Locally strengthened glass-ceramics and methods of making the same

1. A glass-ceramic article comprising:

a body formed of a glass-ceramic material, the body comprising:

a primary glass-ceramic region comprising primary crystal phases of the glass-ceramic material and a fracture toughness of X MPa*m{circumflex over ( )}½, wherein the primary crystal phases of the glass-ceramic material are optically transparent, and

a secondary glass-ceramic region comprising secondary crystal phases of the glass-ceramic material and a fracture toughness of Y MPa*m{circumflex over ( )}½, wherein the secondary crystal phases of the glass-ceramic material are not optically transparent, and wherein Y is greater than X.

2. The glass-ceramic article of claim 1 , wherein the primary crystal phases comprise petalite and lithium disilicate.

3. The glass-ceramic article of claim 1 , wherein the secondary crystal phases comprise beta-spodumene, lithium disilicate, and zirconia.

4. The glass-ceramic article of claim 1 , wherein X is 0.9 MPa*m{circumflex over ( )}½ or more.

5. The glass-ceramic article of claim 1 , wherein Y is 2 MPa*m{circumflex over ( )}½ or more.

6. The glass-ceramic article of claim 1 , wherein Y is at least two times more than X.

7. The glass-ceramic article of claim 1 , wherein the primary crystal phases of the glass-ceramic material comprise a first average grain size and wherein the secondary crystal phases of the glass-ceramic material comprise a second average grain size larger than the first average grain size.

8. The glass-ceramic article of claim 1 , wherein the secondary glass-ceramic region comprises a cross-sectional area defined by the thickness of the secondary glass-ceramic region measured between an inner surface and an outer surface of the body, and wherein a maximum thickness of an area defined by the secondary crystal phases in the cross-sectional area is equal to a maximum thickness of the cross-sectional area.

9. The glass-ceramic article of claim 1 , wherein the secondary glass-ceramic region comprises a cross-sectional area defined by the thickness of the secondary glass-ceramic region measured between an inner surface and an outer surface of the body, and wherein a maximum thickness of an area defined by the secondary crystal phases in the cross-sectional area is less than a maximum thickness of the cross-sectional area.

10. The glass-ceramic article of claim 1 , wherein the secondary glass-ceramic region comprises a cross-sectional area defined by the thickness of the secondary glass-ceramic region measured between an inner surface and an outer surface of the body, and the cross-sectional area comprises a first area defined by the primary crystal phases of the glass-ceramic material and a second area defined by the secondary crystal phases of the glass-ceramic material.

11. The glass-ceramic article of claim 10 , wherein the second area is central area disposed between portions of the first area.

12. The glass-ceramic article of claim 1 , wherein the body consists essentially of the primary crystal phases of the glass-ceramic material and the secondary crystal phases of the glass-ceramic material.

13. The glass-ceramic article of claim 1 , wherein the body comprises less than 25 wt % amorphous phase of the glass-ceramic material.

14. The glass-ceramic article of claim 1 , wherein the body comprises a hollow interior defined by a circumferential sidewall, and wherein the secondary glass-ceramic region defines a circumferential volume of the circumferential sidewall.

15. The glass-ceramic article of claim 14 , comprising at least two separate secondary glass-ceramic regions, each secondary glass-ceramic region defining a circumferential volume of the circumferential sidewall.

16. The glass-ceramic article of claim 15 , wherein, with the exception of the secondary glass-ceramic regions, the circumferential sidewall is defined by the primary glass-ceramic region.

17. The glass-ceramic article of claim 1 , wherein the body comprises a plate defined by a top surface, a bottom surface, and a perimeter edge, and wherein the secondary glass-ceramic region defines the perimeter edge.

18. The glass-ceramic article of claim 17 , wherein the plate is a cover substrate for an electronic display.

19. A glass-ceramic container, comprising:

a body formed of a glass-ceramic material and comprising a hollow interior defined by a circumferential sidewall, an open top end, and a bottom end, wherein the circumferential sidewall comprises:

a primary circumferential glass-ceramic region comprising primary crystal phases of the glass-ceramic material and a fracture toughness of X MPa*m{circumflex over ( )}½, wherein the primary crystal phases of glass-ceramic material are optically transparent, and

a secondary circumferential glass-ceramic region comprising secondary crystal phases of the glass-ceramic material and a fracture toughness of Y MPa*m{circumflex over ( )}½, wherein the secondary crystal phases of the glass-ceramic material are not optically transparent, and wherein Y is greater than X.

20. A glass-ceramic container, comprising:

a body formed of a glass-ceramic material and comprising a hollow interior defined by a circumferential sidewall formed symmetrically around a central vertical axis, an open top end, and a bottom end,

wherein the circumferential sidewall comprises:

a peripheral region defined by a volume of the circumferential sidewall, the peripheral region comprising secondary crystal phases of the glass-ceramic material and a fracture toughness of Y MPa*m{circumflex over ( )}½, wherein the secondary crystal phases of the glass-ceramic material are not optically transparent, and

a contracted region defined by a volume of the circumferential sidewall disposed closer to the central axis than the peripheral region and comprising primary crystal phases of the glass-ceramic material and a fracture toughness of X MPa*m{circumflex over ( )}½, wherein the primary crystal phases of glass-ceramic material are optically transparent, and wherein Y is greater than X.