Tensile Behavior and Superplastic Deformation of Sn–Bi–Cu Alloy

Abstract

The purpose of this study is to clarify the tensile behavior and deformation mechanism of the Sn–40Bi–0.1Cu alloy (mass%). Tensile tests of Sn–40Bi–0.1Cu were performed at temperatures of 298, 333, and 353 K and strain rates from 5.25 × 10⁻⁵ to 5.25 × 10⁻² s⁻¹. The tensile strength decreased and the elongation increased with increasing temperature and decreasing strain rate. Sn–40Bi–0.1Cu shows superplastic behavior at temperatures of >333 K and low strain rates of <5.25 × 10⁻⁴ s⁻¹. Microstructural observation after superplastic deformation of Sn–40Bi–0.1Cu showed that the primary crystal Sn grains could not deform along the axial direction of applied tension in the superplastic regime. The eutectic phase contributed to superplastic deformation. The strain rate sensitivity m for Sn–40Bi–0.1Cu was <0.3.

Fig. 4 Strain rate dependence of maximum strain at various temperatures.