Dynamic fracture kinetics, influence of temperature and microstructure in the atomistic model of aluminum

Microscopic mechanisms and kinetics of dynamic fracture of crystalline materials are analyzed. The work is based on the molecular dynamics modeling and simulation within the embedded atom method model for interatomic interactions in metals. An attempt is made to present the results of molecular dynamics calculations as kinetic constitutive relations for the description of the elementary processes of fracture. The kinetics of melting, rates of nucleation and growth of voids are evaluated separately for a range of pressures and temperatures. The influence of the material microstructure (grain boundaries, dislocation subsystem, nanosize pores and inclusions) on failure mechanisms is studied. An effect of melting in rarefaction waves on the fracture kinetics and the spall strength of monocrystalline and polycrystalline metals is discussed. A comparison with the shock wave experimental data on the spall strength is presented.