Non-Brittle Behavior of Inorganic Glasses

无机玻璃的非脆性行为的存在尚未得到广泛的研究，但从压痕断裂的分析和断裂与静态表面能的比较中可以看出这一点。因此，作为公认的评价非脆性阶数的方法，本研究考察了多种方法。结果表明：在水分子存在的情况下，硼酸盐玻璃的裂纹缓慢扩展行为与硅酸盐玻璃不同，在断裂时表现出较大的非弹性变形，即在应力强度因子很低的区域，硼酸盐玻璃的裂纹扩展与应力无关。采用新开发的应力波断口DCDC慢裂纹扩展测量方法，测量了二硅酸锂和钠钙硅酸盐玻璃在惰性条件下的慢裂纹扩展行为，即不同温度下的本禀慢裂纹扩展行为。在裂纹扩展速率相同的情况下，二硅酸锂玻璃的应力强度因子大于硅酸钠玻璃。前者的慢裂纹扩展激活能比后者小得多。在前一种玻璃中，非阿伦尼乌斯温度依赖性大于150℃。在稀土掺杂六直角体晶体中观察到可见区断裂致发光现象。这一现象的起因应该是六方体在紫外区的断裂发光，激发了稀土离子。

Existence of the non-brittle behavior of inorganic glass has not been studied widely though it will be common from the analysis of indentation-fracture and the comparison between fracture and static surface energies. So, as the commonly accepted method to evaluate the order of non-brittleness, many approaches are examined in this study. Results are as follows :In the existence of water molecules, slow crack growth behavior of borate glasses which shows large inelastic deformation at fracture is found to be different from that of silicate glasses, I.e., stress-independent crack propagation is observed in borate glasses at a region with very low stress intensity factor.Slow crack growth behavior at inert condition, I.e., intrinsic slow crack growth, with various temperatures is measured for lithium disilicate and soda lime silicate glasses using a newly developed DCDC measurement of slow crack growth with stress-wave fractography. The stress intensity factor with the same crack growth rate of the lithium disilicate glass is found to be larger than that of soda lime silicate. The activation energy of slow crack growth for the former glass is much smaller than that of latter one. In the former glass, non-Arrhenius temperature dependence is observer above 150℃.Fracture-induced luminescence in the visible region is observed in rare-earth doped hexacelsian crystals. The origin of this phenomenon should be fractoluminescence of hexacelsian in the UV region that would excite the rare-earth ions.