Internal Friction of Hydrogenated Ti (Ni,Cu) Shape Memory Alloys

Abstract:

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Effects of hydrogen doping on the internal friction (IF) of ternary Ti50Ni50-xCux (x=15, 20, 25) shape memory alloys, prepared by rolling and annealing laminating Ti and Ni-Cu alloy sheets, have been measured with a damping mechanical analyzer in a forced bending oscillation mode at temperatures from 173K to 423K at three frequencies, 0.1, 1 and 5Hz. The effects of hydrogen doping on IF are common to the three alloys: a hydrogen IF peak appears at around 260K; the IF peak value (tanφ) increases rapidly with increasing hydrogen concentration up to tanφ=0.03 at 0.5at% and then decreases; the peak temperature also increases rapidly and then gradually decreases. From the frequency dependence of the peak temperature, the activation energy E and the pre-exponential factor ω0 have been analyzed to be E=0.6-0.7eV and ω0=1013-14s-1. The origin of the hydrogen IF is interpreted to be the Snoek-Koester effect due to interaction of twin boundary dislocations and segregated hydrogen atoms. Effects of hydrogen on mechanical properties of the alloys have also been studied.

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Periodical:

Edited by:

N. Igata and S. Takeuchi

Pages:

39-44

DOI:

10.4028/www.scientific.net/KEM.319.39

Citation:

T. Ueura et al., "Internal Friction of Hydrogenated Ti (Ni,Cu) Shape Memory Alloys ", Key Engineering Materials, Vol. 319, pp. 39-44, 2006

Online since:

September 2006

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Price:

$35.00

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