Shock response of metal-ceramic nanolayered composites

摘要

Shock responses of Cu/SiC nanolayered composites are investigated via molecular dynamics simulations. Both the normal and parallel shocks are carried out to uncover the underlying deformation mechanisms. For normal shock, plastic deformation occurs in Cu layers once the shock pressure reaches the critical value for the Hugoniot elastic limit of Cu single crystal. Such a case is consistent with the Cu single crystal with the same crystalline orientation. As for SiC - layers, SiCCu interfaces act as the nucleation sites of the plastic deformation due to the transmission and reflection of the shock wave. For parallel shocks, drag effect appears in both Cu layers and SiC layers, leading to the increases of particle velocity and stress in Cu layers and their decreases in SiC layers. When the layer thickness increases to a larger value in the case of parallel shocks (e.g., 25 nm), the deformation incompatibility of two different materials is aggravated, resulting in expansive Cu layers, shrunken SiC layers and thus severe shear slip.