EFFECT OF Zn ADDITION ON THE DEFORMATION BHAVIOR OF Sn-3.5Ag LEAD-FREE SOLDER ALLOY

摘要

Deformation behavior of Sn-3.5Ag and Sn-3.5Ag-1.5Zn alloys was investigated at temperatures ranging from 298 to 400 K, and strain rates ranging from 5 x 10~(-4) to 1 x 10~(-2) s~(-1). After melting and casting, the samples were rolled to sheets, from which tensile specimens were punched and pulled to fracture in uniaxial tension tests. Scanning electron microscopy (SEM) was used to study the microstructure and fracture surface of the samples. Addition of 1.5% Zn into the binary alloy resulted in an increase in ultimate tensile strength (UTS) and a decrease in ductility. The increase in strength can be stemmed from particle hardening caused by AgZn, as well as suppressing the formation of the soft β-Sn phase. The decrease in ductility was, however, attributed to the nonuniformity of the microstructure caused by the formation of the relatively coarse AgZn particles in the Sn matrix.