KSN Vikrant, RE García “Electrically charged dislocations in ionic ceramics.” Acta Materialia, 121778, 2025. https://doi.org/10.1016/j.actamat.2025.121778

Abstract

A thermodynamically consistent phase field theory describing coupled electrical, chemical, and mechanical effects on charged dislocations in ionic ceramics is presented. The formulation results in a generalized multiphysical Peach–Köhler force, establishing a critical electro-chemo-mechanical force necessary for dislocation motion, proportional to solute and point defect segregation. For static dislocations in 3% Yttria Stabilized Zirconia (3YSZ), a multipolar electrostatic field develops near the dislocation core, enhancing conductivity along the line. For moving dislocations, three regimes are identified: (1) the small velocity regime, where solute and charge lock the linear defect in place; (2) the intermediate velocity regime, where the electrochemomechanical field stretches ahead of the moving dislocation due to ionic charge shedding; and (3) the high velocity regime, where the dislocation escapes the solute-induced drag forces, enabling large plastic deformation. Conditions for the Portevin–Le Chatelier effect to take place, in agreement with literature accounts, are identified. The resultant temperature-dependent, solute and charge segregation and its effects on sintering are discussed in the context of Joule heating, reduction of local critical stress for densification, and promotion of macroscopic thermal and plastic runaway.