Damping capacity in Fe-Mn binary alloys

The damping capacities of Fe-Mn binary alloys have been investigated in a wide range of manganese content from 5 to 30wt%. The damping capacity increases with increasing manganese content, attains a maximum at approximately 17 wt% Mn, and decreases with further manganese content. It is suggested that the damping mechanisms of Fe-Mn alloys containing gamma and epsilon phases are the stress-induced movement of the defects: stacking fault boundary in gamma, stacking fault boundary in epsilon, epsilon martensite variant boundary, gamma/epsilon interphase boundary. The appearance of the maximum damping capacity at around 17 wt% Mn in Fe-Mn binary system is well explained with the damping mechanisms. The contributions of the damping mechanisms to the overall damping capacities of Fe-17wt%Mn and Fe-21wt%Mn alloys are quantitatively analyzed, which indicates that epsilon martensite bears the major part of their damping capacities.