固体-液体-基底结构中裂纹形貌形成机制

Fracture of the Solid Film in Thin Solid Film-Liquid Film-Substrate Structure

试验发现,在固体膜-液体膜-基底结构中,若固体薄膜具有受压的本征应力,往往会发生开裂破坏,且裂纹呈现正弦波浪状或分叉状.采用细观力学的方法,研究产生此种开裂现象的机制.首先假设两种不同的固体薄膜变形单元,并通过能量的方法研究,结果表明,这两种不同的变形模式单元能同时通过不同的排列,组合成复杂的图纹.以变形模式为基础,给出了固体薄膜中微缺陷扩展成裂纹的准则,解释了产生上述裂纹形貌的机制.最后讨论了裂纹起始时间的预测问题.

A flat film, bonded to a viscous layer and subjected to compression, can wrinkle and form cracks. The appearance of the cracks is similar to a sinusoidal structure. One crack may bifurcate into two or more cracks. The present study presents two wrinkling pattern units of the solid film and shows that the crack appearance is caused by these combined wrinkling pattern units. The energy values of the structure of the two pattern units are obtained respectively. Moreover, the two pattern units of the solid film are found to exist in the same solid film at the same time. In addition, light is shed on how microcrack grows into macrocrack in the solid film. Initiation time for the microcracks is also discussed here.