Thermodynamics of Nitrogen in Fe-Mn-Al-Si-C Alloy Melts

Abstract

Thermodynamic behavior of nitrogen in the entire range of the Fe-Mn-Al-Si-C liquid solution was modeled based on the critical evaluation and optimization of all available experimental data. The Gibbs energy of liquid solution was described using the Modified Quasichemical Model (MQM) in the pair approximation, instead of classical Wagner Interaction Parameter Formalism, to consider the strong interactions between species in liquid state. In particular, the dissolution behavior of N and formation of AlN in the entire ternary and higher order liquids were accurately predicted from the MQM only with binary model parameters of N.

Aluminum Deoxidation Equilibria in Liquid Iron: Part III—Experiments and Thermodynamic Modeling of the Fe-Mn-Al-O System

“…[4][5][6] The comparison of the MQM to the previous thermodynamic models such as Wagner Interaction Parameter Formalism (WIPF), Bragg-Williams Random Mixing Model (BWRMM), and the associate model has been extensively reviewed in the authors' recent studies. [4,13] Gibbs free energies of pure Fe, Mn, Al, and O were taken from Dinsdale. [14] Gibbs free energies of oxides such as solid Al 2 O 3 , liquid Fe x O, solid MnO, MnAl 2 O 4 spinel, and liquid slag of Fe-Mn-Al-O molten oxide were taken from Eriksson et al, [15] Decterov et al, [16] and Chatterjee and Jung, [17] respectively.…”

Critical Evaluation and Optimization of the Fe-N, Mn-N and Fe-Mn-N Systems

“…However, there is still a critical problem in the assessment of Fe-N system [32] related to g o N l ð Þ . When N 2 gas is suppressed, c-FCC phase is calculated to reappears at high-N region (0:4\X N \0:5) of the Fe-N system below 470°C, which is ascribed to the relatively less stable Gibbs energy of pure liquid monoatomic N. The present authors [24] reassessed g o Table 2 Optimized model parameters for the Fe-Mn-N system (J/mol, J/mol K)…”

“…The model parameters of solid phases by Huang and liquid solution by Paek were accepted in the present study. The Gibbs free energy of liquid monoatomic N (g o N l ð Þ ) was recently reassessed by Paek et al [24] to described the nitrogen dissolution behavior in liquid Fe-Mn-Al-Si-C solution. In particular, they proved that MQM can describe nitrogen solubility in the multicomponent liquid solution using very few model parameters.…”

“…In particular, they proved that MQM can describe nitrogen solubility in the multicomponent liquid solution using very few model parameters. The descriptions of liquid Fe-N, Mn-N and Fe-Mn-N solutions by Paek et al [24] were taken in this study without any modification. The Gibbs energies of various solid monoatomic [31] is used widely.…”

“…The parameters of all solid Fe-Mn phases by Huang [10] and those of liquid Fe-Mn solution by Paek [23] were adopted in the present study for the Fe-Mn system. The Gibbs energies of hypothetical liquid monoatomic N (g o N l ð Þ ) [24] and each solid monoatomic N ð Þ were newly assessed as part of the present optimization. All the thermodynamic calculations were performed using FactSage [25] software.…”