Damping Capacity of Graphite-dispersed Al and Cu Casting Alloys

Al and Cu casting alloys were produced with variations in quantity (0∼24 vol%) and size (177∼900 μm) of graphite particles and in matrix composition in order to determine their effect on the damping capacity. The damping capacity Q−1 of graphite-dispersed Al and Cu casting alloys has been investigated in transverse vibration in the temperature range from room temperature to 150°C. The results obtained are as follows. (1) The damping capacity Q−1 of graphite-dispersed Al and Cu casting alloys increases with increasing graphite content and this is independent of matrix composition. (2) Al casting alloy containing 23 vol% graphite and Cu casting alloy containing 16 vol% graphite exhibits damping capacity Q−1 of 6×10−3 and 4×10−3, respectively. (3) The damping capacity Q−1 of Al and Cu casting alloys depends on the graphite size and increases as the graphite size increases. (4) The temperature dependence of the damping capacity Q−1 in graphite-dispersed Al and Cu casting alloys is small.