Method for producing a three-dimensional braided preform with low fiber volume content

Abstract

The application provides a manufacturing method of a three-dimensional braided preform with low fiber volume content, which comprises the following steps: selecting fibers, braiding the fibers to form a first three-dimensional braided bundle, and the fiber volume content in the first three-dimensional braided bundle is 40%-60%; braiding the first three-dimensional braided bundle again to form a second three-dimensional braided preform, and the fiber volume content in the second three-dimensional braided preform is 20-35%. The three-dimensional braided bundle with the same thickness is used to replace the fiber bundle composed of single filaments, so that the size and distribution of the gap in the preform are more uniform, which is beneficial to the densification of the subsequent curing process, reduces the porosity, and improves certain structure and physical and chemical performance indexes.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a three-dimensional woven preform with low fiber volume content. Background Technology

[0002] When weaving artificial bones, carbon-carbon, carbon-ceramic, and ceramic-ceramic preforms, it is often necessary to meet the technical requirement of low fiber volume content. The main advantages of low fiber volume content are better material uniformity, easier matrix infiltration or deposition, lower porosity, and more prominent physical properties of the composite material. For example, the commonly used fiber volume content is 25%-35%, which exceeds the lower limit of 40% for normal three-dimensional woven preforms.

[0003] Typically, three-dimensional woven preforms are made by spinning and weaving fibers (such as high-performance fibers like carbon, glass, aramid, quartz, ultra-strong polyethylene, alumina, silicon carbide, and silicon nitride, as well as biocompatible synthetic or natural fibers like polylactic acid and silk) along a trajectory set on a three-dimensional weaving platform. This causes the yarns to interweave in multiple directions, forming a three-dimensional spatial structure. Three-dimensional weaving is a near-net-shape forming process, meaning the woven preform closely resembles the final composite material product in size and shape. This eliminates the need for further surface machining after curing to protect the fiber structure and reduce additional processing costs. To form and maintain the shape of the preform, the yarn carrier on the spindle maintains a certain fiber tension during the weaving process. This tension binds all the fibers together to form the designed shape. The magnitude of the weaving tension and the three-dimensional weaving structure (such as three-dimensional four-way, five-way, or multi-way) affect the fiber volume content of the preform to some extent. For example, in a typical three-dimensional weaving structure, the fiber volume content of the preform generally exceeds 40%, ranging from 40% to 60%. If used as a structural material, for the goal of being lighter and stronger, higher-performance fibers and higher fiber volume content are usually chosen. This is because, according to relevant theories, the mechanical properties of three-dimensional woven composite materials are mainly determined by several key indicators such as weaving angle, fiber / matrix properties, and fiber volume content. Therefore, a higher fiber volume content precisely meets these requirements. While higher fiber volume content is difficult to achieve, a fiber volume content below 40% is also difficult to form because the fiber bundles involved in the weaving lack the necessary mutual restraint and support. Even if such a preform can be made, the unstable fiber structure during the subsequent curing process will lead to localized fiber density or looseness, affecting the performance of the product.

[0004] Research and analysis have shown that the amount of space between the closely contacting, relying on, and supporting fiber bundles within the prefabricated body, as well as the fiber content ratio of the fiber bundles themselves, are key factors affecting the overall fiber volume content. In other words, the entire volume is composed of the volume of all the fiber filaments, the space between the fiber bundles, and the space between the individual filaments within the fiber bundles. This provides a direction for further reducing the fiber volume content, namely, increasing the space between the fiber bundles and increasing the space between the individual filaments within the fiber bundles. However, as mentioned earlier, this would result in the loss of the constraint and support between the fiber bundles, or in other words, it cannot be achieved due to the existence of fiber weaving tension. Summary of the Invention

[0005] The purpose of this invention is to provide a method for manufacturing a three-dimensional woven preform with low fiber volume content, which can reduce the fiber volume content while maintaining sufficient constraint and support between the fiber bundles.

[0006] The technical solution adopted in this invention is:

[0007] A method for manufacturing a three-dimensional woven preform with low fiber volume content, characterized in that:

[0008] The selected fibers are first woven in three dimensions to form a primary three-dimensional braided bundle, and the fiber volume content in the primary three-dimensional braided bundle is 40%-60%.

[0009] The primary three-dimensional braided bundle is then used to create a secondary three-dimensional braided preform, which has a fiber volume content of 20-35%.

[0010] The method for manufacturing a three-dimensional woven preform with low fiber volume content, wherein the two-dimensional woven preform is further composited with a matrix material.

[0011] The method for manufacturing the three-dimensional woven preform with low fiber volume content, wherein the matrix material is resin, metal, carbon, or ceramic.

[0012] The method for manufacturing a three-dimensional woven preform with low fiber volume content, wherein the two-dimensional woven preform is artificial bone.

[0013] The method for manufacturing a three-dimensional woven preform with low fiber volume content, wherein: the secondary three-dimensional woven preform is a nozzle.

[0014] The method for manufacturing a three-dimensional woven preform with low fiber volume content, wherein: the secondary three-dimensional woven preform is a throat liner.

[0015] The method for manufacturing a three-dimensional braided preform with low fiber volume content, wherein the secondary three-dimensional braided preform is a crucible or a thermal field device.

[0016] The advantages of using the above process to prepare low fiber volume content preforms are:

[0017] 1. By reducing the fiber volume content, it becomes possible to prepare corresponding composite materials for artificial bones and chemical deposition processes such as gas phase and liquid phase in practical applications;

[0018] 2. Because the fiber bundles composed of monofilaments are replaced by three-dimensional braided bundles of the same thickness, the size and distribution of voids in the preform are more uniform, which is beneficial to the compactness of the subsequent curing process, reduces porosity, and improves certain structural and physicochemical properties.

[0019] 3. The effects are even more pronounced in subsequent structural applications, such as for artificial bones (e.g., Figure 4 For artificial bone tissue made of three-dimensional braided bundles, biocompatibility is better. New tissue attaches more easily to the bone and replaces some of the matrix tissue in porous areas to form blood vessels, nerves, and other tissues. The lower fiber volume content in the artificial bone also reduces its mechanical properties, making it closer to real human bone tissue and avoiding the masking effect of higher-performance artificial bone tissue. For carbon-carbon, carbon-ceramic, and ceramic-ceramic materials, the fiber bundles in the preform of this invention can be finer, combined with better matrix deposition, reducing porosity and significantly improving the material's resistance to ablation and thermal shock. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the fiber structure.

[0021] Figure 2 This is a schematic diagram of a first-level three-dimensional braided bundle.

[0022] Figure 3 This is a schematic diagram of the structure of a two-dimensional three-dimensional woven prefabricated body.

[0023] Figure 4 , Figure 5 , Figure 6 These are schematic diagrams of the artificial bone, nozzle, and throat liner manufactured using the method of this invention. Detailed Implementation

[0024] The solution adopted in this invention focuses on reducing the fiber content within the fiber bundle and increasing the porosity, that is, selecting multiple bundles of finer fibers (such as...). Figure 1 As shown) it first undergoes three-dimensional weaving to form a primary three-dimensional woven bundle (such as...). Figure 2As shown), at this point, the fiber volume content within the primary three-dimensional braided bundle drops to 40%-60% of that in a typical three-dimensional braided preform (in contrast, the fiber volume content of yarn directly bundled from monofilaments is approximately 80-87%). Then, this primary three-dimensional braided bundle is used again to form a secondary three-dimensional braided preform (such as...). Figure 3 As shown, the fiber volume content of the secondary three-dimensional woven preform is reduced accordingly. With reasonable weaving process design, it can be reduced to any value between 20-35% to meet the application requirements.

[0025] In the manufacture of rocket nozzles (such as...) Figure 5 ), throat liner (such as Figure 6 When using materials such as carbon fiber and silicon carbide, to improve ablation resistance and high temperature resistance, smaller k-number (also known as small tow) carbon fibers and silicon carbide fibers are generally selected. However, custom-made 3D braiding machines generally have an upper limit on the total number of yarns they can carry. Therefore, the size of the preforms that can be formed and the structural parts formed after curing are relatively small. This cannot meet the needs of some larger preforms and products. At this time, it is necessary to purchase a larger 3D braiding machine that can carry more yarns. This brings further problems to technology, design, manufacturing, cost, cycle and weaving. For example, an existing structural part requires 800 3k carbon fibers to be woven. With the advancement of technology, it is now necessary to use 16,000 3k carbon fibers to weave larger parts. It is difficult to design and manufacture a 3D automatic braiding machine that can carry so many yarns. If multiple small platforms are combined and semi-manual operation is used, it can be solved, but efficiency and cost will become huge problems.

[0026] The method provided by this invention only requires 20 3k fibers to be first woven into a bundle-shaped preform, and then these bundles are used for corresponding three-dimensional weaving to achieve the weaving of 16,000 3k fibers. Moreover, the fiber volume content is low, which is more conducive to the subsequent gas phase / liquid phase deposition process.

[0027] The method provided by this invention can also be used to manufacture crucibles or thermal field devices (such as production equipment for preparing single-crystal silicon rods).

Claims

1. A method for manufacturing a three-dimensional woven preform with low fiber volume content, characterized in that: The selected fibers are first 3D woven to form a primary 3D woven bundle, and the fiber volume content in the primary 3D woven bundle is 40%-60%; the primary 3D woven bundle is then 3D woven again to form a secondary 3D woven preform, and the fiber volume content in the secondary 3D woven preform is 20%-35%. The secondary three-dimensional woven preform also incorporates a matrix material, which may be resin, metal, carbon, or ceramic. The secondary three-dimensional braided prefabricated body is used for artificial bones, nozzles, throat liners, crucibles, or thermal field devices.

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