Damping properties on age hardening of Al–7Si–0.3Mg alloy during T6 treatment

The present study aimed to investigate the effect of age hardening on variation of damping capacity with tensile properties of Al–7Si–0.3Mg aluminum alloy. As an index of damping capacity, the specific damping capacity was chosen and obtained from conversion with logarithmic decrement on fluctuation decay curve by cantilever beam type excitation. The T6 treatment condition for maximum specific damping capacity (SDC) is coincided with the maximum age hardening condition by formation of GP zone (Mg2Si), but it is simultaneously decreased with overaging. Although the SDC of solution-treated specimen decreased with solutionizing time, the SDC at peak aging condition increases with solutionizing time. The damping behavior of Al–7Si–0.3Mg alloy during age hardening was influenced remarkably upon the dislocation damping mechanism based on the Granato–Lücke theory.