Because typical solder joints undergo thermal aging during use, models simulating the behaviors of solder under mechanical stress must accurately reflect the changes in properties caused by thermal aging effects. The uniaxial deformation of SAC305 (96.5Sn–3.0Ag–0.5Cu wt.%) solder under different aging conditions indicates that the mechanical properties of solder are weakened with aging. In this study, the nanoindentation method was used to evaluate the effect of aging on the mechanical properties of the β-Sn dendritic regions and eutectic regions of SAC305. Based on this evaluation, a dual-phase (DP) representative volume element (RVE) crystal plasticity finite-element method (CPFEM) model was developed to simulate the thermal aging effects of SAC305 solder. In situ tensile tests performed with scanning electron microscopy (SEM) showed that the tensile deformation was concentrated in the β-Sn dendritic regions of the solder. The DP CPFEM model was established based on the microstructures shown by electron backscatter diffraction (EBSD) analysis performed during the in situ tensile tests. This model was used to verify the accuracy of the DP CPFEM in simulating the deformation localization by comparison with the strain field distribution observed via SEM–digital image correlation (DIC) technology. The developed DP CPFEM model allows the prediction of the potential failure locations of a microscale solder joint.

由于典型的焊点在使用过程中会发生热老化，因此模拟焊料在机械应力下的行为的模型必须准确反映热老化效应引起的性能变化。SAC305（96.5Sn–3.0Ag–0.5Cu wt.%）焊料在不同时效条件下的单轴变形表明焊料的机械性能随着时效而减弱。本研究采用纳米压痕法评估时效对 SAC305 的 β-Sn 枝晶区和共晶区力学性能的影响。基于此评估，开发了双相 (DP) 代表体积元 (RVE) 晶体塑性有限元法 (CPFEM) 模型来模拟 SAC305 焊料的热老化效应。用扫描电子显微镜 (SEM) 进行的原位拉伸试验表明，拉伸变形集中在焊料的 β-Sn 枝晶区域。DP CPFEM 模型是基于在原位拉伸试验期间进行的电子背散射衍射 (EBSD) 分析显示的微观结构建立的。通过与通过 SEM-数字图像相关 (DIC) 技术观察到的应变场分布进行比较，该模型用于验证 DP CPFEM 在模拟变形定位方面的准确性。开发的 DP CPFEM 模型可以预测微型焊点的潜在故障位置。DP CPFEM 模型是基于在原位拉伸试验期间进行的电子背散射衍射 (EBSD) 分析显示的微观结构建立的。通过与通过 SEM-数字图像相关 (DIC) 技术观察到的应变场分布进行比较，该模型用于验证 DP CPFEM 在模拟变形定位方面的准确性。开发的 DP CPFEM 模型可以预测微型焊点的潜在故障位置。DP CPFEM 模型是基于在原位拉伸试验期间进行的电子背散射衍射 (EBSD) 分析显示的微观结构建立的。通过与通过 SEM-数字图像相关 (DIC) 技术观察到的应变场分布进行比较，该模型用于验证 DP CPFEM 在模拟变形定位方面的准确性。开发的 DP CPFEM 模型可以预测微型焊点的潜在故障位置。