Slow fracture model based on strained silicate structures
Slow fracture model based on strained silicate structures
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DOI：
10.1063/1.333789
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发表时间：
1984-11
影响因子：
3.2
通讯作者：
T. Michalske;B. Bunker
中科院分区：
文献类型：
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作者：
T. Michalske;B. Bunker
慢裂纹扩展数据、分子轨道计算和振动光谱结果用于开发硅玻璃环境控制断裂的原子模型。该模型基于裂纹尖端应变场产生的化学活性粘结缺陷。分子轨道结果表明，键角变形在提高Si-O-Si键的化学活性方面是最有效的。振动光谱识别硅多晶含有高应变键构型。应变键反应性与裂纹扩展结果的比较表明，应变二氧化硅多晶可以用来模拟控制缓慢断裂的裂纹尖端化学反应。基于模型复合体，建立了包含扭结位成核和运动的二维断裂模型。该模型表明，裂纹扩展速率的应力强度依赖关系由二氧化硅结构中形成化学活性缺陷所需的能量控制。绝对比率…
Slow crack growth data, molecular‐orbital calculations, and vibrational spectroscopy results are used to develop an atomistic model for environmentally controlled fracture of silica glass. The model is based on chemically active bond defects generated by the strain field of the crack tip. Molecular‐orbital results suggest that bond angle deformations are most effective in increasing the chemical activity of the Si–O–Si bond. Vibrational spectra identify silica polymorphs containing highly strained bonding configurations. A comparison of strained bond reactivity with crack growth results shows that strained silica polymorphs can be used to model the crack tip chemical reactions controlling slow fracture. Based on model complexes, a two‐dimensional fracture model involving kink site nucleation and motion is developed. The model shows that the stress intensity dependence of the crack growth rate is controlled by the energy required to form chemically active defects in the silica structure. The absolute rate ...