对11.5μm厚中间缺口电镀铜薄膜的单向拉伸疲劳断裂特性进行研究。试件采用准LIGA(lithographie,galvanformung,abformung,光刻、电铸、塑铸的完美结合)工艺制作。试验观测发现,多数电镀铜薄试件断裂发生在缺口根部,断裂表面与缺口Y向对称轴线夹角约成12°,以沿晶断裂为主。利用弹塑性有限元分析,模拟得到断裂危险区域为缺口根部;连接危险区域边界点与缺口曲率中心的边界线,与缺口Y向对称轴线的夹角约成±14.2°范围内,与试样断裂情况相符;缺口根部断裂主要受拉伸应力控制。用Neuber方法所得结果与有限元分析结果进行对比,间接验证有限元分析结果的合理性。
Tension-tension fatigue test of center-notched electroplated Copper thin film with 11.5 μm thickness was carried out. The specimen was fabricated with LIGA(lithographie, galvanformtmg, abformung)-like technology. It was found that, fracture occurred near peak point of notch root about 12 degrees with the Y-direction of notch and the fracture mode was mainly intracrystaUine fracture. In elasto-plastic finite element analysis, the dangerous area was near the notch root within ± 14.2 degree region measured from the notch curvature center, which agreed with the experimental observation. Fracture at notch root was mainly controlled by tensile stress. Comparison between FEM(finite element method) and Neuber' s results shows that the local stress and strain calculated by FEM can be used to estimate the fatigue life.