Creep phenomena in lead-free solders

A critical review of data on microstructure and creep process activation en ergy values for a number of lead-free solder alloys like Sn-Ag; Sn-Bi; Sn-I n was conducted. The review revealed a scatter in experimental data, which could not be explained by the dislocation creep mechanism only, even after the published data was corrected for Young's modulus temperature dependence . An analysis of the data implies that possible origin of such a scatter is nucleation, accumulation and further growth of such internal defects as po res and microcracks during creep, It is shown that these processes may affe ct the measured steady-state creep rates, and may be one of the major reaso ns for the observed scatter in experimental data, and,therefore, must be ta ken into consideration in lead-free solder alloys' creep studies.