In light of the increasing interest in dislocation-tuned functional properties and the technological potential that dislocations may hold in oxides, dislocation-based mechanical properties are also drawing increasing attention. To tackle the challenge of engineering dislocations into brittle ceramic materials without crack formation, we have separately examined the dislocation behavior including dislocation nucleation, multiplication, and motion, enabling us to tune dislocations into some ceramic materials at room temperature [1, 2]. We have achieved a toolbox for engineering dislocation density ranging from ~10¹¹/m² to ~10¹⁵/m² with a plastic zone size of up to hundreds of micrometers, providing a robust platform to study the dislocation-tuned mechanical properties, such as plasticity, fracture toughness, and damage tolerance, over a wide range of length scales. In this talk, I will first briefly introduce the toolbox for room-temperature dislocation engineering in ceramics, and then focus on the nanoindentation hardness, plastic deformation (e.g., pillar compression), and fracture toughness tuned by the pre-engineered dislocations (with different densities up to ~10¹⁵/m² and spatial arrangement). The proofs-of-concept on SrTiO₃ will be demonstrated and further extended to other oxides to showcase the general applicability. In the end, I will briefly discuss the thermal stability of dislocations engineered at room temperature to suggest its potential application at elevated temperatures.

References:

[1] X. Fang, A. Nakamura, J. Rödel, Deform to perform: Dislocation-tuned properties of ceramics, ACerS Bulletin 102(5) (2023) 24-29.

[2] X. Fang, Mechanical tailoring of dislocations in ceramics at room temperature: A perspective, Journal of the American Ceramic Society 107(3) (2024) 1425-1447.