The initiation and propagation of microcracks in the copper thin film on flexible polyimide substrates was examined through the thickness direction following cyclic bending test using a focused ion beam (FIB) and electron backscatter diffraction (EBSD) technique. The EBSD observations of the cross-sectional plane clearly indicated that intergranular fracture was predominant during the initiation and propagation of microcracks. During the cyclic bending testing, through the thickness direction microcracks were propagated mostly along the high-angle grain boundaries (HAGBs) that separated the neighboring grains with a high Schmid factor (SF), instead of at the twin boundaries (TBs).

使用聚焦离子束（FIB）和电子背散射衍射（EBSD）技术，通过循环弯曲试验，沿着厚度方向检查了柔性聚酰亚胺基板上铜薄膜中微裂纹的引发和传播。EBSD对横截面的观察清楚地表明，在微裂纹的萌生和传播过程中，晶间裂缝是主要的。在循环弯曲测试期间，微裂纹主要通过厚度方向沿高角度晶粒边界（HAGB）传播，该高角度晶粒边界以高Schmid因子（SF）分隔相邻晶粒，而不是在孪晶边界（TBs）处传播。