Nanoindentation creep behavior of Sn-Cu lead free solder alloy synthesized by pulse electrodeposition: Assessment of the creep rate

Abstract

A nanoindentation creep test was performed on pulse electrodeposited Sn-Cu lead free solder under a 600 μN load, with a dwell time of 900 s. The modified Garofalo equation was used to evaluate the creep rate using indentation depth vs. time data. Variations in creep rates were observed due to different methods of extracting creep curves and instantaneous depth estimation techniques. The displacement rate to effective depth ratio was employed for accurate creep rate determination, emphasizing the significance of precise depth measurement. This approach was further utilized to examine the effect of current density on creep resistance. Microstructural analysis and stress exponent calculations indicate that both dislocation activity and diffusion mechanisms may contribute concurrently to the deformation process.