Segregation of alloying elements at the TiC/V interface: A first-principles study

Abstract

For precipitation/matrix coherent interface, the interfacial segregation behavior of solute atom plays a vital role in controlling the effectiveness of precipitation strengthening of the alloy. In this study, first-principles calculations based on density functional theory are used to figure out the interfacial structure of precipitates/vanadium and explain how solute atoms segregate at the interface and affect the interfacial strengthening. Firstly, according to the Baker-Nutting orientation relationship, the equilibrium interface structures are obtained. Meanwhiles, the segregation behavior of solute atoms at the different interfaces in vanadium alloys was studied. It is found that elements Sc, Ti, Y, Zr, Hf, and Ta, in the TiC/V(100) interface, tend to segregate at the interface, while other ones are not easy to segregate. The alloy elements show the same segregation trend as the TiC/V(100) interface, except for Nb, which also tends to segregate at the TiC/V(110) interface. According to the calculation, it is found that the alloying element with the larger atomic size and Voronoi volume is more likely to segregate into the interface, indicating that the atomic size effect dominates alloying element segregation at the two interfaces. The findings of this work can be used to develop theoretical approaches for future alloy designs by controlling alloying element doping.