Split-Hopkinson pressure bar tests on pure tantalum

Pure tantalum (Ta) was loaded in compression by a split-Hopkinson pressure bar (SHPB) to strain rates from 450 to 6350 s-1. The results are compared with SHPB data for commercial Ta and with predictions from the constitutive model for Ta developed by Zerilli and Armstrong (Z-A). The main conclusions are: (1) the flow stress versus log strain rate agree with the Z-A constitutive model and other reported data, (2) uniform strain exponents computed on a true stress-strain basis for pure Ta are somewhat greater than those determined from SHPB data for commercial Ta, and (3) in both cases the uniform strain exponents versus log strain rate are in good agreement with predictions from the Z-A constitutive model for strain rates above 1500 s-1 without a clear indication of dislocation generation