DOI number:10.1111/jace.71374
Journal:Journal of the American Ceramic Society
Abstract:Ceramics in miniaturized devices are susceptible to high localized stresses, which can drive microstructural evolution. However, conventional mechanical testing techniques lack the spatial resolution and stress concentration capability required to replicate these conditions. Owing to the highly localized stress field it generates, nanoindentation provides an excellent platform for investigating microstructural evolution of materials under high-stress conditions. In this study, we investigate the microstructural evolution of a ZrO2–SiO2 nanocrystalline-amorphous dual-phase ceramic (NADC) using nanoindentation coupled with scanning transmission electron microscopy (STEM). The studied ceramic consists of monocrystalline ZrO2 nanograins (NGs) embedded in an amorphous SiO2 matrix. The presence of ∼43 vol.% ZrO2 NGs in the NADC does not impair the intrinsic deformation capacity of the amorphous SiO2 matrix. Nanoindentation induces multiscale microstructural alterations: at the micrometer scale, densification and plastic flow of the amorphous SiO2 matrix jointly contribute to the irreversible deformation of the ceramic, while simultaneously increasing the local packing density of ZrO2 NGs; at the nanometer scale, subgrain formation, crystal-to-amorphous transitions within ZrO2 NGs, and stress-induced tetragonal-to-monoclinic phase transformation accommodate high localized stresses and strains; and at the atomic scale, dislocation activation and lattice distortion within ZrO2 NGs further facilitate stress relaxation and energy dissipation. These mechanistic insights provide a foundation for understanding the microstructure evolution of dual-phase ceramics containing both crystalline and amorphous phases under high stress.
Co-author:Yongsheng Chang, Mingxi Deng, Bohan Wang
First Author:Le Fu*
Correspondence Author:Guanghua Liu*
Volume:109
Issue:11
Page Number:e71374
Translation or Not:no
Links to published journals:https://ceramics.onlinelibrary.wiley.com/doi/10.1111/jace.71374