Fatigue and creep properties and crack growth behavior of solder joint under shear stress
Tanaka Tsuneshichi; Nakayama Hideaki; Kobayashi Yukiyoshi; Kawabe Takahiro
Abstract:Troubles of electric components and electronic devices are mainly caused by failure of solder joining parts, which results from thermal cycle fatigue due to the mismatch of thermal expansion coefficients among constituents. Therefore, it is an urgent problem to clear the fatigue and creep properties of solder joint and solder itself. In order to clarify the strength and crack growth behaviors of solder joint in fatigue and creep, a series of fatigue and creep tests was carried out on Cu/60Sn40Pb/Cu joints under shear stress condition. Results of fatigue tests under different loading frequencies indicate that fatigue lives can be evaluated uniformly by taking cumulative loading time to failure as a key parameter. Observations of shear strain behavior during fatigue and creep process make it clear that fatigue lives and creep rapture lives are well predicted by the minimum shear strain rate. Furthermore, results of crack growth tests in fatigue and creep under Mode II shear stress condition reveal that the modified J integral well governs the crack growth rate. Key Words:fatigue creep, crack growth, solder joint, shear stress, modified J integral