Constitutive Description Of Temperature And Strain Rate Dependent Tensile Behaviors Of Solder

A series of tensile tests at constant strain rate were conducted on tin-lead based solders with different Sn content under a wide range of temperatures and strain rates showed that the mechanical properties of solder such as tensile strength, elastic modulus and yield stress have close relationship with test temperature, strain rate and Sn content as well and that the stress-strain relationships have strong temperature- and strain rate- dependence and vary a little in characters due to Sn content.Based on the test results, empirical equations for predicting tensile strength, elastic modulus and yield stress were fitted as a function of temperature, strain rate and Sn content. The predicted values fell with a scatter band of 1.25.The parameters of Anand model for solders with varying Sn content were determined and used to simulate the test data. The results showed that Anand model could adequately predict the rate- and temperature- related constitutive behaviors of eutectic solders at all test temperatures and strain rates. Prediction of solders with high-lead content gave good correlation with test data at lower strain rates and deviation at higher strain rates.With rate-sensitivity and temperature-sensitivity functions introduced into the basic equations, Endochronic constitutive model was also employed to simulate the test results and the prediction showed that this model is effective in predicting visco-plasticity behaviors of solders and has feasibility in the reliability simulation and fatigue analysis of solders.