EFFECTS OF ALLOYING ELEMENTS ON α-FE(100)/CR(100) INTERFACE
Abstract
The α-Fe(100)/Cr(100) interface has an important effect on the precipitation of the Cr-rich phase in ferritic stainless steel, and alloying elements affect the stability of the α-Fe(100)/Cr(100) interface. However, it is difficult to clearly understand the effect of alloying elements on the α-Fe(100)/Cr(100) interface behavior experimentally. Therefore, the first-principles calculation is employed to address this problem in this paper. First of all, the segregation behaviors of alloy elements (Mo, Nb, and Si) on the α-Fe(100)/Cr(100) interface were systematically investigated. And then, the effects of these alloying elements on the property of the α-Fe(100)/Cr(100) interface were studied. Based on the density functional theory, the work of adhesion (Wad), interfacial energy (γint), doping energy (Ef), and electronic properties of the α-Fe(100)/Cr(100) interface were analyzed. The results show that the body-centered α-Fe(100)/Cr(100) interface is constructed by using seven layers of α-Fe(100) and Cr(100) surface models. The Wad is 6.115 J.m−2, and the γint is −0.12 J.m −2. The doping atoms tend to segregate on the surface of α-Fe(100). When the Si atom doped in the interface, the Wad increases, and the γint reduces. The doping of the Si strengthens the bonding strength of the interface and promotes the nucleation of the Cr-rich phase. While the addition of Mo and Nb atoms decreases the Wad of α-Fe(100)/Cr(100) interface, increases the γint. The bonding strength of the interface is weakened and the nucleation of the Cr phase is inhibited. Based on this result, it is clearer to understand the effect of Mo, Nb, and Si atoms on the precipitation of the Cr-rich phase in ferritic stainless steel.
