Influence of Bi content on deformation behavior of Sn-Bi　solder alloys in the tensile test.

Abstract

The tensile behavior of Sn–Bi–Cu, Sn–Bi–Ni, Sn-Bi-Zn, and Sn-Bi-Sb alloys has been widely investigated. The purpose of the present study is to measure the stress-strain curves and the strain rate sensitivity index m of Sn-Bi alloys. Tensile tests of Sn-Bi alloys with various Bi content at 25, 60, and 80 ℃ under strain rate of 5.25×10⁻³ and 5.25×10⁻⁴/s. The results showed that maximum elongation increased with Bi concentration and test temperature. Tensile tests for the measurement of the strain rate sensitivity index m were carried out at 80℃ under various cross head speed. Index m of Sn-Bi alloys at 80℃ is below3.0, 3.0 is the threshold of superplasticity deformation behavior. The Sn-Bi eutectic microstructure has greater effect on the superplasticity deformation in hypoeutectic Sn-Bi alloys.