TiN inducing ferrite nucleation based on the bcc-Fe/TiN interfaces formation at atomic scale by first-principles calculation

The Fe/TiN interface is commonly found in steel and the interface with low interfacial energy can promote the refinement of microstructure and improve the strength and toughness of the material. In this paper, Fe(1 0 0)/TiN (100) and Fe(1 1 0)/TiN(1 1 0) interface with low mismatch are investigated by first-principles calculation. Six specific geometry models with different stacking positions (TS, CS and HS) are established. The results show that after geometric optimization, the interfaces with TS stacking sequence and CS stacking sequence have little change, while the interfaces with HS stacking sequence transforms into CS stacking. The Fe(1 1 0)/TiN(1 1 0) interface with CS stacking possesses the best interfacial bonding strength as the largest adhesion work and the Fe (10 0)/TiN(1 0 0) interface with CS stacking possesses the best stability as the lowest interfacial energy. The main component bonding of interface-1, 2 and 3 is mixture of covalent and metallic. In addition, in the process of TiN introducing ferrite nucleation, Fe atoms are more likely to gather on TiN(1 0 0) surface and form the Fe(1 0 0)/ TiN(1 0 0) interface by layer-by-layer extrapolation. The Fe(1 0 0)/TiN(1 0 0) interface as the most stable interface can provide a basis for the optimal design of TiN-induced ferrite nucleation.

Automated summary

This paper investigates Fe(1 0 0)/TiN(100) and Fe(1 1 0)/TiN(1 1 0) interfaces with low mismatch through first-principles calculations. The results show that CS stacking sequence exhibits the best interfacial bonding strength and stability. Fe atoms tend to gather on TiN(100) surface and form the Fe(100)/TiN(100) interface by layer-by-layer extrapolation.