Abstract: In this work, CaO-MgO-Al₂O₃-SiO₂ (CMAS) system alkali-free aluminosilicate glass was selected as the research object. Eight groups of Fe₂O₃ component variables were designed, and the experimental samples were prepared by high temperature melting method. XRD, SEM, TG-DSC and other test methods were used to tested and analyzed the phase, crystallization kinetics, crystallization behavior and elastic modulus of alkali-free glass samples, and then the effects of Fe₂O₃ content and crystallization treatment on the elastic modulus of alkali-free glass were discussed. The results show that the appropriate addition of Fe₂O₃ improves the elastic modulus of CMAS system alkali-free glass. When the mass fraction of Fe₂O₃ is 1.50% (F-6#), the maximum elastic modulus of F-6# alkali-free glass is 97.87 GPa, the crystallization activation energy is 347.1 kJ/mol, and the crystallization index n is 1.383 4, which is surface crystallization.After crystallization treatment by bulk crystallization method, the main crystalline phase precipitated from F-6# glass-ceramics is anorthite phase (CaAl₂Si₂O₈), and the crystal size is 200~400 nm. After crystallization treatment by sintering method, the main crystalline phase precipitated from F-6# glass-ceramics is anorthite phase (CaAl₂Si₂O₈), and the crystal size is 300~500 nm. With the increase of heat treatment temperature, the number and size of the precipitated main crystal phase increase, but the type of the main crystalline phase keeps unchanged. However, because the elastic modulus of anorthite is smaller than that of the base glass, the elastic modulus of the glass-ceramics obtained after crystallization of F-6# alkali-free glass decreases.

Key words: alkali-free glass, CaO-MgO-Al₂O₃-SiO₂, aluminosilicate glass, elastic modulus, crystallization