First-principles study of NbC heterogeneous nucleation on TiC vs. TiN in microalloy steel

Abstract

The second particles that preferred to epitaxially grow on the habit plane of pre-existing particles would harmful to the microstructure refinement of steel. The interfacial properties and bonding feature of TiN(100)/NbC(100) interface and TiC(100)/NbC(100) interface were studied using first-principles calculation and Bramfitt misfit theory. The results showed that there are two possible stacking sites (Interface-I with N-termination, and Interface-II with Ti-termination) for TiN(100)/NbC(100) interface, and two stacking sites (Interface-III with C-termination, and Interface-IV with Ti-termination) for TiC(100)/NbC(100) interface. Interface-III possesses the largest work of adhesion, followed by Interface-I, Interface-IV and Interface-II. Thus, the atomic binding force and stability of Interface-III are the strongest, followed by Interface-I, Interface-IV and Interface-II. Furthermore, the main component bonding of Interface-I and Interface-III is covalent, and the interactions of interfacial atoms on the Interface-III are stronger than those of atoms on Interface-I. Therefore, the preferred interface for NbC heterogeneous nucleation is Interface-III, and then is Interface-I.