Glass-ceramic articles having specified elastic modulus and fracture toughness

An article, comprising:

• a glass-ceramic substrate comprising a first primary surface and a second primary surface, the first primary surface and the second primary surface opposing one another;
• and
• an optical film structure defining an outer surface, the optical film structure disposed on the first primary surface,
• wherein the glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa·√m,
• the optical film structure comprises a plurality of alternating high refractive index (RI) and low RI layers;
• the optical film structure comprises a scratch-resistant layer, and outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, and the scratch-resistant layer has a thickness from about 100 nm to about 10,000 nm.

An article, comprising:

• a glass-ceramic substrate comprising a first primary surface and a second primary surface, the first primary surface and the second primary surface opposing one another;
• and
• an optical film structure comprising an inner surface and an outer surface, the inner surface of the optical film structure disposed on the first primary surface,
• wherein the glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa·√m, and
• further wherein the optical film structure exhibits a residual compressive stress of greater than or equal to 700 MPa and an elastic modulus of greater than or equal to 140 GPa.

An article, comprising:

• a glass-ceramic substrate comprising a first primary surface and a second primary surface, the first primary surface and the second primary surface opposing one another,
• an optical film structure comprising an inner surface and an outer surface, the inner surface of the optical film structure disposed on the first primary surface,
• wherein the glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa·√m,
• wherein the optical film structure exhibits a residual compressive stress of from 700 MPa to 1100 MPa and an elastic modulus of from 140 GPa to 200 GPa, and,
• further wherein the article exhibits an average failure stress of 700 MPa or greater in a ring-on-ring test with the outer surface of the optical film structure placed in tension.