Critical Assessment of Activities of Structural Units in Fe–Al Binary Melts Based on the Atom and Molecule Coexistence Theory-Reference-Cited by-同舟云学术

Critical Assessment of Activities of Structural Units in Fe–Al Binary Melts Based on the Atom and Molecule Coexistence Theory

Published:2018-10-25 Issue:9-10 Volume:37 Page:815-848
ISSN:0334-6455
Container-title:High Temperature Materials and Processes
language:
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Author:

Yang Xue-min¹,Li Jin-yan²,Yan Fang-jia¹,Duan Dong-ping¹,Zhang Jian³

Affiliation:

1. CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering,Chinese Academy of Sciences, Beijing100190, P. R. China

2. Department of Metallurgy and Raw Materials, China Metallurgical Industry Planning and Research Institute, Beijing100711, P. R. China

3. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing100083, P. R. China

Abstract

AbstractA thermodynamic model for calculating the mass action concentrations

{N_i}

of structural units in Fe–Al binary melts based on the atom–molecule coexistence theory, i. e., AMCT–

{N_i}

model, has been developed and verified to be valid by comparing with reported activities

{a_{{\rm{R, }}i}}

of both Al and Fe relative to pure liquid as standard state in Fe–Al binary melts over a temperature range from 1823 to 1973 K (1550 to 1700 °C). Furthermore, Raoultian activity coefficients

\gamma _i^0

of both Al and Fe in the Fe-rich corner or Al-rich corner of Fe–Al binary melts as well as the standard molar Gibbs-free energy changes

{\Delta _{{\rm{sol}}}}G_{{\rm{m, }}i{\rm{(l)}} \to {{{\rm{[}}i{\rm{]}}}_{{\rm{ [ \% }}i]{\rm{ = 1}}{\rm{. 0}}}}}^{\Theta {\rm{, \% }}}

of dissolved Al or Fe for forming [% Al] or [% Fe] as 1.0 in Fe–Al binary melts have also been determined by the developed AMCT–

{N_i}

model and verified to be accurate.The reported activities

{a_{{\rm{R, }}i}}

of both Al and Fe from the literature can be well reproduced by calculated mass action concentrations

{N_i}

of free Al and free Fe in Fe–Al binary melts. A small effect of changing temperature from 1823 to 1973 K (1550 to 1700 °C) on reaction abilities of both Al and Fe from the available literature is also confirmed by calculated mass action concentrations

{N_i}

of free Al and free Fe in Fe–Al binary melts. The obtained activity coefficients

{\gamma _i}

of both Al and Fe in Fe–Al binary melts can be described by a quadratic polynomial function and a cubic polynomial function, respectively. Furthermore, accurate expressions of Raoultian activity coefficients

\gamma _i^0

of both Al and Fe in Fe-rich corner or Al-rich corner of Fe–Al binary melts are also obtained as

\ln \gamma _{{\rm{Al}}}^0 = - {\rm{9, 646}}{\rm{. 5}}/T{\rm{ + 2}}{\rm{. 196}}

and

\ln \gamma _{{\rm{Fe}}}^0 = - {\rm{6, 799}}{\rm{. 1}}/T - {\rm{0}}{\rm{. 01367}}

, respectively. In addition, expressions of the first-order activity interaction coefficients

\varepsilon _i^i

e_i^i

h_i^i

of both Al and Fe coupled with three activity coefficients

\gamma _i^{}

f_{ \% {\rm{, }}i}^{}