Fig. 1. Microstructures of TiO₂ prepared by flash sintering and comparison of temperature-dependent deformability of flash-sintered TiO₂ with other typical ceramic materials.

(A) Schematics of flash sintering of TiO₂. (B) SEM image of the unpolished flash-sintered TiO₂. (C) Bright-field TEM micrograph showing an area of the flash-sintered TiO2 containing stacking faults. (D and E) TEM micrographs showing high-density dislocations within TiO₂ grains. (F) Ultimate/fracture strain (%) as a function of testing temperatures for flash-sintered TiO₂, conventional TiO₂ (28, 30), and other conventional ceramic systems, including SiCN (31), YSZ (32), and TiC (33). Fracture strain is very low at low temperatures and increases with temperatures for most of the conventional ceramics. However, the flash-sintered TiO₂ exhibits significantly enhanced deformability even at RT (solid magenta circle data points).