Molecular dynamic simulations study on the structure and properties of Li2O-containing magnesium aluminosilicate glasses

Magnesia aluminosilicate glass has important applications value in the fields of composite fiber reinforcement, flat panel display, aircraft windshields and so on because of its excellent chemical stability and good mechanical properties. In this paper, the molecular dynamic simulations were used to obtain structural information of the glasses, and the results were compared with Raman, X-ray photoelectron spectroscopy, Differential thermal analysis, and Vickers hardness to elucidate the effect of Li2O introduction on the structure and properties of MgO-Al2O3-SiO2 glasses. The transformation mechanism of oxygen type and polyhedral with the process of Li2O content was investigated, and focusing on the effect of network connectivity of the glass on the transformation temperature and hardness. The results indicated that at low Li2O content (< 3 mol%), Li ions play the role of charge compensator and reinforce the network structure of MgO-Al2O3-SiO2 glasses. When the Li2O content exceeds 3 mol%, the excess Li2O breaks the backbone of the Al-Si network structures that to the reduction of the glass network connectivity. The glass transition temperature and hardness of Li2O-MgO-Al2O3-SiO2 glasses reach a maximum at a Li2O addition of 3 mol%, while the corresponding simulated structures (AlO5 and Network Connectivity) show the most stable network structure.