Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Sapphire-reinforced NiAl matrix composites with chromium or tungsten as alloying additions were synthesized using casting and zone directional solidification (DS) techniques and characterized by a fiber pushout test as well as by microhardness measurements. The sapphire-NiAl(Cr) specimens exhibited an interlayer of Cr rich eutectic at the fiber-matrix interface and a higher interfacial shear strength compared to unalloyed sapphire-NiAl specimens processed under identical conditions. In contrast, the sapphire-NiAl(W) specimens did not show interfacial excess of tungsten rich phases, although the interfacial shear strength was high and comparable to that of sapphire-NiAl(Cr). The postdebond sliding stress was higher in sapphire-NiAl(Cr) than in sapphire-NiAl(W) due to interface enrichment with chromium particles. The matrix microhardness progressively decreased with increasing distance from the interface in both DS NiAl and NiAl(Cr) specimens. The study highlights the potential of casting and DS techniques to improve the toughness and strength of NiAl by designing dual-phase microstructures in NiAl alloys reinforced with sapphire fibers.
Asthana, R.; Tiwari, R.; and Tewari, Surendra N., "Influence of Cr and W Alloying on the Fiber-Matrix Interfacial Shear-Strength in Cast and Directionally Solidified Sapphire Nial Composites" (1995). Chemical & Biomedical Engineering Faculty Publications. 26.
Asthana, R., Tiwari R., & Tiwari, S.N. (1995). Influence of Cr and W Alloying on the Fiber-Matrix Interfacial Shear-Strength in Cast and Directionally Solidified Sapphire Nial Composites. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science 26, 2175-2184.
Copyright 1995 ASM International. This paper was published in Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 26, Issue 8, pp. 2175-2184 and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.
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