1 Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, China; 2 National Rare Earth Functional Material Innovation Center, Ganzhou 341000, Jiangxi, China
Mechanism of ferrite nucleation induced by Y2O2S inclusion in low carbon steel
1 Faculty of Materials, Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, China; 2 National Rare Earth Functional Material Innovation Center, Ganzhou 341000, Jiangxi, China
摘要 To reveal the mechanism of ferrite nucleation induced by Y2O2S inclusion in steel, the work of adhesion, interfacial energy, structure stability and electronic properties of Fe(111)/YY2O2S(001) interfaces with various terminations were first investigated using the first-principles calculations. Secondly, the steels with and without yttrium were prepared, while the rare earth yttrium-based inclusions in low carbon steel were characterized using an electron probe micro-analyzer, and the grain size of steel was analyzed using a scanning electron microscope with electron backscattered diffraction. The results show that the bonding strength of Fe/Y2O2S interfaces with S- and Y-terminations is stronger than that of the interface with O-terminations. The Fe–hcp–S interfaces with S-termination have the highest work of adhesion (4.01 J/m2) and the lowest interface distance (1.323 Å ). The Fe–hcp–S interface exhibits the highest stability, and its interfacial bonding force is mainly attributed to the strong hybridization of Fe-3d and S-2p orbitals in the energy range of - 7.5–0 eV. Moreover, the interfacial energy of Fe–hcp–S is substantially lower than those of the ferrite(s)/Fe(L) interface and the ferrite–austenite interface, suggesting that Y2O2S inclusions in steel can efficiently promote ferrite nucleation. The experimental observations demonstrate that the ferrite grain size of steel containing 0.03 wt.% Y is much more refined than that of the steel without yttrium, and the average grain size of steel with and without Y is 102 and 258 μm, respectively. This indicates that the results of our calculations match with experimental findings.
Abstract：To reveal the mechanism of ferrite nucleation induced by Y2O2S inclusion in steel, the work of adhesion, interfacial energy, structure stability and electronic properties of Fe(111)/YY2O2S(001) interfaces with various terminations were first investigated using the first-principles calculations. Secondly, the steels with and without yttrium were prepared, while the rare earth yttrium-based inclusions in low carbon steel were characterized using an electron probe micro-analyzer, and the grain size of steel was analyzed using a scanning electron microscope with electron backscattered diffraction. The results show that the bonding strength of Fe/Y2O2S interfaces with S- and Y-terminations is stronger than that of the interface with O-terminations. The Fe–hcp–S interfaces with S-termination have the highest work of adhesion (4.01 J/m2) and the lowest interface distance (1.323 Å ). The Fe–hcp–S interface exhibits the highest stability, and its interfacial bonding force is mainly attributed to the strong hybridization of Fe-3d and S-2p orbitals in the energy range of - 7.5–0 eV. Moreover, the interfacial energy of Fe–hcp–S is substantially lower than those of the ferrite(s)/Fe(L) interface and the ferrite–austenite interface, suggesting that Y2O2S inclusions in steel can efficiently promote ferrite nucleation. The experimental observations demonstrate that the ferrite grain size of steel containing 0.03 wt.% Y is much more refined than that of the steel without yttrium, and the average grain size of steel with and without Y is 102 and 258 μm, respectively. This indicates that the results of our calculations match with experimental findings.
Hai-hui Zhang,Hui-hui Xiong,Jing Qin, et al. Mechanism of ferrite nucleation induced by Y2O2S inclusion in low carbon steel[J]. Journal of Iron and Steel Research International, 2023, 30(6): 1291-1299.
2023, Vol. 30 
