Probing the varying ranges of damping capacity of magnesium alloys containing long-period stacking ordered phases

Traditional high damping Mg alloys, based on the concept of purified matrix, cannot withstand large vibrational strain, inhibiting their practical use. The current study employed Mg alloys containing long-period stacking ordered (LPSO) phase and designed representative microstructures, to probe the varying ranges of damping capacity. It is found that intragranular LPSO lamellae effectively purify the matrix without hindering dislocation vibrations, hence contribute to improving damping capacity at small strain. They also provide additional boost to damping capacity at intermediate strain. Precipitates, as matrix purifiers, are detrimental to damping capacity. Quantitative analyses of damping curves and the correlation with stress-strain data reveal that the transition to the rapidly rising part on damping curves physically corresponds to plastic yielding. This further inspired two perspectives of viewing damping capacity at the characteristic strain values of different materials, representing a paradigm shift of material selection and providing a rational criterion for future alloy development.