Precipitation and growth mechanism of TiN on Y2O3 (110) and (100) surfaces of yttrium-containing T4003 stainless steel

The Y2O3/TiN interface of main complex inclusions in T4003 stainless steel with rare earth element Yttrium (Y) content of 0.014 wt.% was studied. The chemical composition and morphology of composite inclusions were characterized by scanning electron microscope (SEM) and X-ray energy dispersive spectrometer (EDS), the formation process of Y2O3/TiN composite inclusions was calculated by the first-principles calculations of the Vienna Ab-initio Simulation Package (VASP). Compared with Fe matrix, TiN is more likely to grow in an uneven state, and tends to exist in stainless steel in the form of Y2O3(100)/TiN(110). The main reason for the stability of the interface system is that the p orbitals of the O atoms at the interface forms covalent bonds with the d orbitals of the Ti atoms. It provides a new idea for improving the properties of stainless steel effectively by using heterogeneous nucleation of inclusions in steel.