Research on damping characteristics of ternary Ti_49.2Ni_49.3Co_1.5 shape memory alloy

The low-frequency dynamic damping characteristics for Ti_49.2Ni_49.3Co_1.5 shape memory alloy are investigated by means of DMTA (dynamic mechanical thermal analysis) method with temperature, frequency and strain amplitude varied. The experimental results show that the ternary Ti_49.2Ni_49.3Co_1.5 shape memory alloy exhibits different damping properties as the phase transformation occurring under the combined temperature and stresses. It is also found that the damping capacity of martensite phase and R phase are substantially superior to that of parent phase, and maximum damping capacity, with minimum of elastic modulus concomitant, is encountered during the phase transformation. The effects of frequency and strain amplitude on damping capacity of martensite phase and R phase are larger than that on the parent phase, and the damping peak of phase transformation declines with the increase of frequency and strain amplitude. Two-stage phase transformation M-R-P takes place during heating process, in which the damping peak of M-R transformation is much higher than that of R-P transformation.