On the Damping Behaviour of Niti Shape Memory Alloy

Shape memory alloys exhibit a high damping capacity in the mktensite state. Results obtained from both DMA and cyclic tests under tension-compression load show that the martensite damping capacity in NiTi SMAs is a function of both strain amplitude and annealing temperature. Internal friction due to movements of martensite twin boundaries within both elastic (accommodation) and inelastic (reorientation) ranges as a function of strain amplitude seems to be consistent. A critical annealing temperature exists for deformed NiTi SMAs in order to obtain a high martensite damping capacity. Under tension-compression cyclic loading, the martensite damping decreases as the number of cycles increases, and it tends to stabilize with further cycling.