Effect of Cooling Rate on the Microstructural and Mechanical Properties of Sn-0.3Ag-0.7Cu-0.05Ni Solder Alloy

E-ISSN： 1662-9795|2017|751|9-13

ISSN： 1013-9826

Source： Key Engineering Materials, Vol.2017, Iss.751, 2017-09, pp. : 9-13

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Abstract

The effect of cooling rate on the microstructural and mechanical properties of Sn-0.3Ag-0.7Cu-0.05Ni lead-free solder alloy was studied. The microstructure of specimens was characterized by using an optical microscope (OM) and an energy dispersive X-ray spectroscopy (EDX). The mechanical properties were performed by using a universal testing machine (UTM). The results showed that the cooling rate of water-cooled specimens was about 2.37 °C/s and the cooling rate of mold-cooled specimens was about 0.05 °C/s. To compare the different cooling rates, it was found that the grain size of water-cooled specimens was finer than that of the mold-cooled specimens, this resulted in an increment of mechanical properties of solder alloy. A higher tensile strength (33.10 MPa) and a higher elongation (34%) were observed when water-cooled and mold-cooled systems were used, respectively. The microstructure of Sn-0.3Ag-0.7Cu-0.05Ni lead-free solder alloy solidified by both cooling systems exhibited three phases: β-Sn, Ag₃Sn and (Cu,Ni)₆Sn₅ IMCs.