Micro-Crack Healing in Cubic Zirconia (8Y-CSZ) Using Flash Event

The effect of the DC electric field/current on the crack healing behavior was examined in 8 mol% yttria stabilized cubic zirconia (8Y-CSZ) polycrystals. Microcracks formed in 8Y-CSZ using the micro Vickers technique was healed under the flash conditions at sample temperatures of 1040 degrees C and 1230 degrees C by controlling the DC electric field/current. At high temperatures, releasing the external energies, which were stored by the indentation as the elastic/plastic strains and new crack surfaces, would be driving forces for the crack healing. Thus, the crack healing takes place some extent even for the static annealing without the DC electric field/current and the healing length becomes larger in the cracks formed at the larger loads. As compared to the static annealing, the healing behavior was accelerated by several times under the flash event condition even at the same temperatures. This suggests that the accelerated healing behavior cannot be explained only by the thermal activated processes, but ascribed to non-thermal processes accelerated by the flash event. Since the grain growth behavior was accelerated under the flash condition, the flash event enhanced the healing behavior of the microcrack damages by accelerating the diffusional processes.

Automated summary

The effect of the DC electric field/current on the crack healing behavior in 8Y-CSZ polycrystals was investigated. The results showed that at high temperatures, the external energies stored in the indentations were released and acted as driving forces for crack healing. Compared to static annealing, the healing behavior was accelerated several times under flash event conditions, suggesting the involvement of non-thermal processes accelerated by the flash events.