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

Lithium disilicate (Li 2 Si 2 O 5 ) 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 2 Si 2 O 5 whiskers were creatively synthesized via a mild-condition hydrothermal reaction. Self-reinforced Li 2 Si 2 O 5 glass-ceramics were sintered by introducing the Li 2 Si 2 O 5 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 2 Si 2 O 5 whiskers played an important role in inducing crystallization, and improving the microstructure and properties of the glass-ceramics. With increasing amounts of Li 2 Si 2 O 5 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 2 Si 2 O 5 crystals epitaxially grew along with the whiskers, and small crystals directly crystallized from the parent glass-ceramic powders. The Li 2 Si 2 O 5 glass-ceramics exhibited high flexural strength (389.5 ± 11.77 MPa, LDW3), and fracture toughness (3.46 ± 0.10 MPa·m 1/2 , LDW5). The improved properties were attributed mainly to crack deflection and bridge-toughening mechanisms.