Ti-Niスパッタ膜の超弾性 [in Japanese] Superelasticity of Sputter-Deposited Ti-Ni Thin Films [in Japanese]
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The superelasticity of Ti-48.3, 50.0 and 51.5 at% Ni thin films was evaluated by measuring the stress-strain curves on loading and unloading. It was found that perfect superelasticity is obtainable above the reverse R phase transformation finish temperature for both the Ti-48.3 at% Ni and Ti-51.5 at% Ni thin films, while the Ti-50.0 at% Ni thin film does not show perfect superelasticity. The Ti-50.0 at% Ni thin film was found to be susceptible to plastic deformation because of a single phase. This plastic strain hinders the perfect shape recovery after unloading. In contrast, in the Ti-48.3 at% Ni thin film, crystallization from the amorphous state produces fine distribution of coherent Guinier-Preston zones. These precipitates are considered to impede plastic deformation during stress-induced martensitic transformation, resulting in a perfect shape recovery after unloading, that is, a perfect superelasticity. On the other hand, in the Ti-51.5 at% Ni thin film subjected to solution and aging treatments, fine distribution of Ti<sub>3</sub>Ni<sub>4</sub> was observed and this fine precipitate is considered to be responsible for perfect superelasticity by suppression of plastic deformation.
- Journal of The Surface Finishing Society of Japan
Journal of The Surface Finishing Society of Japan 53(4), 267-272, 2002-04-01
The Surface Finishing Society of Japan