PROPERTIES OF GLASSES AT ELEVATED TEMPERATURES.
Technical rept. Jan-Dec 65,
NATIONAL BUREAU OF STANDARDS WASHINGTON D C
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A relationship between the stress at the point of fracture and the size of the mirror on the fracture face of glass rods of varying diameters has been established, and shown not to be affected by a change in the diameter of the rod. The elastic properties of two chemically strengthened glasses were determined. Youngs modulus and shear modulus show a sharp drop in the temperature range from 23.9 C 75 F to 249 C 480 F. Other glasses in the program did not show this inflection. The strength of these glasses as well as the other glasses in the program were determined at -17.8 C 0 F and -45.6 C -50 F, with the results showing that the strength increased at these temperatures as compared to the room temperature strength. Creep curves for the chemically strengthened glasses were obtained at 75 F, and appeared similar to those of earlier glasses in the program. Stress-rupture tests on abraded specimens revealed failures at 75 stress level at most test temperatures, but no failures at 67 at 75 F. Unabraded specimens tested only at 75 F, had failures at 90 but not at 75.
- Ceramics, Refractories and Glass