Impact of Sb additives on solidification performance, microstructure enhancement and tensile characteristics of Sn-6.5Zn-0.3Cu Pb-free solder alloy

Solidification behavior, melting range, microstructure evolution plus tensile characteristics of Sn-6.5Zn–0.3Cu–(x = 0.0, 1.0, 3.0) wt% Sb alloys have been researched [it is abbreviated as SZC–xSb]. Solidification behavior has supported by creating an insoluble intermetallic compounds (IMCs) which sacrificed themselves to act as additional nucleation embryos. Microstructure of the SZC–xSb alloys included black irregular stars of γ-Zn₈ (Cu–Sn)₅ besides dark gray polygons of new Sb₂ZnSn IMC which have been created in solid solution of β-Sn phase. Furthermore, merging of Sb element enhanced most of tensile parameters as results of solid solution formation and uniformly dispersion of IMCs. Furthermore, Garofalo Model was employed to detriment the deformation mechanism from values of activation energy (Q) and stress exponent (n) of investigated alloys. The Q value of SZC–3.0Sb ally is more than SZC–1.0Sb and SZC–0.0Sb by 31.7% and 96.2%, respectively. The augment in Q values with increasing of Sb addition can be attributed to solid solution hardening and dispersion strengthening mechanisms. Based on values of Q and n the deformation mechanism can be proposed as a dislocation climb which dominating with dislocation pipe diffusion as well as lattice diffusion mechanism in range of tested temperature.