The Attenuation of Shock Waves in Nickel

Abstract

The attenuation of planar shock waves generated by plate impact was monitored by their decay throughout massive nickel blocks. This was accomplished, during the passage of the wave, by manganin piezoresistive gages connected to oscilloscopes and, in the post-shocked condition, by hardness measurements and TEM observations at various distances from the impact surface in the nickel blocks. The nickel systems exhibited different metallurgical microstructures before shock loading: preshocked (grain size 150 μm), annealed (grain size 150 μm)and annealed (grain size 32 μm). For each system two different initial shock pressures were used: 10 and 25 GPa. The pulse duration was held constant at 2 μs. The experimental records of oscilloscopes showed that there are no significant effects of grain size and pre-deformation on the attenuation in nickel. The observed attenuation was compared with the calculated one according to hydrodynamic theory and poor agreement was found, An “accumulation” model based on the conservation of energy is presented herein to explain the dissipative processes of shock waves in metals.