Influence of crystallographic orientation on fatigue reliability of β-Sn and β-Sn micro-joint

Abstract

Crystallographic anisotropy of static mechanical characteristics and fatigue reliability of β-Sn single crystal was investigated in this study. The static mechanical properties of β-Sn strongly depend on crystallographic orientation and yield stress is extremely high in the [001] orientation compared with other orientations. The low cycle fatigue life of β-Sn also exhibits remarkable orientation dependence and the life of β-Sn can be predicted by inelastic strain energy density regardless of crystallographic orientation. The finite element analysis based on these experimental data revealed that the thermal fatigue lives of BGA joints, in the case of β-Sn single crystal, differ remarkably as the inelastic strain energy density produced per cycle differs in conjunction with the difference in crystallographic orientation. © 2012 The Japan Institute of Metals.