In situ examination of moving crack tips in ordered intermetallics

J. K. Heuer, N. Q. Lam, P. R. Okamoto, James F Stubbins

Research output: Contribution to journalConference articlepeer-review


Recent studies have shown that high stress concentrations at moving crack tips in the intermetallic compound NiTi can induce a crystalline-to-amorphous (C-A) transformation of the crack tip region. This stress-induced C-A transformation has a temperature dependence and crystallization behavior similar to those of ion irradiation-induced C-A transformation of NiTi. The present study examines if these similarities between stress- and irradiation-induced amorphization hold true for two other intermetallic compounds, CuTi and Ni3Ti. In situ straining was performed in an intermediate-voltage transmission electron microscope. The presence or absence of an amorphous phase was determined by dark field imaging and selected area diffraction of crack tip regions. Crack tips in both CuTi and Ni3Ti were found to remain crystalline upon fracture. The observed absence of stress-induced amorphization in Ni3Ti is consistent with its known absence during irradiation, but the absence in CuTi differs from its known irradiation-induced amorphization behavior. Reasons for the similarity and difference are discussed.

Original languageEnglish (US)
Pages (from-to)29-34
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
StatePublished - 1999
EventProceedings of the 1998 MRS Fall Meeting - The Symposium 'Advanced Catalytic Materials-1998' - Boston, MA, USA
Duration: Nov 30 1998Dec 3 1998

ASJC Scopus subject areas

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


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