Katsuaki Suganuma1, Teruaki Fujita1 and Koichi Niihara2
1Department of Materials Science and Engineering, National Defense Academy, Yokosuka
Squeeze casting of potassium titanate whiskers reinforced 6061 aluminum alloy matrix composites was examined. Distribution of whiskers in a preform was varied by the milling of whiskers in water and by the surface activation treatment of whiskers during stirring in water by adding a surface activation agent. The surface activation treatment was proved to be the best to make a uniform distribution of whiskers in a preform, i.e. in a composite. Then, this treatment increased the tensile strength up to 350 MPa and the Young's modulus up to 92 GPa and reduced the thermal expansion coefiicient down to 16 × 10-6 K-1. These properties are desirable for industrial uses of the aluminum matrix composite, combined with the low cost of composite. Sillica binder used to fix the whiskers preform reacted with aluminum melt during casting and disappeared from the FRM. Instead, small particles of γ-alumina were formed on the whisker by the reaction between whisker and aluminum. An amorphous-like layer exists between the precipitates and whiskers in a few nm thickness.
squeeze casting, metal matrix composite, fiber reinforced metal, potassium titanate whisker, interface, aluminum
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