Nonadiabatically Driven Subcritical Crack Nucleation in Solids

This paper discusses a subcritical crack nucleation mechanism in a brittle solid within a real range of applied stress. A medium deformed by uniaxial tension is considered as an open nonequilibrium system of nuclei and electrons. Structural relaxation of the medium begins with the excitation of dynamic displacements during nonadiabatic Landau–Zener transitions. Dynamic displacements induce the instability of the medium to the longitudinal displacement wave. The kinetics of structural relaxation is described by two nonlinear parabolic kinetic equations for dynamic order parameters. Conditions are derived for the existence of localized solutions (autosolitons). The excitation of autosolitons leads to local elongation and cross-sectional reduction of the specimen. The resulting neck is a subcritical crack.