Damping behaviour and mechanism of graphite particulate reinforced metal matrix composites

The effect of graphite particulate reinforcement on the resultant damping behaviour of ZA27 metal matrix composites (MMCs) has been investigated in an effort to develop a new functional material. The MMCs were processed by a spray atomization and deposition technique. The damping capacity, as well as the relative dynamic modulus, was measured at frequencies of 1 and 4 Hz in the 30 to 200°C temperature range. There exists a transformation point at 55°C in the internal friction and temperature spectrum of the MMCs. It was shown from microstructural analysis that the damping capacity of ZA27 can be significantly improved by the addition of graphite particles through spray deposition processing. Finally, the operative damping mechanism was discussed in light of the data obtained from characterization of microstructure and damping capacity.