摘要
含过渡层的柔性基底薄膜的力学性能对现代电子元器件的广泛应用至关重要,对其力学性能的深入研究变得极为迫切。本文针对其在双向拉伸载荷下的断裂损伤进行了实验研究。对125μm聚酰亚胺上沉积的不同薄膜结构进行不同加载比下的双轴拉伸实验,通过光学显微镜观察裂纹演化过程与饱和裂纹形态。根据最小应变能密度因子理论对裂纹演化的开裂角度进行了理论分析,用有限元分析了加载比例和过渡层泊松比对结构各层双向应力比传递的影响,并在不同薄膜结构和加载比下,对裂纹演化应变进行了比较。研究结果表明,在双向拉伸载荷作用下,薄膜裂纹呈现出网状分布,裂纹演化角度与加载比、裂纹初始角度相关;一级裂纹萌生的临界应变随着加载比降低而降低,二级及以上裂纹萌生的临界应变与各级裂纹的饱和应变随加载比降低而升高;在等双轴拉伸下,不同薄膜结构的含过渡层柔性基底薄膜一级裂纹的临界应变基本一致,二级及以上裂纹的临界应变显现明显差异。
Mechanical properties of Soft Substrate Interlayer Film（SSIF）are very important to the wide application of modern electronic components,and the study of its mechanical properties becomes very urgent.In this paper,fracture damage of SSIF structure subjected to biaxial tensile load is experimentally studied.Biaxial tensile experiment for different film structures deposited on 125μm polyimide was performed under different loading ratios.Crack evolution process and saturated crack pattern were observed by means of optical microscope.Crack initiation angle in crack evolution was analyzed theoretically based on the minimum strain energy density factor theory;the influence of loading ratio and transition Poisson ratio on biaxial stress transfer ratio of each layer were analyzed by finite element method;under the condition of different film structures and loading ratios,crack evolution strain was compared.Experimental results show that under biaxial tensile load action,cracks of thin film present mesh pattern distribution;crack evolution angle is related to loading ratio and crack initiation angle.Critical strain of first-level crack initiation decreases with the decrease of loading ratio;critical strain of the cracks except of first-level crackand saturated strain of each level crack increase with the decrease of loading ratio.Under equivalent biaxial tension,the critical strain of the first-level cracks in the SSIF structure with the same film thickness but different film structures is basically consistent,however,the critical strain of the cracks except of first-level crack presents significant different.
出处
《实验力学》
CSCD
北大核心
2017年第6期741-750,共10页
Journal of Experimental Mechanics
基金
国家自然科学基金(11572218)资助
关键词
双向拉伸
薄膜
柔性基底
过渡层
裂纹
biaxial tension
thin film
flexible substrate
transition layer
crack
