Self-force of high-speed dislocation in anisotropic media based on configurational mechanics

Abstract

Subsonic, transonic, and supersonic dislocations play a critical role during super high strain rate (>105/s) deformation. For these high-speed dislocations, the self-force is history dependent, which is different from and much more complex than the quasi-static dislocations. Solutions to the self-force of high-speed dislocation in continuum media are only known for some special cases, i.e., subsonic dislocation moving in isotropic infinite crystals with a constant speed. However, metals are generally anisotropic, and high-speed dislocations may have complicated histories and interact with the free surface. How crystal anisotropy, complicated motion history and free surface influence their self-force has so far received little attention. In the current work, we proposed an effective calculation method of self-force on high-speed dislocation based on the discrete-continuous model of three-dimensional dislocation elastodynamics and the dynamic J-integral of configurational mechanics. It is applicable to arbitrarily moving subsonic, transonic and supersonic dislocation, in both isotropic and anisotropic crystals, and can automatically consider the image force if the dislocation is close to the free surface. The effectiveness of the method is carefully verified by comparing it with the existing theoretical solutions and the molecular dynamics results. The effect of crystal anisotropy on the elastodynamic stress field, as well as the self-force of high-speed dislocation close to or far from free surface are studied.