合金元素在fcc-Fe/NbX(X=C,N)界面的偏析及影响

基于密度泛函理论(DFT)第一性原理方法,研究了Si、Ni、Mn、Cr、Mo在fcc-Fe/NbX (X=C, N)界面的偏析行为,并分析了合金元素偏析对界面体系的影响。结果表明,fcc-Fe/NbN界面结合强度相较于fcc-Fe/NbC界面结合强度略有提升;Si稳定存在于Fe基体中,Ni、Mn在界面有轻微偏析倾向,Cr、Mo在界面和NbX (X=C,N)内均存在偏析,其中,Mo向界面偏析倾向更大;Cr、Mo偏析在fcc-Fe/NbC界面一定程度上降低了界面的结合能力,但体系稳定性有所提升,Cr、Mo偏析在fcc-Fe/NbN界面一定程度上提高了界面的结合能力,但Mo使得体系稳定性下降。

Segregation and influence of alloying elements at fcc-Fe/NbX ( X=C,N) interface

Based on the first-principles method of density functional theory (DFT), the segregation behavior of Si, Ni, Mn, Cr, and Mo at the fcc-Fe/NbX (X=C, N) interface was studied, and the influence of alloying element segregation on interface system was analyzed. The results show that the bonding strength of the fcc-Fe/NbN interface is slightly improved compared to that of the fcc-Fe/NbC interface. Si exists stably in the Fe matrix, Ni and Mn have a slight tendency to segregate at the interface, and Cr and Mo segregate in the interface and NbX (X=C, N). Among them, Mo has a greater tendency to segregate toward the interface. The segregation of Cr and Mo at the fcc-Fe/NbC interface reduces the bonding ability of the interface to a certain extent, but the stability of the system is improved. The segregation of Cr and Mo at the fcc-Fe/NbN interface improves the bonding ability of the interface to a certain extent, but Mo reduces the stability of the system.