Effect of Al Content on Damping Capacity of Cast Iron

Flake graphite cast iron has high damping capacity. Among the various theories on the damping mechanism of cast iron, the viscoelastic layer between iron matrix and graphite is an important factor. This indicates that the increase in surface area and quantity of graphite would be effective for improving the damping capacity of cast iron. In this research, aluminum, which is a graphitizing element, was added to the flake graphite cast iron. The concentration of aluminum in the cast iron specimens was controlled from 0 to 7 mass%. The graphite and matrix structure were examined by optical microscopy. The perimeter and area ratio of graphite in the cast irons and the damping capacity were measured. Addition of aluminum increased the area ratio and surface area of flake graphite in the cast iron. Addition of 3 mass% aluminum improved the damping capacity of the flake graphite cast irons.