AUTHOR=Yan Jingyu , Liu Xiaoming , Wu Xiuping , Wu Xiao , Zhang Yanjie , Li Bing 

TITLE=Microstructure and Mechanical Properties of Li2Si2O5 Whisker-Reinforced Glass-Ceramics

JOURNAL=Frontiers in Materials

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2022.849601

DOI=10.3389/fmats.2022.849601

ISSN=2296-8016

ABSTRACT=<p>Lithium disilicate (Li<sub>2</sub>Si<sub>2</sub>O<sub>5</sub>) glass-ceramics are an ideal material for dental restoration; however, their intrinsic brittleness and low defect tolerance limit the scope of their clinical applications. In this study, Li<sub>2</sub>Si<sub>2</sub>O<sub>5</sub> whiskers were creatively synthesized via a mild-condition hydrothermal reaction. Self-reinforced Li<sub>2</sub>Si<sub>2</sub>O<sub>5</sub> glass-ceramics were sintered by introducing the Li<sub>2</sub>Si<sub>2</sub>O<sub>5</sub> whiskers, and their effects on phase, microstructure, and mechanical properties were systematically studied. The crystal-growth and toughening mechanisms were also discussed. The results showed that the Li<sub>2</sub>Si<sub>2</sub>O<sub>5</sub> whiskers played an important role in inducing crystallization, and improving the microstructure and properties of the glass-ceramics. With increasing amounts of Li<sub>2</sub>Si<sub>2</sub>O<sub>5</sub> whiskers, the crystallinities increased slightly, and the average crystal size also increased. The microstructure was composed of crystals of bimodal size distributions, in which some large, rod-like Li<sub>2</sub>Si<sub>2</sub>O<sub>5</sub> crystals epitaxially grew along with the whiskers, and small crystals directly crystallized from the parent glass-ceramic powders. The Li<sub>2</sub>Si<sub>2</sub>O<sub>5</sub> glass-ceramics exhibited high flexural strength (389.5 ± 11.77 MPa, LDW3), and fracture toughness (3.46 ± 0.10 MPa·m<sup>1/2</sup>, LDW5). The improved properties were attributed mainly to crack deflection and bridge-toughening mechanisms.</p>