ナトリウムケイ酸塩ガラスにおける高速度領域の亀裂伸長挙動

概要

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The crack growth behavior in the high crack velocity region (region III) for binary sodium silicate glasses was investigated by using a DCDC(double cleavage drilled compression) specimen under compressive stress. For 15 mol%Na_2O glass, despite the anomalous characteristic of the bulk modulus, subcritical crack growth in region III was detected. The slope of stress intensity factor (K_I)-crack velocity (ν) curve for silicate glass depended on the number of non-bridging oxygen per SiO_4 tetrahedron rather than on the alkali content in the glass. This compositional dependence of the slope of K_I-ν curve for silicate glasses could not be explained in terms of thermally activated crack growth process where the crack-tip shape would vary with the pressure derivative of bulk modulus. The smaller K_I-ν slope and the higher K_<IC> value of 35mol% Na_2O glass may be related to the structural change from a three-dimensional network to a two-dimensional network because of the introduction of many non-bridging oxygens into the silica network.
社団法人日本セラミックス協会の論文
2000-10-01