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

doi:10.1016/j.scriptamat.2016.06.022

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 journal › Article › peer-review

50 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 language	English
Pages (from-to)	59-62
Number of pages	4
Journal	Scripta Materialia
Volume	124
DOIs	https://doi.org/10.1016/j.scriptamat.2016.06.022
Publication status	Published - 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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10.1016/j.scriptamat.2016.06.022

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

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.",

author = "Hadi Razavi-Khosroshahi and Kaveh Edalati and Mokoto Arita and Zenji Horita and Masayoshi Fuji",

note = "Funding Information: This work was supported in part by the Advanced Low Carbon Technology Research and Development Program, ALCA (No. 11102789 ), Japan, and in part by a Grant-in-Aid for Scientific Research (S) from the MEXT , Japan (No. 26220909 ). The HPT process was carried out in the International Research Center on Giant Straining for Advanced Materials (IRC-GSAM) at Kyushu University. Publisher Copyright: {\textcopyright} 2016 Acta Materialia Inc.",

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T1 - Plastic strain and grain size effect on high-pressure phase transformations in nanostructured TiO2 ceramics

AU - Razavi-Khosroshahi, Hadi

AU - Edalati, Kaveh

AU - Arita, Mokoto

AU - Horita, Zenji

AU - Fuji, Masayoshi

N1 - Funding Information: This work was supported in part by the Advanced Low Carbon Technology Research and Development Program, ALCA (No. 11102789 ), Japan, and in part by a Grant-in-Aid for Scientific Research (S) from the MEXT , Japan (No. 26220909 ). The HPT process was carried out in the International Research Center on Giant Straining for Advanced Materials (IRC-GSAM) at Kyushu University. Publisher Copyright: © 2016 Acta Materialia Inc.

PY - 2016/11/1

Y1 - 2016/11/1

N2 - 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.

AB - 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.

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JO - Scripta Materialia

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

Abstract

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