J. Mater. Sci. Technol. ›› 2023, Vol. 142: 216-224.DOI: 10.1016/j.jmst.2022.08.050

• Research article • Previous Articles     Next Articles

Can orientations of directionally solidified dual-phase Al2O3/YAG eutectics be induced by single-phase sapphire seeds?

Liangting Hea, Xu Wangb,*, Jiaze Lia, Wangshuai Xianga, Fuxue Yana, Bailing Jianga, Qiaodan Huc,*   

  1. aSchool of Materials Science and Engineering, Xi’an University of Technology, 5 South Jinhua Road, Xi’an 710048, China;
    bCenter for Advanced Structural Materials, Department of Mechanical Engineering, City University of Hong Kong, Hong Kong 999077, China;
    cSchool of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2022-05-24 Revised:2022-05-24 Accepted:2022-05-24 Online:2022-11-08
  • Contact: *E-mail addresses: . xwang@alum.imr.ac.cn (X. Wang), qdhu@sjtu.edu.cn (Q. Hu)

Abstract: Directionally solidified dual-phase Al2O3/Y3Al5O12 (YAG) eutectic ceramics (DSECs) typically exhibit strong anisotropy. To improve their properties, various single-phase sapphire seeds, including r-axis [1-102], m-axis [10-10], c-axis [0001], and a-axis [11-20], were used as seeds to induce the orientation of the Al2O3/YAG DSECs. The results showed that Al2O3 in the eutectics could be governed by the sapphire seeds. The YAG in each induced eutectic had a specific growth direction endowed by Al2O3 in the as-induced eutectics or the sapphire seed. Herein, we calculated the planar lattice misfits and interfacial strain energies of four crystallographic orientation relationships based on the constructed lattice models. It was elucidated the constraint of the sapphire seed caused YAG to grow following the rule of minimizing the interfacial strain energy. This revealed the reason why Al2O3/YAG DSECs orientation can be successfully induced. These results may provide a novel method for the design of high-performance eutectic ceramic materials.

Key words: Al2O3/Y3Al5O12, Directional solidification, Single-phase sapphire seed, Crystallographic orientation relationship, Interfacial strain energy