Crystalline‐amorphous dual‐phase ceramic nanocomposites regulated by entropy engineering

Abstract

AbstractSolid‐state reaction (SSR) is frequently used to fabricate bulk high‐entropy ceramics (HECs). However, a high temperature and a long dwelling time are typically required to allow the occurrence of SSR. Meanwhile, conventional HECs were typically composed of single‐phase solid solution with micrograins. It is of great interest to develop nanocrystalline dual‐phase HECs under mild conditions. Here, we fabricated entropy‐mediated crystalline‐amorphous dual‐phase ceramic nanocomposites, and the fabrication process showed significantly higher energy and time efficiency than the conventional SSR. The nanocomposites were composed of entropy‐mediated nanoparticles (EM‐NPs) embedded in an amorphous SiO2 matrix. The constituent elements were homogeneously distributed in the EM‐NPs at the atomic level. The EM‐NPs were dislocations‐free but with lattice strain, and they showed a strong coarsening tendency during annealing. The nanocomposites showed a significant solid solution hardening effect. The reported results would provide useful guidance to fabricate nanocrystalline HECs with crystalline‐amorphous dual‐phase microstructure.