| Ferritic/ Martensitic steels have excellent geometric stability, resistance to irradiation swelling and excellent corrosion resistance and other characteristics in strong irradiation, so it is considered as an important candidate structure material of demonstration fusion reactor and fourth-generation nuclear reactor in future. Research shows that, the addition of Cr has a great impact on the radiation performance of FeCr alloy, research the behavior of Cr in alloy, which has an important significance for understanding theirradiation performance of FeCr alloy. During the irradiation process of F/M steel, can appear the a’phase of rich Cr, which leads to the embrittlement of rich Cr in FeCr alloy. However, the nucleation process of a’phase is not clearly, in order to understand the nucleation mechanism, we must understand the alloy atomic diffusion process. So in this paper the diffusion process of Cr in Fe-Cr alloy is investigated by atomic computer simulation method.Firstly, through the atomic simulation method, the energy characteristics of vacancies and point defects are calculated by the 2BM(two band model) potential function model and the Fe-lat%Cr alloys containing different concentration of vacancies are simulated by molecular dynamics at different temperatures. Then the diffusion coefficients of pure iron and Cr in alloy are obtained via the mean square displacement of atoms. In addition, the diffusion coefficient of Cr in alloy is calculated according to the five frequency model for diffusion of impurities in solids,and the results obtained by this five frequency model method are compared with the calculation of molecular dynamics,the results are consistent.In addition, selected Fe-5%Cr, Fe-10%Cr, Fe-15%Cr, Fe-20%Cr four kinds of high concentration of Cr alloy systems, calculate the diffusion coefficient of Cr using the molecular dynamics method again, the results shows that with the increase of Cr concentration, the diffusion coefficient is increasing. |
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