Effect of Y2O3/La2O3 on structure and mechanical properties of Li2O–Al2O3–SiO2 glass

• High dissociation energy oxides have positive effects on improving glass network structure and mechanical properties. • Co-doping of two rare earth element oxides (Y 2 O 3 and La 2 O 3 ) in LAS glass can effectively improve the mechanical properties of the glass. • The as-prepared LAS glass has excellent hardness, elastic modulus and bending strength. Effect of Y 2 O 3 and La 2 O 3 substitution for SiO 2 on the structure and mechanical properties of Li 2 O-Al 2 O 3 -SiO 2 (LAS) glass was investigated. The structural changes were characterized by 27 Al magic angle spinning nuclear magnetic resonance (MAS-NMR), Fourier transform infrared spectrometer (FTIR) and viscosity-temperature tests. The results showed that LAS glass network structures depolymerized firstly and then polymerized with increasing Y 2 O 3 or La 2 O 3 content. Atomic packing density of LAS glasses monotonically increased as the addition of Y 2 O 3 or La 2 O 3 and its best measurement value is 0.5824 with the Y 2 O 3 and La 2 O 3 doping content are 4 mol% and 2 mol% (denoted as LAS-42). Simultaneously, Vickers hardness, elastic modulus and bending strength were measured and their best values corresponded to 712.80 H V , 99.72 GPa and 140.47 MPa when the glass is LAS-42, with the increases of 13.1%, 14.9% and 59.9%, respectively. This study revealed that high dissociation energy oxides, in terms of Y 2 O 3 and La 2 O 3 , have obvious effects on improving mechanical properties of LAS glass.