The Weibull statistical analysis for evaluating microstructural effects on electrification–fusion phenomenon of Sn–xZn alloys

Microstructural features of Sn–xZn alloys with varying zinc content of 7, 9, and 14 wt.% on the electrification–fusion phenomenon was investigated in this study. Experimental results showed that the electrical conductivity of Sn–xZn alloys increases with increasing zinc content. The increase of zinc-rich phase is the main factor in the increase of the electrical conductivity. The melting latent heat of Sn/Zn eutectic phase tended to decrease with increasing zinc content, the evidence was consistent with the increase of critical fusion current density of Sn–xZn alloys. Based on the data fluctuation of fusion current densities, the Weibull model provided a powerful statistical analysis for assessing the minimum critical fusion current density, the fusion-failure mechanism and the reliability for the solders. The statistical Weibull model analysis results indicated that the Weibull modulus of Sn–xZn alloys decreases with increasing zinc content. The hypereutectic Sn–14Zn alloy, which shows microstructural inhomogeneity and a large data fluctuation of critical fusion current density, was unreliable for further electronic devices and PCB applications.