An Investigation on Effects of Modes of Cooling on Mechanical Property of Sn-Cu Alloy

Abstract 63Sn–37Pb solder alloy is widely used as filler materials in electronic packaging industries. However, due to environmental and human health concern use of lead (Pb) in electronic applications is restricted. Thus, Pb−free solders are preferred in electronic packaging to replace Sn–37Pb solder. Sn–0.7Cu lead free solder alloy has attracted considerable attention. However, research works on effects of modes of cooling of Sn–0.7Cu Pb−free solder are scant. The cooling or solidification behaviour controls the metallurgical microstructure of solder alloys. To work satisfactorily in electronic packaging applications, good hardness is essential for reliability of Sn–Cu solder alloy. Hence in the current research work, the effect of casting moulds on solidification behaviour, microstructure and mechanical property (hardness) of Sn–0.7Cu alloy is assessed. Two cooling moulds mild steel (MS) and Graphite around water and two different cooling media (Furnace, air) were used for solidification to achieve different cooling modes. Further, an effect of grain morphology and hardness on Sn–0.7Cu alloy cooled in different moulds/media were assessed.