Notch Effect on Low Cycle Fatigue of Sn–3.5Ag Solder

This paper studies the notch effect on low cycle fatigue of Sn–3.5Ag solder. Strain controlled push-pull low cycle fatigue tests were carried out using three circumferential notched specimens at $313K$⁠. Cycles to crack initiation were measured by an a.c. potential method, and cycles to failure and for crack propagation were also determined in experiments. Cycles to failure, to crack initiation, and for propagation decreased with elastic stress concentration factor but cycles to crack initiation were most sharply reduced with elastic stress concentration factor. Prediction methods of cycles to crack initiation, for propagation, and to failure were discussed from the data fitting and the local strain approach utilizing finite element analysis.