Effects of amount of ε martensite, carbon content and cold working on damping capacity of an Fe-17% Mn martensitic alloy

Damping capacity of an Fe-17% Mn alloy has been studied with respect to several factors such as volume fraction of ε martensite, carbon content, and cold rolling. In the case of subzero cooling, the damping capacity of an Fe-17% Mn alloy increases with increasing ε martensite content. In case of thermal cycling, however, the damping capacity decreases with increasing ε martensite content, because the dislocations, which act as barriers to operation of damping sources, are introduced during the thermal cycling. The carbon contents above 0.06 wt.% deteriorate the damping capacity of the Fe-17% Mn alloy, which is ascribed to an interaction between damping sources and carbon atoms and to the decrease in volume fraction of ε martensite with the increase in carbon content. The damping capacity of the Fe-17% Mn alloy shows a maximum value around 10% reduction in thickness, and decreases with further deformation. The increase in damping capacity up to 10% deformation is attributed to an increase in ε martensite volume fraction with increasing deformation, and a decrease in damping capacity above the 10% deformation is ascribed to the stress-induced α′ martensite and dislocations formed during deformation, which act as barriers to operation of damping sources.