Alumina fiber-glass matrix composite

Michalske, T.A. and Hellmann, J. (1988). Strength and toughness of continuous alumina fiber reinforced glass matrix composites. J. Am. Ceram. Soc. 71, 725 731. 

Use the Halpin-Tsai equations to determine the five elastic constants of a unidirectional fiber composite in which alumina fibers are dispersed in a glass matrix. The Young s modulus and Poisson s ratio of polycrystalline AljOj are 400 GPa and 0.23 and for the glass, 70 GPa and 0.20. 

Oxide fibers find uses both as insulation and as reinforcements. Glass fibers, based on silica, possess a variety of compositions in accordance with the characteristics desired. They represent the biggest market for oxide fibers. Unlike other oxide fibers, glass fibers are continuously spun from the melt and are not used at temperatures above 250°C. Short oxide fibers can be melt blown whilst other aluminasilicate and alumina based continuous fibers are made by sol-gel processes. Initial uses for these fibers were as refractory insulation, up to 1600°C, but they are now also produced as reinforcements for metal matrix composites. Continuous oxide fibers are candidates as reinforcements for use up to and above 1000°C. 

Oxide fibers include glass fibers, mullite fibers, zirconia fibers and alumina fibers. Of these, a-alumina-based fibers have been used intensively for ceramic matrix composites. Fiber FP, manufactured by Du Pont in 1979, was the first wholly a-alumina fiber produced [34]. At present, Almax (Mitsui Mining Material Co. Ltd., Japan) and Nextel 610 (3M Co., USA) are commercially available a-alumina fibers. Almax contains 99.5% alumina and has an elastic modulus of 330 GPa, and Nextel 610 has a tensile strength of 2.4 GPa and an elastic modulus of 380 GPa [35]. 

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