The synthesis of TiAl intermetallic films by a rf magnetron sputtering and the mechanical properties of the microcomposi
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The intermetallic matrix composites reinforced with heat-resistive fibers are expected to improve the ductility and the toughness of intermetallic compounds. Titanium aluminide, TiAl, shows a unique behavior that increases the mechanical strength with increasing temperature up to 1000 K. Vapor phase processings for manufacturing near-net-shaped composites or continuous fiber-reinforced composites will be hopeful methods. The synthesis of TiAl by a magnetron sputtering using a multiple target has been successfully established, and the microcomposites with SiC fibers have been prepared. The TiAl film was evaluated by Auger electron spectroscopy and the x-ray analysis and so on. The tensile strength properties of the SiC/TiAl microcomposites, of which the interface bonding was controlled with the powers of sputtering, were estimated. The results show that the strength properties of SiC/TiAl microcomposites are decreasing with increasing the power of the sputtering, and the irradiation-cured SiC fiber has better compatibility with TiAl than the oxidation-cured SiC fiber.
I. INTRODUCTION
II. EXPERIMENTAL
Titanium aluminides tend to have very attractive properties of a low density and an excellent oxidation resistance at around 1000 K. They, however, suffer from lack of adequate creep strength and, in most cases, from inadequate ductility and toughness.1 The intermetallic matrix composites reinforced with heat-resistive fibers are expected to improve the ductility and the toughness of intermetallic compounds. Titanium aluminide, TiAl, shows a unique behavior that increases the mechanical strength with increasing temperature up to 1000 K. Studies of a synthesis of TiAl by vapor deposition processings are very few. Hardwick and Cordi demonstrated that TiAl was deposited by sputtering from targets of composition Ti-53Al-3Nb and TiB 2 , which never contained less than 6 at. % oxygen.2 The synthesis of TiAl by using a rf magnetron sputtering with multiple targets made of Al and Ti has been successfully established. The relationship between the powers of magnetron sputtering and the strength of SiC/TiAl microcomposites has been clarified. On the other hand, the synthesis of TiAl by chemical vapor deposition using metal-organic compounds has been studied.3 However, the results of the magnetron sputtering are the focus of this paper.
A. Apparatus for rf magnetron sputtering
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J. Mater. Res., Vol. 9, No. 4, Apr 1994
The apparatus for sputtering is shown in Fig. 1. The two-way process in which the substrate is replaced upside down was used to produce a more uniform deposit on fibrous substrate.
50mm Upper view
Cooling
100mm FIG. 1. A principle of the rf magnetron sputtering apparatus applied. 1994 Materials Research Society
T. Suzuki, H. Umehara, and R. Hayashi: The synthesis of TiAl intermetallic films by a rf magnetron sputtering
B. Preparation for multiple target The radial target made of Ti and Al was used to investigate the optimum condition for the TiAl deposition. A 99.9 wt. % purity Ti plate and a 99.999 wt
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