High-entropy R2O3-Y2O3-TiO2-ZrO2-Al2O3 glasses with ultrahigh hardness, Young's modulus, and indentation fracture toughness

Yongchang Guo; Jianqiang Li; Ying Zhang; Shaowei Feng; Hong Sun

doi:10.1016/j.isci.2021.102735

High-entropy R₂O₃-Y₂O₃-TiO₂-ZrO₂-Al₂O₃ glasses with ultrahigh hardness, Young's modulus, and indentation fracture toughness

iScience. 2021 Jun 17;24(7):102735. doi: 10.1016/j.isci.2021.102735. eCollection 2021 Jul 23.

Authors

Yongchang Guo^{1

2}, Jianqiang Li^{1

3

2

4}, Ying Zhang^{1

2}, Shaowei Feng^{1

2}, Hong Sun^{1

2}

Affiliations

¹ CAS Key Laboratory of Green Process and Engineering, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China.
² University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
³ School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China.
⁴ Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, P. R. China.

Abstract

Glasses with high hardness, high Young's modulus, and high fracture toughness become crucial materials which are urgently needed in the protective covers for various electronic displays. Here, a paradigm is presented that the conceptual design of high-entropy materials is adaptable to high performance oxide glasses. We designed the multi-component glass compositions of 18.77R₂O₃-4.83Y₂O₃-28.22TiO₂-8.75ZrO₂-39.43Al₂O₃ (R = La, Sm, Gd) and elaborated successfully the glassy samples through a containerless solidification process. The as-prepared samples demonstrated the outstanding mechanical and optical properties. The measured hardness, Young's modulus, and indentation fracture toughness of the high-entropy (R = Gd) glass are 12.58 GPa, 177.9 GPa, and 1.52 MPa·m^0.5, respectively, in which the hardness and Young's modulus exhibit the highest value among the reported oxide glasses. Structural analysis revealed that the excellent mechanical properties are attributed to the large dissociation energies and the high field strength of Al₂O₃, TiO₂, and ZrO₂ and the complex interaction between atoms caused by high entropy.

Keywords: Materials characterization; Materials design; Materials mechanics; Optical Materials.