Creep–fatigue life of Sn–8Zn–3Bi solder under multiaxial loading

This paper describes a creep–fatigue life of Sn–8Zn–3Bi solder under multiaxial loading. A push–pull and a reversed torsion tests were carried out using seven types of strain waveforms, which are a fast–fast, a fast–slow, a slow–fast and a slow–slow waveforms and three types trapezoidal strain waveforms with different strain holding times. The strain waveforms had a significant effect on creep–fatigue life and the shortest creep–fatigue life was found in the slow–fast strain waveform while the longest life in the slow–slow waveform in the push–pull and the reversed torsion tests. Creep–fatigue life in the reversed torsion test was approximately twice longer than that in the push–pull test at each strain waveform. Applicability of common used creep–fatigue damage models for life evaluation was discussed based on the obtained experimental results and only a grain boundary sliding model could evaluate the lives within a small scatter.