Material performance and phase transformation of super rapidsolidified shape memory TiNiCu ribbon with nano-amorphous microstructures

Masanori Yokoyama, Yasubumi Furuya, Yoshiaki Shinya, Teiko Okazaki, Setsuo Kajiwara, Takehiko Kikuchi, Kazuyuki Ogawa, Hisamichi Kimura, Akihisa Inoue

Research output: Contribution to journalArticle

Abstract

The sputter-deposited nano-structured thin films of shape memory TiNiCu alloy show excellent shape memory properties by the addition of Ti composition over 50at%, which are brought by the unique nano-precipitation produced by low temperature crystallization (=Tx) treatment. However, the applicability of thin film actuator is restricted to only very small and tiny micro-machines due to the small mass and, hence, small recovery force as a mechanical actuator. In the present paper, we have investigated the possibility of obtaining larger mass of actuator material as well as improvement of shape memory properties of the same kind of TiNiCu for rapidsolidified (RS) thin ribbons that were about 2-5 times thickness than sputtered film. As a result, 1) an amorphous state was formed in the rapid-solidified Ti-rich Ti50Ni40Cu10 composition (Ti54Ni40Cu6 ,at%) under a roll-speed over 45m/sec. condition as in the sputtering process, 2)by annealing just below Tx(=754K) for amorphous ribbons, nano-crystalline structures with nanoprecipitation of bct (non-equilibrium phase) were observed in the matrix. These nano-microstructured TiNiCu ribbons showed good material properties of tensile strength and almost the shape recovery stress to those of sputtered films.

Original languageEnglish
Pages (from-to)233-236
Number of pages4
JournalJournal of Metastable and Nanocrystalline Materials
Volume24-25
DOIs
Publication statusPublished - 2005 Dec 1

Keywords

  • Amorphous
  • Nano-structured material
  • Nitinol
  • Phase transformation
  • Rapid-solidification
  • Shape memory alloy

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Materials Science(all)
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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