SiC fiber reinforced metal matrix composite sample with controllable fiber breakage defects and preparation method and application thereof

Abstract

The present application belongs to the technical field of high-performance metal matrix composites, and particularly relates to a SiC fiber reinforced metal matrix composite sample with controllable fiber fracture defects and a preparation method and application thereof. The preparation method of the sample comprises the following steps: (1) taking a SiC fiber reinforced metal matrix composite precursor filament; (2) making the precursor filaments axially parallel to each other and adhering and fixing them with an adhesive to obtain a precursor filament bundle, and then loading the precursor filament bundle into an alloy sheath; (3) plugging the two ends of the alloy sheath with plugs; and (4) performing hot isostatic pressing. According to a preset defect proportion, a defect distribution plane and a defect distribution mode, the present application calculates the cutting quantity, cutting position and distribution mode of the composite precursor filament sample. The present application changes the common fiber fracture defect phenomenon in the composite from a passive problem that needs to be avoided in the traditional way into an independent research variable that can be actively designed and controlled, and establishes a new type of "preformed defect" experimental method.

Description

Technical Field

[0001] This invention belongs to the field of high-performance metal matrix composite technology, specifically relating to a SiC fiber-reinforced metal matrix composite sample with controllable fiber fracture defects, its preparation method and application, and particularly to a method that can actively and precisely introduce fiber fracture defects in composite materials with controllable location, quantity and distribution. Background Technology

[0002] Continuous SiC fiber-reinforced metal matrix composites possess low density, high specific strength, high specific stiffness, and excellent high-temperature resistance, creep resistance, and fatigue resistance. They can be applied to lightweight, high-strength structural components in the aerospace industry, such as integral engine blade rings, turbine shafts, connecting rods, and piston rods, and have become key candidate materials for high-end equipment like aerospace vehicle engines. However, their performance is highly dependent on the continuity of the reinforcing fibers. In actual manufacturing processes, due to factors such as mold design and molding processes, fiber breakage is often unavoidable at some locations. These defects caused by fiber breakage disrupt the continuity, potentially leading to material performance dispersion and decreased reliability. Therefore, evaluating the performance of composite materials with defects is a crucial part of composite material research. However, directly using actual structural components to evaluate the performance of composite materials with defects is not only costly in sample preparation and testing, but also has a long testing cycle. More importantly, in actual components, multiple defects usually coexist, making it impossible to isolate a single defect and study its impact on composite material performance and fracture mode. This evaluation method is not conducive to exploring the influence of defects on composite materials.

[0003] Currently, the introduction of defects typically involves machining (e.g., wire cutting, milling) intact rod-shaped or plate-shaped samples. During machining, defects are artificially created by sequentially cutting away the outer sheath, composite fibers, and internal matrix. However, this method doesn't only produce fiber fracture defects; it also includes defects in the matrix and sheath, failing to investigate the impact of a single variable (fiber fracture) on the composite material. Therefore, there is an urgent need to establish a method for actively and precisely introducing standardized defects to further understand the influence of the composite material's microstructure on its performance and failure mechanisms. This method would be used to effectively assess the impact of fiber fracture defects on component performance, thereby providing a basis for component reliability evaluation. Summary of the Invention

[0004] To address the passive, random, and uncontrollable fiber fracture defects in existing composite material components, this invention provides a SiC fiber-reinforced metal matrix composite sample with controllable fiber fracture defects, its preparation method, and its applications. Compared to directly testing large components, conducting exploratory experiments using small samples offers advantages such as low cost, convenient operation, and short cycle time. It can replace actual components for effective evaluation of composite material performance and service safety.

[0005] This method can pre-determine the number, spatial location, and distribution pattern of fiber fracture defects, thereby preparing standard specimens with known defect characteristic parameters for systematic research on the influence mechanism of defects on the tensile properties of composite materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing SiC fiber-reinforced metal matrix composite specimens with controllable fiber fracture defects includes the following steps: (1) Take the SiC fiber reinforced metal matrix composite precursor wire, clean it and set it aside; the precursor wire has SiC fiber as the core and is covered with a metal alloy layer on the outer periphery; (2) Take more than 100 pioneer wires from step (1) and attach them together in parallel axial direction, and fix them with adhesive to obtain a pioneer wire bundle, so that the two ends of the pioneer wire bundle are aligned; then insert the pioneer wire bundle into the cylindrical alloy sheath with open ends along the direction parallel to the axis of the pioneer wire bundle and the axis of the alloy sheath, so that the two ends of the pioneer wire bundle and the alloy sheath are aligned; the pioneer wire bundle includes complete pioneer wires and pioneer wires that have been cut and glued together; the number and position of the cut pioneer wires are set according to the preset defect ratio P, defect distribution plane D and defect distribution pattern M. The defect ratio P refers to the percentage of cut precursor fibers in the precursor fiber bundle out of the total number of precursor fibers. The defect distribution plane D refers to the cross section of the pilot wire bundle formed by one or more cutting planes perpendicular to the axial direction of the alloy sheath. The defect distribution pattern M refers to random distribution or concentrated distribution. When the defect distribution plane (D) = 1, the number of adjacent broken precursor wires is ≤ 3, which means that the defects are randomly distributed in the precursor wire bundle. If the number of adjacent broken precursor wires is > 3, the defects are concentrated in the precursor wire bundle. When the defect distribution plane (D) ≥ 2, it means that the defects are randomly distributed in the precursor fiber bundle; (3) Seal both ends of the alloy sheath containing the pilot wire bundle with plugs to obtain a preform of a composite material defect sample; (4) The composite defect sample preform is subjected to hot isostatic pressing to obtain a SiC fiber reinforced metal matrix composite sample containing fiber fracture defects.

[0007] The length of the alloy sheath is the same as the length of the pilot wire; the composition of the alloy sheath and the plug is the same as the metal composition in the SiC fiber-reinforced metal matrix composite pilot wire.

[0008] Furthermore, the SiC fiber-reinforced metal matrix composite precursor filament described in step (1) is prepared by magnetron sputtering, specifically: using continuous SiC fibers as the substrate and a metal alloy as the target material, with a vacuum degree lower than 4×10⁻⁶. -4 The sputtering parameters are: Pa, target distance 10~150 mm, sputtering power 200~4500 W, sputtering current 1~5 A, deposition rate 0.5~2 μm / h, and gas pressure controlled at 0.5~1.0 Pa during sputtering; the volume fraction of SiC fiber in the precursor wire is controlled by adjusting the magnetron sputtering time. The metal alloy mentioned is one of titanium alloy, aluminum alloy, and titanium-aluminum alloy; In the SiC fiber-reinforced metal matrix composite precursor filament, the SiC fiber volume fraction is 40%-80%, and the precursor filament diameter is 120-160 μm.

[0009] Furthermore, in step (2), the distance between two adjacent precursor filaments in the precursor filament bundle is ≤100μm; the cutting refers to cutting only one position for each precursor filament.

[0010] Furthermore, in step (3), the plug is cylindrical in shape and its diameter is equal to the inner diameter of the alloy sheath; The sealing process specifically involves: removing the adhesive used to bond the pilot wire through vacuum heat treatment, followed by electron beam welding to seal the end caps; the vacuum heat treatment is performed at a temperature of 200-500 ℃ for 2-6 hours; the electron beam welding process requires an electron gun vacuum degree ≤9.0×10⁻⁶. -3 Pa; Vacuum chamber vacuum < 4.0 × 10⁻⁶ Pa; -2 Pa; High voltage: 85-100 kV, welding beam current 10-20 mA; Focusing current: 500-1000 mA, welding depth ≤3 mm.

[0011] Furthermore, the hot isostatic pressing process described in step (4) has a temperature of 400-950 ℃, a pressure of 80-180 MPa, and a constant temperature and pressure time of 60-240 min.

[0012] Furthermore, the SiC fiber-reinforced metal matrix composite specimen with fiber fracture defects obtained in step (4) is machined into a dumbbell-shaped tensile specimen to ensure that the cutting positions of the defective fibers are distributed within the parallel segments of the specimen test.

[0013] A SiC fiber-reinforced metal matrix composite sample with controllable fiber fracture defects was prepared by the above-described preparation method.

[0014] An application of a SiC fiber-reinforced metal matrix composite specimen with controllable fiber fracture defects was conducted. A standard tensile test was performed on the specimen, and the mechanical properties and cross-sectional SEM images of the specimen were compared and analyzed with those of a defect-free specimen to determine the threshold of the maximum defect ratio P that is equivalent to the performance of the defect-free specimen. When P ≤ the threshold, the performance of the specimen is equivalent to that of the defect-free specimen.

[0015] Furthermore, when M is randomly distributed and D is set to four or more locations, the threshold for P is 9%; when M is centrally distributed and D is set to one or more locations, the threshold for P is 5%.

[0016] Advantages and benefits of the present invention 1. This invention transforms the phenomenon of fiber fracture defects, which is common in composite materials, from a passive problem that needs to be avoided in the traditional sense into an independent research variable that can be actively designed and controlled, thereby establishing a new experimental method for "pre-made defects".

[0017] 2. This invention prepares a series of standard specimens with standardized defect characteristics by quantitatively controlling defect parameters (such as defect ratio, spatial distribution, etc.), providing key experimental materials for systematic research on the relationship between "defect parameters and mechanical properties".

[0018] 3. The defective samples introduced by the method of the present invention can provide reliable experimental data and theoretical support for damage tolerance design, residual strength assessment and service life prediction of defective or damaged components, thereby improving the safety and reliability of composite material structures in key fields. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the sample preparation process of the present invention; wherein, 1, composite material precursor wire, 2, composite material precursor wire after cutting and gluing, 3, prefabricated defective precursor wire bundle, 4, composite material defective sample preform, 5, plug, 6, alloy sheath, 7, composite material with defects; Figure 2 This is a schematic diagram illustrating the fabrication process of the tensile test bar in the embodiments and comparative examples of the present invention; Figure 3 The defect fiber distribution and fracture location diagram of the defective composite material prepared in Example 1 of the present invention; Figure 4 Industrial CT image of a defective composite material prepared according to Example 1 of the present invention; Figure 5 This is a SEM image of the defect location morphology in Embodiment 1 of the present invention; Figure 6 This is a SEM image of the defect location morphology in Embodiment 2 of the present invention; Figure 7 This is a SEM image of the molding process in Comparative Example 1 of the present invention; Figure 8 This is a SEM image of the defect location in Comparative Example 2 of the present invention; Figure 9 This is a SEM image of the defect location in Comparative Example 3 of the present invention; Figure 10 This is a SEM image of the defect location in Comparative Example 4 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with specific embodiments.

[0021] Example 1: Preparation of SiC fiber-reinforced Ti-55531 composite material with randomly distributed defects, fiber breakage rate of 9% (defect ratio of 9%), and four defect distribution planes. The schematic diagram of this embodiment is as follows: Figure 1 As shown, sample preparation includes the following steps: (1) Select a sufficient number of SiC fiber-reinforced Ti-55531 titanium-based composite precursor wires 1, and clean them sequentially with acetone and anhydrous ethanol using ultrasonic cleaning before use. SiC f The structure of the Ti-55531 precursor wire is as follows: The precursor wire has a SiC fiber core, a length of 50 mm, and is surrounded by a Ti-55531 titanium alloy layer; the SiC fiber has a diameter of 100 μm; SiC... f The Ti-55531 precursor wire has a total diameter of 146 μm and a SiC fiber volume fraction of 47%. This precursor wire was prepared using magnetron sputtering: continuous SiC fibers were used as the substrate, Ti-55531 alloy was used as the target, and the vacuum level was below 4 × 10⁻⁶. -4 Pa was used to deposit a metal alloy layer on the surface of SiC fiber using magnetron sputtering technology. The sputtering target distance was controlled at 150 mm, the sputtering power was 4500 W, the sputtering current was 5 A, the deposition rate was 2 μm / h, and the gas pressure in the coating chamber was controlled at 1.0 Pa during sputtering.

[0022] (2) Prepare a Ti-55531 alloy sheath with an outer diameter of 10 mm, an inner diameter of 3 mm, and a length of 40 mm. Take 300 precursor wires from step (1) and cut them to 40 mm. According to the defect ratio (P) of this example, it is calculated that there are 27 precursor wires that need to be cut. Cut the 27 precursor wires at one of the five equal parts of the 10 mm length at the center length of 20 mm excluding the two ends of the sample to obtain the broken precursor wire. That is, the defect distribution plane (D) is located at 14 mm (6 wires), 18 mm (7 wires), 22 mm (7 wires), and 26 mm (7 wires) from the end, respectively, for a total of 4 locations. Next, the two ends of the cut precursor wire are bonded together using an adhesive (polystyrene and xylene mixed and dissolved in a 1:5 weight ratio) to obtain the cut and bonded composite precursor wire 2. To achieve precise control over the defect distribution plane (D) and the defect distribution pattern (M) of the broken precursor wire within the defect distribution plane, the broken precursor wire and the unbroken precursor wire are axially parallel and bonded together with an adhesive to align the two ends of the precursor wire bundle, resulting in a pre-fabricated defective precursor wire bundle 3. The precursor wire bundle is then inserted into the alloy sheath 6 along a direction parallel to the axis of the precursor wire bundle and the axis of the alloy sheath, with the two ends of the precursor wire bundle aligned with the two ends of the alloy sheath, so that the broken precursor wires are randomly distributed in the precursor wire bundle (in this embodiment, there are 4 defect distribution planes, which conform to random distribution). In this embodiment, the defect distribution pattern (M) within the defect distribution plane is random. Ti-55531 plugs 5 (3 mm in diameter and 5 mm in thickness) are filled at both ends, and the bundle is placed in a vacuum heat treatment furnace (vacuum degree better than 1×10⁻⁶). -3 The adhesive at the defect location was removed by heating to 430℃ and holding for 120 min, and the plug was then welded using a vacuum electron beam. The welding parameters were as follows: electron gun vacuum degree ≤ 9.0 × 10⁻⁶ Pa. -3 Pa; Vacuum chamber vacuum < 4.0 × 10⁻⁶ Pa; -2 Pa; High voltage: 85 kV, welding beam current 15 mA; Focusing current: 500 mA, fusion welding depth ≤3 mm. Finally, a composite material defect sample preform 4 was obtained.

[0023] (3) The defect location matrix (Ti-55531) was filled by hot isostatic pressing and the pilot wire and the sheath were compacted. The specific parameters are as follows: temperature 830 ℃, pressure 140 MPa, constant temperature and pressure time 3 h, and then cooled to room temperature with the furnace to obtain the composite material 7 with defects.

[0024] (4) Process the above composite material into the following form: Figure 2 Prepare bar-shaped tensile specimens of the specifications shown and conduct tensile tests (refer to GB / T 228.1-2010).

[0025] Step (3) yields industrial CT images of the composite material, such as... Figure 3 , 4 As shown, where Figure 3 This diagram illustrates the distribution of defective and intact fibers in the sample, as well as the location of defects. It shows that there are four defect distribution planes, and the broken fibers are randomly distributed. Figure 4 The image shows a plane containing broken fibers, and the formation of the defect location is as follows. Figure 5 As shown, it can be observed that the defective parts of the composite material are filled by the matrix, and the SiC and the matrix are tightly connected at the bonding site to form a reaction layer.

[0026] Example 2: Preparation of SiC fiber-reinforced Ti-55531 composite material with concentrated defect distribution, fiber breakage rate of 5% of the total, and defect distribution plane in one location. The preparation method in this embodiment is the same as in Example 1, except that the defect ratio (P) is 5% and the number of broken precursor filaments is calculated to be 17. These 17 precursor filaments are then cut at the center, resulting in only one defect distribution plane (D). When placing the sample in the sheath, the defective fibers are concentrated near the axis of the alloy sheath (less than 200 μm from the axis), and the remaining positions are filled with unbroken precursor filaments. This results in a concentrated distribution of defective fibers (broken precursor filaments), leading to a concentrated defect distribution pattern (M) within the defect distribution plane. (Concentrated distribution means that if the number of adjacent broken precursor filaments is greater than 3 within a defect distribution plane, the fiber defects within that plane conform to a concentrated distribution; when the defect distribution plane (D) = 1, the defects are concentrated in the precursor filament bundle.) The defect location formation is as follows: Figure 6 As shown, it can be observed that the defective parts of the composite material are filled by the matrix, and the SiC and the matrix are tightly connected at the bonding site to form a reaction layer.

[0027] Comparative Example 1: Preparation of defect-free SiC fiber reinforced Ti-55531 composite material Using the same precursor fiber material, arrangement, and hot isostatic pressing process parameters as in Example 1, but without any fiber cutting operation in step 2, a composite material without prefabrication defects was prepared, with no defects in the fiber axial direction and good continuity.

[0028] Comparative Example 2: Preparation of SiC fiber-reinforced Ti-55531 composite material with randomly distributed defects, fiber fractures accounting for 9% of the total number of fibers, and defects distributed in a single plane. Using the same precursor fiber material, arrangement, and hot isostatic pressing process parameters as in Example 1, but in step 2, the broken precursor fiber is cut only once at the center position, that is, the defect distribution plane (D) is located 20 mm from the end, and a SiC fiber reinforced Ti-55531 composite material with randomly distributed defects, fiber breakage of 9% of the total number, and defect distribution plane at one location is obtained.

[0029] Comparative Example 3: Preparation of SiC fiber-reinforced Ti-55531 composite material with randomly distributed defects, fiber breakage rate of 11% of the total, and defect distribution plane of four locations. Using the same precursor fiber material, arrangement, and hot isostatic pressing process parameters as in Example 1, but with the number of broken fibers in step 2 being 11% of the total number of fibers (defect ratio P = 11%), a SiC fiber reinforced Ti-55531 composite material with randomly distributed defects, 11% of the total number of broken fibers, and four defect distribution planes was prepared.

[0030] Comparative Example 4: Preparation of SiC fiber-reinforced Ti-55531 composite material with concentrated defect distribution, fiber breakage rate of 7% of the total, and defect distribution plane in one location. Using the same precursor fiber material, arrangement, and hot isostatic pressing process parameters as in Example 2, but with the number of broken precursor fibers in step 2 being 7% of the total number of precursor fibers (defect ratio P = 7%), a SiC fiber reinforced Ti-55531 composite material with concentrated defect distribution, fiber breakage of 7% of the total number, and defect distribution plane in one location was prepared.

[0031] Figures 7-10The images show SEM images of the molding conditions or defect locations of Comparative Examples 1-4. From the images, it can be seen that Example 1 and Comparative Example 1 are a group of samples with and without defects under the same preparation conditions. It can be observed that after the hot isostatic pressing process, the matrix can completely fill the defect locations, achieving densification. Example 1 and Comparative Example 2 are a group of samples with different defect distribution planes (D) under the same preparation conditions. It can be observed that when the defect ratio (P) and defect distribution pattern (M) are the same, the more defect distribution planes (D) there are, the more dispersed the defects, and the easier it is for the sample to become dense. Example 1 and Comparative Example 3 are a group of samples with different defect ratios (P) under the same preparation conditions. It can be observed that when the defect distribution plane (D) and defect distribution pattern (M) are the same, the higher the defect ratio (P), the more difficult it is for defects to be filled, and the more difficult it is for the sample to become dense. When M is randomly distributed, D is set to four or more locations, and P ≤ 9%, the voids at the defects are filled by the metal matrix during the hot isostatic pressing process, achieving complete densification. Example 2 and Comparative Example 4 are a group of samples with different defect ratios (P) under the same preparation conditions. It can be found that when the defect distribution plane (D) and defect distribution pattern (M) are the same, the higher the defect ratio (P), the more difficult it is for the defects to be filled and the more difficult it is for the sample to be dense. When M is concentrated, D is set to one or more locations, and P≤5%, the voids at the defects are filled by the metal matrix during hot isostatic pressing, achieving complete density.

[0032] Tensile test results show that the defect-free Ti-55531 composite material in Comparative Example 1 (P=0%, D=0) has a room temperature tensile strength of 1764 MPa. The sample in Comparative Example 2 (P=9%, D=1, M=random distribution) has a room temperature tensile strength of 1628 MPa, the sample in Comparative Example 3 (P=5%, D=1, M=concentrated distribution) has a room temperature tensile strength of 1649 MPa, and the sample in Comparative Example 4 (P=7%, D=1, M=concentrated distribution) has a room temperature tensile strength of 1658 MPa. The sample in Example 1 (P=9%, D=4, M=random distribution) has a room temperature tensile strength of 1719 MPa, and the sample in Example 2 (P=5%, D=1, M=concentrated distribution) has a room temperature tensile strength of 1689 MPa. Compared to the defect-free sample, the room temperature tensile strength of the sample with 9% defects and random distribution is only reduced by 2.6% (≤5%, considered equivalent). Furthermore, when the defect ratio (P) and defect distribution pattern (M) are the same, the more defect distribution planes (D) there are, the better the filling and the higher the tensile strength. When the number of defect distribution planes (D) and defect distribution pattern (M) are the same, the larger the defect ratio (P), the worse the filling and the lower the tensile strength. When the defect distribution pattern (M) is concentrated and the number of defect distribution planes (D) is the same, the larger the defect ratio P, the worse the filling and the lower the tensile strength. This indicates that the location of fully filled defects has little impact on the properties of the composite material. Therefore, the SiC obtained by this invention... f / Ti composite material specimens allow for the artificial control of defect ratio and distribution, with dense filling locations. The preparation process is mature and controllable. The prepared samples can be used for subsequent experiments to investigate the impact of defects on composite materials and to evaluate the impact of fiber fracture defects on component performance, thereby providing a basis for component reliability evaluation.

[0033] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing SiC fiber-reinforced metal matrix composite specimens with controllable fiber fracture defects, characterized in that, Includes the following steps: (1) Take the SiC fiber reinforced metal matrix composite precursor wire, clean it and set it aside; the precursor wire has SiC fiber as the core and is covered with a metal alloy layer on the outer periphery; (2) Take more than 100 pioneer wires from step (1) and attach them together in parallel axial direction, and fix them with adhesive to obtain a pioneer wire bundle, so that the two ends of the pioneer wire bundle are aligned; then insert the pioneer wire bundle into the cylindrical alloy sheath with open ends along the direction parallel to the axis of the pioneer wire bundle and the axis of the alloy sheath, so that the two ends of the pioneer wire bundle and the alloy sheath are aligned; the pioneer wire bundle includes complete pioneer wires and pioneer wires that have been cut and glued together; the number and position of the cut pioneer wires are set according to the preset defect ratio P, defect distribution plane D and defect distribution pattern M. The defect ratio P refers to the percentage of cut precursor fibers in the precursor fiber bundle out of the total number of precursor fibers. The defect distribution plane D refers to the cross section of the pilot wire bundle formed by one or more cutting planes perpendicular to the axial direction of the alloy sheath. The defect distribution pattern M refers to random distribution or concentrated distribution. When the defect distribution plane (D) = 1, the number of adjacent broken precursor wires is ≤ 3, which means that the defects are randomly distributed in the precursor wire bundle. If the number of adjacent broken precursor wires is > 3, the defects are concentrated in the precursor wire bundle. When the defect distribution plane (D) ≥ 2, it means that the defects are randomly distributed in the precursor fiber bundle; (3) Seal both ends of the alloy sheath containing the pilot wire bundle with plugs to obtain a preform of a composite material defect sample; (4) The composite defect sample preform is subjected to hot isostatic pressing to obtain a SiC fiber reinforced metal matrix composite sample containing fiber fracture defects.

2. The method for preparing SiC fiber-reinforced metal matrix composite material specimens with controllable fiber fracture defects according to claim 1, characterized in that: The length of the alloy sheath is the same as the length of the pilot wire; the composition of the alloy sheath and the plug is the same as the metal composition in the SiC fiber-reinforced metal matrix composite pilot wire.

3. The method for preparing SiC fiber-reinforced metal matrix composite material specimens with controllable fiber fracture defects according to claim 1, characterized in that: The SiC fiber-reinforced metal matrix composite precursor filament described in step (1) is prepared by magnetron sputtering, specifically: using continuous SiC fibers as the substrate and a metal alloy as the target material, with a vacuum degree lower than 4×10⁻⁶. -4 The sputtering parameters are: Pa, target distance 10~150 mm, sputtering power 200~4500 W, sputtering current 1~5 A, deposition rate 0.5~2 μm / h, and gas pressure controlled at 0.5~1.0 Pa during sputtering; the volume fraction of SiC fiber in the precursor wire is controlled by adjusting the magnetron sputtering time. The metal alloy mentioned is one of titanium alloy, aluminum alloy, and titanium-aluminum alloy; In the SiC fiber-reinforced metal matrix composite precursor filament, the SiC fiber volume fraction is 40%-80%, and the precursor filament diameter is 120-160 μm.

4. The method for preparing SiC fiber-reinforced metal matrix composite material specimens with controllable fiber fracture defects according to claim 1, characterized in that: In step (2), the distance between two adjacent precursor filaments in the precursor filament bundle is ≤100 μm; the cutting refers to cutting only one position for each precursor filament.

5. The method for preparing SiC fiber-reinforced metal matrix composite material specimens with controllable fiber fracture defects according to claim 1, characterized in that: In step (3), the plug is cylindrical in shape and its diameter is equal to the inner diameter of the alloy sheath. The sealing process specifically involves: removing the adhesive used to bond the pilot wire through vacuum heat treatment, followed by electron beam welding to seal the end caps; the vacuum heat treatment is performed at a temperature of 200-500 ℃ for 2-6 hours; the electron beam welding process requires an electron gun vacuum degree ≤9.0×10⁻⁶. -3 Pa; Vacuum chamber vacuum < 4.0 × 10⁻⁶ Pa; -2 Pa; High voltage: 85-100 kV, welding beam current 10-20 mA; Focusing current: 500-1000 mA, welding depth ≤3 mm.

6. The method for preparing SiC fiber-reinforced metal matrix composite material specimens with controllable fiber fracture defects according to claim 1, characterized in that: The hot isostatic pressing process described in step (4) involves a temperature of 400-950 ℃, a pressure of 80-180 MPa, and a constant temperature and pressure time of 60-240 min.

7. The method for preparing SiC fiber-reinforced metal matrix composite material specimens with controllable fiber fracture defects according to claim 1, characterized in that: The SiC fiber-reinforced metal matrix composite specimens containing fiber fracture defects obtained in step (4) are machined into dumbbell-shaped tensile specimens to ensure that the cut positions of the defective fibers are distributed within the parallel segments of the specimen test.

8. A SiC fiber-reinforced metal matrix composite sample with controllable fiber fracture defects, characterized in that: The composite material sample is prepared by the preparation method according to any one of claims 1-7.

9. An application of a SiC fiber-reinforced metal matrix composite specimen with controllable fiber fracture defects, characterized in that: A standard tensile test was performed on the specimen. By comparing and analyzing the mechanical properties and cross-sectional SEM images of the specimen with those of the defect-free specimen, the threshold value of the maximum defect ratio P that is equivalent to the performance of the defect-free specimen was determined. When P ≤ the threshold value, the performance of the specimen is equivalent to that of the defect-free specimen.

10. The application of the SiC fiber-reinforced metal matrix composite specimen with controllable fiber fracture defects according to claim 9, characterized in that: When M is randomly distributed and D is set to four or more locations, the threshold for P is 9%; when M is centrally distributed and D is set to one or more locations, the threshold for P is 5%.

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