Damping characteristics of TiNi shape memory alloy wires reinforced epoxy resin

TiNi-based shape memory alloys possess good-damping capacity at the martensite state because of abundant easily movable twin boundaries. However, most TiNi-based shape memory alloys only show an extremely low damping capacity at temperature above room temperature because their martensitic transformation temperature is not high enough. Incorporating the TiNi-based shape memory alloys into a host polymer-matrix could improve the extremely low damping capacity at higher temperatures. In this study, we investigate the damping properties of TiNi shape memory alloy wires reinforced epoxy resin by dynamic mechanical analysis. The peak temperature and apparent activation energy of the glass transition peak (Tg peak) for TiNi wires/epoxy composites do not show significant difference with the number of inserted TiNi wires. With the increase of inserted TiNi wires in the composite, the damping capacity of the martensitic transformation peak increases, but that of the Tg transition peak decreases. The martensitic transformation peak of the annealed TiNi wires/epoxy composite exhibits a higher damping capacity since the defects/dislocations, which restrain the volume of the transformed martensite in TiNi wires can be eliminated after annealing.