Non-equilibrium local phase formation by high-speed deformation in NiTi

S. Watanabe, K. Kawata, T. Kokie, T. Suda, S. Ohnuki, H. Takahashi, Y. Matsukawa, M. Kiritani

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Materials responses under non-equilibrium conditions, especially in the state far-equilibrium, have been attracting great interest. Although of limited use, there are some tools available for investigating the phenomena, e.g. theoretical approaches such as non-equilibrium thermodynamics or atomistic computer simulation. The present study centers on high-resolution TEM of ordered NiTi specimens subjected to ultra-high-speed plastic deformation at Hiroshima Institute of Technology. Various local non-equilibrium nano-phases were observed to form due to high-speed deformation. Image analysis using high-resolution electron microscopy (HREM) simulation and the FFT technique revealed that those meta-stable phases in the Ni-Ti system were R-phases (Ni4Ti3), O-phases (Ni3Ti2) and amorphous phases. The current study also elaborates on the formation and nature of deformation-induced lattice invariant shear bands. Our results suggest that ultra-high-speed deformation is a promising tool to study the material responses in far-from-equilibrium states.

Original languageEnglish
Pages (from-to)145-149
Number of pages5
JournalMaterials Science and Engineering A
Issue number1-2
Publication statusPublished - 2003 Jun 15


  • Amorphous
  • HREM
  • High-speed deformation
  • Nano-phase
  • NiTi
  • Non-equilibrium

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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