Abstract
Under the pursuit of the trend of light, thin, and flexible electronic products, the flexible electronic technology develops fast in recent years. However, the breakage of the silver line on the flexible electronic products are formed because of frequent bends, and it often leads to the failure of the products. Therefore, the discuss for the mechanical properties and behaviors of the silver line is extremely important for raising the reliability of flexible electronic products. Owing to the measurement of the material properties for silver line is limited by its small size, it is not easy to obtain it by tensile tests. Although the hardness and Young’s modulus can be measured by nanoindentation tests, the elastoplastic properties of silver line are still not obtained accurately. Dao et al. (2001) proposed a material analysis model. Although it can explore the elastoplastic properties for materials in the range of 10~210 GPa for Young’s modulus, 30~3000 MPa for yield stress and 0~0.5 for strain hardening exponent, the relationships in the analysis model are logarithmic form which are easy to solve unreasonable or negative material properties and result in the limitation of the application for the analysis model. In order to solve the problems, Hu (2015) revised Dao et al.’s material analysis model, but it doesn’t cover the material properties of silver line. Based on the modified Dao material analysis model of Hu (2015), an analytical process which is suitable for the range of the material properties of the silver line is constructed in this study and it combines the results of nanoindentation tests and finite element simulation to predict elastoplastic material properties of the silver line with different proportions of solvent added. In addition, the surface structures and the distribution of the inner elements of the silver line are observed by field emission scanning electron microscopy and transmission electron microscopy to find out the reasons which cause the changes of the elastoplastic material properties of the silver line with different proportions of solvent added. Finally, the elastoplastic material properties of the silver line at different temperatures are also discussed in this study. The achievement of this research is helpful for the analysis of the bending fatigue life of flexible electronics, and enhances the reliability of flexible electronic products.