Electric current stressing altered damping performance of aged inhomogeneous solders for low-temperature interconnection

To assess the vibration resistance of low-temperature inhomogeneous SnBi–based solders during long-term service, the damping capacities of Sn58Bi and Sn57.6Bi0.4Ag solders after different aging time (0, 120, 480, 960, and 1440 h) at 120 °C were tested under different electric currents (0, 3.0, 6.0, and 9.0 A). The results showed that the critical strain of strain–amplitude–related damping capacity curve increased with increasing aging time. While, the damping capacity decreased with prolonged aging time and increasing frequency, and it was elevated in exponent function of the square of electric current. The dominant damping mechanism shifted from dislocation movement to phase boundary sliding with increasing temperature, and the damping mechanism transition temperature increased with prolonged aging time and increasing frequency, but it decreased with increasing electric current. Additionally, the increase rate of the damping mechanism transition temperature was high in frequency of 0.1 to 1.0 Hz, while it slowed down to a low level in the frequency of 1.0 to 10.0 Hz. Moreover, the activation energy remained in the range of 0.64 to 0.88 eV for both solders regardless of electric current, and it decreased generally with prolonged aging time.