The Theoretical Exploration of Fracture Mechanics for Lead-Free Solder Joints

This paper discusses on the experimental and theoretical aspects of circular shear fatigue test, the test system, from the design will be applied to the solder joint reliability evaluation. The study found that test system must be carefully designed to avoid or reduce the error. Under special circumstances, the deformation of the chip mode must be suppressed in order to realize the precise control of shear displacement. No such consideration, circulation shear fatigue can produce misleading data and lost its advantage is a kind of effective method in the study, the fatigue performance and reliability of joints. The fact is, is found in solder fractures by shear mode by the crack-tip open mode, even load. This is because of the uneven joints of plastic deformation in the body. An application to the different shear test cycle alloy and treatment SAC305 exhibits that best fatigue resistance and Pb - Sn is the worst.