Stability of Binary and Ternary M₂₃C₆ Carbides from First Principles

Abstract

First-principles calculations were performed to study the phase stability of M23C6, (M = V, Cr, Mn, Fe, Co, Ni) and the solubility of d-impurities (Fe, Co, Ni, W) in Cr23C6, which is the most prevalent carbide in chromium steels. Our results correctly predict the relative stability of binary carbides, among which the most stable compounds are V23C6, Cr23C6 and Mn23C6. Stability of the M23C6 and MC carbides was related to the Md-filling, where the M-M and M-C bonds provide the cohesive properties, respectively. We demonstrated that iron and nickel should always be present in Cr23C6, where their concentrations may reach 50 at.% and 30 at.%, respectively. To predict the ways to control the carbide stabilization and distribution in iron matrix, both of which govern the microstructure and mechanical properties of high-alloy steels, we also investigated the effect of tungsten addition on the stability of quaternary carbides, namely (Cr, W, M)23C6 (M = Fe, Co, Ni). We found that tungsten strongly enhances the solubility of iron and nickel in chromium carbide, but it does not affect the cobalt solubility. A similar stabilizing effect was predicted for molybdenum, and it can be suggested that both tungsten and molybdenum should accelerate the formation of M23C6 and influence the kinetics of carbide precipitation.

Department(s)

Materials Science and Engineering

Second Department

Physics

Research Center/Lab(s)

Center for High Performance Computing Research

Keywords and Phrases

Alloy Steel; Calculations; Chromium; Convergence of Numerical Methods; Iron; Iron Alloys; Iron Compounds; Manganese; Mechanical Properties; Molybdenum; Nickel; Phase Stability; Solubility; Stabilization; Tungsten; Ab Initio Calculations; Carbide Precipitation; Electronic and Magnetic Properties; First-Principles Calculation; M23C6; Microstructure and Mechanical Properties; Relative Stabilities; Transition Metal Carbide; Tungsten Carbide

International Standard Serial Number (ISSN)

0927-0256

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2015 Elsevier, All rights reserved.

Publication Date

01 Jan 2015

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