Glass articles exhibiting improved fracture performance

Abstract

Embodiments of this disclosure pertain to a strengthened glass article including a first surface and a second surface opposing the first surface defining a thickness (t) of about less than about 1.1 mm, a compressive stress layer extending from the first surface to a depth of compression (DOC) of about 0.1·t or greater, such that when the glass article fracture, it breaks into a plurality of fragments having an aspect ratio of about 5 or less. In some embodiments, the glass article exhibits an equibiaxial flexural strength of about 20 kgf or greater, after being abraded with 90-grit SiC particles at a pressure of 25 psi for 5 seconds. Devices incorporating the glass articles described herein and methods for making the same are also disclosed.

What is claimed is: 
     
         1 . A method for producing a strengthened glass-based article comprising:
 immersing a glass-based substrate having a thickness (t) of 3 mm or less into a first molten salt bath for about 2 hours to about 48 hours, the first molten salt bath comprising a temperature from about 350° C. to 500° C. and sodium ions and potassium ions;   immersing the glass-based substrate into a second molten salt bath, after the immersing into the first molten salt bath, for 10 hours or less, the second molten salt bath comprising a temperature of about 350° C. to about 500° C. and potassium ions;   whereby the immersing into the first molten salt bath and the immersing into the second molten salt bath results in a strengthened glass-based article comprising a compressive stress layer extending from a first surface of the substrate to a depth of compression (DOC) of greater than 0.16·t, the compressive stress layer comprising a surface compressive stress of 624.5 MPa or greater; and a maximum central tension that is 50 MPa or greater.   
     
     
         2 . The method of  claim 1 , wherein:
 the DOC is as measured by scattered light polariscope;   the compressive stress is as measured by a combination of scattered light polariscope and surface stress meter; and   the central tension is as measured by scattered light polariscope.   
     
     
         3 . The method of  claim 1 , wherein the strengthened glass-based article comprises a stored tensile energy of 20 J/m 2  or greater. 
     
     
         4 . The method of  claim 1 , wherein the ratio of the maximum central tension to the surface compressive stress is in the range from about 0.1 to about 1, and wherein the maximum central tension is 100 MPa/√(t/1 mm) or greater (in units of MPa), wherein t is in mm. 
     
     
         5 . The method of  claim 1 , further comprising disposing the strengthened glass-based article on a containment layer. 
     
     
         6 . The method of  claim 1 , the strengthened glass-based article further comprising:
 a CT region of the stress profile, wherein the CT region is defined by the equation Stress(x)=MaxCT−(((MaxCT·(n+1))/0.5 n )·|(x/t)−0.5| n ),   wherein MaxCT is the maximum CT value and is provided as a positive value in units of MPa, x is position along the thickness (t) in micrometers, and n is between 1.5 and 2.2.   
     
     
         7 . The method of  claim 1 , wherein, after the strengthened glass-based article fractures according to a Frangibility Test, the strengthened glass-based article includes a plurality of fragments, wherein at least 90% of the plurality of fragments have an aspect ratio of about 5 or less. 
     
     
         8 . The method of  claim 7 , wherein the strengthened glass-based article fractures into the plurality of fragments in 1 second or less, as measured by the Frangibility Test. 
     
     
         9 . The method of  claim 7 , wherein at least 80% of the plurality of fragments have a maximum dimension that is less than or equal to 3·t. 
     
     
         10 . The method of  claim 7 , wherein at least 50% of plurality of fragments comprises an aspect ratio of 2 or less. 
     
     
         11 . The method of  claim 7 , wherein at least 50% of the plurality of fragments comprises a volume of less than or equal to about 10 mm 3 . 
     
     
         12 . The method of  claim 7 , wherein the plurality of fragments comprises an ejected portion of fragments, wherein the ejected portion of fragments comprises 10% or less of the plurality of fragments. 
     
     
         13 . The method of  claim 7 , wherein the strengthened glass-based article comprises a first weight prior to fracture and wherein the plurality of fragments comprises an ejected portion of fragments and a non-ejected portion of fragments, the non-ejected portion of fragments having a second weight, and the difference between the first weight and the second weight is 1% of the first weight. 
     
     
         14 . The method of  claim 1 , further comprising a compressive stress value at a maximum Potassium depth of layer that is in the range from about 50 MPa to about 300 MPa. 
     
     
         15 . The method of  claim 1 , wherein the strengthened glass-based article exhibits a load to failure of about 10 kgf or greater, after being abraded with 90-grit SiC particles at a pressure of 25 psi for 5 seconds. 
     
     
         16 . The method of  claim 15 , wherein the strengthened glass-based article comprises a stored tensile energy of 20 J/m 2  or greater. 
     
     
         17 . The method of  claim 16 , wherein the ratio of the maximum central tension to the surface compressive stress is in the range from about 0.1 to about 1, and wherein the maximum central tension (CT) is 85 MPa or greater. 
     
     
         18 . The method of  claim 17 , wherein the DOC comprises about 0.2t or greater. 
     
     
         19 . The method of  claim 18 , wherein the strengthened glass-based article is adhered to a substrate. 
     
     
         20 . The method of  claim 15 , wherein t is 0.4 mm or more.