Resonant vibration behavior of Sn-Zn-Ag solder alloys

The effects of Ag content on the microstructure and the vibration deformation properties of a potential lead-free solder, Sn-9Zn-xAg (x = 0.5-3.5 wt.%), are examined in this study. Results show that Ag additions gave rise to microstructural changes in Sn-Zn eutectic alloys used, resulting in the appearance of proeutectic Sn-rich dendrites, and Ag-Zn intermetallics (epsilon-AgZn3 and gamma-Ag5Zn8) which replaced the Zn-rich phase. These microstructural changes strongly affect the vibration-deformed structure morphology and vibration properties. When the Ag content is higher than 1.5 wt.%, the specimens possess high damping capacity and thus a long vibration life. This can be attributed to the proeutectic Sn dendrites improving the damping capacity and Ag-Zn intermetallics increasing vibration-fracture resistance. (C) 2004 Elsevier B.V. All rights reserved.