EVOLUTION OF PLASTIC DEFORMATION AND TEMPERATURE AT THE REFLECTION OF A SHOCK PULSE FROM SUPERFICIES WITH A NANORELIEF OR WITH SUPPLIED NANOPARTICLES

Abstract

Intense irradiation and high-speed collision of metals results in the formation and dissemination of shock compression pulses in them. The recent development of experimental technology using high-power subpicosecond laser pulses makes it possible to obtain shock pulses of the picosecond range. A molecular dynamics simulation of high-speed collisions for aluminium samples is conducted. The presence of a nanorelief or precipitated nanoparticles on the back superficies of the sample may essentially enhance the rear splitting threshold. The cooperation of a shock wave with a nanorelief or precipitated nanoparticles results in strong plastic deformation. Consequently, part of the compression pulse energy is spent on plastic deformation, which prevents spall destruction. The effect of increasing the threshold can reach hundreds of meters per second in terms of collision speed and tens of gigapascals in amplitude of the incident shock wave. The distribution of shear strain and temperature in the sample is considered. It is shown that the maximum degree of deformation and maximum heating are observed in those parts of the nanorelief, for which the greatest change in shape is observed. The maximum temperature reaches the melting point, but no obvious traces of melting are found, which may be related to the speed of the processes.