A mesoscale multiphysics model of field-assisted sintering

Athermal mechanisms like the generation of Frenkel pairs under electric fields and thermal mechanisms of Joule heating have been suggested to explain the accelerated kinetics of field-assisted sintering. However, there is no consensus in the scientific community regarding the predominant mechanism responsible for accelerating the sintering kinetics under electric fields. In this study, we present a multiphysics model of field-assisted sintering to directly simulate the sintering kinetics in the mesoscale, considering thermal mechanisms only. With yttria-stabilized zirconia as the model system, our simulations reveal that the rapid kinetics of field-assisted sintering cannot be caused by Joule heating alone. Also, there is no evidence in our simulations to support the mechanisms of overheating and incipient melting at the grain boundaries. Our work provides a direct assessment of the efficacy of the thermal mechanisms of field-assisted sintering and indicates that the athermal mechanisms are critical to the rapid sintering rates observed experimentally.