Plastic strain and grain size effect on high-pressure phase transformations in nanostructured TiO2 ceramics. (November 2016)

• Record Type: Journal Article
• Authors: Razavi-Khosroshahi, Hadi; Edalati, Kaveh; Arita, Mokoto; Horita, Zenji; Fuji, Masayoshi
• Is Part Of: Scripta materialia. Volume 124(2016)
• Page Start: 59
• Page End: 62
• Publication Date: 2016-11
• Subjects: Titanium oxide (titania) -- Nanostructured ceramics -- High-pressure torsion (HPT) -- Severe plastic deformation (SPD) -- Photoluminescence (PL) spectroscopy; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2016.06.022
• Languages: English
• ISSNs: 1359-6462

Abstract

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. Graphical abstract: