Damping properties of Ti50Ni50-xCux alloys utilizing martensitic transformation

The internal friction (IF) and elastic modulus of rigidity were investigated for Ti50Ni50-xCux shape memory alloys for the composition range of 8 less than or equal to x less than or equal to 20 by utilizing a low frequency inverted torsion pendulum method. The observed extraordinarily large internal friction and large softening in rigidity are discussed, paying attention to low twinning shears of B19 (orthorhombic) martensite. The attained large internal friction Q(-1) = 0.2 for Ti50Ni30Cu20 at peak temperature, and the shoulder temperature of IF indicate that the alloy system is a good damping material which can be used at temperatures higher than room temperature. (C) 2003 Elsevier Science B.V. All rights reserved.