Influence of rapid solidification on the damping behaviour of some magnesium alloys

Rapid solidification processing of magnesium alloys leads to changes in their microstructure. This paper describes the damping behaviour of Mg, a series of Mg-Ca alloys and QE22 alloy prepared by rapid solidification. We use the logarithmic decrement as the characteristic parameter. The strain dependence of the logarithmic decrement exhibits two regions. At lower strains the logarithmic decrement is strain independent. In the second region the logarithmic decrement depends strongly on strain amplitude. The amplitude independent logarithmic decrement for the specimens prepared by rapid solidification is higher than that for cast specimens. The amplitude independent logarithmic decrement for Mg-Ca alloys prepared by rapid solidification decreases with increasing Ca concentration. Possible mechanisms are discussed.