Effect of SiC and graphite particulates on the damping behavior of metal matrix composites

Abstract

The effect of SiC and graphite (Gr) particulates on the resultant damping behavior of 6061 A1 metal matrix composites (MMCs) was investigated in an effort to develop a high damping material. The MMCs were processed by a spray atomization and deposition technique and the damping characterization was conducted on a dynamic mechanical thermal analyzer. The damping capacity, as well as the dynamic modulus, was measured at frequencies of 0.1, 1, 10 and 30 Hz over a 30 to 250°C temperature range. The microstructural analysis was performed using scanning electron microscopy, optical microscopy and image analysis. The damping capacity of the 6061 Al/SiC and 6061 Al/Gr MMCs, with two different volume fractions of reinforcements, were compared with that of as-received 6061-T6 Al and spray deposited 6061 Al. It was shown that the damping capacity of 6061 Al could be significantly improved by the addition of either SiC or graphite particulates through spray deposition processing. Finally, the operative damping mechanisms were discussed in light of the data obtained from characterization of microstructure and damping capacity.