Plastic strain and grain size effect on high-pressure phase transformations in nanostructured TiO2 ceramics

Hadi Razavi-Khosroshahi, Kaveh Edalati, Mokoto Arita, Zenji Horita, Masayoshi Fuji

    Research output: Contribution to journalArticlepeer-review

    41 Citations (Scopus)

    Abstract

    Anatase TiO2 was severely deformed using high-pressure torsion and the effect of plastic strain and grain size on phase transformations was investigated. A high-pressure TiO2-II phase (columbite) with the orthorhombic structure was formed under pressures of 1 and 6 GPa. Fraction of TiO2-II increased with increasing the plastic strain and remained stable at ambient pressure. Microstructural analysis showed that TiO2-II was stabilized in grains with sizes less than ~ 15 nm because of high energy barrier for reverse phase transformation, while larger grains had the anatase structure. Large densities of oxygen vacancies and dislocations were also formed after severe plastic deformation.

    Original languageEnglish
    Pages (from-to)59-62
    Number of pages4
    JournalScripta Materialia
    Volume124
    DOIs
    Publication statusPublished - Nov 1 2016

    All Science Journal Classification (ASJC) codes

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

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