Constant Strain-Rate Garofalo Creep Behavior of Intermediate 83Pb/10Sb/5Sn2Ag and 91.5Sn/8.5Sb Solder Materials

Modern electronics reliability prediction models require materials-specific failure data across a range of conditions. For solder creep data, Garofalo models are preferred due to their ability to accurately predict performance over a wide temperature range. However, Garofalo data on intermediate solders is sparse, especially regarding performance at cold temperatures. Here, we report on creep phenomena of 83Pb/10Sb/5Sn2Ag (Indalloy 236) and 91.5Sn/8.5Sb (Indalloy 264). Indalloy 236 creep exhibits an activation energy of 83.6 kJ/mol, n=4.46 and a=0.0673, while Indalloy 264 exhibits an activation energy of 57.59 kJ/mol, n=5.89 and a=0.0306 from -20°C to 175°C. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were used to characterize the changes in the alloy phases as a result of the creep. Microstructural analysis indicates that Indalloy 236 experiences void coalescence with high diffusion rates while Indalloy 264 precipitates antimony-rich phases on the grain broundaries.