Paper number 521

INTERFACE MODIFICATION OF POLYMER-DERIVED SIC SINGLE-FIBER AND TI ALUMINIDE COMPOSITES

T. Suzuki, H. Umehara, and X.L. Guo

National Institute of Materials and Chemical Research
1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan

Summary SiC-based-fiber-reinforced Ti aluminide (TiAl) composites whose interfaces were modified by C, BN, W, and Mo coatings were prepared by thermal decomposition of a hydrocarbon, of BCl3 and NH3, and by sputtering. The interface structure and composition were analyzed by scanning electron microscopy, electron probe microanalysis and transmission electron microscopy. The tensile strength properties of composites were tested using model TCM-50 and determined by Weibull analysis. Results showed that the interface between the SiC-based fiber and TiAl matrix was modified markedly by C, BN, W, and Mo coatings compared to non-coated SiC-based-fiber-reinforced TiAl composites. C enrichment by coatings strongly affected interface modification. Of the modified coatings used, W improved the stability of SiC-based-fiber-reinforced TiAl composite interfaces the best, especially above 1200 K.
Keywords polymer-derived SiC-based fiber, Ti aluminide, tensile strength, interface, C, BN, Mo, W coating, compatibility.

Theme : Metal Matrix Composites ; Interface and Interphase

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