Investigation on multi-temperature short-term stress and creep relaxation of Sn-Ag-Cu-In solder alloys under the effect of rotating magnetic field

Abstract

In this study, using one single specimen and viscous strain εv of ≤0.0001, the short-term stress and creep relaxation tests are developed and performed on SAC(307)-2In alloy before and after applying rotating magnetic field (RMF), to predict the creep mechanisms at different temperatures and strain rates. The global strain rate εp is shown to follow the same power-law with stress exponents of 4.8–8.1, while the activation energies Q were 55.7–51.2 kJ/mol, indicating the climb-controlled dislocation creep enhanced by pipe diffusion mechanism. Because of the grain refinement after applying RMF, significant enhancement has been detected in viscous strain εv, elastic strain εe, delayed strain εd, young modulus E, stress exponents n and activation energy Q, whereas the thermal properties are rather sensitive to it. Moreover, significant drop in stress-time relationship rather than saturation stress was observed at different strain rates after applying RMF, indicating the viscoelastic response of creep, which has good predictions for next-generation electronic devices and engineering alloy design due to the contribution of εv/εe ratio.