Characterization of dynamic behavior of Pb-free material 95.7Sn3.8Ag0.5Cu and its determination of dynamic constitutive model parameters

A series of impact tests for Pb-free solder material 95.7Sn3.8Ag0.5Cu are performed with a wide range of strain rates to get the valid dynamic model parameters input for modeling. By using a split Hopkinson pressure bar (SHPB) experimental system, dynamic stress-strain characteristics data of 95.7Sn3.8Ag0.5Cu are measured. Comparison of the dynamic test data with the quasi-static test data shows that the dynamic stress strength is nearly 4 times greater than the static sresss strength. The saturation stresses of 95.7Sn3.8Ag0.5Cu increase significantly with the rapid increment of the strain rate. The test results have also shown that both the static and dynamic behaviors of 95.7Sn3.8Ag0.5Cu are highly rate dependent Four material constitutive models are introduced. The parameter determination of these constitutive models through data fitting is studied and the related parameters are obtained. Finally, the comparison of the data-fitting constitutive models with experimental data is presented and discussed.