Peraluminous lithium aluminosilicates with high liquidus viscosity

Abstract

The embodiments described herein relate to glass articles that include mechanically durable glass compositions having high liquidus viscosity. The glass articles may include glass compositions having from 50 mol. % to 80 mol. % SiO 2 ; from 7 mol. % to 25 mol. % Al 2 O 3 ; from 2 mol. % to about 14 mol. % Li 2 O; 0.4 mol. % P 2 O 5 ; and less than or equal to 0.5 mol. % ZrO 2 . The quantity (Al 2 O 3 (mol. %)-R 2 O (mol. %)-RO (mol. %)) is greater than zero, where R 2 O (mol. %) is the sum of the molar amounts of Li 2 O, Na 2 O, K 2 O, Rb 2 O, and Cs 2 O in the glass composition and RO (mol. %) is the sum of the molar amounts of BeO, MgO, CaO, SrO, BaO, and ZnO in the glass composition. A molar ratio of (Li 2 O (mol. %))/(R 2 O (mol. %)) may be greater or equal to 0.5. In embodiments, the glass composition may include B 2 O 3 . The glass compositions are fusion formable and have high damage resistance.

What is claimed is: 
     
         1 . A glass article comprising a composition, the composition comprising:
 greater than or equal to 50 mol. % and less than or equal to 80 mol. % SiO 2 ;   greater than or equal to 2 mol. % and less than or equal to 25 mol. % Al 2 O 3 ;   greater than or equal to 2 mol. % and less than or equal to 15 mol. % Li 2 O;   wherein SiO 2  (mol %)≥[4*Li 2 O+6*(Na 2 O+K 2 O)+2.5*MgO+2*(CaO+SrO+BaO)] (mol %),   wherein (Al 2 O 3  (mol. %)-R 2 O (mol. %)-RO (mol. %)) is greater than zero, where R 2 O (mol. %) is the sum of the molar amounts of Li 2 O, Na 2 O, K 2 O, Rb 2 O, and Cs 2 O in the composition and RO (mol. %) is the sum of the molar amounts of BeO, MgO, CaO, SrO, BaO, and ZnO in the composition,   wherein a molar ratio of (Li 2 O (mol. %))/(R 2 O (mol. %)) is greater or equal to 0.35,   wherein P 2 O 5  (mol %)/[(Al 2 O 3 -R 2 O—RO)](mol %) is greater than or equal to 0.25,   wherein TiO 2  (mol %)+ZrO 2  (mol %) is greater than or equal to 0 mol. % and less than or equal to 1 mol. %,   wherein a total content of rare earth metal oxides is greater than or equal to 0 mol. % and less than or equal to 0.5 mol %, and   wherein A is greater than or equal to 17, where:
     A= 13.2+ P *[(1/673−1( A.P.+ 273))],
 
     P= 0.6/[(1/( A.P.+ 273))−(1/( T   12 +273))],
 
 A.P. is the annealing point in ° C., and 
 T 12  is the temperature in ° C. corresponding to when the glass has a viscosity of 10 12  Poises. 
   
     
     
         2 . The glass article of  claim 1 , wherein P 2 O 5  (mol %)/[(Al 2 O 3 -R 2 O—RO)](mol %) is greater than or equal to 0.8 and less than or equal to 1.25. 
     
     
         3 . The glass article of  claim 1 , wherein P 2 O 5  (mol %)/[(Al 2 O 3 -R 2 O—RO)](mol %) is greater than or equal to 0.9 and less than or equal to 1.1. 
     
     
         4 . The glass article of  claim 1 , wherein a Young's modulus is greater than or equal to 70 GPa. 
     
     
         5 . The glass article of any  claim 1 , wherein a Young's modulus is greater than or equal to 80 GPa. 
     
     
         6 . The glass article of  claim 1 , wherein a fracture toughness is greater than or equal to 0.7 MPa*m 1/2 . 
     
     
         7 . The glass article of  claim 1 , wherein a fracture toughness is greater than or equal to 0.8 MPa*m 1/2 . 
     
     
         8 . The glass article of  claim 1 , wherein A is greater than or equal to 19.