Effect of Deformation on the Mechanical Properties of Sn-5wt%Sb Alloy

Sn–5wt%Sb is one of the materials considered for replacing Pb-bearing alloys in electronic packaging. The mechanical response of Sn–5wt% Sb solder alloy has been tested under different strain rates and three deformation temperatures. The behavior of true strain–time of Sn–5wt% Sb solder alloy has been investigated over strain rates of and deformation temperatures of 313, 333, and 353 K. Three-load creep tests were carried out at each temperature for of the wire samples to alloys. The deformation behavior and grain growth mechanism were investigated by strain-time curve analysis and microstructure observations. The results obtained show that the general characteristics of strain-time curve and microstructure of Sn-5wt% Sb alloy sensitively depend on the deformation temperature and strain rate. New free grains have been nucleated in microstructures in the process of dynamic recrystallization. These grains grow during deformation, forming coarser structure and elongation. The dynamic recrystallization and grain growth increase with increasing deformation temperature and decreasing strain rate. From the steady state creep rate the stress exponent is described in terms of the heat treatment temperatures. The stress exponent (n) were determined to clarify the deformation mechanism. Based on the n values, it is suggested that the rate controlling creep-deformation mechanism is dislocation climb. This study revealed that the solder alloy Sn–5wt%Sb have potential to give a good combination of higher creep resistance and rupture time.