Surprising Results of a Study on the Plasticity in Strontium Titanate

Abstract

Oxides such as SrTiO3 are expected to fail via brittle fracture at low temperatures. Surprisingly, in the present study, SrTiO3 single crystals could be plastically deformed in compression in two temperature ranges: from 78 K to ∼1050 K and from 1500 K to 1800 K. SrTiO3 was brittle at temperatures between these two ranges (∼1050–1500 K). This phenomenon of a ductile–brittle–ductile transition, together with microstructural investigations, suggests that the role of dislocations in the plasticity of ceramics must be reconsidered.

First principles determination of dislocations properties of MgSiO3 perovskite at 30GPa based on the Peierls–Nabarro model

“…In the following, the pseudo-cubic setting will be referred by the subscript "c" while no indication will be given when the actual orthorhombic symmetry will be used. Transformations from cubic to orthorhombic (Pbnm) or orthorhombic to cubic directions are given by: (Doukhan & Doukhan 1986;Wright et al 1992, Besson et al 1996, BaTiO 3 (Doukhan & Doukhan 1986;Lin & Lu 2002), SrTiO 3 (Nishigaki et al 1991, Wang et al 1993, Mao & Knowles 1996, Matsunaga & Saka 2000Brunner et al 2001;Gumbsch et al 2001;Zhang et al 2002a, b;Jia et al 2005) { } c family.…”

Room-Temperature Plastic Deformation of Strontium Titanate Crystals Grown from Different Chemical Compositions

“…The mechanical properties of strontium titanate (SrTiO 3 ) crystals have received growing interest due to the fact that they can exhibit a large degree of plasticity even at low temperatures [3][4][5][6][7][8][9][10][11]. SrTiO 3 is an oxide with a cubic perovskite structure belonging to the Pm3m space group.…”

“…SrTiO 3 is an oxide with a cubic perovskite structure belonging to the Pm3m space group. It has been reported that SrTiO 3 crystals can plastically deform in temperature ranges from 78 K to 1050 K [3,4]. In addition, SrTiO 3 crystals can deform up to and over 10% if they deform at a slow strain rate of 10 −4 (s −1 ) [6,7].…”

Dislocations in plastically deformed SrTiO3

“…It is cubic except below 105 K where the crystal structure changes to tetragonal and below 65 K to orthorhombic (c/a = 1.002). Despite this seemingly simple structure the plastic behaviour (under compression) of this material recently turned out to exhibit quite a spectacular ductile-to-brittle-to-ductile transition (DBDT) [1,2] (see Fig.1). …”