Abstract: Transparent glass-ceramics are widely used in the electronic field due to their excellent mechanical properties. Y₂O₃-Al₂O₃-SiO₂ (YAS) glass-ceramics with different mass fractions of Li₂O and Na₂O were prepared by melting method, and the structural characteristics, crystallization and mechanical properties were investigated by Raman, DSC, XRD, FESEM, UV-VIS-NIR. The results show that when the total content of R₂O (R=Li, Na) remains unchanged, the transition temperature, softening temperature and crystallization peak temperature of YAS glass-ceramics decrease as the content of Li₂O replacing Na₂O increases, the content of structure units Q⁴ gradually decreases, indicating that Li₂O as a network modifier gradually depolymerizes the structure of YAS glass-ceramics and promotes the crystallization ability of glass. It is also found that with the increase of Li₂O content, the Vickers hardness of YAS glass-ceramics increases significantly, while the transmittance decreases significantly at the same heat treatment. Under the heat treatment at 680 ℃ for 10 h and 750 ℃ for 1 h, YAS glass-ceramics with uniform crystal size and distribution and yttrium stabilized zirconia as the main crystalline phase can be prepared. At present, YAS glass-ceramics containing 2% (mass fraction,the same below)Na₂O and 4% Li₂O exhibits favorable overall performance. The Vickers hardness is 646 HV, the fracture toughness is 1.07 MPa·m^1/2 and the transmittance is 85.7%, which has great potential for many applications.

Key words: Y₂O₃-Al₂O₃-SiO₂, transparent glass-ceramics, alkali metal oxide, structure, crystallization, Vickers hardness