Temperature- and stress-dependent creep behavior of SAC305 solder alloy through tensile characterization and CPFE simulation

• Creep tests and characterizations of Sn3.0Ag0.5Cu solder were carried out under different temperatures and stress levels. • A crystal plasticity model based on dislocation density evolution containing the β-Sn and eutectic regions was established. • Microscopic deformation characteristics of Sn3.0Ag0.5Cu creep were clarified from the strain distribution, operation of slip systems and loading direction. Effective characterization of creep properties of Sn3.0Ag0.5Cu (SAC305) solder alloy is of great significance for improving the service reliability of electronic interconnection solder joint and increasing the lifetime of electronic products. The elastic and creep properties of SAC305 were investigated by uniaxial tensile and creep tests under different temperatures and stress levels, from which the elastic modulus, creep stress exponent and activation energy of SAC305 were determined. Through electron back-scattered diffraction (EBSD) test the micro-structure information of SAC305 was obtained, and a crystal plasticity model based on dislocation density evolution, containing the β-Sn and eutectic regions, was established to study the creep deformation mechanism of SAC305. From the strain distribution, operation of slip systems and loading direction, the related microscopic deformation characteristics of creep of SAC305 dependent on temperatures and stress were clarified. The verified crystal plasticity model allows the further understanding of micro-scale deformation behaviour and the guidance of texture optimization for solder alloy.