Phase-field modeling of corrosion fatigue in solder joint structures

Corrosion fatigue significantly reduces the reliability of solder joints subjected to cyclic loading in aggressive environments. In this study, a coupled phase-field model is developed to simulate corrosion degradation and fatigue fracture in solder joint structures. Corrosion and fracture are represented by two separate phase-field variables. The effects of local stress, accumulated plastic strain, temperature, and loading frequency are introduced through the interfacial kinetics coefficient and the fatigue-induced reduction in fracture resistance. The model is validated against corrosion-fatigue experiments on hourglass-shaped solder joints and reproduces the observed fracture mode and the evolution of the maximum shear force. Parametric simulations are then performed to examine the effects of temperature and loading frequency on the corrosion-fatigue damage evolution. The results show that elevated temperature accelerates corrosion and shifts the damage process toward corrosion-controlled degradation. Increasing the loading frequency promotes both deformation-assisted corrosion and fatigue crack propagation. However, the relative contribution of corrosion to the overall damage process decreases as the loading frequency increases, because fatigue-induced damage becomes more pronounced. The proposed framework provides a useful computational method for evaluating solder-joint reliability under coupled corrosion and cyclic loading.