A Method for Rapid Wetting of Carbon Fibers in Ceramic Matrix Composites Using Fe as Active Element

Abstract

The invention discloses a method for quickly wetting carbon fibers in ceramic matrix composite materials with Fe as an active element, that is, using Fe-based or alloy-type solders containing sufficient Fe as high-temperature active solders, through the generation of active element Fe and carbon fibers The way of eutectic reaction realizes fast and dense wetting of carbon fibers. Its advantages are: the use of eutectic reaction to achieve rapid wetting of carbon fibers, and the densification of the original pores in the base metal of the composite material near the seam and the densification of the brazing seam, avoiding the formation of a continuous interface reaction phase from the interface reaction; The carbon is fully graphitized, which can reduce thermal stress; the brazing temperature is above 1154°C, which can increase the service temperature of the brazed joint; there is no need for long-term heat preservation, and no need to modify the surface of the composite material before welding; it does not contain or contain a small amount precious metals. The invention solves the problems of low joint heat resistance temperature and long heat preservation time of traditional Ag-based active solder and Ni-based solder respectively when they are used for brazing ceramic matrix composite materials.

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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