Mechanical properties of Sn-3.5Ag-0.5La lead-free solder alloy for green electronics

Eutectic Tin-Lead solder, commonly 63Sn-37Pb, has been used for times in the electronic industry. However, due to the harmful effects of lead on the environment, many alternatives have been investigated. The Tin-Silver alloys are acknowledged on a large scale as a replacement for traditional Tin-Lead solders due to their excellent mechanical properties. However, to further enhance the properties of Tin-Silver alloys, doping of additional elements is highly acknowledged. In this study, the investigation on the mechanical properties of Sn-3.5Ag solder alloy is carried out after doping 0.5 wt% Lanthanum. The yield strength (YS), ultimate tensile strength (UTS), creep behaviour and hardness are evaluated using tensile tests, creep tests and Brinell hardness measurement, respectively. The composition of alloys is confirmed using energy dispersive spectroscopy, and phase analysis is done by X-ray diffraction. The results showed a significant increase in all mechanical properties after adding Lanthanum into the Tin- Silver alloy.