Superelastic Properties of Ti-Ni-Cu Alloy Under Mild Hydrogen Absorbing Condition
Tokyo Denki University, 350-03 Hatoyama, Hiki-gun, Saitama, Japan
Superelastic properties of a Ti-Ni-Cu alloy under mild hydrogen absorbing conditions have been studied. It was found that a Ti50Ni40Cu10 alloy indicated higher life cycles, compared with a Ti-Ni alloy, for cyclic superelasticity test under such hydrogen conditions. During cyclic tests, hydrogen reduced superelastic properties by interaction with dislocations due to accumulation of plastic deformation. Possible states of hydrogen in the alloys were supposed to be solid solutioned state and weakly trapped state. Difference in the properties of surface oxide layer seemed to affect the amount of absorbed hydrogen. As a result, the Ti-Ni-Cu alloy was recomended, in comparison with the Ti-Ni alloy, to be applied under higher hydrogen absorbing conditions.
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