Structure, Magnetism, Electronic Properties and High Magnetic-Field-Induced Stability of Alloy Carbide M7C3

38 Pages Posted: 6 Jan 2020

See all articles by Y. Wang

Y. Wang

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

T.P. Hou

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

Z.H. Li

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

H.F. Lin

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

X.P. Yang

Chinese Academy of Sciences (CAS) - Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions

G.H. Wu

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

K.M. Wu

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

Abstract

Previous experiments have proven that a high magnetic field can make alloy carbide M7C3 (M = Fe, Cr) precipitate ahead of time at intermediate temperatures. First-principles calculations are employed to search the source of magnetic-field-induced alloy carbides precipitation behaviors of orthorhombic M7C3. The basic building units for M7C3 crystals are polyhedrons formed by metal atoms and C atoms. The framework structure of o-M7C3 consists of metal tetrahedrons, metal octahedrons and triangular metal prisms. Magnetic calculations show that the substitution of Cr atoms causes the magnetic moments of the Fe atoms to decrease to different extents. Moreover, Cr atoms also have a magnetic moment antiparallel to the Fe atoms. Electronic structure calculations indicate that the bonds in M7C3 are a mixture of ionic, covalent and metal bonds. The substitution of Cr atoms weaken the ionic and covalent bonds between the Fe and C atoms; however, strengthen the metal bonds between the Fe and Cr atoms. The magnetic free energy change of M7C3 is larger than that of M2C and M3C at 823 K with a 12 Tesla field, which agrees well with the experimental results for a magnetic field promoting the precipitation of M7C3. This study provides a theoretical basis for the precipitation behaviors induced by magnetic field in steels.

Keywords: Alloy carbide, Magnetic moment, Electronic structure, High magnetic field

Suggested Citation

Wang, Y. and Hou, T.P. and Li, Z.H. and Lin, H.F. and Yang, X.P. and Wu, G.H. and Wu, K.M., Structure, Magnetism, Electronic Properties and High Magnetic-Field-Induced Stability of Alloy Carbide M7C3. Available at SSRN: https://ssrn.com/abstract=3509318 or http://dx.doi.org/10.2139/ssrn.3509318

Y. Wang (Contact Author)

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

Wuhan, 430081
China

T.P. Hou

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy ( email )

Wuhan, 430081
China

Z.H. Li

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

Wuhan, 430081
China

H.F. Lin

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

Wuhan, 430081
China

X.P. Yang

Chinese Academy of Sciences (CAS) - Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions

Hefei, 230031
China

G.H. Wu

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy

Wuhan, 430081
China

K.M. Wu

Wuhan University of Science and Technology - State Key Laboratory for Refractories and Metallurgy ( email )

Wuhan, 430081
China

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