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Tempered glass. Tempered or toughened glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Tempering puts the outer surfaces into compression and the interior into tension. Such stresses cause the glass, when broken, to shatter into small granular chunks ...
Toughening. In materials science, toughening refers to the process of making a material more resistant to the propagation of cracks. When a crack propagates, the associated irreversible work in different materials classes is different. Thus, the most effective toughening mechanisms differ among different materials classes.
Safety glass is glass with additional safety features that make it less likely to break, or less likely to pose a threat when broken. Common designs include toughened glass (also known as tempered glass), laminated glass, and wire mesh glass (also known as wired glass). Toughened glass was invented in 1874 by Francois Barthelemy Alfred Royer de ...
Also unlike toughened glass, chemically strengthened glass may be cut after strengthening, but loses its added strength within approximately 20 mm of the cut. Similarly, when the surface of chemically strengthened glass is deeply scratched, this area loses its additional strength. Another negative of chemically strengthened glass is the added cost.
Glass typically has a tensile strength of 7 megapascals (1,000 psi). [1] However, the theoretical upper bound on its strength is orders of magnitude higher: 17 gigapascals (2,500,000 psi). This high value is due to the strong chemical Si–O bonds of silicon dioxide. Imperfections of the glass, such as bubbles, and in particular surface flaws ...
Annealing is a process of slowly cooling hot glass objects after they have been formed, to relieve residual internal stresses introduced during manufacture. Especially for smaller, simpler objects, annealing may be incidental to the process of manufacture, but in larger or more complex products it commonly demands a special process of annealing in a temperature-controlled kiln known as a lehr. [1]
Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (≈3 × 10 −6 K −1 at 20 °C), making them more resistant to thermal shock than any other common glass. Such glass is subjected to less thermal ...
Fracture toughness is a quantitative way of expressing a material's resistance to crack propagation and standard values for a given material are generally available. Morphology of fracture surfaces in materials that display ductile crack growth is influenced by changes in specimen thickness.