Dynamic material properties of refractory metals: tantalum and tantalum/tungsten alloys

Abstract

We have made a careful set of impact wave-profile measurements (16 profiles) on tantalum and tantalum-tungsten alloys at relatively low stresses (to 15 GPa). Alloys used were Ta96.5W3.5 and Ta86.5W13.5 (wt%) with oxygen contents of 30–70 ppm. Information available from these experiments includes Hugoniot, elastic limits, loading rates, spall strength, unloading paths, reshock structure and specimen thickness effects. Hugoniot and spall properties are illustrated, and are consistent with expectations from earlier work. Modeling the tests with the Steinberg-Guinan-Lund rate-dependent material model provides for an excellent match of the shape of the plastic loading wave. The release wave is not well modeled due to the absence of the dynamic Bauschinger effect. There is also a discrepancy between experiments and calculations regarding the relative timing of the elastic and plastic waves that may be due to texture effects.