Microstructural and Hardness Evaluations of a Centrifuged Sn-22Pb Casting Alloy Compared with a Lead-Free SnAg Alloy

A great preoccupation with replacing the traditional Sn-Pb alloy with a Pb-free alloy (“green alloy”) is recognized. There are industrial sectors that demand metallurgical improvements to attain certain unsoundness and adequate properties as a function of imposed operational parameters. In this experimental investigation, two distinctive centrifuged casting alloys (i.e., Sn-2 wt pct Ag and Sn-22 wt pct Pb) are compared. It is found that centrifuged castings have similar microstructure constituents, although distinctive cooling rates and solute contents are considered. It is also found that Ag3Sn intermetallic particles are responsible for attaining similar tensile strength, since more dislocations between Ag3Sn particles and the Sn-rich phase are provided. In order to replace the Sn-Pb alloys with a successor alloy containing sustainability and environmental aspects associated with castability and to guarantee the desired properties, it seems that a green alloy (Pb free) with intermetallic particles finely and homogeneously distributed provides an interesting benefit to various industrial applications.