Method for rapidly wetting carbon fibers in ceramic matrix composite material by taking Fe as active element

Abstract

The invention discloses a method for rapidly wetting carbon fibers in a ceramic matrix composite material by taking Fe as an active element, namely, Fe-based or alloy type brazing filler metal containing enough Fe is taken as high-temperature active brazing filler metal, and rapid and compact wetting of the carbon fibers is realized in a manner that the active element Fe and the carbon fibers aresubjected to eutectic reaction. The method has the advantages that rapid wetting of the carbon fibers and densification of original pores and brazing seams in the composite material base material in the near-seam area are achieved through eutectic reaction, and a continuous interface reaction phase formed by interface reaction is avoided; the dissolved carbon in the brazing seams is fully graphitized, so that the thermal stress can be reduced; the brazing temperature reaches 1154 DEG C or above, and the service temperature of a brazed joint can be increased; long-time heat preservation is notneeded, and the surface of the composite material does not need to be modified before welding; no or a small amount of precious metal is contained. The problems that when traditional Ag-based active brazing filler metal and Ni-based brazing filler metal are used for brazing ceramic-based composite materials, the joint heat-resisting temperature is low, and the heat preservation time is long are solved.

Description

technical field [0001] This invention relates to C-oriented f / C (that is, C / C) and C f Active solder design and brazing method for carbon fiber reinforced ceramic matrix composites such as C / SiC (i.e. C / SiC). Background technique [0002] Carbon fiber reinforced ceramic matrix composites (such as C f / C, C f / Compared with metal materials, SiC has two advantages: (1) high temperature strength (C f / C begins to oxidize above 450°C in an oxidizing atmosphere, reference [1]); (2) light density (only 1 / 4 of nickel-based superalloy, 1 / 2 of ceramic material, reference [2, 3]); therefore, it is widely used as a high-temperature structural material. Among them, C f / C composite materials are currently mainly used in aircraft brake systems and spacecraft heat-resistant and ablation-resistant structural materials. [0003] The welding method of carbon fiber reinforced ceramic matrix composites mainly adopts brazing (References [4, 5]). Similar to ordinary ceramic materials, t...

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Problems solved by technology

[0043] For (1) the existing Ag-based active solder (Ag-Cu-Ti) has a low melting point (780°C) and a large noble metal content (~70%); (2) traditional commercially available Ni-based solder (such as BNi-2, BNi-3, etc.) have high brittleness, low melting point (~1000°C), and need a long time of heat preservation to achieve wetting and isothermal solidification; Inherent problems (difficult wetting; thermal stress; poor high temperature resistance), the present invention proposes a method for quickly wetting carbon fibers in ceramic matrix composites with Fe as the active element

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