A Novel Approach for Plate Impact Experiments to Obtain Properties of Materials Under Extreme Conditions
In this paper we present a novel approach to conduct normal plate impact experiments at elevated temperatures up to 1000 °C. To enable this approach, custom adaptations are made to the breech-end of the single-stage gas-gun at Case Western Reserve University. These adaptations include a precision-machined steel extension piece, which is strategically designed to mate the existing gun-barrel by providing a high tolerance match to the bore and keyway. The extension piece contains a vertical cylindrical heater-well, which houses a resistive coil heater attached to a vertical stem with axial/rotational degrees of freedom. The assembly enables thin metal specimens held at the front-end of a heat-resistant sabot to be heated uniformly across the diameter to the desired test temperatures. Using the configuration, symmetric normal plate impact experiments are conducted on 99.6% tungsten carbide (no binder) using a heated (room temperature to 650 °C) WC flyer plate and a room temperature WC target plate at impact velocities ranging from 233 to 248 m/s. The measured free-surface particle velocity profiles are used to obtain the elastic/plastic behavior of the impacting WC plates as well as the temperature-dependent shock impedance of the flyer. The results indicate a dynamic strength of approximately 6 GPa for the WC used in the present study (strain-rates of about 105), and a decreasing flyer plate longitudinal impedance with increasing temperatures up to 650 °C.
KeywordsNormal plate impact Incipient plasticity Elevated temperatures Tungsten carbide Hugoniot elastic limit Longitudinal impedance
The authors would like to acknowledge the financial support of the U.S. Department of Energy through the Stewardship Science Academic Alliance (DE-NA0001989 and DE-NA0002919).
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