Heterogenity of Microstructure Evolution in NiTi (50 at% Ni) Alloy Severely Deformed by High Pressure Torsion

R. Singh*, J. Fiebig, S. Ostendorp, H. Rösner, E. A. Prokofyev, R. Z. Valiev, S. V. Divinski, G. Wilde

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Citation (Scopus)


An equiatomic B2 NiTi alloy, severely deformed by high-pressure torsion, was investigated. Nanocrystallization of the as-deformed amorphous matrix has been examined. The formation of internal porosity after long-time annealing was established by the radiotracer technique. Such a porosity prohibited reliable measurements of grain boundary diffusion of the 44Ti tracer in the nanocrystallized NiTi alloy. The percolating porosity does not exist in the as-deformed state of NiTi alloy; its formation was affected by free volume redistribution during nanocrystallites' growth under residual stresses. The atomic force microscopy study reveals a highly modified surface with average roughness of about 50 nm after annealing the samples at 600 K for 7 d.

Original languageEnglish
Title of host publicationSupplemental Proceedings
Subtitle of host publicationMaterials Fabrication, Properties, Characterization, and Modeling
PublisherJohn Wiley and Sons Inc.
Number of pages8
ISBN (Electronic)9781118062142
ISBN (Print)9781118029466
Publication statusPublished - Apr 20 2011
Externally publishedYes


  • Grain boundary
  • Nanocrystalline material
  • Porosity

ASJC Scopus subject areas

  • General Engineering
  • General Materials Science


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