Corning Incorporated
HIGH FRACTURE TOUGHNESS GLASSES WITH HIGH CENTRAL TENSION

Abstract:

A glass-based article of a composition comprising: from 48 mol. % to 75 mol. % SiO.sub.2; from 8 mol. % to 40 mol. % Al.sub.2O.sub.3; from 9 mol. % to 40 mol. % Li2O; from 0 mol. % to 3.5 mol. % Na.sub.2O; from 9 mol. % to 28 mol. % R.sub.2O, wherein R is an alkali metal and R.sub.2O comprises at least Li.sub.2O and Na.sub.2O; from 0 mol. % to 10 mol. % Ta.sub.2O.sub.5; from 0 mol. % to 4 mol. % ZrO.sub.2; from 0 mol. % to 4 mol. % TiO.sub.2; from 0 mol. % to 3.5 mol. % R'O, R' being a metal selected from Ca, Mg, Sr, Ba, Zn, and combinations thereof; and from 0 mol. % to 8 mol. % RE.sub.2O.sub.3, RE being a rare earth metal selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and combinations thereof. The glass is ion exchangeable. R.sub.2O+R'O-Al.sub.2O.sub.3-Ta.sub.2O.sub.5+1.5*RE.sub.2O.sub.3-ZrO.sub.- 2-TiO.sub.2 is in a range from -8 mol. % to 5 mol. %. ZrO.sub.2+TiO.sub.2+SnO.sub.2 is in a range from greater than or equal to 0 mol % to less than or equal to 2 mole %. The composition is free of As.sub.2O.sub.3, Sb.sub.2O.sub.3, and PbO.