The effects of 0.05Ni and 0.5Zn additives on the microstructure, microhardness and tensile behavior of SAC(205) alloys have been investigated. Significant conclusions obtained in this research are as follows:
(1)
The addition of small amount of Ni and Zn to SAC(205) alloy not only suppressed the formation of brittle Ag3Sn IMC phase and refines the large β-Sn dendrites, but also promoted the formation of new (Cu,Ni)6Sn5 and Cu5Zn8 IMC particles in the SAC(205), respectively.
(2)
The addition of 0.05Ni and 0.5Zn to SAC(205) alloy resulted in an increase in YS and UTS as well as the ductility at all temperatures and strain rates due to the formation of new IMC particles in the SAC(205) with the refinement of grain size of β-Sn matrix.
(3)
Due to both (Cu,Ni)6Sn5 and Cu5Zn8 IMC particles and uniform microstructure of the new solders, the Vickers microhardness improved, in good agreement with the prediction of the classic theory of dispersion strengthening.
(4)
According to the obtained stress exponents and activation energies, it is proposed that the dominant deformation mechanism in SAC(105) solders is lattice-diffusion-controlled dislocation climb over the whole temperature range investigated.