite plate, and belongs to the technical field of metal-based composite plate preparation, and solves the problems of easy warping deformation of the plate processed by the plate processing method in the prior art, a complex processing process and poor plate performance. In the preparation method, ultrafine powder is used to replace foil in whole or in part, so that the powder can fully enter the internal gap of the braided fiber, the defects of poor flowability and many bonding defects of the foil are effectively overcome, the prepared plate is not easy to warp and deform, the plate is convenient to process, and the plate has good performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal matrix composite plate preparation, and particularly relates to a preparation method of SiC woven fiber reinforced titanium matrix composite plate. BACKGROUND

[0002] During the process of crossing or flying in the atmosphere, the surface of a hypersonic vehicle is subjected to strong aerodynamic heating, and the surface can reach an extremely high temperature, which puts forward extremely high temperature and strength requirements for the skin. The conventional materials such as aluminum alloy and resin matrix composite cannot withstand the requirements. The SiC fiber reinforced titanium matrix composite still has good strength performance in a high temperature environment, and has superior performances such as high specific strength, high specific stiffness, high specific modulus and high fatigue strength, and is an ideal material for heat-resistant skin.

[0003] However, the skin type part requires isotropy, but the fiber type composite material has the characteristics of anisotropy, and is usually improved by weaving and forming using bundle thin fibers. When selecting a processing technology, a solid method is usually used for processing, including foil-fiber-foil method, fiber coating method and plasma spraying method. Among them, the foil-fiber-foil method has the following disadvantages for preparing plate type parts: the foil material is used as the matrix, the flowability is poor, and the prepared composite material has many internal defects. Especially for woven bundle thin fibers, the foil matrix is more difficult to enter the fiber inside and be combined together. The thickness of the foil material cannot be very thin, and the size of the foil material cannot be too large, so the fiber volume fraction and the size of the composite material are limited. The main disadvantage of the fiber coating method is that the single fiber needs to be processed, the operation is complicated, the cost is high, batch production is difficult, and the coating method is difficult to make the matrix enter the bundle thin fibers. The main disadvantage of the plasma spraying method is that the spraying process produces non-uniform microstructure, and it is difficult to control the alloy composition, and the molten alloy droplets will damage the fibers. This method requires very complex equipment, and the price is high, the damage to the fibers is large, and many parameters need to be controlled. Similarly, the plasma spraying method is also difficult to make the matrix enter the bundle thin fibers. From the above analysis, the existing processes have some disadvantages, especially for the bundle thin fibers, the matrix cannot be impregnated therein, which limits the use of SiC bundle thin fibers. SUMMARY

[0004] In view of the above problems, the application provides a preparation method of SiC woven fiber reinforced titanium matrix plate, which solves the problems of easy warping deformation of the plate prepared by the plate processing method in the prior art, complex processing process and poor plate performance.

[0005] The application provides a package for preparing a SiC woven fiber reinforced titanium matrix composite plate, which comprises a bottom plate, a side plate, an upper plate and an air suction head.

[0006] The suction head is arranged on the upper plate; the bottom plate, the side plate and the upper plate enclose a hollow chamber, and the hollow chamber constitutes a forming cavity of the target piece;

[0007] The thickness of the bottom plate satisfies the following formula:

[0008]

[0009] Another aspect of the present application provides a preparation method of a SiC woven fiber reinforced titanium matrix composite plate, comprising the following steps:

[0010] Step one, forming a package according to the size and shape of the target piece;

[0011] Step two, preparing a matrix powder according to the material requirements of the target piece;

[0012] The particle size of the matrix powder is not more than the diameter of the SiC woven fiber;

[0013] Step three, weaving SiC fiber cloth according to the performance requirements of the target piece;

[0014] Step four, layer design: obtaining the SiC fiber volume fraction according to the performance requirements of the target piece; obtaining the number of fiber cloth layers, the number of powder layers and the thickness of each layer of powder according to the thickness of the target piece and the fiber volume fraction; the fiber cloth layers and the powder layers are arranged alternately, and the bottom layer and the top layer are both powder layers; designing the layer angle of the fiber cloth according to the direction requirements of the target piece;

[0015] Step five, filling the matrix powder and placing the SiC fiber cloth according to the layer design of step four;

[0016] Step six, vacuumizing the package and fixing it;

[0017] Step seven, placing the vacuumized package in a hot isostatic pressing device, so that the matrix powder is densified and the matrix powder is combined with the SiC fiber;

[0018] Step eight, removing the package to obtain a SiC fiber reinforced titanium matrix composite plate.

[0019] Optionally, in step four, the number of fiber cloth layers is calculated according to the following formula:

[0020]

[0021] Optionally, in step four, the thickness of each layer of powder is calculated according to the following formula:

[0022]

[0023] Optionally, in step five, the matrix powder is filled on a vibration table, so that the powder loading density of the matrix powder is not less than 60%.

[0024] Optionally, the vibration frequency of the vibration table is 10-30 Hz, and the vibration time is 60-180 s.

[0025] Optionally, the temperature of the hot isostatic pressing in step seven is 700-1100 ℃, the pressure is 50-180 MPa, and the time is 0.5-5 h.

[0026] Optionally, heat treatment is performed after the hot isostatic pressing is completed; the heat treatment includes stress relief annealing, recrystallization annealing, solid solution treatment, and / or aging treatment.

[0027] Compared with the prior art, the present application can achieve the following beneficial effects:

[0028] (1) The preparation method of the present application replaces foil with ultra-fine powder entirely or partially, so that the powder can fully enter the internal gap of the woven fiber, effectively overcoming the shortcomings of poor flowability of the foil and many bonding defects.

[0029] (2) The present application can effectively control the volume fraction of the composite material by controlling the addition amount of the powder, especially high volume fraction can be achieved. Due to the flexible flow characteristics of the powder, the problem of easy deformation and large residual stress in the preparation process caused by the large difference in thermal expansion coefficient between the metal matrix and the fiber can be effectively alleviated.

[0030] (3) The present application can accurately prepare composite material plate parts, and has the advantages of quasi-isotropy, high fiber volume fraction, unlimited size, high material utilization rate, etc. Compared with the current method of needing fiber coating, the present application does not need to process single fibers, is simple to operate, has high efficiency, low cost, and can be mass-produced. Moreover, due to the good flowability and easy preparation of the powder, the present application has good applicability and can also be applied to other shapes of target pieces (such as small curvature plates) and other types of composite materials.

[0031] (4) The present application uses fine fibers, which can achieve isotropy through weaving, and improve the anisotropy of unidirectional fibers. The plate manufactured in this way has good transverse performance, and the plate has stronger torsional stiffness, transverse stiffness and impact resistance, so the reinforcing effect is obvious, which is beneficial to expand the application range of the composite material plate.

[0032] (5) The present application uses powder as the base material, so that higher temperature and greater pressure can be used in the forming process for hot isostatic pressing, thereby making the powder completely dense and forming a complex-shaped part.

[0033] (6) The present application sets a bottom plate with a large thickness, which can prevent the plate from warping and deforming during plate forming.

[0034] (7) The present application uses foil to fix fibers, and makes the powder preliminarily dense and then completely dense. The fiber movement problem caused by powder shrinkage deformation can be prevented. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0036] Figure 1 Schematic diagram of target piece to be prepared by the preparation method of the present application.

[0037] Figure 2 Schematic diagram of the sleeve structure of the preparation method of the present application.

[0038] Figure 3 Microstructure diagram of the composite plate of the example.

[0039] Figure 4 Microstructure diagram of the composite plate of the example.

[0040] Reference signs:

[0041] 1. target piece; 2. bottom plate; 3. side plate; 4. upper plate; 5. suction head; 6. spherical powder; 7. first SiC woven fiber cloth; 8. second SiC woven fiber cloth; 9. third SiC woven fiber cloth; 10. suction pipe. DETAILED DESCRIPTION

[0042] In order to enable a clearer understanding of the above-mentioned objects, features and advantages of the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. In addition, the present application can also be implemented in other ways different from those described herein, and therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0043] One specific embodiment of the present application, as Figures 1-2 , discloses a preparation method of a SiC woven fiber reinforced titanium-based plate, the target piece of the plate has a forming thickness of 1 mm and a fiber volume fraction of 50%, and comprises the following steps:

[0044] Step one, forming a sleeve according to the size and shape of the target piece; the sleeve comprises a bottom plate 2, a side plate 3, an upper plate 4 and a suction head 5;

[0045] Optionally, the suction head 5 is arranged on the upper plate 4; the bottom plate 2, the side plate 3 and the upper plate 4 enclose a hollow chamber, and the hollow chamber constitutes a forming cavity of the target piece.

[0046] Optionally, the shape of the sleeve is arranged according to the shape of the target piece; the upper plate 4 is not welded first.

[0047] Optionally, if the target piece is a flat plate, the thickness of the bottom plate 2 satisfies the following formula, which can prevent the flat plate from being deformed in the forming process, so that the flatness of the target piece prepared is not more than 0.1 mm;

[0048]

[0049] Optionally, the bottom plate 2 and the side plate 3 are integrally manufactured.

[0050] Optionally, the upper plate 4 and the suction head 5 are integrally manufactured, avoiding welding holes and pipes on the upper plate, and preventing the welding part from cracking in the forming process.

[0051] Optionally, the top of the side plate 3 is provided with a welding boss for welding the upper plate 4.

[0052] Optionally, the sheath material is stainless steel, pure titanium or titanium alloy.

[0053] Step two, preparing the base powder according to the material requirements of the target piece;

[0054] Optionally, the base material is pure titanium, titanium alloy or titanium aluminum intermetallic compound; preferably, the base material is Ti6Al4V titanium alloy.

[0055] Optionally, the base material is processed into small-particle-size spherical powder 6, and the particle size of the spherical powder 6 is 0-250μm, and preferably the particle size of the spherical powder 6 is 0-15μm, that is, the average particle size (i.e. D50 particle size) of the powder is not more than the diameter of the SiC fiber.

[0056] Step three, weaving SiC fiber cloth according to the performance requirements of the target piece;

[0057] Optionally, the diameter of a single SiC fiber is 0-20μm, and preferably 13μm; 500-3000 single fibers can constitute a bundle, and preferably 500 single fibers constitute a bundle; the thickness of the fiber cloth is 0.1-5mm, the fiber area density is 250-1000g / m 2 , the SiC fiber density is 2.5-3g / cm 3 , preferably the thickness of the fiber cloth is 0.25mm, the fiber area density is 263g / m 2 , and the SiC fiber density is 2.7g / cm 3 .

[0058] Optionally, the single SiC fiber is used for plain weave, twill weave and satin weave, and the weaving dimension is 2D, 2.5D or 3D.

[0059] Optionally, the woven SiC fiber cloth is coated. The coating material is C (carbon), and the coating process is chemical vapor deposition (CVD) or chemical vapor infiltration (CVI). The advantage of coating is to improve the chemical and physical compatibility of the fiber and the matrix, increase the bonding strength of the interface, prevent excessive reaction of the interface to protect the fiber, and relieve the interface stress caused by the difference in thermal expansion coefficient and elastic modulus between the fiber and the matrix.

[0060] Optionally, the thickness of the SiC fiber cloth is obtained after the SiC fiber cloth is woven or after the woven SiC fiber cloth is coated.

[0061] Step four, cutting the SiC woven fiber cloth according to the shape of the target piece;

[0062] Step five, lay-up design: obtaining the SiC fiber volume fraction according to the performance requirements of the target piece; obtaining the number of fiber cloth layers, the number of powder layers and the thickness of each layer of powder according to the thickness of the target piece and the fiber volume fraction; the fiber cloth layers and the powder layers are arranged alternately, and the bottom layer and the top layer are both powder layers; designing the lay-up angle of the fiber cloth according to the direction requirements of the target piece;

[0063] The formula for calculating the fiber volume fraction is:

[0064]

[0065] Or

[0066]

[0067] Preferably, the interface bonding correction coefficient is 0.8.

[0068] The calculation of the number of fiber cloth layers, the number of powder layers and the thickness of each layer also needs to consider the surface density of the fiber cloth, the fiber density and the powder loading density.

[0069] The formula for calculating the number of fiber cloth layers is:

[0070]

[0071] The formula for calculating the number of powder layers is:

[0072] The number of powder layers = the number of fiber cloth layers + 1;

[0073] The formula for calculating the thickness of each layer of powder is:

[0074]

[0075] The thickness of the fiber cloth satisfies the following formula:

[0076]

[0077] The number of fiber cloth layers and the thickness of each layer of powder obtained by using the method for obtaining the number of fiber cloth layers and the thickness of each layer of powder takes into account the shrinkage of the matrix powder, so that the obtained plate is not prone to warping deformation and has excellent tensile properties.

[0078] In the embodiment, the target piece thickness is 1 mm, the fiber cloth thickness is 0.25 mm, the fiber area density is 263 g / m 2 , the fiber volume fraction is 50%, and the SiC fiber density is 2.7 g / cm 3 . Thus, the number of fiber cloth layers is calculated to be 3.

[0079] The number of powder layers is one more than the number of fiber cloth layers, and the fiber cloth layers and the powder layers are arranged alternately, and the bottom layer and the top layer are both powder layers; in the embodiment, the number of powder layers is 4.

[0080] Thus, the thickness of each layer of powder is calculated to be 0.12 mm.

[0081] The layup needs to meet the principles of balanced and symmetrical layup, layup orientation, layup orientation selection according to bearing, layup sequence, and minimum layup ratio; in the embodiment, the fiber cloth angles from bottom to top are 0 degrees, 45 degrees, and 90 degrees, respectively.

[0082] Optionally, the SiC fibers are fixed on the foil, so that the movement of the fiber cloth caused by the deformation of the powder can be further controlled. The thickness of the foil is not more than 500 μm, and is preferably 100 μm.

[0083] The surface treatment method of the foil is to use sandpaper with different mesh sizes to polish the upper and lower surfaces of the foil in sequence, so as to remove the oxide film and other impurity components on the surface of the foil. After polishing, an ultrasonic cleaning machine is used to clean the foil in acetone or anhydrous ethanol solution for 5-20 min, so as to remove the oil stains and polishing impurities on the surface of the foil, and then the foil is dried.

[0084] In summary, the layup design is to arrange three layers of fiber cloth and four layers of powder alternately; the three layers of fiber cloth from bottom to top are 0 degrees (fiber cloth 7), 45 degrees (fiber cloth 8), and 90 degrees (fiber cloth 9); the fiber volume fraction is 50%, the target piece 1 thickness is 1 mm, the powder loading density is 60%, and the powder loading thickness of each layer is 0.12 mm.

[0085] Step six, fill the powder according to the layup design of step five and place the SiC fiber cloth;

[0086] Optionally, the powder is filled on the vibration table, so that the powder loading density reaches the design value.

[0087] In order to prevent the powder from shrinking too much, the powder loading density is not less than 60%, and preferably the powder loading density is 60%.

[0088] The vibration frequency should be such that the powder does not exhibit "boiling" motion, particle stratification and size segregation. Preferably, the vibration frequency is 10-30 Hz and the vibration time is 60-180 s.

[0089] Because the fine powder is more easily suspended, the upper plate 4 is placed over the package during vibration to prevent the powder from being blown up. The formula for calculating the packing density of the powder is:

[0090]

[0091] In the example, the actual density of the Ti6Al4V powder is 4.5 g / cm 3 .

[0092] Step seven, welding the package: the upper plate 4 is welded to the side plate 3;

[0093] Because the fine powder is more easily oxidized, in order to prevent the powder from being oxidized by heat during welding in air, a vacuum welding method is preferably used to weld the package plate, such as vacuum electron beam welding.

[0094] Step eight, the package is first subjected to vacuum treatment at room temperature through the air exhaust pipe, then subjected to heat treatment in a vacuum state and continues to be vacuumed, and after reaching the vacuum state, the air exhaust head 5 is sealed;

[0095] The inside of the package is vacuumed at room temperature through the air exhaust pipe, so that the vacuum degree in the package reaches 1 x 10 -3 Pa, then placed in a heating furnace for heating and vacuuming, the heating temperature and the heating and vacuuming time are determined according to the desorption capacity of the powder of the material, the heating temperature is 300-600°C, and the heating and vacuuming time is not less than 2 h, finally the vacuum degree in the inside of the package reaches 1 x 10 -4 Pa, and after reaching the vacuum state, the air exhaust pipe is sealed, thereby avoiding oxidation of the fine spherical powder;

[0096] For the Ti6Al4V of the example: the inside of the package is vacuumed at room temperature through the air exhaust pipe, so that the vacuum degree in the package reaches 1 x 10 -3 Pa, then placed in a heating furnace for heating, and the adsorbed gas is extracted at 400°C and 500°C for 2 h respectively, finally the vacuum degree in the inside of the package reaches 1 x 10 -4 Pa again, and after reaching the vacuum state, the air exhaust pipe is sealed;

[0097] A filter screen is laid under the air exhaust head 5 and inserted into the air exhaust head 5 to prevent the fine spherical powder 6 from being extracted, the pore size of the filter screen should not be more than the average particle size of the spherical powder 6. In the example, a 2800 mesh (pore size 3 μm) stainless steel filter screen is selected.

[0098] Step nine, the vacuumized package is placed in a hot isostatic pressing device to realize the densification of the matrix powder and the combination of the matrix powder and the SiC fiber under high temperature and high pressure, the densification of the matrix powder requires no pore and hole defects and no original particle boundary, the combination of the matrix and the SiC fiber requires no unconnected defects, the interface layer has a thickness of 0-5 μm, preferably, the interface layer has a thickness of 1-2 μm;

[0099] Optionally, the hot isostatic pressing temperature is 0.5-0.75 of the melting point of the matrix powder material according to the type or grade of the specific powder, the hot isostatic pressing temperature is not too high and the hot isostatic pressing time is not too long because the fine powder is easier to be densified and the excessive reaction between the fiber and the matrix is prevented, preferably, the hot isostatic pressing temperature is 700-1100 ℃, the pressure is 50-180 MPa, and the time is 0.5-5 h; preferably, the hot isostatic pressing temperature is 920 ℃, the pressure is 120 MPa, and the time is 2 h for the Ti6Al4V powder material.

[0100] Optionally, the vacuumized package is subjected to pressureless sintering, low-pressure sintering or hot pressing to preliminarily densify the powder, wherein the holding temperature is 0.65-0.80 of the melting point of the powder material, and then the powder is completely densified by hot isostatic pressing, and the process parameters are the same as those of the hot isostatic pressing described above, and this method can further control the movement of the fiber cloth caused by the deformation of the powder.

[0101] Optionally, heat treatment is performed after the hot isostatic pressing; the heat treatment can improve the structure and performance of the composite material or eliminate residual stress, and the specific heat treatment system and the obtained effects are as follows:

[0102] stress relief annealing: temperature 450-650 ℃, holding time 1-4 h, air cooling, and the purpose is to eliminate residual stress;

[0103] recrystallization annealing: temperature 550-800 ℃, holding time 1-3 h, air cooling, and the purpose is to eliminate work hardening, improve the processing performance, and obtain good toughness;

[0104] solid solution treatment: temperature 760-1100 ℃, holding time 5-120 min, water cooling, and the purpose is to improve the strength and hardness;

[0105] aging treatment: temperature 450-550 ℃, holding time 2-20 h, air cooling, and the purpose is to improve the strength and hardness.

[0106] Step ten, the package is removed to obtain a SiC fiber reinforced titanium matrix composite plate part.

[0107] In order to illustrate the effectiveness of the method provided by the present application, the technical effects of the above technical solutions of the present application are described in detail through a specific embodiment.

[0108] Example 1 is a SiC braided fiber reinforced titanium matrix composite plate material obtained by using Ti6Al4V powder, hot isostatic pressing temperature of 920℃, pressure of 120MPa, and time of 2h, Figure 3 It is shown that the method of the present application enables the SiC fiber to be well combined with the titanium alloy matrix without unconnected defects, the interface reaction is moderate, the interface layer thickness is 1-2μm, and the matrix powder can be completely densified without pores, hole defects, and original particle boundaries. Figure 4 It is shown that the method of the present application enables the matrix powder to enter between the bundle fiber and achieve densification. The mechanical properties of the SiC braided fiber reinforced titanium matrix composite obtained in this example and the matrix are compared in Table 1.

[0109] The matrix plate 1 is a plate material processed by hot isostatic pressing (920℃ / 120MPa / 2h) using Ti6Al4V powder.

[0110] The mechanical properties of the SiC braided fiber reinforced titanium matrix composite obtained by hot isostatic pressing at a pressure of 40MPa in Comparative Example 2 are lower than those of Example 1, because the pressure is too low and the matrix powder does not completely enter the fiber, resulting in low mechanical properties of the composite material.

[0111] The mechanical properties of the SiC braided fiber reinforced titanium matrix composite obtained by hot isostatic pressing at a temperature of 650℃ in Comparative Example 3 are lower than those of Example 1, because the temperature is too low and the fiber is not well combined with the matrix, resulting in low mechanical properties of the composite material.

[0112] Table 1 Comparison of mechanical properties of the composite material plate and the matrix plate of the present application

[0113]

[0114] The above description is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto, any changes or replacements within the technical range disclosed by the present application can be easily thought by those skilled in the art, which should be covered within the protection scope of the present application.

Claims

1. A can for producing a SiC braided fiber reinforced titanium matrix composite panel, characterized by, The bottom plate, the side plate, the upper plate and the suction head are included. The suction head is arranged on the upper plate; the bottom plate, the side plate and the upper plate enclose a hollow chamber, and the hollow chamber constitutes a forming cavity of the target piece. The thickness of the bottom plate satisfies the following formula: The calculation formula of the number of layers of the fiber cloth is: The calculation formula of the number of layers of the powder is: The number of layers of the powder = the number of layers of the fiber cloth + 1; The calculation formula of the thickness of each layer of the powder is: The thickness of the fiber cloth satisfies the following formula: In use, the particle size of the matrix powder is not more than the diameter of the SiC woven fiber; the fiber cloth is a woven SiC fiber cloth.

2. A method for producing a SiC woven fiber reinforced titanium matrix composite sheet using the can as claimed in claim 1, characterized by, The method comprises the following steps: Step one, forming a package according to the size and shape of the target piece; Step two, preparing a matrix powder according to the material requirements of the target piece; The particle size of the matrix powder is not more than the diameter of the SiC woven fiber; Step three, weaving a SiC fiber cloth according to the performance requirements of the target piece; Step four, layer design: obtaining the volume fraction of the SiC fiber according to the performance requirements of the target piece; obtaining the number of layers of the fiber cloth, the number of layers of the powder and the thickness of each layer of the powder according to the thickness of the target piece and the volume fraction of the fiber; the fiber cloth layer and the powder layer are arranged alternately, and the bottom layer and the top layer are both powder layers; designing the layer angle of the fiber cloth according to the direction requirements of the target piece; Step five, filling the matrix powder and placing the SiC fiber cloth according to the layer design of step four; Step six, vacuumizing and fixing the package; Step seven, placing the vacuumized package in a hot isostatic pressing device, so that the matrix powder is densified and the matrix powder is combined with the SiC fiber; Step eight, removing the package to obtain a SiC fiber reinforced titanium matrix composite plate.

3. The production method according to claim 2, characterized by, In step five, the matrix powder is filled on a vibration table, so that the powder loading density of the matrix powder is not less than 60%.

4. The production method according to claim 3, characterized by, The vibration frequency of the vibration table is 10-30 Hz, and the vibration time is 60-180 s.

5. The preparation method according to claim 2, characterized in that, In step seven, the temperature of the hot isostatic pressing is 700-1100℃, the pressure is 50-180 MPa, and the time is 0.5-5 h.

6. The preparation method according to claim 2, characterized in that, After the hot isostatic pressing is completed, heat treatment is performed; the heat treatment includes stress relief annealing, recrystallization annealing, solid solution treatment and / or aging treatment.

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