Abstract
It is generally known that conventional P/M aluminum alloy parts show remarkable damping characteristics against mechanical vibrations. However, there is few internal friction (Q-1) data available to support this. Accordingly, we measured strainamplitude-dependent Q-1 of 2014 grade Al-(3-6)%Cu-0.5%Mg-0.8%Si sintered materials which were prepared from elemental mixes, at the ambient temperature by the cantilever method, with the density ratio of about constant 93%. The results are as follows: (1) In the strain-amplitude-independent part, the Q-1 measured is 7.5-8.1x10-3, which is about 10 times higher than the value of sintered iron. Moreover, after T6 treating these materials, they were found to have an even higher Q-1 than the as-sintered materials. (2) An increase in Cu content resulted in a decrease in the Q-1 of both the as-sintered and T6 treated materials. (3) Damping mechanisms appeared to be relaxations due to dislocation motion and reversible multiphase boundary sliding.
