Method for preparation of ceramic matrix composites by ultrashort pulse laser processing assisted CVI

Abstract

The invention relates to a method for preparing a ceramic matrix composite through ultrashort pulse laser processing assisted CVI (chemical vapor infiltration). The method comprises steps as follows: a preformed body is subjected to boundary layer deposition in a graphite furnace; the preformed body is subjected to densification process with a CVI method, and the preformed body is taken out when the relative density of the preformed body reaches 30%-70%; the composite is subjected to super-fine micro-pore processing through ultrashort pulse laser, so that a transmission channel of a gaseous precursor is dredged; circular deposition is performed, and the ceramic matrix composite with high density is acquired. The method has the advantages as follows: (1), a preformed body pore structure in the deposition process is improved, the bottleneck effect of deposition is eliminated, and the uniformity and the density of the composite are improved; (2), the strength of the composite is improved; (3), the deposition time is shortened.

Description

technical field [0001] The invention belongs to the field of CVI preparation of ceramic matrix composite materials, and in particular relates to a method for preparing ceramic matrix composite materials assisted by CVI by ultrashort pulse laser processing. In the traditional chemical vapor infiltration (CVI) process, ultrashort pulse laser is used Micropores are processed to regulate the diffusion channels of gaseous precursors, thereby reducing the density gradient of the composite material, shortening its manufacturing cycle, and improving the compactness, density uniformity and mechanical properties of the ceramic matrix composite material. Background technique [0002] Ceramic matrix composites overcome the Achilles heel of ordinary ceramic materials, which are brittle and poor in reliability, and make them have the characteristics of metal-like fracture behavior, insensitivity to cracks, and no catastrophic damage. At the same time, they have the high temperature resista...

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Problems solved by technology

In U.S. Patent US5411763, when the thermal gradient CVI method is used to prepare porous structure composite materials, the uniformity of densification can be effectively improved, but the gas transmission is slow, the densification rate of the material is limited, and it is difficult to prepare large-sized and heterogeneous components.

In US Patent 4580524, the FCVI method is used to prepare ceramic matrix composites, which can effectively shorten the densification process and improve the density uniformity. However, the heating of each area in the preform mainly depends on heat conduction, resulting in insufficient densification of the cold surface of the preform.

In the German patent DE4142261, the isothermal pressure gradient CVI process is used to prepare porous structure composite materials, which effectively improves the gas transmission capacity, but there is still the problem of uneven densification

The Journal of Inorganic Materials reported in 2007 that Zeng Xierong and others proposed a microwave heating CVI process. By rationally designing the flow field and selecting a suitable precursor gas for this process, the effective mass transfer efficiency of the precursor gas in the prefabricated body can be effectively improved, thereby accelerating the overall process. The densification rate of the prefabricated body, but the process requires high equipment and is still in the experimental stage

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