SnAgCu: Microstructural evolution and mechanical properties

The fact that the great majority of the solder pastes contain lead is an environmental threat. In order to eliminate this undesirable environmental impact associated with their production, a new family of lead free solder joint, Sn-3.8Ag-0.7Cu, is proposed. Microstructural and mechanical data of this new solder joint have been acquired and compared with the most common used SnPbAg solder paste. Consequently the purpose of this paper is to understand the evolution of the microstructure, failure mode and mechanical properties of SnAgCu solder joint with stain rate, annealing treatments and testing temperature. Tensile tests, at temperature ranging from -50 to +150degreesC, have been performed on bulk samples. TEM investigations have shown that microstructural changes are correlated with the modification of the mechanical properties of bulk tested samples.