Damping Evolution During Precipitation in Al-Mg-Si Alloys

Abstract

Damping capacity and shear elastic modulus measurements have been carried out during precipitation in AlMgSi alloys. After the specimen has been aged at the temperature corresponding to the lowest thermoelectric power, both damping and elastic modulus increase comparing with the as-quenched state. The effect of strain amplitude was investigated in specimens aged at different temperatures. A critical strain amplitude, E,, has been observed. For strain amplitudes higher than E,, the damping capacity increases strongly with strain amplitude. In addition a relaxation peak appears around 420K after ageing. The strong damping-amplitude effect and the relaxation peak are attributed to the breakaway of the dislocation from the solute atoms at low temperature and to the dragging of these solute atoms by the dislocations at high temperature respectively.

Microstructural Characteristics and Vibration Fracture Properties of Al-Mg-Si Alloys with Excess Cu and Ni

“…2) In the past decade, several research works have been devoted to the vibration behavior of Al-Mg-Si alloys. [3][4][5][6] With respect to the effect of aging conditions, it was found that aging conditions significantly affect the resonant vibration properties, such as vibration deformation feature and damping capacity. The peak aged samples possess a poor damping capacity mainly due to the decrease in dislocation mobility.…”