First-Principles Calculations of Oxygen Solution and Segregation Effect on Mo/Cr Interface

Abstract

The stability mechanism of an interface forming from Cr-coating deposited on the Mo matrix surface has been performed using a DFT+U method. First, we have obtained the lattice constant, bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio for Mo and Cr bulk, respectively. The oxygen atom is inclined to solute in the tetrahedral interstitial site for Mo, while for Cr, an octahedral location is well. By substitute mechanism, it has suggested that a Cr atom is easier to take over a Mo atom. Subsequently, based on the surface energy and work function analysis, we have established the corresponding the interface models. Our results suggested that Mo(110)/Cr(110) interface was most stable among the possible Mo/Cr interfaces. Furthermore, the effect the impurity oxygen atom on the interface stability has also been studied. It has predicted that the impurity O atom prefers to solute into the near Cr surface edge. The work of adhesion for interface with impurity O atom is higher than that of the clean interface, which means that the impurity O atom could generate the positive effect on the adhesion mechanism of Cr-coating Mo alloys. Furthermore, to analysis the interface cracking, we have performed the SEDG distributions to study fracture behavior along the cracking paths through the CFE method.

Keywords: Surface, Interface, Bonding Strength, Cracking