Shock response of cobalt-based cemented tungsten carbides at pressures up to 100 GPa

In the present study, shock wave experiments are conducted on General Carbide cemented tungsten carbides with 3.7 wt.% and 6.0 wt.% cobalt binder to determine their shock compression response up to 100 GPa. A three-stage particle velocity profile is observed in the experiments -- an initial elastic-rise to the Hugoniot elastic limit (HEL), an elastic-plastic ramp indicating post-yield hardening, and finally a rise to the peak shocked Hugoniot state. The results of the experiments are used to determine the HEL, shock velocity (Us) vs. particle velocity (up) Hugoniot relationship, and the longitudinal stress vs. specific volume Hugoniot relationship for the two samples. The HEL for the WC 3.7wt% Co and WC 6.0wt% Co samples was determined to be∼4.45 GPa and 3.72 GPa, respectively. The Us – up relation was determined to be Us=4.97(0.006)+1. 446 (0.018) up for WC 3.7 wt.% Co and Us=4.93(0.006)+1. 454(0.017)up for the WC 6.0 wt.% Co sample at peak particle velocities>0.75 km/s. For both WC grades, in the particle velocity regime less than ∼ 0.75 km/s, the measured shock wave velocities were found to be larger than those predicted by the linear Us−up Hugoniot relationship, indicating the two WC samples to preserve substantial strength in the post-yield deformation regime. Both WC grades show a catastrophic drop in shear stress carrying capacity when shocked to longitudinal stresses greater than∼70 GPa.