SiCf/SiC composite material flame tube and automatic preparation method thereof

Abstract

The invention discloses an automatic preparation method of a SiCf / SiC composite material flame tube. The preparation method comprises the following steps: preparing an interface layer from SiC fibersby adopting chemical vapor deposition, so as to obtain SiC fibers with a continuous interface layer; performing unidirectional tape laying and filament winding on the SiC fibers with the continuous interface layer according to the fiber volume and fiber orientation obtained by simulation calculation, so as to obtain net size forming preform; performing densifying treatment on the obtained preformby adopting a reactive melt infiltration process and the chemical vapor deposition process; preparing an environmental barrier coating on the surface of the obtained preform; finally, continuously preparing a thermal barrier coating on the surface, thereby fully intelligently obtaining the high-density SiCf / SiC composite material flame tube. The SiCf / SiC composite material flame tube prepared withthe method disclosed by the invention has the characteristics of high temperature resistance and long service life and also has the advantages such as low thermal expansion coefficient, high thermalconductivity, high thermal shock resistance and excellent mechanical property. Meanwhile, the preparation method is high in degree of automation, short in production cycle, low in cost and controllable in quality.

Description

technical field [0001] The invention relates to the technical field of aviation structural materials, in particular to a SiC f / SiC composite material flame cylinder and its automatic preparation method. Background technique [0002] The combustion chamber is one of the core components of an aero-engine. Its main function is to convert the chemical energy of the fuel into heat energy through combustion, so as to improve the ability of the gas to expand in the turbine and nozzle. In the structural composition of the combustion chamber, the flame tube is The place where the combustion is organized is a key component to ensure air splitting, sufficient combustion, uniform mixing and effective cooling of the wall. The reliability, economy and life of the combustion chamber depend to a large extent on the reliability and reliability of the flame tube. Therefore, the development of a high-performance and long-life combustor flame cylinder plays a vital role in improving engine pe...

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Problems solved by technology

[0003] Existing silicon carbide fiber reinforced ceramic matrix (SiC f / SiC) composites have excellent performance and are the first choice to replace superalloys as materials for the hot end components of aero-engines. However, the stress in the service environment will promote the cracking of the composite material matrix, accelerate the damage and corrosion of the material, and affect its performance. The requirement of long service life in high temperature gas environment seriously restricts SiC f / SiC composite material in the application of engine combustion chamber flame tube; for example, the patent of US20120076927A1 provides a method to improve the mechanical properties of fiber-reinforced silicon-carbon composite materials. In the patent, the fiber interface coating is improved by controlling the heat treatment of composite materials. layer and ceramic matrix, and can remove excess silicon in the phase matrix, but the patent has very strict restrictions on treatment time-temperature-environmental conditions, heat treatment even reaches a treatment temperature of 1900 ° C, in vacuum or at a purity greater than 99% In an inert gas environment, the processing time is as long as 100 hours. In addition, the CVI process is used to prepare the ceramic matrix. Although the free silicon can be effectively controlled, the high density of the material cannot be guaranteed, which is not conducive to the application in the market. Therefore, the development of a low-cost Cost-effective preparation of high-performance SiC with high density and removal of excess silicon f The preparation method of the / SiC composite flame cylinder is particularly necessary;

[0004] In addition, in the patent CN106966738B, the three-dimensional four-step method is used to weave the prefabricated body of the combustion chamber flame tube, and the connection part adopts fiber sewing technology. When the flame tube is in a high-temperature gas environment, stress concentration and slight cracks will be formed at the connection, thereby accelerating the damage of the material. and corrosion, seriously restricting the performance of the composite material flame tube; and through figure 1 The finite element method analysis of the temperature field distribution diagram of the flame tube shows that there is a temperature difference of about 240°C between the cold and hot ends of the flame tube, and the temperature gradient inside the flame tube is relatively large, so the temperature difference will cause stress inside the material , and then produce cracks, so the flame tube must have a low coefficient of thermal expansion to ensure the stability of the component size when the temperature changes. At the same time, it must have high thermal conductivity to avoid the failure of the flame tube caused by the concentration of thermal stress; The four-step weaving method basically adopts the method of hand weaving, which has high cost, long construction period and uncontrollable quality. f / SiC composites play a vital role in the wide application of flame tubes

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