Damping behaviours of open cell pure Al foams fabricated by sintering and dissolution process

Abstract

The damping behaviours of the open cell pure Al foams fabricated by sintering and dissolution process (SDP) with the relative density of 0·20–0·25 and the pore size of 1·25–2·5 mm were experimentally investigated. The damping characterisation was conducted on a multifunction internal friction apparatus (MFIFA). The internal friction (IF) as well as relative dynamic modulus (RDM) was measured at frequencies of 1·0, 3·0 and 6·0 Hz over the temperature range 298– 725 K. The measured IF shows that the pure Al foams has a damping capacity enhanced in comparison with pure Al. Especially, an IF peak was found and corresponding to a rapid drop of RDM in the pure Al foams. The temperatures of the internal friction peaks at frequencies of 1·0, 3·0 and 6·0 Hz are respectively 488, 502, and 512 K during ascending temperatures. It is clear that the IF peak is relaxational type and the activation energy associated with the IF peak is about 1·68 ± 0·02 eV. The damping mechanisms can be interpreted in terms of defect effects.

Keywords:

• METAL FOAM
• DAMPING BEHAVIOUR
• INTERNAL FRICTION
• SINTERING