Uniaxial ratcheting behavior of 63Sn37Pb solder with loading histories and stress rates

Uniaxial ratcheting characteristics of 63Sn/37Pb at room temperature were studied experimentally and particular attention was paid to ratcheting behavior under different loading rates. The effects of stress amplitude, mean stress, and loading history on the ratcheting behavior of 63Sn37Pb were analyzed, respectively. It can be concluded that the ratcheting strain amplitude and ratcheting strain rate of 63Sn37Pb increases with increasing stress amplitude or mean stress correspondingly. At the meantime, the loading history and loading sequence were found to have significant influence on ratcheting strain. In addition, the experimental results indicated that the ratcheting strain rate was very sensitive to the applied cyclic stress rate. In the range of 0.4-8 MPa/s, the ratcheting strain rate had an inversely proportional relationship with stress rate, the ratcheting rate under stress rate of 0.4 MPa/s was approximately 120 times as large as that under stress rate of 8 MPa/s.