Ion exchangeable glass with high crack initiation threshold

1. An alkali aluminosilicate glass comprising MgO, from about 40 mol % to about 70 mol % SiO 2 , from about 4 mol % to about 15 mol % P 2 O 5 , about 11 mol % to about 25 mol % Al 2 O 3 , about 13 mol % to about 20 mol % Na 2 O, and less than 1 mol % K 2 O, wherein:

i. the alkali aluminosilicate glass is free of Li 2 O; and

ii. 1.3<[(P 2 O 5 +R 2 O)/M 2 O 3 ]≦2.3, where M 2 O 3 =Al 2 O 3 +B 2 O 3 , and R 2 O is the sum of monovalent cation oxides present in the alkali aluminosilicate glass.

2. The alkali aluminosilicate glass of claim 1 , wherein the glass satisfies:

1.5<[(P 2 O 5 +R 2 O)/M 2 O 3 ]≦2.0.

3. The alkali aluminosilicate glass of claim 1 , wherein the alkali aluminosilicate glass comprises 0 mol % K 2 O.

4. The alkali aluminosilicate glass of claim 1 , wherein the monovalent cation oxides are selected from the group consisting of Na 2 O, K 2 O, Rb 2 O, and Cs 2 O.

5. The alkali aluminosilicate glass of claim 1 , wherein the alkali aluminosilicate glass comprises from about 50 mol % to about 65 mol % SiO 2 ; from about 14 mol % to about 20 mol % Al 2 O 3 ; from about 4 mol % to about 10 mol % P 2 O 5 ; and from about 14 mol % to about 20 mol % Na 2 O.

6. The alkali aluminosilicate glass of claim 1 , comprises less than 1 mol % B 2 O 3 .

7. The alkali aluminosilicate glass of claim 6 , wherein the alkali aluminosilicate glass comprises 0 mol % B 2 O 3 .

8. The alkali aluminosilicate glass of claim 1 , wherein the alkali aluminosilicate glass has a potassium/sodium interdiffusion coefficient of at least about 2.4×10 −10 cm 2 /s at 410° C.

9. The alkali aluminosilicate glass of claim 8 , wherein the potassium/sodium interdiffusion coefficient is in a range from about 2.4×10 −10 cm 2 /s up to about 1.5×10 −9 cm 2 /s at 410° C.

10. The alkali aluminosilicate glass of claim 1 , wherein the glass is ion exchanged to a depth of layer of at least about 10 μm.

11. The alkali aluminosilicate glass of claim 10 , wherein the alkali aluminosilicate glass has a compressive layer extending from a surface of the glass to the depth of layer, and wherein the compressive layer is under a compressive stress of at least about 300 MPa.

12. The alkali aluminosilicate glass of claim 10 , wherein the ion exchanged alkali aluminosilicate glass has a Vickers indentation crack initiation load of at least about 7 kgf.

13. The alkali aluminosilicate glass of claim 12 , wherein the ion exchanged alkali aluminosilicate glass has a Vickers indentation crack initiation load of at least about 12 kgf.

14. An electronic device comprising the alkali aluminosilicate glass of claim 1 .