Strengthened glass articles, edge-strengthened laminated glass articles, and methods for making the same

A method of forming a surface-crystallized or semi-crystallized glass article, the method comprising:

• contacting a glass body with a salt composition, the glass body free or substantially free of TiO2, ZrO2, and ZnO, the salt composition comprising major and minor components, the major components comprising Li2SO4—K2SO4, Li2SO4—Na2SO4, or both, and the minor components comprising 0.01 to 5 mol % of one or more basic additives, the one or more basic additives selected from the group consisting of potassium carbonate, sodium carbonate, magnesium carbonate, calcium carbonate, and lithium carbonate;
• and
• nucleating and growing crystals at or near a surface portion of the glass body, the crystals substantially formed from and integral with a bulk of the glass body;
• wherein the surface portion has a lower average coefficient of thermal expansion (CTE) than the bulk of the glass body.

A method of manufacturing a laminated glass article comprising at least one glass cladding layer and a glass core layer adhered to the at least one glass cladding layer, the method comprising:

• removing a portion of the laminated glass article such that an exposed surface of the glass core layer is exposed on at least one edge of the laminated glass article;
• and
• heat treating at least a portion of the exposed surface of the glass core layer to form a crystallized or semi-crystallized surface of the glass core layer, the portion of the glass core layer having a lower coefficient of thermal expansion (CTE) than a remainder of the glass core layer, wherein the heat treating comprises:
• heating at least the exposed surface of the glass core layer to a nucleation temperature in a range of from about 500° C. to about 850° C.;
• cooling at least the exposed surface of the glass core layer to a temperature below about 500° C.;
• and
• reheating at least the exposed surface of the glass core layer to a crystallization temperature in a range of from about 500° C. to about 850° C., where the crystallization temperature is at least about 5 degrees higher than the nucleation temperature.

A method of manufacturing a laminated glass article comprising at least one glass cladding layer and a glass core layer adhered to the at least one glass cladding layer, the method comprising:

• removing a portion of the laminated glass article such that an exposed surface of the glass core layer is exposed on at least one edge of the laminated glass article;
• heat treating at least a portion of the glass core layer at the exposed surface to form a crystallized or semi-crystallized surface of the glass core layer, the portion of the glass core layer having a lower coefficient of thermal expansion (CTE) than a remainder of the glass core layer, wherein the heat treating comprises heating at least the exposed surface of the glass core layer to a nucleation temperature and a crystallization temperature;
• and
• shielding the at least one glass cladding layer during the heat treating to maintain the at least one glass cladding layer below the nucleation temperature and the crystallization temperature during the heat treating.