Silicon carbide fiber turbine rotor blade preform and preparation method thereof

Abstract

The invention discloses a silicon carbide fiber turbine rotor blade preform and a preparation method thereof, and belongs to the field of material science and engineering. The method comprises the steps that low-buckling silicon carbide fiber cloth is adopted for preparation, the turbine rotor blade is prepared by dividing the turbine rotor blade into an inner core and an outer layer, and the inner core and the outer layer are both prepared through an overall layer laying forming method, so that a blade body and a tenon in the inner core are integrated, and the bearing capacity and stability of the blade are improved to a great extent; in addition, the low-buckling silicon carbide fiber cloth has low buckling performance and good in-plane performance, yarn is easier to deform in the blade forming process, and the original mechanical performance of fibers is kept; compared with a blade prepared by a traditional method, the blade which is formed by combining the satin-weave silicon carbide fiber cloth and the overall laying layer has better oxidation resistance, creep resistance and higher damage tolerance and energy absorption performance.

Description

Technical Field

[0001] The invention relates to a silicon carbide fiber turbine rotor blade preform and a preparation method thereof, and belongs to the field of material science and engineering. Background Art

[0002] Turbine rotor blades are a typical hot section component in aircraft engines. They convert the heat energy and pressure potential energy in high-temperature and high-pressure combustion gas into mechanical energy. Therefore, during the operation of aircraft engines, turbine rotor blades must withstand extremely high temperatures and huge centrifugal forces caused by high-speed rotation, which places extremely high demands on the heat resistance, lightweight and load-bearing performance of turbine rotor blades. The material used in the traditional method is nickel-based high-temperature alloy turbine blades, but the mechanical-thermal performance of traditional nickel-based high-temperature alloys has reached the limit of use and cannot meet the requirements of high temperature resistance, high load-bearing and lightweight use; while silicon carbide fiber reinforced silicon carbide-based composite materials have the characteristics of low density, high specific strength, high temperature resistance, oxidation resistance, and corrosion resistance. Compared with nickel-based high-temperature alloys, they have stronger temperature bearing capacity, lighter weight, lower thermal expansion coefficient, higher material anisotropy and design, and are ideal materials for the preparation of advanced aircraft engine turbine rotor blades.

[0003] In the prior art, the silicon carbide fiber preform structures of turbine rotors mainly include 2D lamination, 2.5D and 3D weaving. Compared with 2D lamination preforms, the silicon carbide fiber reinforced silicon carbide-based composite materials obtained by combining 2.5D and 3D weaving structure preforms have insufficient in-plane tensile properties, and the material properties cannot be fully utilized under the huge centrifugal force brought by the high-speed rotation of the turbine rotor.

[0004] In order to solve the above problems, a Chinese patent with publication number CN108897931A discloses a design method for a ceramic-based turbine rotor blade preform, which adopts a 2D laying method to prepare the turbine rotor blade preform. However, this laying method is to divide the entire blade into individual modules for laying, and perform interlayer stitching at key positions, which improves the interlayer strength to a certain extent; however, the overall performance of the blade is poor.

[0005] In addition, the general preparation of 2D silicon carbide fiber reinforced silicon carbide-based composite materials mainly uses silicon carbide fiber plain weave cloth, but silicon carbide fiber has a high modulus and poor weavability, and the plain weave has many interlacing points, and the stress concentration and friction of the yarn at these points are large, resulting in great damage to the yarn. In addition, the high price of silicon carbide fiber will cause a huge waste of cost. At the same time, as a complex thin-walled curved surface component, the silicon carbide fiber reinforced silicon carbide-based composite turbine rotor blade preform will produce torsional deformation during the manufacturing process, increasing the damage to the yarn. Summary of the invention

[0006] In order to solve at least one of the above problems, the present application proposes a silicon carbide fiber turbine rotor blade preform and a preparation method thereof, with a silicon carbide fiber bundle as the core layer, and aramid yarn wrapped around the outer layer of the silicon carbide fiber bundle to form a wrapped yarn, and the yarn is used to weave a low-bend silicon carbide fiber fabric. The turbine rotor blade preform is layered as a whole using a low-bend silicon carbide fiber fabric 2D layering method, and the silicon carbide fiber turbine rotor blade preform is divided into two parts: an inner core and an outer layer; the inner core is a whole that runs through the entire blade, including an inner layer of the blade body and an inner layer of the tenon. The outer layer is a whole piece of fabric covering the blade, and the edge plate is formed by bending and overlapping the outer layer of fabric.

[0007] Compared with 2.5D and 3D woven preforms, the fiber preforms with 2D ply structures have stronger tensile strength and greater damage tolerance, and can meet the requirements of complex geometric shapes of different products; the preform structure uses low-buckling fabric ply. Compared with plain weave fabric, low-buckling fabric has fewer interlacing points, which can effectively reduce the damage to the yarn caused by fiber buckling, stress concentration and friction. Aramid yarn has high strength and good wear resistance. Aramid yarn wrapping can protect silicon carbide fiber bundles and effectively reduce the problems of wrinkling, fiber bundle fuzzing, and fiber brittle fracture of silicon carbide fiber preforms in turbine rotors during torsion molding.

[0008] The present invention provides a silicon carbide fiber turbine rotor blade preform and a preparation method thereof, comprising the following steps:

[0009] Step 1: Statistics of turbine rotor blade parameters;

[0010] The dimensions of the turbine rotor blades are measured according to the turbine rotor blade model to obtain the overall dimension parameters of the blade body, tenon and edge plate.

[0011] Step 2: Selection of silicon carbide fiber cloth and layer structure;

[0012] The selected silicon carbide fiber cloths are all low-buckling fabrics, including unidirectional and satin, and the ply structure is a 2D overall ply method with 0 / 90° alternating ply along the 0° direction of the blade height. The silicon carbide fiber cloth is woven with wrapped yarn obtained by wrapping silicon carbide fiber bundles with aramid yarn. The silicon carbide fiber bundles are made of Nextel, hi-Nicalon, Tyranno, and Sylramic, with a fineness of 2 to 3k; the aramid fiber bundles are 80 to 100 tex fineness, and are wrapped around the silicon carbide fiber bundles in an eight-shaped weaving manner through a braiding machine; the warp density of the fiber cloth is 8 strands / cm, the weft density is 5 strands / cm, and the thickness of a single layer of fabric is controlled at 0.3-0.4mm.

[0013] Step 3: Laying the inner core of the turbine rotor blade preform;

[0014] S1: Turbine rotor blade prefabricated body core blade body layer:

[0015] According to the thickness distribution parameters of the cross section at different blade heights obtained in step 1 and the thickness of the extracted outer layer of equal thickness, the structural parameters of the main fiber layer are obtained, and the uniform change of the longitudinal and transverse thickness of the blade preform is achieved by adopting the method of decreasing the layers.

[0016] S2: Turbine rotor blade prefabricated body core tenon insertion layer:

[0017] The longitudinal thickness gradient of the tenon is achieved by inserting layers between the main fiber layers. The fiber cloth extending from the main fiber layer of the blade body constitutes the main layer of the tenon part. The initial number of warp yarn layers and rows is determined according to the thickness and width of the equal-thickness area at the connection between the edge plate and the tenon. It extends downward to the dovetail neck and bends, and unfolds to both sides at the bottom of the tenon with the same angle difference. Smaller fiber cloth inserts are inserted between these main layers in a decreasing manner as filling.

[0018] Step 4: Laying the outer layer of the turbine rotor blade preform;

[0019] According to the blade outer layer of equal thickness obtained in step 2, the outer surface of the blade outer layer is extracted for flattening to obtain the required blade outer layer ply shape and size parameters. The flattened outer layer can be approximately regarded as two trapezoids spliced ​​together, so the ply plan is designed according to the trapezoid; part of the fabric of the blade outer layer is reserved to extend downward as the edge plate and the tenon outer layer.

[0020] Step 5: Cut the low-buckling silicon carbide fiber cloth according to the layer design in steps 3-4.

[0021] Step 6: integrally forming the turbine rotor blades;

[0022] The whole layer is laid in the order of inner core, tenon insert layer and outer layer, and the outer layer is sewed after the whole layer is laid.

[0023] In one embodiment of the present invention, the inner core variable thickness design method in step 3 complies with the composite material ply design criteria in the aviation field, and adopts a ply decreasing method to achieve uniform changes in the longitudinal and transverse thicknesses of the blade preform.

[0024] In one embodiment of the present invention, the fiber layer with the thickness of the blade tip part in the main fiber layer of the turbine rotor blade in step 3 extends from the blade tip to the tenon part to ensure the continuity of the blade body through the entire blade; the part other than the blade tip thickness is uniformly changed by the method of decreasing layer laying.

[0025] In one embodiment of the present invention, in the intercalation structure design of the tenon in step 3, all intercalations between two adjacent main fiber layers are a group, and each group of intercalations adopts a decreasing layer structure, and each intercalation is named 1, 2, 3, 4, 5, ..., n in order of decreasing intercalation height, and the laying order is adjusted to 1, 3, 5, 7, ..., n, n-1, n-3, ..., 6, 4, 2, wherein layer No. 1 is close to one side of the outer surface, so that each group of intercalations forms a "bamboo shoot shell"-shaped intercalation structure.

[0026] In one embodiment of the present invention, the angle difference of the initial warp yarns spreading to both sides in step 3 is determined according to the actual situation of the tenon part.

[0027] In one embodiment of the present invention, the thickness of the outer layer of the blade body with equal thickness in step 4 is 1.5 mm.

[0028] In one embodiment of the present invention, the outer layer of the blade in step 4 is formed by splicing and sewing two identical trapezoidal fiber cloths. The length and width of the reserved part of the fabric on the outer layer of the blade depends on the size of the edge plate and the outer surface of the tenon after flattening. The edge plate part is formed by bending and overlapping the outer layer fabric of the blade.

[0029] In one embodiment of the present invention, the amount of low-buckling silicon carbide fiber cloth in step 5 is obtained by dividing the maximum thickness of the turbine rotor blade by the thickness of a single layer of silicon carbide fiber cloth. The fiber cloth is cut according to the design requirements of steps 3-4.

[0030] The beneficial effects of the present invention are:

[0031] The present invention proposes a silicon carbide fiber turbine rotor blade preform and a preparation method thereof. The turbine rotor blade preform is integrally laminated by a 2D lamination method, and the blade is prepared by dividing the entire blade into two parts, an inner core and an outer layer. The inner core and the outer layer are both formed by an integral lamination method, thereby realizing the preparation of a turbine rotor blade preform with a complex curved surface and thin-walled structure, and having better tensile bending performance. The blade body and the tenon in the inner core are an integral whole, wherein the fiber layer runs through the blade body and the tenon, and a thickness gradient transformation of the blade body is realized by a decreasing lamination method. The gradient change of the tenon thickness is achieved by inserting layers between the main layers; the outer layer takes the edge plate into consideration, and the entire fabric covers the blade body, edge plate and tenon, ensuring the continuity of the silicon carbide fiber bundle, greatly improving the load-bearing capacity and stability of the blade; and the fiber cloth used in the present invention is low-buckling silicon carbide fiber cloth, which has lower buckling. During the blade molding process, the yarn is more easily deformed and maintains the original mechanical properties of the fiber. Compared with the common woven structure, it has better in-plane performance, oxidation resistance, creep resistance, higher damage tolerance and energy absorption performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 This is a schematic diagram of the integral forming process of a turbine rotor blade provided in the first embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of specific layering of a turbine rotor blade provided in the first embodiment of the present invention;

[0035] Figure 3 Schematic diagram of a single group of intercalation of tenons of turbine rotor blades provided in the first embodiment of the present invention;

[0036] Figure 4 It is a schematic diagram of the structure of the turbine rotor blade model provided in the first embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0038] Embodiment 1

[0039] This embodiment provides a silicon carbide fiber turbine rotor blade preform and a preparation method thereof. The overall design flow chart is shown in Figure 1 , the method comprising:

[0040] Step 1: Statistics of turbine rotor blade parameters;

[0041] The dimensions of the turbine rotor blades were measured to obtain the overall dimension parameters of the blade body, tenon and edge plate. The blade body height is 120mm, and a cross-section analysis is performed every 6mm to obtain the thickness distribution parameters of the cross section at different blade body heights. From the root to the tip, the maximum thickness decreases uniformly from 12mm to 6mm, and the cross-sectional circumference decreases uniformly from 151mm to 108mm. The edge plate is 74mm long, 32mm wide, and 3mm thick. The tenon is 50mm long, 15.5mm wide, 6mm wide, and 13mm high.

[0042] Step 2: Selection and layer structure of silicon carbide fiber cloth;

[0043] The selected silicon carbide fiber cloths are all low-buckling silicon carbide fiber cloths, and the ply structure is a 2D overall ply method with 0 / 90° alternating ply along the blade height direction. The silicon carbide fiber cloth is woven with a wrapped yarn obtained by wrapping a silicon carbide fiber bundle with aramid yarn. The silicon carbide fiber bundle is a 3kSylramic fiber bundle with a warp yarn density of 8 strands / cm and a weft yarn density of 5 strands / cm. The thickness of a single layer of fabric is 0.3mm.

[0044] Step 3: Laying the inner core of the turbine rotor blade preform;

[0045] S1: Turbine rotor blade preform body core layup:

[0046] Flatten the twisted blade model, and extract a 1.5mm uniform thickness outer layer from the blade model after the flattened blade. Obtain the structural parameters of the main fiber layer based on the thickness distribution parameters of the cross section at different blade heights obtained in step 1 and the thickness of the extracted uniform thickness outer layer. From the root to the tip of the blade, the maximum thickness of the main fiber layer decreases evenly from 9mm to 3mm. According to the single layer thickness obtained in step 2, a total of 30 layers need to be laid. Among them, 10 layers extend downward as the main layer of the tenon, with a thickness of 3mm. Figure 2 As shown, the method of decreasing the layers is adopted to achieve uniform changes in the longitudinal and transverse thickness of the blade preform.

[0047] S2: Turbine rotor blade tenon insert:

[0048] The longitudinal thickness gradient of the tenon is achieved by inserting layers between the main fiber layers. The main layer is composed of fiber cloth extending from the inner core layer of the blade body. The initial number of warp yarn layers and rows is determined according to the thickness and width of the equal thickness area at the connection. It extends downward to the dovetail neck and bends, and unfolds to both sides at the bottom of the tenon with the same angle difference. Smaller fiber cloth inserts are inserted between these main layers in a decreasing ply structure as filling, such as Figure 3 As shown, taking n=9 as an example, all intercalations between two adjacent main fiber layers are grouped together, and each group of intercalations adopts a decreasing layer structure. Each intercalation layer is named 1, 2, 3, 4, 5, 7, and 9 in descending order of intercalation height, and the laying order is adjusted to 1, 3, 5, 7, 9, 8, 6, 4, and 2, wherein layer No. 1 is close to the outer surface side, so that each group of intercalations forms a "bamboo shoot shell"-shaped intercalation structure.

[0049] Step 4: Unfolding and laying out the outer layer of the turbine rotor blade prefabricated body:

[0050] According to the blade outer layer of equal thickness obtained in step 2, the outer surface of the blade outer layer is extracted for flattening operation to obtain the required blade outer layer ply shape and size parameters. The flattened outer layer can be approximately regarded as two trapezoids spliced ​​together, so the ply plan is designed according to the trapezoid. The thickness of the outer layer is 1.5mm, and a total of 6 layers are required. Part of the fabric of the blade outer layer is reserved to extend downward as the edge plate and the tenon outer layer.

[0051] Step 5: Cut the silicon carbide fiber cloth according to the layer design in steps 3 and 4.

[0052] Step 6: Integral Forming of Turbine Rotor Blades:

[0053] The layers are laid in the order of inner core, tenon insert and outer layer. The outer layer is sewn together after laying. The blade torsion is achieved through precise control of the mold.

[0054] The model structure of the turbine rotor blade obtained by the above method is as follows Figure 4 As shown, Figure 4 a in the figure is the front view of the turbine rotor blade. Figure 4 b is the side view of the turbine rotor blade. Figure 4 c in the figure is a top view of the turbine rotor blade. Figure 4 d in the figure is a bottom view of the turbine rotor blade.

[0055] With reference to the national standard, the basic mechanical properties of 3mm thick (10 layers of fiber cloth laminated) 5 pieces of 3-fly satin 0 / 90° silicon carbide fiber reinforced silicon carbide-based composite flat plate specimens were tested at room temperature. The measured tensile strength is 400MPa, bending strength is 705MPa, compression strength is 630MPa, in-plane shear strength is 160MPa, and elastic modulus is 174GPa. Satin silicon carbide fiber reinforced silicon carbide-based composite materials have high strength and excellent in-plane performance.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a silicon carbide fiber turbine rotor blade preform, characterized in that: The method comprises: Step 1: Measure the turbine rotor blade model and count the blade parameters; Step 2: Selection of silicon carbide fiber cloth and layer structure; Step 3: Design of core layup in turbine rotor blade preform; Step 4: Outer layer development and layup design of turbine rotor blade preform; Step 5: Cut the silicon carbide fiber cloth according to the layer design of steps 3 and 4; Step 6: Perform overall lamination according to the lamination design of steps 3 and 4. After the lamination is completed, sew the outer layer and twist the blade body to obtain the turbine rotor blade.

2. The method according to claim 1, characterized in that: The step 2 comprises: The selected fiber cloths are all low-buckling silicon carbide fiber cloths, and the layer structure is a 2D integral layering method with 0 / 90° alternating layers along the blade height direction.

3. The method according to claim 2, characterized in that The step 3 comprises: S1: Turbine rotor blade prefabricated body core blade body layer: The structural parameters of the main fiber layer are designed according to the thickness distribution parameters of the blade body, and the method of decreasing the layers is adopted to achieve uniform changes in the longitudinal and transverse thickness of the blade preform; S2: Turbine rotor blade prefabricated body core tenon layup: The longitudinal thickness gradient change of the tenon is achieved by inserting layers between the main fiber layers; the main layer of the tenon part is composed of fiber cloth extended from the main fiber layer of the blade body, and the initial number of warp yarn layers and rows is determined according to the thickness and width dimensions of the equal-thickness area at the connection between the edge plate and the tenon, extending downward to the dovetail neck and bending, and unfolding to the bottom of the tenon on both sides with the same angle difference; fiber cloth inserts are inserted between the main layers as filling by using the method of decreasing layer laying.

4. The method according to claim 3, characterized in that: The step 4 comprises: The outer surface of the outer layer of the blade is extracted and flattened to obtain the required shape and size parameters of the outer layer of the blade; the flattened outer layer can be approximately regarded as two trapezoids spliced ​​together, so the layup plan is designed according to the trapezoid; part of the fabric on the outer layer of the blade is reserved to extend downward as the edge plate and the outer layer of the tenon; The edge plate is formed by bending and overlapping a portion of fabric reserved on the outer layer of the blade.

5. The method according to claim 4, characterized in that The step 1 comprises: The dimensions of the turbine rotor blades were measured to obtain the overall dimension parameters of the blade body, tenon and edge plate; the blade body height was 120 mm, and a cross-section analysis was performed every 6 mm to obtain the thickness distribution parameters of the cross section at different blade body heights; The maximum thickness of the blade body is uniformly reduced from 12mm to 6mm, among which the maximum thickness of the main fiber layer of the inner core blade body is uniformly reduced from 9mm to 3mm; the thickness of the outer layer of the blade body is 1.5mm; the circumference of the maximum thickness section is uniformly reduced from 151mm to 108mm; the edge plate is 74mm long, 32mm wide, and 3mm thick; the tenon is 50mm long, the maximum width is 15.5mm, the minimum width is 6mm, and the height is 13mm.

6. The method according to claim 5, characterized in that S2 in step 3 includes: All interlayers between two adjacent main fiber layers are grouped together, and each group of interlayers adopts a decreasing layer structure. Each interlayer is named 1, 2, 3, 4, 5, ..., n in descending order of interlayer height, and the laying order is adjusted to 1, 3, 5, 7, ..., n, n-1, n-3, ..., 6, 4, 2, among which layer No. 1 is close to the outer surface side.

7. The method according to claim 6, characterized in that The main fiber layer with a thickness of 3 mm at the tip part of the inner core of the blade body runs through the entire blade.

8. The method according to claim 7, characterized in that The length and width of the reserved part of fabric on the outer layer of the blade body depend on the size of the flattened outer surfaces of the edge plate and the tenon.

9. A silicon carbide fiber turbine rotor blade preform, characterized in that: The preform is prepared according to the method according to any one of claims 1 to 8.

10. The preform according to claim 9, characterized in that The preform is used in an aeroengine.

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