Development of High-Strain-Rate Superplastic Oxide Ceramics Based on Flow Mechanism

Abstract

In order to attain high-strain-rate superplasticity (HSRS) in ceramics, flow behavior was examined with ZrO2reference sample. The results suggest that the enhancement of the accommodation processes of grain boundary sliding (GBS) is important in addition to the careful controlling the microstructural factors, such as stable fine grain structure, reducing residual pores and so on. The spinel particles dispersion can simultaneously provide the following positive factors to ZrO2: i) suppressed grain growth due to pinning effect of spinel particles, enhanced accommodation due to ii) accelerated relaxation of stress concentrations exerted by GBS through dislocation motion and iii) accelerated lattice diffusion caused by the dissolution of aluminum and magnesium into ZrO2from the spinel particles. The positive factors due to spinel dispersion make it possible to attain HSRS in ZrO2ceramics.