Al2O3/SiO2对Li2O-Al2O3-SiO2-MgO 微晶玻璃析晶行为及力学性能的影响OA

Li2O-Al2O3-SiO2-MgO glass-ceramics has attracted much attention due to its excellent thermal and mechanical properties,and its glass network structure,crystal phase composition and final mechanical properties are significantly affected by Al2O3/SiO2 molar ratio.In this study,a series of glass samples with different Al2O3/SiO2 mole ratios compositions were prepared by high-temperature melting method,and a series of glass-ceramics with LixAlxSi1-xO2 as the main crystalline phase was successfully obtained by a two-step heat treatment process.Research findings indicate that with the increase of Al2O3/SiO2 mole ratio,Q3 and Q4 units within the glass network transform into Q1 and Q2 units,and this apparent change is essentially caused by the disturbance caused by the increase of[AlO4].The coefficient of thermal expansion gradually rises from 5.31 ×10-6 ℃-1 to 5.98×10-6 ℃-1,with a incremental tendency.The crystal morphology evolves from spherical to irregular,and finally to a honeycomb structure.The crystal phase changes from LixAlxSi3-xO6,MgAl2Si4O12,and SiO2 to LixAlxSi1-xO2,MgAl2Si4O12,LiAlSi3O8,and SiO2,and ultimately to LiAlSi2O6,and LixAlxSi1-xO2.The mechanical property tests show that the maximum Vickers hardness of glass-ceramics is 8.89 GPa,and the subsequent decay of the performance is mainly attributed to the transition of crystal phase and the evolution of the microscopic morphology of the crystal to honeycomb structure.