A silicon carbide fiber turbine rotor blade preform and method of making the same

Abstract

The application 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 following steps: preparing by using low-buckling silicon carbide fiber cloth, preparing by dividing the turbine rotor blade into an inner core and an outer layer, and using the integral layer forming method for the inner core and the outer layer, so that the blade body and the tenon in the inner core are an integral whole, and the carrying capacity and the stability of the blade are greatly improved; and the low-buckling silicon carbide fiber cloth has low buckling, good in-plane performance, and the yarn is easier to deform and keep the original mechanical properties of the fiber in the forming process of the blade; compared with the blade prepared by the traditional method, the blade prepared by combining the satin silicon carbide fiber cloth and the integral layer forming has better oxidation resistance, creep resistance, higher damage tolerance and energy absorption performance.

Description

Technical Field

[0001] This invention relates to a silicon carbide fiber turbine rotor blade preform and its preparation method, belonging to the field of materials science and engineering. Background Technology

[0002] Turbine rotor blades are a typical hot-section component in aero-engines. They convert the thermal and pressure potential energy of high-temperature, high-pressure combustion gases into mechanical energy. Therefore, during the operation of an aero-engine, turbine rotor blades must withstand extremely high temperatures and enormous centrifugal forces from high-speed rotation. This places extremely high demands on the heat resistance, lightweight design, and load-bearing capacity of turbine rotor blades. Traditionally, nickel-based superalloys are used for turbine blades. However, the mechanical-thermal properties of traditional nickel-based superalloys have reached their limits and cannot meet the requirements for high temperature resistance, high load-bearing capacity, and lightweight design. In contrast, silicon carbide fiber-reinforced silicon carbide matrix composites have characteristics such as low density, high specific strength, high temperature resistance, oxidation resistance, and corrosion resistance. Compared with nickel-based superalloys, they have stronger heat resistance, lighter weight, lower coefficient of thermal expansion, and greater material anisotropy and design flexibility, making them an ideal material for manufacturing advanced aero-engine turbine rotor blades.

[0003] In the existing technology, the silicon carbide fiber preform structure of turbine rotor mainly includes 2D lay-up, 2.5D and 3D braiding. Compared with 2D lay-up preforms, the silicon carbide fiber reinforced silicon carbide matrix composite material obtained by 2.5D and 3D braided preforms has insufficient in-plane tensile properties. Under the huge centrifugal force brought about by the high-speed rotation of the turbine rotor, the material properties cannot be fully utilized.

[0004] To address the aforementioned issues, Chinese Patent No. CN108897931A discloses a design method for a ceramic-based turbine rotor blade preform. This method employs a 2D layup approach to prepare the turbine rotor blade preform. However, this method involves dividing the blade into modules for layup and performing interlayer stitching at critical locations, which improves interlayer strength to some extent; however, the overall performance of the blade is poor.

[0005] Furthermore, silicon carbide fiber-reinforced silicon carbide matrix composites typically use plain weave silicon carbide fiber fabric for preparation. However, silicon carbide fibers have a high modulus and poor weaveability, while plain weave has many interlacing points, resulting in stress concentration and high friction on the yarns at these points, leading to significant yarn damage. Moreover, silicon carbide fibers are expensive, resulting in substantial cost waste. Additionally, as complex thin-walled curved surface components, silicon carbide fiber-reinforced silicon carbide matrix composite turbine rotor blades undergo torsional deformation during manufacturing, further increasing yarn damage. Summary of the Invention

[0006] To address at least one of the aforementioned problems, this application proposes a silicon carbide fiber turbine rotor blade preform and its preparation method. The method uses a silicon carbide fiber bundle as the core layer, and aramid yarn is wrapped around the outer layer of the silicon carbide fiber bundle to form a wrapping yarn. This yarn is then used to weave a low-crimp silicon carbide fiber fabric. The turbine rotor blade preform is integrally laid up using a 2D layup method with the low-crimp silicon carbide fiber fabric, dividing the preform into an inner core and an outer layer. The inner core is a single piece of fabric that runs through the entire blade, including an inner blade body layer and a tenon inner layer. The outer layer is a single piece of fabric covering the blade, and the edge plate is formed by bending and overlapping the outer fabric.

[0007] Compared to 2.5D and 3D woven preforms, 2D layered fiber preforms exhibit higher tensile strength and greater damage tolerance, and can meet the requirements of complex geometries in various products. The preform structure utilizes low-crimp fabric layups, which, compared to plain weave fabrics, have fewer interlacing points, effectively reducing damage to the yarns caused by fiber crimping, stress concentration, and friction. Aramid yarn, with its high strength and good abrasion resistance, can protect the silicon carbide fiber bundles through wrapping, effectively reducing problems such as wrinkling, fiber bundle fuzzing, and fiber breakage during the torsion forming process of the turbine rotor silicon carbide fiber preform.

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

[0009] Step 1: Turbine rotor blade parameter statistics;

[0010] The dimensions of the turbine rotor blades are measured based on the turbine rotor blade model to obtain the overall dimensional parameters of the blade body, tenon, and rim plate.

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

[0012] The selected silicon carbide fiber fabrics are all low-crimp fabrics, including unidirectional and satin weaves, with a 2D integral layup structure consisting of alternating 0 / 90° layups along the 0° direction of the blade height. The silicon carbide fiber fabric is woven from aramid yarn wrapped around silicon carbide fiber bundles. The silicon carbide fiber bundles are one of Nextel, hi-Nicalon, Tyranno, or Sylramic, with a fineness of 2–3k. The aramid fiber bundles have a fineness of 80–100 tex and are wrapped around the silicon carbide fiber bundles in a herringbone weave pattern using a braiding machine. The warp density of the fiber fabric is 8 yarns / cm, the weft density is 5 yarns / cm, and the thickness of a single layer is controlled at 0.3–0.4 mm.

[0013] Step 3: Core layup of turbine rotor blade prefabrication;

[0014] S1: Turbine rotor blade prefabrication core blade layup:

[0015] Based on 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. By adopting the layer-by-layer reduction method, the uniform variation of the longitudinal and transverse thickness of the blade preform is achieved.

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

[0017] The longitudinal thickness gradient of the tenon is achieved by intercalating main fiber layers. The main layer of the tenon is formed by fiber cloth extending from the main fiber layer of the blade. The initial number of warp layers and rows is determined based on the thickness and width of the equal-thickness area at the connection between the blade and the tenon. This warp cloth extends downwards to the dovetail neck, bends, and then spreads outwards at the same angle at the bottom of the tenon. Smaller intercalating fiber cloth layers are inserted between these main layers using a decreasing layup method as filler.

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

[0019] Based on the uniform thickness of the outer blade layer obtained in step 2, the outer surface of the outer blade layer is extracted and flattened to obtain the required blade outer layer layup shape and size parameters. The flattened outer layer can be approximated as two trapezoids spliced ​​together, so the layup scheme is designed according to the trapezoids; a portion of the fabric in the blade outer layer is reserved to extend downwards as the edge plate and tenon outer layer.

[0020] Step 5: Cut the low-buck silicon carbide fiber cloth according to the layup design in Steps 3-4.

[0021] Step 6: Integral forming of turbine rotor blades;

[0022] The entire layer is laid out in the order of inner core, tenon insert, and outer layer. After the entire layer is laid out, the outer layer is sewn together.

[0023] In one embodiment of the present invention, the core variable thickness design method in step 3 conforms to the composite material layup design guidelines in the aerospace field, and adopts a layup reduction method to achieve uniform changes in the longitudinal and transverse thicknesses of the blade preform.

[0024] In one embodiment of the present invention, in step 3, the fiber layer of the turbine rotor blade main fiber layer with a thickness of the blade tip extends from the blade tip to the tenon portion, ensuring continuity of the blade body by penetrating the entire blade; the portion other than the blade tip thickness achieves uniform variation of gradient thickness through a layer-by-layer reduction method.

[0025] In one embodiment of the present invention, in the design of the tenon intercalation structure in step 3, all intercalations between two adjacent main fiber layers are grouped together. Each group of intercalations adopts a decreasing layup structure. Each intercalation is named 1, 2, 3, 4, 5, ..., n according to the decreasing order of the intercalation height. The layup order is adjusted to 1, 3, 5, 7, ..., n, n-1, n-3, ..., 6, 4, 2, where the No. 1 layup is closer to the outer surface, so that each group of intercalations forms a "bamboo shoot" shaped intercalation structure.

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

[0027] In one embodiment of the present invention, the thickness of the outer layer of the blade 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 made by splicing and sewing together two identical trapezoidal fiber fabrics. The length and width of the reserved part of the outer layer of the blade depends on the size of the outer surface of the edge plate and the tenon after being flattened. The edge plate part is formed by bending and overlapping the outer layer of the blade fabric.

[0029] In one embodiment of the present invention, the quantity 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 this invention are as follows:

[0031] This invention proposes a silicon carbide fiber turbine rotor blade preform and its preparation method. A 2D layup method is used to integrally lay up the turbine rotor blade preform. The blade is prepared by dividing the entire structure into an inner core and an outer layer, both of which are integrally laid up. This method enables the fabrication of turbine rotor blade preforms with complex curved thin-walled structures, resulting in better tensile and bending performance. Furthermore, the blade body and tenon in the inner core are integrated, with the fiber layer running through both the blade body and the tenon. A layer-decreasing layup method is used to achieve a thickness gradient transformation of the blade body. The tenon thickness is gradient-transformed by intercalating layers into the main layer; the outer layer incorporates the fin plate, and the entire fabric covers the blade, fin plate, and tenon, ensuring the continuity of the silicon carbide fiber bundle and greatly improving the blade's load-bearing capacity and stability; furthermore, the fiber cloth used in this invention is a low-bending silicon carbide fiber cloth, which has lower bending, making it easier for the yarn to deform and maintain the original mechanical properties of the fiber during the blade forming process. Compared with common woven structures, it has better in-plane properties, oxidation resistance, creep resistance, higher damage tolerance, and energy absorption performance. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

[0034] Figure 2 This is a schematic diagram of the specific layup of the turbine rotor blades provided in Embodiment 1 of the present invention;

[0035] Figure 3 This is a schematic diagram of a single-unit insertion of the turbine rotor blade tenon provided in Embodiment 1 of the present invention;

[0036] Figure 4 This is a schematic diagram of the turbine rotor blade model structure provided in Embodiment 1 of the present invention. Detailed Implementation

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

[0038] Example 1

[0039] This embodiment provides a silicon carbide fiber turbine rotor blade preform and its preparation method. See the overall design flowchart below. Figure 1 The method includes:

[0040] Step 1: Turbine rotor blade parameter statistics;

[0041] The turbine rotor blades were dimensionally measured to obtain the overall dimensional parameters of the blade body, tenon, and shroud. The blade height was 120 mm, and cross-sectional analysis was performed every 6 mm to obtain the thickness distribution parameters of the cross-section at different blade heights. From the blade root to the blade tip, the maximum thickness decreased uniformly from 12 mm to 6 mm, and the cross-sectional perimeter decreased uniformly from 151 mm to 108 mm. The shroud was 74 mm long, 32 mm wide, and 3 mm thick. The tenon was 50 mm long, with a maximum width of 15.5 mm, a minimum width of 6 mm, and a height of 13 mm.

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

[0043] The selected silicon carbide fiber fabrics are all low-crimp silicon carbide fiber fabrics, with a 2D integral layup structure consisting of alternating 0 / 90° layups along the blade height direction. The silicon carbide fiber fabric is woven from aramid yarn wrapped around silicon carbide fiber bundles, which are 3kSylramic fiber bundles. The warp density is 8 yarns / cm, and the weft density is 5 yarns / cm. The thickness of a single layer of fabric is 0.3mm.

[0044] Step 3: Core layup of turbine rotor blade prefabrication;

[0045] S1: Core layup of turbine rotor blade preform:

[0046] Flatten the twisted blade model, and extract a 1.5mm thick outer layer from the flattened blade model. Based on the thickness distribution parameters of the cross-section at different blade heights obtained in step 1 and the thickness of the extracted outer layer, obtain the structural parameters of the main fiber layer. From the blade root to the blade tip, the maximum thickness of the main fiber layer decreases uniformly from 9mm to 3mm. According to the single-layer thickness obtained in step 2, a total of 30 layers are required. Ten of these layers extend downwards as the tenon main layer, with a thickness of 3mm. Figure 2 As shown, a layer-decreasing method is used 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 intercalating the main fiber layers. The main layer consists of fiber cloth extending from the inner core layer of the blade. The initial number of warp layers and rows is determined based on the thickness and width of the uniform thickness area at the joint. This extends downwards to the dovetail neck, bending and unfolding at the same angle difference to both sides at the bottom of the tenon. Smaller fiber cloth intercalations are inserted between these main layers using a decreasing layup structure as filler, such as… Figure 3 As shown, taking n=9 as an example, all intercalation layers between two adjacent master fiber layers are grouped together. Each group of intercalation layers adopts a decreasing layup structure. Each intercalation layer is named 1, 2, 3, 4, 5, 7, 9 according to the decreasing intercalation height. The layup order is adjusted to 1, 3, 5, 7, 9, 8, 6, 4, 2, where the No. 1 layup is closer to the outer surface, so that each group of intercalation layers forms a "bamboo shoot" shaped intercalation structure.

[0049] Step 4: Development and layup of the outer layer of the turbine rotor blade prefabrication:

[0050] Based on the uniform thickness of the outer blade layer obtained in step 2, the outer surface of the outer blade layer is extracted and flattened to obtain the required blade outer layer layup shape and size parameters. The flattened outer layer can be approximated as two trapezoids joined together, so the layup scheme is designed according to trapezoids. The outer layer thickness is 1.5mm, and a total of 6 layers are required. A portion of the fabric in the blade outer layer is reserved to extend downwards as the edge plate and tenon outer layer.

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

[0052] Step 6: Integral forming of turbine rotor blades:

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

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

[0055] Based on national standards, the basic mechanical properties of a 3mm thick (10-layer fiber cloth laminate) five-layer 3-fly satin-weave 0 / 90° silicon carbide fiber-reinforced silicon carbide matrix composite plate specimen were tested at room temperature. The measured tensile strength was 400 MPa, flexural strength was 705 MPa, compressive strength was 630 MPa, in-plane shear strength was 160 MPa, and elastic modulus was 174 GPa. The satin-weave silicon carbide fiber-reinforced silicon carbide matrix composite exhibits high strength and excellent in-plane properties.

[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 principles of the present invention should be included within 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 includes: Step 1: Measure the turbine rotor blade model and statistically analyze the blade parameters; Step 2: Selection of silicon carbide fiber cloth and layup structure; Step 3: Core layup design of turbine rotor blade prefabrication; Step 4: Development and layup design of the outer layer of the turbine rotor blade prefabrication; Step 5: Cut the silicon carbide fiber cloth according to the layup design in Steps 3 and 4; Step 6: Perform overall layup according to the layup design in Steps 3 and 4. After the layup is completed, sew the outer layer together and twist the blade to obtain the turbine rotor blade. Step 2 includes: The selected fiber fabrics are all low-bending silicon carbide fiber fabrics. The low-bending silicon carbide fiber fabrics are woven from aramid yarn wrapped around silicon carbide fiber bundles. The layup structure is a 2D integral layup method with alternating 0 / 90° layup along the blade height direction. Step 3 includes: S1: Turbine rotor blade prefabrication core blade layup: The structural parameters of the main fiber layer are designed based on the thickness distribution parameters of the blade, and the layering reduction method is adopted to achieve uniform changes in the longitudinal and transverse thickness of the blade preform. S2: Turbine rotor blade prefabricated core tenon layup: The longitudinal thickness gradient of the tenon is achieved by intercalating the main fiber layers. The main layer of the tenon is formed by the fiber cloth extending from the main fiber layer of the blade. The initial number of warp layers and columns is determined according to the thickness and width of the equal thickness area at the connection between the blade and the tenon. The warp extends downward to the dovetail neck and bends, and then spreads to both sides towards the bottom of the tenon at the same angle difference. Fiber cloth intercalation layers are inserted between the main layers using a layer-by-layer decreasing method as filler. In S2: All intercalation layers between two adjacent master fiber layers are grouped together. Each group of intercalation layers adopts a decreasing layup structure. Each intercalation layer is named 1, 2, 3, 4, 5, ..., n according to the decreasing intercalation height. Their layup order is adjusted to 1, 3, 5, 7, ..., n, n-1, n-3, ..., 6, 4, 2, where layup 1 is closer to the outer surface. The 3mm thick main fiber layer in the inner core and tip of the leaf extends through the entire leaf.

2. The method according to claim 1, characterized in that, Step 4 includes: The outer surface of the blade outer layer is extracted and flattened to obtain the required blade outer layer layup shape and size parameters. The flattened outer layer can be approximately regarded as two trapezoids spliced ​​together, so the layup scheme is designed according to the trapezoids. A portion of the fabric in the blade outer layer is reserved to extend downwards as the edge plate and tenon outer layer. The rim plate is formed by bending and overlapping a portion of the fabric reserved on the outer layer of the blade.

3. The method according to claim 2, characterized in that, Step 1 includes: The dimensions of the turbine rotor blades were measured to obtain the overall dimensional parameters of the blade body, tenon, and shroud. The blade height was 120 mm, and cross-sectional analysis was performed every 6 mm to obtain the thickness distribution parameters of the cross-section at different blade heights. The maximum thickness of the blade is uniformly reduced from 12mm to 6mm, wherein the maximum thickness of the inner core blade main fiber layer is uniformly reduced from 9mm to 3mm; the outer layer of the blade is 1.5mm thick; the perimeter 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, 15.5mm wide at its maximum, 6mm wide at its minimum, and 13mm high.

4. The method according to claim 3, characterized in that, The length and width of the reserved portion of the fabric on the outer layer of the blade depend on the size of the outer surface of the edge plate and tenon after it has been flattened.

5. A silicon carbide fiber turbine rotor blade preform, characterized in that, The preform is prepared based on the method described in any one of claims 1-4.

6. The preform according to claim 5, characterized in that, The preform is used in aero engines.

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