Introduction of low strain energy GdAlO3 grain boundaries into directionally solidified Al2O3/GdAlO3 eutectics

• DOI: 10.1016/j.actamat.2021.117355
• Publication Date: 2021-09-30T13:54:41Z
• Authors: Xu Wang; Wen Zhang; Yujie Zhong; Luchao Sun; Qiaodan Hu; Jingyang Wang
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract In order to tune the mechanical properties of the Al2O3/GdAlO3 (GAP) eutectic ceramics, low energy GAP grain boundaries (GBs) were introduced into Al2O3/GAP eutectic ceramics. We prepared single-crystal Al2O3/bi-crystal GAP eutectic ceramics with the directional solidification technique, in which the Al2O3 was single-crystal, but the GAP was bi-crystal. The crystallographic orientation relationships between Al2O3 and GAP was determined as [ 10 1 ¯ 0 ] Al2O3 || [001] GAP-I || [ 1 1 ¯ 0 ]GAP-II, ( 11 2 ¯ 0 ) Al2O3 || (200) GAP-I, ( 11 2 ¯ 0 )Al2O3 || (112) GAP-II, and (110) GAP-I || (110) GAP-II. Such GAP GB had ultra-low strain energy. The phase boundaries (PBs) strain energies are higher than that of the GAP GB. However, the difference in the interfacial strain energy between the two PBs was quite small. The reason for the successful preparation of single-crystal Al2O3/bi-crystal GAP eutectic ceramics was attributed to almost the same driving force requirements for the two PBs during solidification. We envisaged that the concept of interfacial structure design could open new pathways for high-performance materials design.