Dislocations enabled plasticity in rutile TiO2-x at room temperature

Abstract

Ceramics are widely perceived to be brittle. Recent research showed that the deformability of brittle ceramic can be improved by introducing dislocations into the ceramics by using flash sintering. However, many ceramic materials, including TiO2, have limited room-temperature dislocation mobility. In this work we explored the potential route to toughen ceramic materials by introducing oxygen vacancies into rutile TiO2. Nanoindentation method was employed to investigate the deformation behavior of the oxygen deficient TiO2-x. Detailed post-deformation transmission electron microscopy analyses revealed significant increase in dislocation density. The improved fracture toughness is attributed to the abundant dislocation plasticity in the reduced TiO2 rich in oxygen vacancies. This study provides insight into understanding the influence of point defects and dislocations on the deformation behavior of ceramic materials towards future designs of ductile ceramics under room temperatures.