Solubility Product and Equilibrium Equations of Nonstoichiometric Niobium Carbonitride in Steels: Thermodynamic Calculations.

Autor: Lei, Xuan-Wei, Yang, Rong-Bo, Liu, Jin-Ming, Zeng, Long-Fei, Lai, Chao-Bin, Luo, Xiang
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Zdroj: Metallurgical & Materials Transactions. Part A; Oct2021, Vol. 52 Issue 10, p4402-4412, 11p
Abstrakt: Thermodynamic models were established based on our previous studies to describe the equilibrium between the nonstoichiometric compound Nb(C,N) and the Fe-base solid solution (austenite and ferrite). With the assumption of equilibrium between fcc Nb and the Fe-based solid solution, the solubility of fcc Nb in the Fe-based solid solution was developed. Thus, the solubility product and equilibrium equations of NbCxNy in the Fe-base solid solution were further deduced. Two other thermodynamic interaction parameters for NbCxNy were considered in this study. The deduced solubility product of NbCxNy was in accordance with previous studies. The calculation results on compound NbCxNy in this study were in good agreement with both the measured data from the references and the calculation results from ThermoCalc. The deduced solubility expressions of fcc Nb provided references for developing solubility products of nonstoichiometric fcc Nb compounds in Fe-based solid solutions. This study offers guidance on the equilibrium of nonstoichiometric compounds in solid solutions. The solubility product of NbCxNy is (the solubility products of NbC and NbN are referenced from our previous work) log α / γ K NbC x N y ≅ x log α / γ K NbC + y log α / γ K NbN + 1 - x - y log α / γ K Nb + x y 98 T - x 1 - x - y 4439 T - y 1 - x - y 3413 T + x log x + y log y + 1 - x - y log 1 - x - y log α K Nb = 1.92 + 1227 T + 0.051 - 46.8 T wt pct Mn + 0.013 - 6.0 T wt pct Ni log γ K Nb = 1.65 + 1365 T + 0.008 - 20.9 T wt pct Mn + 0.012 + 23.3 T wt pct Ni + 0.003 - 9.7 T wt pct Cr - 0.004 wt pct Mo [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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