Microstructure and damping behavior of as-cast ZK51 alloys

The microstructure and damping behavior of as-cast ZK51 magnesium alloys are investigated in the present paper. The results show that the microstructure of as-cast ZK51 magnesium alloys consists of a-Mg and a small quantity of Mg₇Zn₃ phase distributing on grain boundaries or inner grains. At room temperature, damping capacity of as-cast ZK51 magnesium alloys is almost independent on the frequency but increase with strain amplitude. Whereas, damping capacity decreases exponentially with the increasing of frequency at the high temperature of 200°C. Furthermore it is necessary to point out that there is a relaxation damping peak at about 280°C. Damping mechanism of as-cast ZK51 magnesium alloys can be explained by Granato-Lücke theory.