Aluminum Deoxidation Equilibria in Liquid Iron: Part II. Thermodynamic Modeling

Title
Aluminum Deoxidation Equilibria in Liquid Iron: Part II. Thermodynamic Modeling
Author
박종진
Keywords
QUASI-CHEMICAL MODEL; FE-AL; OXYGEN EQUILIBRIUM; PURE IRON; DEGREES C; ALLOYS; SOLUBILITY; MELTS; SYSTEM; RANGE
Issue Date
2015-10
Publisher
SPRINGER
Citation
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE, v. 46, No. 5, Page. 2224-2233
Abstract
Al deoxidation equilibria in liquid iron over the whole composition range from very low Al ([pct Al] = 0.0027) to almost pure liquid Al were thermodynamically modeled for the first time using the Modified Quasichemical Model in the pair approximation for the liquid phase. The present modeling is distinguished from previous approaches in many ways. First, very strong attractions between metallic components, Fe and Al, and non-metallic component, O, were taken into account explicitly in terms of Short-Range Ordering. Second, the present thermodynamic modeling does not distinguish solvent and solutes among metallic components, and the model calculation can be applied from pure liquid Fe to pure liquid Al. Therefore, this approach is thermodynamically self-consistent, contrary to the previous approaches using interaction parameter formalism. Third, the present thermodynamic modeling describes an integral Gibbs energy of the liquid alloy in the framework of CALPHAD; therefore, it can be further used to develop a multicomponent thermodynamic database for liquid steel. Fourth, only a small temperature-independent parameter for ternary liquid was enough to account for the Al deoxidation over wide concentration (0.0027 < [pct Al] < 100) and wide temperature range [1823 K to 2139 K (1550 A degrees C to 1866 A degrees C)]. Gibbs energies of Fe-O and Al-O binary liquid solutions at metal-rich region (up to oxide saturation) were modeled, and relevant model parameters were optimized. By merging these Gibbs energy descriptions with that of Fe-Al binary liquid modeled by the same modeling approach, the Gibbs energy of ternary Fe-Al-O solution at metal-rich region was obtained along with one small ternary parameter. It was shown that the present model successfully reproduced all available experimental data for the Al deoxidation equilibria. Limit of previously used interaction parameter formalism at high Al concentration is discussed.
URI
https://link.springer.com/article/10.1007/s11663-015-0369-zhttp://hdl.handle.net/20.500.11754/40263
ISSN
1073-5615; 1543-1916
DOI
10.1007/s11663-015-0369-z
Appears in Collections:
COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > MATERIALS SCIENCE AND CHEMICAL ENGINEERING(재료화학공학과) > Articles
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