Effect of shock-wave loading on the internal microstructure and mechanical properties of fine-grained copper

It is shown that preloading of fine-grained copper with a the grain size of 0.5 m by a shock wave of intensity $\approx$25–50 GPa does not lead to changes in its internal microstructure and mechanical properties, and the dislocation density increases only slightly from 1.8 $\cdot$ 10$^{11}$ cm$^{-2}$ in the initial state to (3.1–3.6) $\cdot$ 10$^{11}$ cm$^{-2}$ after shockwave loading. An increase in shock wave intensity to pressures $>$ 55 GPa leads to a decrease in the dislocation density to 2.5 $\cdot$ 10$^9$ cm$^{-2}$, an increase in the grain size to $\approx$19 fum, the occurrence of microtwins inside the grains, and a reduction in the mechanical properties of fine-grained copper to the level of coarse-crystalline copper.