The effect of solutes on the precipitate/matrix interface properties in the Vanadium alloys: A first-principles study

A correct description of the interaction between solutes and interface is the prerequisite for an understanding of the evolution and growth kinetics of precipitate. In this study, we use the first-principles calculations to characterize the solute (Cr, Ti, and Y) behaviors at the TiO-precipitate/V-matrix interface in Vanadium (V) alloys. After obtaining the equilibrium interface structure, the formation heat and segregation energies for solutes (Cr, Ti, and Y) are studied in detail to obtain the site preference and segregation behaviors for solutes in the interface region. We found that solute Ti prefer to the interface site and shows a segregation tendency at the interface. To the contrary, solute Cr and Y prefer to retain in the V matrix. However, from the standpoint of energy, the site preferences for all solutes are extremely weak when no vacancy is introduced to the interface. Considering the vacancy effect, the site preference of solute Y is changing and shows a segregation tendency at the interface. We also calculate the Griffith rupture work to uncover how the solutes influence the interfacial strength with or without the vacancy effect. Solute Cr is favorable for improving the interfacial rupture strength of the V alloys no matter where solute Cr is positioned. As for solute Ti and Y, when solutes are close to the interface, the interface-weakening effect is obvious. The improvement of solutes in interfacial strength is ascribed to the increased the hybridization behaviors between the solute atom and the Ti atoms in the precipitate.