Kinetics of segregation formation in the vicinity of edge dislocation in fcc metals

A V Nazarov,A G Zaluzhnyi,I V Ershova,A A Mikheev

doi:10.1088/1757-899x/130/1/012062

Abstract

We use new equations for the interstitial impurity diffusion fluxes under strain to study impurity atom redistribution in the vicinity of dislocations taking into account the strain generated by mentioned defects. Two levels of simulation are applied. First one is evaluation of coefficients that determine the influence of strain tensor components on interstitial diffusion fluxes in fcc structures for different kinds of atom jumps. For this purpose we have developed a model into the framework of molecular static method taking into account an atom environment as near the interstitial site as for the saddle-point configuration. The second level is modeling of interstitial segregation formation based on nonlinear diffusion equations taking strains generated by defects. The results show, that the distributions of the interstitials near the dislocations have quite complicated characters and the vacancy distribution has qualitatively different character as compared with carbon distribution.

Highlights

Elastic fields, generated by defects of the structure, influence the diffusion processes
In presented work we study redistribution kinetics of defects in the vicinity of dislocations using our theory of diffusion under stress [5-7] and taking into account the strain generated by dislocations
We model redistribution of impurity atoms with the help of a numerical solution of non-linear diffusion equation taking into account the strain generated by dislocations

Summary

Introduction

Elastic fields, generated by defects of the structure, influence the diffusion processes. In the first part of our paper we give a brief consideration to the main features of the theory of diffusion under strain [5-7] and to present the general equations for the fluxes in interstitial alloys under strain. This approach gives the possibility to use the mentioned equations at low temperatures, in conditions where the strain influence on the diffusion fluxes is manifested in maximal degree. The coefficients are very sensitive to the atomic structure in the nearest vicinity of a defect and still more sensitive to the atomic structure of the saddle-point configuration For these purposes we use the advanced model developed by us earlier [8-10]. The last part is concerned with a simulation of the vacancy redistribution in the vicinity of dislocations under similar conditions

General Equations

Models and Results

Conclusion