Kinetics of segregation formation in elastic field of edge dislocation in bcc iron

TL;DR

This study employs multi-stage computer simulations to analyze how impurity atoms, specifically carbon, redistribute and form segregations around edge dislocations in bcc iron, considering elastic deformation effects.

Contribution

It introduces a comprehensive multi-stage simulation approach combining dislocation structure modeling, diffusion coefficient calculation, and segregation kinetics analysis in bcc iron.

Findings

Distribution of interstitial atoms varies with time and temperature.

Elastic fields significantly influence impurity segregation patterns.

The models successfully predict segregation formation dynamics.

Abstract

We study the kinetics of the redistribution of impurity atoms in the elastic fields of dislocations by computer simulation methods. A work consists of several stages. The first is the simulation of a dislocation core structure with a Burgers vector along [100] direction by using the modified molecular static method. The second is obtaining the coefficients that determine the influence of the components of the strain tensor on the diagonal elements of the matrix of diffusion coefficients and in the equations for fluxes of carbon atoms in bcc iron. The third stage is associated with modeling the diffusion characteristics of carbon atoms by the method of molecular dynamics in a crystal without defects. The fourth and final stage uses the data about atomic structure that we obtained at first stage, as well as the characteristics calculated in the second and third, is a simulation of the formation of segregations of interstitial atoms, which is based on solving diffusion equations that take into account the elastic deformations created by the dislocation. The complex of developed models is used to analyze the kinetics of segregation formation. 3D graphs illustrate the distribution of interstitial atoms in the vicinity of a dislocation for different times at certain temperatures.