Plastic deformation characteristic of Ta-W alloy at shock loading

The deformation behaviour of Ta-W alloy under the strain rates between 10(4)/sec, and 10(6)/sec. is studied by means of an air gun loading and shock wave measuring technique. The characterization of the alloy under the strain rates above were determined by the measurments of the shock wave propagation through the thickness of alloy targets. The results show that the value of yield strength of the alloy under the tests of air gun is almost twice the quasistatic value. Based on the experimental results and the elastic-plastic-fluid dynamics theory, the constitutive equation has been constructed for Ta-W alloy. The microstructure observation shows that the twinning is the major dynamic plastic deformation mode of Ta and Ta-W alloy. The influences of tungsten addition and the strain rate on the dynamic mechanical responce are also discussed in detail.