Effect of Zn content and solution treatment on damping capacities of MgZn casting alloys

Abstract

The effects of Zn content and solution treatment on the damping capacities of Mg-(0-6)% Zn casting alloys were investigated. In the ascast state, increasing Zn content led to an increase in the volume fraction of the MgZn phase, and to the deterioration of the damping levels, both in the strain-amplitude-independent and strain-amplitude-dependent regions. The microstructural evaluation indicated that the increased Zn concentration in the α-(Mg) matrix and increased number of MgZn particles are responsible for the deterioration of the damping in the strainamplitude-independent and strain-amplitude-dependent regions, respectively. The solution-treated Mg-6% Zn alloy exhibited better strainamplitude-dependent damping than the as-cast one, but the tendency was reversed in the strain-amplitude-independent region. The dissolution of the MgZn phase and the correspondingly increased Zn concentration in the α-(Mg) matrix after the solution treatment can explain the reversed damping behaviors in the strain-amplitude-dependent and strain-amplitude-independent regions, respectively.