Excellent thermal stability of nanostructured Al2O3–Y3Al5O12–ZrO2 eutectic ceramic composites by high-speed directional solidification

Di Zhao, Haijun Su, Shuqi Hao, Zhonglin Shen, Yuan Liu, Yinuo Guo, Peixin Yang, Zhuo Zhang, Min Guo

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The contradiction between the nanostructure and thermal stability is the major obstacle on the way of the practical applications of nanomaterials. Here we demonstrated a simple solution for reconciling this contradiction, i.e., the high-speed directional solidification of a ternary eutectic ceramic composite. Its highly textured lamellar and rod-like nanostructures and low-energy interfaces contributed to an outstanding thermal stability that the nanostructure was maintained after being heated at 1573 K for 100 h. It was uncovered that the high solidification rate of 1080 mm/h had an evident restriction on the growth orientation of the faceted crystals during the solidification process, forming a highly textured nanostructure. Combining with the interface energy minimization mechanism, the low-energy interfaces were simultaneously obtained. The evolution of microstructure and interface characteristics during the coarsening process at the higher temperature was further studied. The lamellar structure presented a better thermal stability than that of the rod-like structure since the former had a constraint on the diffusion dimensions. Moreover, a novel structural evolution pattern in the coarsening process was revealed, which was completely different from that of traditional sintered ceramics. The solidified specimens could further keep stable in density, homogeneity of structure and size of internal pores during heat treatment, contributing to a better stability in hardness than that of traditional sintered specimens.

Original languageEnglish
Article number111035
JournalComposites Part B: Engineering
Volume266
DOIs
StatePublished - Nov 2023

Keywords

  • A. Ceramic-matrix composites (CMCs)
  • A. Layered structures A. Nano-structures
  • Directional solidification
  • E. High-temperature properties

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