The strengthening of aluminum alloy 6061 by fiber and platelet silicon carbide

Abstract An investigation was undertaken to determine the magnitude of the strengthening effect of fiber and platelet silicon carbide in an aluminum alloy 6061 matrix. In addition to a series of tensile tests, a scanning electron microscopy investigation of the silicon carbide morphology and composite void density and a determination of the length-to-diameter ratios of the fibers and the length-yo-thickness ratios of the platelets were conducted. The level of strengthening, which was attributable to the presence of either fiber or platelet silicon carbide, was much greater than that predicted by continuum mechanics theories. The mechanism by which the strengthening occurred is due to the differences between the coefficient of thermal expansion of silicon carbide and that of aluminum, which resulted in a high dislocation density in the matrix.