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A New Low‐Brittleness Glass in the Soda‐Lime‐Silica Glass Family

1998; Wiley; Volume: 81; Issue: 9 Linguagem: Inglês

10.1111/j.1151-2916.1998.tb02649.x

1551-2916

J.D. Sehgal, Setsuro Ito,

Advanced materials and composites

In the soda‐lime‐silica glass family, the effect of each constituent of the composition on the brittleness was first investigated. Vickers indentation was employed to estimate the brittleness (ratio of harness ( H ) to fracture toughness ( K c )) by measuring the C / a ratios (where C and a are the characteristic crack and indentation diagonal lengths, respectively). It was observed that a higher silica content and a lower lime content helped to lower the brittleness. Substitution of potash and magnesia for soda and calcia, respectively, was effective in lowering the brittleness. From these results, a higher molar volume was found to be a key factor for reducing the brittleness. A new low‐brittleness glass was then developed with a brittleness as low as 5.1 µm ‐1/2 as compared with the brittleness of 7.1 µm ‐1/2 for commercial soda‐lime‐silica glass. The crack initiation load ( P *), measured by the Vickers indentation method, for this new low‐brittleness glass was almost 10 times as high as P * of commercial soda‐lime‐silica glass. The new glass shows lower hardness and higher fracture toughness than the commercial soda‐lime‐silica glass.