Dislocation-enabled plasticity in rutile TiO_2-x at room temperature

Area of Science:

• Materials Science
• Ceramic Engineering
• Solid State Physics

Background:

• Ceramics are typically brittle, limiting their applications.
• Flash sintering can introduce defects to improve ceramic deformability.
• Titanium dioxide (TiO2) exhibits limited room-temperature dislocation mobility.

Purpose of the Study:

• To explore toughening ceramic materials by introducing oxygen vacancies into rutile TiO2.
• To investigate the deformation behavior of oxygen-deficient TiO2-x using nanoindentation.
• To understand the role of point defects and dislocations in ceramic deformation.

Main Methods:

• Nanoindentation was used to assess the mechanical properties of TiO2-x.
• Transmission electron microscopy (TEM) was employed for post-deformation analysis.
• Oxygen vacancies were controllably introduced into the TiO2 lattice.

Main Results:

• Oxygen-deficient TiO2-x showed significantly increased dislocation density.
• The introduction of oxygen vacancies enhanced dislocation plasticity.
• Improved fracture toughness was observed in reduced TiO2 specimens.

Conclusions:

• Oxygen vacancies are a viable route to enhance the ductility of ceramic materials like TiO2.
• Abundant dislocation plasticity in reduced TiO2 contributes to improved fracture toughness.
• This research offers insights for designing more ductile ceramics at room temperature.