COMPOSITION CONTROL IN ALUMINUM BORON CARBIDE COMPOSITES

The Dow Chemical Company's Aluminum-Boron Carbide Composite (AlBC) is a material which has the density of aluminum combined with significantly improved stiffness, hardness and ability to perform in continuous use at temperatures substantially higher than aluminum. AlBC composite is electrically conductive, has high compressive strength and high heat capacity. AlBC represents a broad family of materials which can be tailored during the manufacturing process to the material requirements of different applications. AlBC composites span the composition range from ceramics to metals in the ratios from 99:1 to 1:99. In the upper range of ceramic content, the properties of AlBC composites are similar to those of ceramics with improved toughness and in the lower range similar to metals but with improved hardness, wear resistance and higher temperature resistance. This paper discusses the design and properties of AlBC materials in the intermediate compositional range between similar to 65% and 90% ceramic content. The composition at the lower boundary of this range is an alternative to conventional aluminum metal-matrix composite (Al-MMC) for applications that require performance beyond the useful range of typical Al-MMC. The upper boundary composition is an alternative to cast iron in weight-sensitive applications that require temperature stability up to 500-600 degrees C.