We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Critical Assessment of Activities of Structural Units in Fe–Al Binary Melts Based on the Atom and Molecule Coexistence Theory.
- Authors
Yang, Xue-min; Li, Jin-yan; Yan, Fang-jia; Duan, Dong-ping; Zhang, Jian
- Abstract
A thermodynamic model for calculating the mass action concentrations N i {N_i} of structural units in Fe–Al binary melts based on the atom–molecule coexistence theory, i. e., AMCT– N i {N_i} model, has been developed and verified to be valid by comparing with reported activities a R , i {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 γ i 0 \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 Δ s o l G m , i (l) → [ i ] [ % i ] = 1 . 0 Θ , % {\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 {N_i} model and verified to be accurate. The reported activities a R , i {a_{{\rm{R, }}i}} of both Al and Fe from the literature can be well reproduced by calculated mass action concentrations N i {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 {N_i} of free Al and free Fe in Fe–Al binary melts. The obtained activity coefficients γ i {\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 γ i 0 \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 γ A l 0 = − 9 , 646 . 5 / T + 2 . 196 \ln \gamma _{{\rm{Al}}}^0 = - {\rm{9, 646}}{\rm{. 5}}/T{\rm{ + 2}}{\rm{. 196}} and ln γ F e 0 = − 6 , 799 . 1 / T − 0 . 01367 \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 ε i i \varepsilon _i^i or e i i e_i^i or h i i h_i^i of both Al and Fe coupled with three activity coefficients γ i \gamma _i^{} or f % , i f_{ \% {\rm{, }}i}^{} or f H , i f_{{\rm{H, }}i}^{} relative to three standard states are also obtained from the developed AMCT– N i {N_i} model for Fe–Al binary melts.
- Subjects
THERMODYNAMICS; FREE energy (Thermodynamics); ENERGY dispersive X-ray spectroscopy; ALUMINUM alloys; INTERMETALLIC compounds
- Publication
High Temperature Materials & Processes, 2018, Vol 37, Issue 9/10, p815
- ISSN
0334-6455
- Publication type
Article
- DOI
10.1515/htmp-2017-0018