Toward hard and highly crack resistant magnesium aluminosilicate glasses and transparent glass‐ceramics

Abstract

Abstract High hardness and high crack resistance are usually mutually exclusive in glass materials. Through the aerodynamic levitation and laser melting technique, we prepared a series of magnesium aluminosilicate glasses with a constant MgO content, and found a striking enhancement of both hardness and crack resistance with increasing Al 2 O 3 . The crack resistance of the magnesium aluminosilicate glass is about five times higher than that of the binary alumina‐silica glass for the similar [Al]/([Al] + [Si]) molar ratio (around 0.6). For the selected magnesium aluminosilicate glass with R = 0.32, when subjected to isothermal treatment at 1283K, we observed a further drastic enhancement of both hardness and crack resistance by extending the heating time. Based on the structural analyses, we propose an atomic‐scale model to explain the mechanism of synergetic enhancement in hardness and crack resistance for the magnesium aluminosilicate glasses and glass‐ceramics.