DC electric field-assisted sintering for Al2O3/TiC composites: Percolative conduction networks enable uniform densification and enhanced mechanical properties

The advancement of flash sintering (FS) for insulating ceramics, such as Al 2 O 3 , has long been stifled by a persistent thermal-mechanical instability paradox: the extreme electric fields required for initiation inevitably trigger localized Joule heating and runaway densification, culminating in catastrophic structural failure. Herein, we report a DC electric field-assisted sintering paradigm that successfully decouples the beneficial electronic activation of a flash event from its destructive densification kinetics. By architecting a percolative TiC conductive skeleton, we lower the flash initiation threshold to an unprecedented 50 V·cm −1 . Crucially, an immediate transition to a current-controlled regime post-initiation effectively mitigates thermal runaway while sustaining a non-equilibrium, flash-activated state. This state, characterized by a dramatic surge in oxygen vacancies (