Spatially resolved measurements of grain size effects on the shock and spall response of quasi-Taylor wave loaded pure copper

Quasi-Taylor wave loaded plate impact experiments have been used to study the effects of bulk grain size on the shock and spall response of pure copper samples. Using line-Velocity Interferometry System for Any Reflector velocimetry, an increased particle velocity dispersion was measured for larger bulk grain size samples resulting in lower mean peak particle velocities and a lower reload velocity following spall. Spall voids were located in a surface layer of similarly sized grains for both bulk grain size materials tested. The spall strength was observed to vary with the tensile strain-rate but was unaffected by the bulk grain size. Post-mortem studies of voids in samples showed narrow void planes for the small bulk grain size materials and a larger spread of voids in the larger bulk grain size materials consistent with the free surface particle velocity data and observed particle velocity dispersion.