Graded toughened ultrahigh-temperature ceramic-based composite material inspired by leaves and preparation method thereof

Abstract

The invention belongs to the field of ultrahigh-temperature ceramic-based composite materials, and particularly relates to a graded toughened ultrahigh-temperature ceramic-based composite material inspired by leaves and a preparation method thereof. The preparation method includes the steps that firstly, carbon fibers are coated with a polyethersulfone coating, then silicon carbide nanowires growon the carbon fibers with polyethersulfone as a carbon source, and first-level veins and second-level veins are constructed; secondly, impregnating the carbon fiber on which the silicon carbide nanowires grow into the ultrahigh-temperature ceramic slurry containing the carbon nanotubes, constructing third-stage veins, and drying to obtain a pre-sintered blank; and finally, preparing the graded toughened ultrahigh-temperature ceramic-based composite material inspired by the leaves through hot-pressing sintering. According to the special hierarchical structure, the expansion direction of crackscan be changed through mechanisms such as pulling out, debonding and bridging of the first-stage vein, the second-stage vein and the third-stage vein, the expansion path of the cracks is increased, more breaking energy is absorbed, and the prepared composite material has excellent thermal shock resistance and breaking resistance.

Description

technical field [0001] The invention belongs to the field of ultra-high-temperature ceramic-based composite materials, and in particular relates to a hierarchically toughened ultra-high-temperature ceramic-based composite material inspired by leaves. Background technique [0002] Due to their excellent high-temperature mechanical properties, oxidation resistance, wear resistance, and excellent chemical stability, ultra-high temperature ceramics are expected to be used in key parts of hypersonic aircraft (such as nose cones, leading edges of wings, and belly of the fuselage) . However, it has high brittleness, is very sensitive to cracks, has low fracture toughness (2-5MPa·√m), and low thermal shock resistance (critical temperature difference is 300-500°C). In order to improve the reliability of service in extreme environments (high temperature and oxygen atmosphere), it is urgent to improve the fracture resistance and thermal shock resistance of ultra-high temperature ceram...

AI Technical Summary

Problems solved by technology

[0004] In view of the low fracture resistance and thermal shock resistance of ultra-high temperature ceramics, inspired by leaves, carbon fiber is used as the primary vein (main vein), and silicon carbide nanowires are used as the secondary vein (parallel vein). Carbon nanotubes are used as tertiary leaf veins (reticular veins), and a hierarchically toughened ultra-high temperature ceramic matrix composite inspired by leaves is prepared. Excellent fracture resistance, thermal shock resistance, and good strength, in order to achieve the purpose of the present invention, through the following technical solutions:

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