Enthalpies of mixing in liquid alloys of iron with the lanthanides

Abstract

The enthalpies of mixing in binary liquid alloys of iron with the lanthanides (Pr, Nd, Gd, Tb, Dy and Lu) were determined at 1550–1950 K by means of isoperibolic calorimetry. They show exothermic effects (in the Fe–Pr system partially endothermic) which increase across the lanthanides row from the Fe–Pr system (ΔHmin = −0.35 ± 0.10 kJ · mol−1 at xPr = 0.22; ΔHmax = 0.75 ± 0.24 kJ · mol−1 at xPr = 0.76; T = 1829 K) to the Fe–Lu system (ΔHmin = −11.58 ± 0.50 kJ · mol−1 at xLu = 0.35; T = 1950 K).

Critical Systematic Evaluation and Thermodynamic Optimization of the Fe-RE System: RE = Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y

“…It is rather unusual to have minima of enthalpy of mixing where no solid compound exists. In addition, the results of Ivanov et al [52] are consistent with the systematic trend of enthalpy of mixing of all other binary liquid Fe-RE solutions, which will be discussed later in section 4. Therefore, the present model parameters of liquid solution were optimized to reproduce the more recent enthalpy data by Ivanov et al [52] in Fig.…”

“…[34] The Gibbs energies of bcc Ho and fcc RE elements were taken from the FactSage FTLite database [15] hcp Gd solution was also needed to reproduce the rapidly increasing solubility of Fe in hcp Gd solution by Savitskii et al [46] The integral and the partial enthalpy of mixing of the Fe-Gd liquid were reported by Nikolaenko and Nosova [51] at 1850 K and Ivanov et al [52] at 1833 K as presented in Fig. 2.…”

“…In all the previous assessments by Liu et al, [39] Zinkevich et al [40] and Konar, [41] the liquid enthalpy was optimized using the data by Nikolaenko and Nosova [51] as the experiments of Ivanov et al [52] were not available at the time of the assessments. Liu et al [39] assessed the DH o 298…”

“…In both the assessments by Liu et al [39] and Zinkevich et al, [40] all the DH o 298 and S o 298 of intermetallic compounds were not concomitantly optimized, and therefore several intermetallic phases were calculated to be unstable at room temperature. [51,52] and assessment. [39] (a) Integral enthalpy of mixing and (b) partial enthalpy of mixing [53,54] Fig.…”

“…The experiments were conducted using a high flux high-temperature isoperibolic calorimeter (SC) under high purity [51] Ar and He [52] gas. Nikolaenko and Nosova [51] used yttria-coated alumina crucibles, whereas in the recent study by Ivanov et al [52] the partial enthalpy of mixing of the Fe-rich and the Gd-rich compositions was measured using zirconia crucibles and Mo crucibles, respectively. The integral enthalpy of mixing was calculated at 1833 K and presented in Fig.…”