The mechanical properties of tungsten-based composites at very high strain rates

The high strain rate behavior of two different tungsten-based composites (WBCs) has been investigated using a combination of compression Kolsky bar and high strain rate pressure—shear plate impact experiments. The two materials investigated are (a) a W/(WNiFe) “heavy alloy” containing 91 wt.% W with a WNiFe matrix/binder phase and (b) a W/Hf composite containing 72 wt.% W and Hf matrix/binder phase. For each materials, stress-strain curves are obtained in compression and shear over the strain rate range of 103 to 105 s−1. The flow stresses observed in the W/Hf composite during these dynamic deformations are comparable to those observed in the W/(WNiFe) material, in spite of the lower tungsten content of the W/Hf composite. Further, the W/Hf composite displays approximately the same degree of strain-rate hardening as the W/(WNiFe) composite. The observed behaviorof the W/(WNiFe) composite is compared with the predictions of several phenomenological models for high-rate deformations, including the Johnson-Cook and Zerilli-Armstrong models.