Shape of dislocation line in stochastic shear stress field

Abstract

The shape of the dislocation line in the stochastic shear stress field in the glide plane was studied using the method of discrete dislocation dynamics. Stochastic shear stresses can occur due to the distortion of the crystal lattice. Such distortion may exist, for example, in a solid solution. Different atoms in a solid solution induce atomic size misfit and elastic modulus misfit into crystal lattice. These misfits result in crystal lattice distortions which varies spatially. The distortions are the origin of internal stresses in the lattice. Such internal stress in certain location has stochastic value normally distributed. The particular case of such stresses is shear stress distribution in the glide plane. The special method was developed to model such stress distribution. The stochastic shear stress field results in movement of different segments of dislocation line to form its equilibrium shape. The important characteristic parameters of the equilibrium shape can be measured by numerical methods. This shape also includes a "long-wavelength" component that has a non-zero amplitude and was formed without thermal activation. The shape of the dislocation line determines to some extent the yield strength of the material. Thus, the study of dislocation line shape and modeling its formation in the field of stochastic shear stresses can help to determine the yield strength of multicomponent alloys, especially multi-principal element alloys. Keywords: dislocation, discrete dislocation dynamics, shear stresses.