Mechanical properties of Sn-Ag lead-free solder alloys based on the dendritic array and Ag3Sn morphology

The aim of this experimental investigation is to evaluate the tensile properties of as-cast Sn-Ag alloys as a function of both the resulting secondary dendritic arm spacings and the morphology of the Ag3Sn IMC (intermetallic compound). This comparative experimental investigation was carried out with a view to assess the application of Sn-Ag alloys as alternative solder materials. A directional water-cooled solidification apparatus was used to obtain the as-cast samples. The resulting microstructures, ultimate and yield tensile strengths and elongation of Sn-2 wt.% Ag and Sn-3.5 wt.% Ag alloys were experimentally determined and compared with the corresponding results of the traditional Sn-40 wt.% Pb solder alloy. It was found that the Sn-Ag alloys examined comply with the compromise between compatible mechanical strength and environmental protection. (C) 2013 Elsevier B. V. All rights reserved.