| Full text | |
| Author(s): |
Silva, Antonio A. A. P.
;
Lamoglia, Marcela S.
;
Silva, Gilbert
;
Fiorani, Jean-Marc
;
David, Nicolas
;
Vilasi, Michel
;
Coelho, Gilberto C.
;
Nunes, Carlos A.
;
Eleno, Luiz T. F.
Total Authors: 9
|
| Document type: | Journal article |
| Source: | Journal of Alloys and Compounds; v. 878, p. 7-pg., 2021-05-21. |
| Abstract | |
The molar heat capacities of the Fe2Nb and Fe7Nb6 intermetallic compounds are reported here for the first time. The results were obtained via Differential Scanning Calorimetry (DSC) measurements, performed in a temperature range between 348 and 1038 K. The alloys were prepared by arc-melting high purity metals under argon flux and later heat-treated at 1200 degrees C for 336 h encapsulated in quartz tubes under argon to ensure thermodynamic equilibrium. The resulting samples were then characterized using X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM). The heat-capacity DSC measurements were carried out using an alternating step method with 20 and 50 K steps, with the resulting C-p associated with the midpoint of each temperature interval. A fit to a simplified C-p(T) curve was employed, due to the scatter in the data. Quasi-Harmonic Approximation (QHA) calculations were also performed, showing a good agreement with the measured values. Experimental results of heat capacity, along with other thermodynamic properties and phase equilibria, are key information for binary and ternary systems, specially for CALPHAD-type assessments. The results were therefore compared with the Kopp-Neumann approximation, used in recent assessments, showing that the parameters of both compounds can be improved in current CALPHAD databases, which motivates future work on the Fe-Nb system. (C) 2021 Elsevier B.V. All rights reserved. (AU) | |
| FAPESP's process: | 19/05005-7 - Computational Materials Laboratory for the ab initio study of the stability of intermetallic compounds |
| Grantee: | Luiz Tadeu Fernandes Eleno |
| Support Opportunities: | Regular Research Grants |