Experimental study of solder/copper interface under varying strain rates

Abstract

This thesis investigates the mechanical behavior of the copper-solder interface when subjected to dynamic axial loads at strain rates between 10.0 s-1 and 0.05 s-1. The copper is alloy 101 and the lead-free solder has a composition of 96% tin and 4% silver. The tests results revealed that as the strain rate increases so do the ultimate and yield strengths but the elastic modulus diminishes. When the specimens were heated to 65.5 degrees Celsius, the ultimate and yield strengths were significantly lower. Specimens were also tested at varying strain rates to compare and contrast the differences with the single strain rate data. Analysis of the fracture strain of the single and multiple strain rate tests revealed that the fracture strain from multiple-strain rate loadings fell between the fracture strains of the two singlestrain rates. From this observation, simple averaging could be utilized to predict the fracture strain when a coppersolder specimen was subjected to varying strain rates.