Platinum Metals Rev., 2000, 44, (4), 157
Damping in Ruthenium Alloys
An important physical property of an alloy is its damping capacity in response to an imparted mechanical force. High damping in iron-ruthenium alloys is closely linked to the amount of ε martensite present.
Scientists at Yonsei University, Seoul, Korea, have investigated the damping capacity of iron-ruthenium alloys, containing 25 and 13 per cent Ru at room temperature, using samples processed to contain various amounts of ε martensite (H.-C. Shin, J.-H. Jun and C.-S. Choi, Scr. Mater ., 2000, 42, (10), 981–986).
Fe-13% Ru, which undergoes a γ→α′ martensite transformation to give α′ single phase, showed poor damping capacity. Fe-25% Ru undergoes a γ→ε martensite transformation and has high damping capacity, dependent on the strain amplitude. For Fe-25% Ru, damping capacity increases with increasing E martensite content at < 3 × 10−4 strain amplitude. At strain amplitude > 4 × 10−4 it reached a peak for a volume fraction of ∼ 42 per cent of ε martensite. Stacking fault boundaries inside the ε martensite plates act as damping sources.