21. Structure of Shock Waves and Inelasticity in Shock-Compressed Cemented Tungsten Carbides

In the present study, shock wave experiments are conducted on General Carbide cemented tungsten carbide with 3.7 wt.% cobalt binder to determine its shock-induced compression behavior up to 100 GPa. The measured wave profiles indicate the cemented tungsten carbide undergoes elastic-plastic deformation during shock compression. 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 substantial post-yield hardening, and finally a rise to the peak shocked Hugoniot state. The results of the experiments are used to determine the HEL, the shock velocity (U_s) vs. particle velocity (u_p) Hugoniot relation, and the longitudinal stress (σ_x) vs. specific volume (V) curve for the samples. The HEL of the material was determined to lie between 4.41 and 4.58 GPa. The U_s − u_p relation was determined to be U_s = 4.97 + 1.457u_p for particle velocities greater than 0.75 km/s. The measured plastic shock velocities for particle velocities less than 0.7 km/s were found to be larger than those predicted using the linear U_s − u_p Hugoniot relationship, indicating the cemented WC samples to preserve substantial shear strength in the post-yield deformation region. No phase transformation was observed up to 100 GPa.