Investigation of vibration fracture behavior of Sn-Ag-Cu solders under resonance

This study investigated the vibration fracture properties of Sn-Ag-Cu alloys with various Cu contents. Results show that the microstructure becomes finer with a higher Cu content. This leads to a lower damping capacity, higher deflection amplitude, and thus inferior vibration fracture resistance under a constant vibration force. It is of interest that when the Cu content reaches 1.5 wt%, the specimen possesses the highest damping capacity and greatest vibration life. The presence of massive primary Cu₆Sn₅ intermetallics probably accounts for this phenomenon.