Development of a low-cycle fatigue life curve for 80In15Pb5Ag

The purpose of this study is to develop a methodology to predict the low-cy cle (large strain-from 0.1 to 0.35 strain) fatigue life of solders subject to thermal cycling. Solders are commonly used in electronic assemblies. Usi ng thermal fatigue data measured for 80In15Pb5Ag, a low-cycle fatigue curve for 80In15Pb5Ag solder subject to thermal cycling was developed. Specifica lly a Coffin-Manson relationship was derived for the solder, with a high de gree of correlation (see Table I), for four different failure criteria, def ined in the body of the paper. This relationship, together with calculated strains in the solder joint, allows the low-cycle fatigue life of the solde r joint to be predicted.