Compositional effects on the microstructure and vibration fracture properties of Sn-Zn-Bi alloys

This study investigated the effect of Bi content on the microstructure and mechanical properties of the Sn-Zn-Bi alloys, especially the vibration fracture behavior. Results show that Sn-Zn-Bi alloys exhibit an alternate normal-irregular eutectic structure due to the inhomogeneous dissolution feature of Bi in Sn matrix. With an increased Bi addition, the vibration properties including damping capacity and vibration fracture resistance became inferior. This can be ascribed to hardening effect caused by Bi dissolution in the Sn matrix. Also, Bi-rich precipitates appeared in high Bi samples led to quick crack propagation.