Dynamic Failure of Pure Tungsten Carbide Under Simultaneous Compression and Shear Plate Impact Loading

In this paper, we present the results from a series of plate impact experiments designed to study dynamic response of commercial 99.6% purity tungsten carbide (WC) under simultaneous compression-and-shear stress wave loading. The symmetric oblique plate-impact experiments are conducted using progressively increasing angles of inclination (5°, 10°, and 22°). The longitudinal and transverse components of the measured particle velocity history at the free surface of the target plate in experiments with inclination angles of up to 10° and impact velocities ~100 m/s coincide well with their corresponding elastic particle velocity predictions. However, the normal particle velocity profiles for experiments conducted at an oblique impact angle of 22° are markedly different and exhibit a sudden increase in particle velocity from their plateau levels reminiscent of failure waves observed by other investigators in soda lime glass and silicon carbide (SIC-B). The increase in normal particle velocity (recompression/re-acceleration signal) in the shocked state of the target and the relatively large undulations present in the measured transverse particle velocity profiles are indicative of heterogeneous dynamic brittle failure processes in WC under the simple-shear state of stress, and are used to provide estimates for the critical range of pure-shear (tensile) loading that can initiate catastrophic failure in pure WC.