Use of Zr–Ti Alloy Melt Infiltration for Fabricating Carbon-Fiber-Reinforced Ultrahigh-Temperature Ceramic Matrix Composites

Yutaro Arai,Ryo Inoue,Tomoki Marumo

doi:10.3390/jcs5070186

Abstract

Carbon-fiber-reinforced ultrahigh-temperature ceramic (C/UHTC) matrix composites are an attractive candidate for fabricating various hot structures. The present study aimed to establish a Si-free Zr–Ti melt-infiltration method for fabricating C/UHTC matrix composites. To achieve this, the wettability of Zr–Ti alloys on carbon and their reactivity to carbon were examined. The alloys were melted on graphite plates and infiltrated into model preforms, which were made of porous carbon and had median pore diameters of 3 μm. The results showed that the apparent contact angle between Zr–Ti and C measured from melted alloys on carbon in room temperature was ~20–42° and that the alloys infiltrated into the preforms regardless of the Zr or Ti content. However, with an increase in the Zr content in the alloys, carbon disappeared and was absorbed into the alloys since the reactivity of Zr was higher than that of Ti and the specific surface area of the porous preform was higher than that of carbon-fiber-reinforced carbon composites, which are a typical preform of C/UHTC matrix composites. These results clearly indicate that not only the capillary flow during infiltration but also the reactivity of alloys to preforms should be considered in the process design for fabricating high-density composites via Zr–Ti infiltration.

Highlights

Transition metal borides and carbides with melting temperatures of >2500 ◦ C are well known as ultrahigh-temperature ceramics (UHTCs) [1,2,3]
The angle increased with a decrease in the Ti content in the Zr–Ti alloys
The wetting of Zr–Ti alloys on carbon is favorable since the alloys are spread on the graphite plate and the wetting angles estimated from solidified samples are 20–42◦

Summary

Introduction

Transition metal borides and carbides with melting temperatures of >2500 ◦ C are well known as ultrahigh-temperature ceramics (UHTCs) [1,2,3]. UHTCs and their composites with a dispersed second phase, such as SiC, MoSi2 , and ZrSi2 can be used in oxidizing atmospheres due to the fact that an oxide scale is formed, which prevents further oxidation [4,5,6,7]. Matrix composites have been developed [8]. C/UHTC matrix composites are classified as ceramic matrix composites (CMCs) and have good damage tolerance since carbon fibers prevent unstable crack propagation even after matrix cracking occurs in UHTCs [9,10]. Since the oxidation behavior of C/UHTC matrix composites is similar to that of monolithic

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Conclusion